HK1204401B

HK1204401B - Satellite navigation signal, generating method, generating device, receiving method and receiving device

Info

Publication number: HK1204401B
Application number: HK15104795.2A
Authority: HK
Inventors: 姚铮; 陆明泉
Original assignee: 清华大学
Priority date: 2012-06-07
Filing date: 2013-06-06
Publication date: 2018-05-11

Description

Satellite navigation signal, and generation method, generation device, reception method and reception device thereof

Technical Field

The present application relates to the field of satellite navigation, and more particularly, to a satellite navigation signal, and a generation method, a generation device, a reception method, and a reception device thereof.

Background

With the continuous construction of Global Navigation Satellite Systems (GNSS), the demand for navigation services is expanding. The number of signals broadcast by each satellite navigation system on the same frequency band is increasing, so that the originally limited satellite navigation frequency spectrum becomes more crowded. With the increase of the number of signals broadcast by the same system in the same frequency band, the complexity of satellite load is continuously increased.

If different service signals in a frequency band use mutually independent transmitting antennas and amplifier chains, the requirements on antenna design and the aspects of total power, cost, volume, weight and the like of loads bring great cost. Therefore, it is desirable to multiplex and combine a plurality of signals on one carrier. At the same time, in the case of limited satellite transmit power, it is desirable for the high-power transmitters on the satellite to have as high a power efficiency as possible in order to maintain sufficient receive power at the receiving end. This requires the High Power Amplifier (HPA) on the satellite to operate in a nonlinear saturation region. However, when the HPA is near the saturation point, if the input signal does not have a constant envelope, the output component will generate distortion such as amplitude modulation and amplitude-to-phase conversion, which causes amplitude-to-phase distortion of the transmitted signal and greatly affects the performance of the receiving end. It is therefore necessary to ensure the constant envelope characteristic of the synthesized signal.

For constant envelope multiplexing of multiple DSSS signals on the same frequency point, there are some mature technologies, for example, two different DSSS signals may be placed on two mutually orthogonal phases of a carrier to form a QPSK signal for transmission. In early GPS, constant envelope multiplexing of C/a code signals and p (y) code signals at the L1 frequency bins was accomplished in this manner. However, when the number of signals increases, more complex constant envelope multiplexing techniques are required, such as US6430213, US 2002/0075907a1, US 2002/0150068a1, and US2011/0051783a 1. The techniques described above are primarily directed to constant envelope multiplexing of multiple signal components at the same frequency point.

The prior art, such as the constant envelope AltBOC modulation technique (US 2006/0038716a1) and the time division multiplexing AltBOC (TD-AltBOC) technique (chinese patent publication No. CN102209056A), provides a method for performing constant envelope multiplexing on a combination of DSSS signals at two different frequency points, such as combining two sets of BPSK-R (10) signals respectively modulated at two frequency points spaced by 30.69MHz into a composite constant envelope signal. However, the AltBOC modulation technique requires a phase mapping table to be generated in advance, and a constant envelope of the multiplexed signal is realized by means of table lookup. Furthermore, in the AltBOC modulation technique, the powers of the DSSS signal components participating in the multiplexing must be equal. In TD-AltBOC, time division multiplexing used by this technique significantly deteriorates the multiple access performance between the multiplexed DSSS signal and other spread spectrum signals on the same frequency band. Furthermore, in TD-AltBOC, the power of the signal components participating in the multiplexing must also be equal. This limitation in technology reduces the flexibility of use of AltBOC and TD-AltBOC. As is known, in GNSS systems, since ranging is the primary purpose of signals, signal system designs prefer to allocate more power to pilot channels than to data channels, so as to improve the accuracy and robustness of pseudorange measurement and carrier phase tracking, and different spreading chip waveforms (e.g. BPSK-R, sine phase BOC, cosine phase BOC, TMBOC, QMBOC, etc.) used for signal components will exhibit different acquisition, tracking and demodulation performances in receivers, so it is necessary to provide a more flexible dual-frequency constant envelope multiplexing technique for satellite navigation signals.

Disclosure of Invention

It is an object of the present application to provide a satellite navigation signal, a method for generating the same, a device for generating the same, a method for receiving the same, and a device for receiving the same, which are capable of at least partially overcoming the above-mentioned drawbacks of the prior art.

According to an aspect of the present application, a satellite navigation signal generating apparatus is disclosed, comprising: a baseband signal generator for generating a first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄(ii) a A multiplex signal generator for setting the first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Generating a multiplexed signal having a constant envelope by the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal; and a modulator for modulating the multiplexed signal with constant envelope to radio frequency to generate a satellite navigation signal, wherein the first baseband signal S₁And said second baseband signal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated on a second carrier frequency f₂And the carrier phases are orthogonal to each other.

According to one aspect of the application, a satellite navigation signal generation method is disclosed, comprising: generating a first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄(ii) a Setting the first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Generating a multiplexed signal having a constant envelope by the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal; and modulating the multiplex signal with the constant envelope to radio frequency to generate a satellite navigation signal, wherein the first baseband signal S₁And said second baseband signal S₂Is modulated inFirst carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated on a second carrier frequency f₂And the carrier phases are orthogonal to each other.

According to an aspect of the present application, a satellite navigation signal generated by the aforementioned satellite navigation signal generation method or satellite navigation signal generation apparatus is disclosed.

According to an aspect of the application, an apparatus is disclosed, comprising means for processing a satellite navigation signal as described above, or as generated by a satellite navigation signal generation method or a satellite navigation signal generation means.

According to an aspect of the present application, a satellite navigation signal receiving apparatus is disclosed, which receives a satellite navigation signal generated by the aforementioned satellite navigation signal, or a satellite navigation signal generation method or a satellite navigation signal generation apparatus.

According to an aspect of the present application, there is disclosed a signal receiving apparatus for receiving a satellite navigation signal generated by the aforementioned satellite navigation signal, or a satellite navigation signal generation method or a satellite navigation signal generation apparatus, comprising: a receiving unit that receives the satellite navigation signal; a demodulation unit that demodulates a signal component modulated on a first carrier in the received satellite navigation signal, and demodulates the received signal component modulated on a second carrier; and a processing unit for obtaining a first baseband signal S from the signal component modulated on the first carrier wave demodulated by the demodulation unit₁And a second baseband signal S₂And a demodulated signal component modulated on a second carrier to obtain a third baseband signal S₃And a fourth baseband signal S₄。

According to an aspect of the present application, there is disclosed a signal receiving method of receiving a satellite navigation signal generated by the aforementioned satellite navigation signal, or a satellite navigation signal generating method or a satellite navigation signal generating apparatus, comprising: receiving the satellite navigation signal; demodulating the received signalObtaining a first baseband signal S by modulating a signal component of the first carrier in the satellite navigation signal₁And a second baseband signal S₂(ii) a And demodulating the signal component modulated on the second carrier in the received satellite navigation signal to obtain a third baseband signal S₃And a fourth baseband signal S₄。

According to an aspect of the present application, there is disclosed a signal receiving apparatus for receiving a satellite navigation signal generated by the aforementioned satellite navigation signal, or a satellite navigation signal generation method or a satellite navigation signal generation apparatus, comprising: a receiving unit that receives the satellite navigation signal; the demodulation unit is used for demodulating the satellite navigation signal to obtain an in-phase baseband component and an orthogonal baseband component of a multiplex signal; and a processing unit for obtaining a first baseband signal S based on the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄。

According to an aspect of the present application, there is disclosed a signal receiving method of receiving a satellite navigation signal generated by the aforementioned satellite navigation signal, or a satellite navigation signal generating method or a satellite navigation signal generating apparatus, comprising: receiving the satellite navigation signal; demodulating the satellite navigation signal to obtain an in-phase baseband component and an orthogonal baseband component of a multiplex signal; and obtaining a first baseband signal S from the amplitude and phase of the in-phase baseband component and the quadrature baseband component of said multiplexed signal₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄。

According to an aspect of the application, a program is disclosed comprising executable instructions for implementing a method, an apparatus, a device as described above or for generating a satellite navigation signal as described above.

According to an aspect of the present application, a machine readable memory storing a program of executable instructions as described above for implementing a method, apparatus, device or for generating satellite navigation signals as described above is disclosed.

Drawings

Fig. 1 shows a block diagram of a satellite navigation signal generating apparatus according to an embodiment of the present application.

Fig. 2 shows a block diagram of a baseband signal generator according to an embodiment of the present application.

Fig. 3 shows a block diagram of a multiplex signal generator according to an embodiment of the present application.

Fig. 4 shows a block diagram of a modulator according to an embodiment of the present application.

Fig. 5 shows a schematic diagram of a specific implementation of a satellite navigation signal generating apparatus according to an embodiment of the present application.

Fig. 6 shows a schematic diagram of another specific implementation of a satellite navigation signal generating apparatus according to an embodiment of the present application.

FIG. 7 illustrates when the power ratio of four signal components is c according to an embodiment of the present application₁:c₂:c₃:c₄Constellation of the composite baseband signal in case of 1:2:3: 8.

Fig. 8 illustrates a power spectral density of a multiplexed signal according to an embodiment of the present application.

FIG. 9 shows a flow chart of a method of satellite navigation signal generation according to an embodiment of the present application.

Fig. 10 shows a block diagram of a satellite navigation signal receiving apparatus according to an embodiment of the present application.

Fig. 11 shows a schematic diagram of a specific implementation of a satellite navigation signal receiving apparatus according to an embodiment of the present application.

Detailed Description

The constant envelope multiplexing method, the generating device, and the receiving method for satellite navigation signals disclosed in the present application will be described in detail below with reference to the drawings. For simplicity, the same or similar reference numbers are used for the same or similar devices in the description of the embodiments of the present application.

Fig. 1 shows a satellite navigation signal generating apparatus 1 according to an embodiment of the present application. As shown, the signal generating apparatus 1 includes a baseband signal generator 100, a multiplexed signal generator 200, and a modulator 300. The baseband signal generator 100 generates a first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄. The multiplex signal generator 200 sets the first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄The amplitude and phase of the in-phase baseband component i (t) and the quadrature baseband component q (t) of the multiplexed signal to generate a multiplexed signal having a constant envelope. The modulator 300 modulates the multiplexed signal having a constant envelope to a radio frequency, generating a satellite navigation signal. Wherein the first baseband signal S₁And a second baseband signal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated on a second carrier frequency f₂And the carrier phases are orthogonal to each other. According to the satellite navigation signal generating device, two frequency points (f) can be realized₁，f₂) Four signal components (S) of₁,S₂,S₃,S₄) Constant envelope multiplexing.

According to one embodiment, each baseband signal S can be set according to actual needs_iPower parameter c of₁,c₂,c₃And c₄I.e. baseband signalsMay have different power parameters. According to one embodiment, the power parameter may be an absolute power of each baseband signal, such as an actual transmit power of each baseband signal. It will be appreciated that the power parameter may be the relative power of each baseband signal according to another embodiment, since the absolute power of the signal will vary after passing through a device such as an amplifier. For example, when the power ratio c of each baseband signal₁:c₂:c₃:c₄Is 1: 1: 1: when 1, the relative power of the four baseband signals is 1. When the power ratio c of each baseband signal₁:c₂:c₃:c₄Is 1: 3: 1: and 3, the relative power of the four baseband signals is 1, 3, 1 and 3 respectively. In addition, any one, any two, or any three of the power parameters of the baseband signals generated by the baseband signal generator 110 may be zero.

The multiplexed signal generator 200 may set the amplitude and phase of the in-phase baseband component and quadrature baseband component of the multiplexed signal according to the power parameter of each baseband signal.

According to one embodiment of the present application, the baseband signal is a signal that takes on a value of +/-1. The multiplex signal generator 200 may set the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplex signal according to the value of each baseband signal.

As shown in fig. 2, the baseband signal generator 100 may include a source 110, a spread spectrum modulator 120, and a spread chip shaper 130, according to one embodiment.

The source 110 generates information that needs to be broadcast. Such as sync words, time information, ephemeris, etc., required to accomplish positioning in the satellite navigation system, and encoded into a bit stream. Those skilled in the art will appreciate that for some signals dedicated for ranging purposes, such as the pilot channel signal in a satellite navigation system, no specific information may be conveyed and the bit stream it broadcasts may be considered constant 0 or constant 1.

The spread spectrum modulator 120 performs spread spectrum modulation on the bit stream/information generated by the source using the spread spectrum sequence, and obtains a spread spectrum sequence modulated with the text information.

The spreading chip shapers 130 shape each bit of the spreading sequence modulated with the textual information with a waveform. This waveform may be a rectangular pulse, a return to zero waveform, a square wave, a Binary Coded Symbol (BCS) waveform commonly used in the field of satellite navigation, and the like. Those skilled in the art will appreciate that the spreading chip waveforms used for BPSK-R, BOC, TMBOC, etc. modulation are all particular examples of BCS waveforms. It can be understood that the satellite navigation signal generating device according to the present application can flexibly select the spreading chip waveform used by each baseband signal component.

The output of the spreading chip shapers 130 is a baseband signal with a value of +/-1. Those skilled in the art will appreciate that the amplitude of +/-1 in the baseband signal is not a limiting description and that any amplification or reduction in amplitude of the baseband signal does not depart from the scope of the present application.

According to one embodiment, the multiplexed signal generator 200 may be based on the baseband signal S₁，S₂，S₃And S₄And the baseband signal S₁，S₂，S₃And S₄Calculates the amplitude and phase of the in-phase baseband component i (t) and the quadrature baseband component q (t) of the multiplexed signal to generate a multiplexed signal having a constant envelope.

As shown in fig. 3, the multiplexed signal generator 200 may further include a calculation unit 210, an in-phase branch generation unit 220, and a quadrature branch generation unit 230.

The calculating unit 210 is used for calculating the first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Calculating the amplitude A (t) and phase of the in-phase baseband component I (t)And calculates the amplitude A' (t) of the quadrature baseband component Q (t)And phase

The in-phase branch generation unit 220 generates the amplitude a (t) and the phase according to the amplitude a (t) and the phase calculated by the calculation unit 210Generating an in-phase baseband component I (t) expressed as

The quadrature branch generation unit 230 generates the amplitude a (t) and the phase according to the amplitude a (t) and the phase calculated by the calculation unit 210Generating quadrature baseband component Q (t), which is expressed as

Wherein f is_s＝|f₁-f₂I/2, sgn is a sign function

It is understood that in the present embodiment, the in-phase baseband component i (t) is a square wave function with amplitude a (t), the quadrature baseband component q (t) is a square wave function with amplitude a' (t), and f_s＝|f₁-f₂I/2 represents the frequency of the square wave.

According to one embodiment, the calculation unit 210 calculates the amplitude a (t) and the phase of the in-phase baseband component i (t) of the multiplexed signal according to the following formulaAnd the amplitude A' (t) and phase of the quadrature baseband component Q (t)

Wherein s is_i(t), i ═ 1,2,3,4 denotes the ith baseband signal, which has values of +/-1, c_iSignal S for indicating ith baseband signal_iThe power parameter of (a);

wherein atan2 is a four quadrant arctangent function

As will be appreciated by those skilled in the art, the multiplexed signal generated by the multiplexed signal generator 200 may be expressed as s (t) ═ i (t) + jq (t), where i (t) is the in-phase baseband component of the multiplexed signal and q (t) is the quadrature baseband component of the multiplexed signal, as viewed in the time domain. The envelope of the multiplexed signal beingWhen the envelope of the signal is a constant value and does not change with time, the signal is called a constant envelope signal. Root of herbaceous plantAccording to an embodiment of the present application, the signal S can be based on a baseband signal_i(i ═ 1,2,3,4), and each baseband signal S_iCalculates the amplitude and phase of the in-phase baseband component i (t) and the quadrature baseband component q (t) of the multiplexed signal, and generates a multiplexed signal having a constant envelope. For example, in the present embodiment,i.e. the envelope of the multiplexed signal does not change over time, the resulting multiplexed signal is a multiplexed signal with a constant envelope. It is understood that the first baseband signal S can be converted by the multiplex signal generator 200 if viewed from the frequency domain₁And a second baseband signal S₂Modulated on a carrier frequency f_sAnd the carrier phases are orthogonal to each other, and the third baseband signal and the fourth baseband signal are modulated at a carrier frequency-f_sAnd the carrier phases are orthogonal to each other.

In addition, each baseband signal S can be set according to actual needs_iPower parameter c of₁,c₂,c₃And c₄That is, each baseband signal may have different power parameters. In addition, any one, any two or any three of the power parameters of the baseband signals generated by the baseband signal generator 110 may be zero, i.e., c₁,c₂,c₃And c₄Any one, any two, or any three of them can be zero.

According to one embodiment of the present application, the modulator 300 modulates the multiplexed signal with a constant envelope onto a radio frequency carrier to generate a satellite navigation signal.

As shown in fig. 4, the modulator 300 may include a carrier generator 310, a first multiplier 321, a second multiplier 322, and an adder 330. The modulator 300 modulates the multiplexed signal having a constant envelope generated by the multiplexed signal generator 200 to a radio frequency transmission. Wherein carrier generator 310 generates a carrier signal having a center frequency f_RF＝(f₁+f₂) Carrier of/2. Through the first multiplier 321, will be composed ofThe in-phase baseband component I (t) of the multiplexed signal generated by the multiplexed signal generator 200 is modulated to a center frequency f_RFModulated to a carrier cos (2 π f), for example_RFt). Quadrature baseband component q (t) of the multiplexed signal generated by the multiplexed signal generator 200 is modulated to a center frequency f by a second multiplier 322_RFIs orthogonal to the phase of the carrier modulated by the first multiplier 321, e.g. to the carrier sin (2 pi f)_RFt). The outputs of the first multiplier 321 and the second multiplier 322 pass through an adder 330 to obtain a satellite navigation signal S with a constant envelope_RF. Wherein the satellite navigation signal S_RFCan be expressed as

S_RF(t)＝I(t)cos(2πf_RFt)-Q(t)sin(2πf_RFt)。

Thus, the satellite navigation signal S emitted by the satellite_RFWill be a satellite navigation signal with constant envelope characteristics.

Fig. 5 shows a specific application of the satellite navigation signal generating apparatus 1 according to an embodiment of the present application.

As shown in fig. 5, the signal generating apparatus 1 includes a baseband signal generator 100, a multiplexed signal generator 200, and a modulator 300. The baseband signal generator 100 may include a source 110, a spread spectrum modulator 120, and a spread spectrum chip shaper 130. The multiplexed signal generator 200 may include a calculation unit 210, an in-phase branch generator 220, a quadrature branch generator 230, and the modulator 300 includes a carrier wave generator 310, a first multiplier 321, a second multiplier 322, a pi/2 phase shift circuit 323, and an adder 330.

Specifically, the source 110 generates four-way binary textual data. Those skilled in the art will appreciate that if a pilot channel is required in some applications, the corresponding message data is always 0 or 1. The four channels of message data are respectively sent to spread spectrum modulators 120-1, 120-2, 120-3 and 120-4 for spread spectrum modulation, and four channels of spread spectrum sequences with modulated message information are obtained. Spread spectrum sequence division with modulated message informationRespectively sent to spreading chip shapers 130-1, 130-2, 130-3 and 130-4. The input spread spectrum sequence modulated with message information is shaped by chip, and the output results are respectively recorded as baseband signals s₁(t)、s₂(t)、s₃(t)、s₄(t)。

The calculation unit 210 receives the baseband signal s from the spreading chip shapers 130-1, 130-2, 130-3, 130-4₁(t)、s₂(t)、s₃(t)、s₄(t) from the baseband signal s₁(t)、s₂(t)、s₃(t)、s₄(t) power parameter and current time s₁(t)、s₂(t)、s₃(t)、s₄(t) taking value, calculating amplitude A and phase deviation of baseband composite signal of in-phase branchAmplitude A' and phase offset of quadrature branch baseband composite signal

Wherein the base band signal s₁(t)、s₂(t)、s₃(t)、s₄The power parameter (t) can be set to any value according to actual needs.

The calculation rule can be expressed as

The in-phase branch generator 220 receives the amplitude a and the phase offset of the in-phase branch baseband composite signal from the calculation unit 210The in-phase baseband component of the output multiplexed signal, i.e., the output of the in-phase branch generator 220, may be represented as

Quadrature branch generator 230 receives amplitude a' (t) and phase offset of the quadrature branch baseband composite signal from calculation unit 210The quadrature baseband component of the output multiplexed signal, i.e., the output of the quadrature branch generator 230, may be represented as

The carrier generator 310 generates a frequency f_RFThe carrier signal is divided into two branches, wherein the outputs of the first branch 340 and the in-phase branch generator 220 are fed into the first multiplier 321. The second branch 341, after passing through the pi/2 phase shift circuit 323, becomes a carrier wave in quadrature with the phase of the branch 340. The outputs of the second branch 341 and the quadrature branch generator 230 are fed to a second multiplier 322, and the outputs of the two multipliers are fed to an adder 330, so as to obtain a constant envelope satellite navigation signal 339.

Fig. 6 shows another specific application of the satellite navigation signal generating apparatus 1 according to an embodiment of the present application. In this application, the driving clocks of the modules are all the reference frequency clock f₀Frequency division or frequency multiplication, and adopts a clock synchronization mode.

As shown in fig. 6, the baseband signal generator 100 may include a reference frequency clock 20, a frequency converter 21, a data information generator 22, a frequency converter 23, a spread spectrum modulator 24, a frequency converter 25, and a spread spectrum chip shaper 26. The multiplexed signal generator 200 may include an I-branch status selector 27, a Q-branch status selector 28, a frequency converter 29, a frequency converter 30, a first composite signal generator 31, and a second composite signal generator 32. The modulator 300 may include a first multiplier 33, a second multiplier 34, a pi/2 phase shift circuit 35, a frequency converter 36, a first carrier generator 37, and a first adder 38.

Specifically, the reference frequency clock 20 is converted into a frequency f by a frequency converter 21_DDrives the data information generator 22 to generate four-way binary text data. If the pilot channel is needed in some applications, the corresponding circuit text data is constantly 0 or 1. The reference frequency clock is converted into a frequency f by frequency converters 23-1, 23-2, 23-3 and 23-4 respectively_c1、f_c2、f_c3、f_c4Respectively driving the spread spectrum modulators 24-1, 24-2, 24-3 and 24-4 to generate four-way binary spread spectrum sequences, wherein the respective spread spectrum code rates are respectively f_c1、f_c2、f_c3、f_c4. Each spreading code rate is f_DPositive integer multiples of.

The four circuits of text data generated by the data information generator 22 are respectively sent to the spread spectrum modulators 24-1, 24-2, 24-3 and 24-4 to perform modulo two addition operation with the spread spectrum sequence. The results of the modulo two addition are fed to spreading chip shapers 26-1, 26-2, 26-3, 26-4, respectively. The spread spectrum chip shape generator is converted into a frequency f by a clock 20 through frequency converters 25-1, 25-2, 25-3 and 25-4 respectively_sc1、f_sc2、f_sc3、f_sc4The subcarrier of (1) drives a clock drive, carries out BCS chip shaping on an input spread spectrum sequence modulated with message information, and respectively records output results as baseband signals s₁(t)、s₂(t)、s₃(t)、s₄(t)。f_sc1＝K₁f_c1，f_sc2＝K₂f_c2，f_sc3＝K₃f_c3，f_sc4＝K₄f_c4In which K is₁、K₂、K₃、K₄Are integers of 1 or more.

The clock 20 is converted to the frequency f by a frequency converter 29_MDrives the I branch status selector 27 and the Q branch status selector 28. f. of_MGreater than f_sc1、f_sc2、f_sc3、f_sc4Minimum common multiple f of_κAnd has f_M＝Mf_κAnd M is a positive integer. Can ensure each s_iThe value symbol reversal points of (t) (i ═ 1,2,3 and 4) are all equal to f_MSynchronous at t ∈ [ n/f ]_M,(n+1)/f_M) Within a time period of s_i(t) symbol s_i,n∈ { +1, -1} is left unchanged.

s₁(t)、s₂(t)、s₃(t)、s₄(t) is sent to the I-branch state selector 27, and the state selector 27 selects s in the current time slot according to the power parameter of each baseband signal₁(t)、s₂(t)、s₃(t)、s₄(t) calculating amplitude A and phase offset of I branch baseband composite signal by taking valueThe calculation rule is

The clock 20 is converted to a frequency f by a frequency converter 30_sDrives the first complex signal generator 31 to generate a signal having a frequency f_sThe I-branch state selector 27 sums the amplitudes a of the composite signalPhase shiftThe values are fed to the first complex signal generator 31 to control the amplitude and phase shift of the square wave sub-carriers generated by the first complex signal generator 31, i.e. the output of the first complex signal generator 31 can be expressed as

s₁(t)、s₂(t)、s₃(t)、s₄(t) sending the signal to the Q-branch state selector 28, and the state selector 28 according to the power parameter of each baseband signal and s in the current time slot₁(t)、s₂(t)、s₃(t)、s₄(t) calculating amplitude A' and phase offset of Q branch baseband composite signal by valueThe calculation rule is

Frequency f_sDriving the second complex signal generator 32 to generate a frequency f_sThe Q-branch phase selector 28 shifts the amplitude a' and phase of the composite signalThe values are fed into the second complex signal generator 32 to control the amplitude and phase shift of the square wave sub-carriers generated by the second complex signal generator 32, i.e. the output of the second complex signal generator 32 can be represented as

The reference clock 20 is converted to a frequency f by a frequency converter 36_RFDrives the first carrier generator 37 to generate a frequency f_RFThe carrier wave of (3) is divided into two branches, wherein the outputs of the branch 40 and the first composite signal generator 31 are sent to a first multiplier 33, the other branch 41 becomes a carrier wave orthogonal to the phase of the branch 40 after passing through a pi/2 phase shift circuit 35, the output of the second composite signal generator 32 and the output of the branch are sent to a second multiplier 34, the outputs of the two branches of multipliers are sent to a first adder 38 for addition, and a constant envelope satellite navigation signal 39 is generated.

FIG. 7 shows that when c₁:c₂:c₃:c₄The Fresnel constellation diagram of the composite baseband signal in case of 1:2:3:8 shows that the composite signal is a 16-PSK signal but the constellation points are not uniformly spaced. With c₁:c₂:c₃:c₄Other ratios, the number of constellation points and the distribution of constellation points may be different from the present embodiment.

FIG. 8 shows the equation when c₁:c₂:c₃:c₄＝1:2:3:8，f_c1＝f_c2＝f_c3＝f_c4Each signal component adopts a rectangular pulse spread spectrum waveform (namely BPSK-R modulation), and f is 10.23MHz_sThe Power Spectral Density (PSD) of the multiplexed baseband signal at 15.345 MHz. In PSD, two signal components at the same frequency point are superposed together and cannot be distinguished, but f is used for₁The power ratio of the upper band main lobe 51 at the center frequency is f₂The lower sideband main lobe 50 power at the center frequency is about 5.5dB lower, corresponding exactly to the ratio of the upper sideband signal component total power to the lower sideband signal component total power of this embodiment as (c)₁+c₂)/(c₃+c₄) 3/11(-5.6 dB). Therefore, the satellite navigation signal generation method can achieve the effect that the four signal components are subjected to constant envelope multiplexing at different power ratios.

Another aspect of the present application provides a satellite navigation signal generating method according to which two frequency points (f) can be implemented₁，f₂) Four signal components (S) of₁,S₂,S₃,S₄) Constant envelope multiplexing.

FIG. 9 shows a flow chart of a method of satellite navigation signal generation according to an embodiment of the present application. As shown, in step 901, a first baseband signal S is generated₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄. In step 902, a first baseband signal S is set₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄The amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal to generate a multiplexed signal having a constant envelope. In step 903, the multiplexed signal with the constant envelope is modulated to a radio frequency to generate a satellite navigation signal. Wherein the first baseband signal S₁And a second baseband signal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated at a second carrier frequency f₂And the carrier phases are orthogonal to each other.

According to one embodiment, each baseband signal S can be set according to actual needs_iPower c of₁,c₂,c₃And c₄. In step 902, the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal may be further set according to the power parameter of each baseband signal.

According to an embodiment, in step 902, the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal may be further set according to the value of each baseband signal.

According to one embodiment, in step 903 the multiplexed signal with a constant envelope may be modulated to a center frequency f_RF＝(f₁+f₂) And/2, generating satellite navigation signals.

According to an embodiment of the present application, the method for generating satellite navigation signals further includes generating a first baseband signal S from the received satellite navigation signals₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Calculating the amplitude A (t) and phase of the in-phase baseband component I (t)And calculates the amplitude A' (t) and phase of the quadrature baseband component Q (t)According to the calculated amplitude A (t) and phaseGenerating an in-phase baseband component I (t), wherein the in-phase baseband component I (t) is represented by

And

according to the calculated amplitude A (t) and phaseGenerating quadrature baseband component Q (t), which is expressed as

Wherein f is_s＝|f₁-f₂I/2, sgn is a sign function

According to the applicationIn one embodiment, the method further comprises calculating the amplitude a (t) and phase of the in-phase baseband component i (t) according to the following formulaAnd calculates the amplitude A' (t) and phase of the quadrature baseband component Q (t)

Wherein s is_i(t), i is 1,2,3,4, and represents the ith baseband signal S_i，c_iSignal S for indicating ith baseband signal_iThe power parameter of (a);

wherein atan2 is a four quadrant arctangent function

Although the specific embodiments and specific applications of the apparatus and method for generating satellite navigation signals have been described above with reference to the accompanying drawings, the above embodiments are merely examples for illustrative purposes and are not intended to be limiting. It will be appreciated by those skilled in the art that any modifications, equivalents, etc. which fall within the teachings and purview of this application are intended to be included within the scope of the invention as claimed.

The embodiments of the present application described above have focused on the transmitting end, that is, on the generation method and generation apparatus of the satellite navigation signal. However, embodiments of the present application also relate to signals generated by a method and apparatus for generating satellite navigation signals such as those described above.

Further, those skilled in the art will appreciate that the system, method and apparatus for inverting can be employed to receive and process satellite navigation signals generated in embodiments of the present application. Accordingly, embodiments of the present application also relate to systems, methods, and apparatus for processing satellite navigation signals such as those described above.

According to an embodiment of the present application, there is provided a signal receiving apparatus for a satellite navigation signal, which receives the satellite navigation signal generated by the above-mentioned satellite navigation signal generation method or generation apparatus. In this embodiment, the signal components modulated on the first carrier and the second carrier may be processed separately. As shown in fig. 10, signal receiving apparatus 500 includes receiving section 510, demodulating section 520, and processing section 530. The receiving unit 510 receives a satellite navigation signal; a demodulation unit 521 for demodulating a signal component modulated on a first carrier wave in the received satellite navigation signal and demodulating a signal component modulated on a second carrier wave; and a processing unit 530 for obtaining a first baseband signal S based on the signal component modulated on the first carrier wave demodulated by the demodulation unit₁And a second baseband signal S₂And a demodulated signal component modulated on a second carrier to obtain a third baseband signal S₃And a fourth baseband signal S₄。

Fig. 11 shows a schematic diagram of a specific implementation of a satellite navigation signal receiving apparatus according to an embodiment of the present application. According to an embodiment, the receiving unit 510 may include an antenna 61; the demodulation unit 520 may include a filtering amplification unit 62, a down converter 63, and an analog-to-digital converter 64; the processing unit 530 may include a digital signal processing module 65.

Referring to fig. 11, when a signal component is received alone, satellite navigation signal 60 is received by antenna 61. The antenna 61 inputs the received satellite navigation signal 60 into the filtering and amplifying unit 62, and the filtering and amplifying unit 62 filters the satellite navigation signal 60 to block strong interference signals and out-of-band noise and amplifies the satellite navigation signal 60. If s of the upper sideband is to be processed₁(t) or s₂(t) signal component, the center frequency of the filter being set at f₁Nearby, bandwidth greater than or equal to s desired to be received₁(t) or s₂(t) bandwidth of signal component to ensure s₁(t) or s₂(t) the signal component has sufficient energy to pass through the filter; similarly, if s of the lower sideband is to be processed₃(t) or s₄(t) signal component, the center frequency of the filter being set at f₂Nearby, bandwidth greater than or equal to s desired to be received₃(t) or s₄(t) bandwidth of signal component to ensure s₃(t) or s₄(t) the signal component has sufficient energy to pass through the filter.

The filtering amplification unit 62 inputs the filtered and amplified signal to a down-converter 63 to convert the carrier frequency of the signal component to be processed to a corresponding intermediate frequency; and then sent to an analog-to-digital converter 64 to complete the sampling and quantization of the signal, and obtain a digital intermediate frequency signal.

The analog-to-digital converter 64 sends the digital intermediate frequency signal to a digital signal processing module 65, which may be implemented by FPGA, ASIC, general computing unit, or a combination of the above devices, and performs the function of processing the baseband signal component to be processed by using corresponding capturing, tracking, and demodulating methods.

In addition, according to an embodiment of the present application, there is provided a signal receiving method for a satellite navigation signal, which receives a satellite navigation signal generated by the above-described satellite navigation signal generation method or generation apparatus. The signal receiving method comprises the following steps: receiving a satellite navigation signal; demodulating received satellite navigation signalsModulating the signal component of the first carrier to obtain a first baseband signal S₁And a second baseband signal S₂(ii) a And demodulating the signal component modulated on the second carrier in the received satellite navigation signal to obtain a third baseband signal S₃And a fourth baseband signal S₄。

According to an embodiment of the present application, there is provided a signal receiving apparatus for a satellite navigation signal, which receives the satellite navigation signal generated by the above-mentioned satellite navigation signal generation method or generation apparatus. In the present embodiment, the received center frequency can be processed as a whole as (f)₁+f₂) A satellite navigation signal of/2. As shown in fig. 10, signal receiving apparatus 500 includes receiving section 510, demodulating section 520, and processing section 530. A receiving unit 510 that receives a satellite navigation signal; a demodulation unit 520 for demodulating the satellite navigation signal to obtain an in-phase baseband component and an orthogonal baseband component of the multiplexed signal; and a processing unit 530 obtaining a first baseband signal S based on the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄。

It will be appreciated that since the baseband signals are of +/-1, the four baseband signals are of a combination of values S₁,S₂，S₃，S₄]There are a maximum of 16 combination states. The processing unit 530 may perform a correlation operation on the locally reproduced in-phase baseband component and the locally reproduced quadrature baseband component corresponding to the 16 combination states and the in-phase baseband component and the quadrature baseband component of the multiplexed signal obtained by the demodulation unit 540, so as to determine the received first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄The value of (a).

Referring also to fig. 11, when the entire composite signal as a whole is subjected to reception processing, the receiver receives satellite navigation signal 60 via antenna 61. The antenna 61 filters the received satellite navigation signal 60A large cell 62. The filtering and amplifying unit 62 completes filtering of the satellite navigation signal 60 to block strong interference signals and out-of-band noise, and amplifies the satellite navigation signal 60; the center frequency of the filter is set at (f)₁+f₂) A bandwidth of 2f or more in the vicinity of/2_sAt the very least, it is ensured that the entire composite signal has sufficient energy to pass through the filter, and if the filter design allows, it is ensured that the first main lobe of the power of each signal component can pass through the filter.

The analog-to-digital converter 64 sends the digital intermediate frequency signal to a digital signal processing module 65, which may be implemented by an FPGA, an ASIC, a general-purpose computing unit, or a combination of the above. The digital intermediate frequency signal is multiplied by an in-phase carrier and a quadrature carrier generated inside the receiver to remove the intermediate frequency and doppler of the digital signal, resulting in a receiver in-phase baseband signal si (t) and a receiver quadrature baseband signal sq (t).

The spread spectrum sequences of the four signal components shaped by the spread spectrum chips are generated in the digital signal processing module 65, and at each moment, according to all possible value combinations of the local reproduction baseband binary signals of the four signal components, corresponding local reproduction in-phase baseband waveform is generated in the digital signal processing module 65 for each combinationAnd locally reproducing quadrature baseband waveformsThe number of the value combinations is recorded as g, the calculation is easy, and if the N signal components are data channels, g is 2^NFor each particular case of the g combinations of valuesAndis generated as

Wherein

I-th group (i ═ 1,2, …, g) locally reproduces the in-phase baseband waveformMultiplying the signals respectively with receiver in-phase baseband signals SI (t) and receiver quadrature baseband signals SQ (t), sending the result to an integration and elimination filter for coherent integration with the length TI, and respectively obtaining first in-phase correlation values corr1I of an ith group (i is 1,2, …, g)_iAnd the orthogonal correlation value corr1Q_i(ii) a Each set of locally reproduced quadrature baseband waveformsAlso multiplies the signals by the receiver in-phase baseband signal SI (t) and the receiver quadrature baseband signal SQ (t), and sends the result to an integration clearing filter to carry out coherent integration with the length TI, and second in-phase correlation value corr2I of the ith group (i is 1,2, …, g) is obtained respectively_iAnd the orthogonal correlation value corr2Q_i；

Seventh step, the first in-phase correlation value corr1I of the ith group (i ═ 1,2, …, g)_iAnd a first quadrature correlation value corr1Q_iSecond in-phase correlation value corr2I_iAnd a second orthogonal correlation value corr2Q_iCombining according to the following rule to obtain the in-phase combination correlation value I of the ith group_i' and Quadrature combined correlation value Q_i', where the rule is:

let the preferred in-phase combined correlation value I 'and the preferred quadrature combined correlation value Q' be equal to all I sets of in-phase combined correlation values I, respectively_i' and Quadrature combined correlation value Q_i' middle satisfactionThe largest group, I 'and Q', can be processed using conventional acquisition methods and tracking loops.

In addition, according to an embodiment of the present application, there is provided a signal receiving method for a satellite navigation signal, which receives a satellite navigation signal generated by the above-described satellite navigation signal generation method or generation apparatus. The signal receiving method comprises the following steps: receiving a satellite navigation signal; demodulating the satellite navigation signal to obtain an in-phase baseband component and an orthogonal baseband component of the multiplex signal; and obtaining a first baseband signal based on the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signalS₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄。

Although specific embodiments and specific applications of the receiving apparatus and the receiving method of satellite navigation signals have been described above with reference to the accompanying drawings, the above embodiments are merely examples for illustrative purposes and are not intended to be limiting. Those skilled in the art will appreciate that the system, method and apparatus for generating satellite navigation signals in embodiments of the present satellite navigation signal generation method and apparatus can be used in an inverse manner to receive and process satellite navigation signals. Accordingly, embodiments of the present application relate to any system, method and apparatus for processing or receiving satellite navigation signals generated in accordance with embodiments of the satellite navigation signal generation methods and apparatus of the present application.

Embodiments according to the present application may be implemented in hardware, software, or a combination thereof. One aspect of the present application provides a computer program comprising executable instructions for implementing a satellite navigation generation method, a reception apparatus, a satellite navigation reception method, a reception apparatus, a device, or a satellite navigation signal according to embodiments of the present application. Further, such computer programs may be stored using any form of memory, such as an optically or magnetically readable medium, a chip, a ROM, a PROM, or other volatile or non-volatile device. A machine readable memory storing such a computer program is provided according to an embodiment of the present application.

Exemplary embodiments of the present application are described above with reference to the accompanying drawings. It will be appreciated by those skilled in the art that the above-described embodiments are merely exemplary for purposes of illustration and are not intended to be limiting, and that any modifications, equivalents, etc. that fall within the teachings of this application and the scope of the claims should be construed to be covered thereby.

Claims

1. A satellite navigation signal generating apparatus, comprising:

a baseband signal generator for generating a first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄；

A multiplex signal generator for generating a multiplex signal based on the power parameter c of each baseband signal₁，c₂，c₃，c₄Setting the first baseband signal S according to the value of each baseband signal₁Second baseband signal S₂Third base band signalNumber S₃And a fourth baseband signal S₄The amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal to generate a multiplexed signal having a constant envelope; and

a modulator for modulating the multiplexed signal with a constant envelope to a radio frequency to generate a satellite navigation signal,

wherein the first baseband signal S₁And said second baseband signal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated on a second carrier frequency f₂And the carrier phases are orthogonal to each other, wherein the envelope of the generated multiplexed signal having a constant envelope is based onAnd (4) determining.

2. The satellite navigation signal generation apparatus of claim 1, wherein the power parameter is an absolute power of each baseband signal or a relative power of each baseband signal.

3. The satellite navigation signal generating apparatus according to claim 2, wherein the power parameter of one, two, or three baseband signals in each baseband signal is zero, or the power parameter of four baseband signals is not zero.

4. The satellite navigation signal generating apparatus of claim 1, wherein the multiplex signal generator comprises:

a calculating unit for calculating the first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Calculating the amplitude A (t) and phase of the in-phase baseband component I (t)And calculates the amplitude A' (t) and phase of the quadrature baseband component Q (t)

An in-phase branch generation unit for generating an amplitude A (t) and a phase according to the amplitude A (t) and the phase calculated by the calculation unitGenerating an in-phase baseband component I (t), wherein the in-phase baseband component I (t) is represented by

And

a quadrature branch generation unit for generating a quadrature branch based on the amplitude A' (t) and the phase calculated by the calculation unitGenerating quadrature baseband component Q (t), which is expressed as

Wherein f is_s＝|f₁-f₂I/2, sgn is a sign function

5. The satellite navigation signal generation apparatus according to claim 4, wherein the calculation unit calculates the amplitude A (t) and the phase of the in-phase baseband component I (t) according to the following formulaAnd calculates the amplitude A' (t) and phase of the quadrature baseband component Q (t)

1

Wherein s is_i(t), i is 1,2,3,4, and represents the ith baseband signal S_i，c_iSignal S for indicating ith baseband signal_iA power parameter;

wherein atan2 is a four quadrant arctangent function

6. The satellite navigation signal generating apparatus of claim 1, wherein the baseband signal generator comprises:

the information source generates telegraph text information needing to be broadcast;

the spread spectrum modulator is used for carrying out spread spectrum modulation on the message information generated by the information source by using a spread spectrum sequence; and

the spread chip shaper generates a baseband signal by applying a waveform to each bit of the spread sequence modulated with the text information.

7. The satellite navigation signal generating apparatus of claim 1, wherein the modulator comprises:

a carrier generator for generating a radio frequency carrier;

a first multiplier for modulating the in-phase baseband component of the multiplexed signal generated by the multiplexed signal generator to a radio frequency carrier;

a second multiplier for modulating the quadrature baseband component of the multiplexed signal generated by the multiplexed signal generator to a radio frequency carrier;

and an adder for adding the in-phase baseband component of the multiplexed signal modulated onto the radio frequency carrier and the quadrature baseband component of the multiplexed signal modulated onto the radio frequency carrier to generate a satellite navigation signal.

8. A satellite navigation signal generation method, comprising:

generating a first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄；

According to power parameter c of each baseband signal₁，c₂，c₃，c₄Setting the first baseband signal S according to the value of each baseband signal₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄The amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal to generate a multiplexed signal having a constant envelope; and

modulating the multiplexed signal with the constant envelope to a radio frequency, generating a satellite navigation signal,

wherein the first baseband signal S₁And said second groupSignal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated on a second carrier frequency f₂And the carrier phases are orthogonal to each other, wherein the envelope of the generated multiplexed signal having a constant envelope is based onAnd (4) determining.

9. The satellite navigation signal generation method of claim 8, wherein the power parameter is an absolute power of each baseband signal or a relative power of each baseband signal.

10. The method for generating satellite navigation signals according to claim 9, wherein the power parameter of one, two, or three baseband signals in each baseband signal is zero, or the power parameter of four baseband signals is not zero.

11. The satellite navigation signal generating method of claim 8, further comprising:

according to the first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Calculating the amplitude A (t) and phase of the in-phase baseband component I (t)And calculates the amplitude A' (t) and phase of the quadrature baseband component Q (t)

According to the calculated amplitude A (t) and phaseGenerating in-phase baseband componentsQuantity I (t), where the in-phase baseband component I (t) is expressed as

And

Wherein f is_s＝|f₁-f₂I/2, sgn is a sign function

12. The satellite navigation signal generating method of claim 11, further comprising:

the amplitude A (t) and phase of the in-phase baseband component I (t) are calculated according to the following formulaAnd calculates the amplitude A' (t) and phase of the quadrature baseband component Q (t)

wherein atan2 is a four quadrant arctangent function

13. The satellite navigation signal generation method of claim 8, wherein the generating a first baseband signal S₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄Comprises the following steps:

generating message information to be broadcast;

spread spectrum modulation is carried out on the message information generated by the information source by using a spread spectrum sequence; and

each bit of the spread sequence modulated with the text information is given a waveform to generate a baseband signal.

14. The satellite navigation signal generating method of claim 8, wherein the modulating the multiplexed signal with the constant envelope to a radio frequency, the generating of the satellite navigation signal comprises:

generating a radio frequency carrier;

modulating an in-phase baseband component of the multiplexed signal to a radio frequency carrier;

modulating quadrature baseband components of the multiplexed signal to a radio frequency carrier;

and adding the in-phase baseband component of the multiplex signal modulated to the radio frequency carrier and the orthogonal baseband component of the multiplex signal modulated to the radio frequency carrier to generate a satellite navigation signal.

15. A signal receiving apparatus that receives a satellite navigation signal generated by the satellite navigation signal generating apparatus according to any one of the preceding claims 1 to 7, or the satellite navigation signal generated by the satellite navigation signal generating method according to any one of the preceding claims 8 to 14, comprising:

a receiving unit for receiving the satellite navigation signal, wherein the satellite navigation signal comprises a four-path baseband signal S₁，S₂，S₃And S₄Wherein the first baseband signal S is a constant envelope multiplexed signal₁And a second baseband signal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated at a second carrier frequency f₂And the carrier phases are orthogonal to each other;

a demodulation unit for demodulating the received satellite navigation signal modulated on the first carrier f₁And demodulates said received signal component modulated on a second carrier f₂A signal component of (a); and

a processing unit for modulating the first carrier wave f according to the modulation demodulated by the demodulation unit₁Obtaining a first baseband signal S from the signal component of₁And a second baseband signal S₂And demodulated on a second carrier f₂To obtain a third baseband signal S₃And a fourth baseband signal S₄。

16. A signal receiving method of receiving a satellite navigation signal generated by the satellite navigation signal generating apparatus of any one of the preceding claims 1-7 or the satellite navigation signal generated by the satellite navigation signal generating method of any one of the preceding claims 8-14, comprising:

receiving the satellite navigation signal, wherein the satellite navigation signal comprises a four-way baseband signal S₁，S₂，S₃And S₄Wherein the first baseband signal S is a constant envelope multiplexed signal₁And a second baseband signal S₂Modulated on a first carrier frequency f₁And the carrier phases are orthogonal to each other, the third baseband signal and the fourth baseband signal are modulated at a second carrier frequency f₂And the carrier phases are orthogonal to each other;

demodulating the received satellite navigation signal modulated on a first carrier f₁To obtain a first baseband signal S₁And a second baseband signal S₂(ii) a And

demodulating the second carrier f in the received satellite navigation signal₂To obtain a third baseband signal S₃And a fourth baseband signal S₄。

17. A signal receiving apparatus that receives a satellite navigation signal generated by the satellite navigation signal generating apparatus according to any one of the preceding claims 1 to 7, or the satellite navigation signal generated by the satellite navigation signal generating method according to any one of the preceding claims 8 to 14, comprising:

the demodulation unit is used for demodulating the satellite navigation signal to obtain an in-phase baseband component and an orthogonal baseband component of a multiplex signal; and

a processing unit for obtaining a first baseband signal S according to the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplex signal₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄。

18. A signal receiving method of receiving a satellite navigation signal generated by the satellite navigation signal generating apparatus of any one of the preceding claims 1-7 or the satellite navigation signal generated by the satellite navigation signal generating method of any one of the preceding claims 8-14, comprising:

demodulating the satellite navigation signal to obtain an in-phase baseband component and an orthogonal baseband component of a multiplex signal; and

obtaining a first baseband signal S based on the amplitude and phase of the in-phase baseband component and the quadrature baseband component of the multiplexed signal₁Second baseband signal S₂Third baseband signal S₃And a fourth baseband signal S₄。

19. A signal receiving method of receiving a satellite navigation signal generated by the satellite navigation signal generating apparatus of any one of the preceding claims 1-7 or the satellite navigation signal generated by the satellite navigation signal generating method of any one of the preceding claims 8-14, comprising:

receiving satellite navigation signals, filtering and amplifying the satellite navigation signals, wherein the center frequency of the filter is set at (f)₁+f₂)/2；

Converting the carrier frequency of the signal component to be processed to a corresponding intermediate frequency, and then performing digital-to-analog conversion to finish the sampling and quantization of the signal;

multiplying the converted digital intermediate frequency signal with an in-phase carrier and a quadrature carrier respectively to obtain a receiver in-phase baseband signal SI (t) and a receiver quadrature baseband signal SQ (t);

generating the converted digital intermediate frequency signal into a spread spectrum sequence of four signal components shaped by spread spectrum chips in a digital signal processor, and generating corresponding local reproduction in-phase baseband waveform corresponding to each combination according to all possible value combinations of local reproduction baseband binary signals of the four signal components at each momentAnd locally reproducing quadrature baseband waveformsThe number of the value combinations is recorded as g, g is less than or equal to 16, and for each specific case in the g value combinationsAndis generated as

Wherein the content of the first and second substances,

f_s＝(f₁-f₂)/2

c_i(i ═ 1,2,3,4) power parameters for i baseband signals, a andrespectively representing the amplitude and phase, A 'and A', of a locally reproduced in-phase baseband waveformRespectively representing the amplitude and phase of a locally reproduced quadrature baseband waveform;

locally reproducing each set of in-phase baseband waveformsMultiplying the signals respectively with a receiver in-phase baseband signal SI (t) and a receiver quadrature baseband signal SQ (t), and performing coherent integration with the length TI to respectively obtain a first in-phase correlation value corr1I of a q-th group (q is 1,2, …, g)_qAnd a first quadrature correlation value corr1Q_q(ii) a Each set of locally reproduced quadrature baseband waveformsThe signals are also multiplied by the receiver in-phase baseband signal si (t) and the receiver quadrature baseband signal sq (t), respectively, and the results are coherently integrated by length TI to obtain a second in-phase correlation value corr2I of the qth group (q 1,2, …, g), respectively_qAnd the orthogonal correlation value corr2Q_q；

The first in-phase correlation value corr1I_qAnd a first quadrature correlation value corr1Q_qSecond in-phase correlation value corr2I_qAnd a second orthogonal correlation value corr2Q_qThe combination is carried out according to the following rules:

obtaining the q group in-phase combined correlation value I_q' and Quadrature combined correlation value Q_q′；

Take all q groups satisfiedSet of maximum values I_q' and Q_qThe I 'and Q's can be processed using conventional acquisition methods and tracking loops.

20. The constant envelope multiplexing method of the navigation signal comprises the following steps:

generating baseband of individual signal componentsSpread spectrum signal s_i(t)，i＝1,2,3,4，s₁(t) and s₂(t) the carrier phases are orthogonal to each other, s₃(t) and s₄(t) the carrier phases are orthogonal to each other;

at a frequency f_MIs driven by the driving clock to spread the baseband signals s_i(t) multiplexing the waveforms according to s in the time period of t_iSymbol s of (t)_i,n∈ { +1, -1} to generate a multiplexed in-phase baseband waveform I (t) and a multiplexed quadrature baseband waveform Q (t), wherein f_MIs s is_i(t) minimum common multiple of the inverse of the symbol minimum hold time to ensure each s_i(t) sign inversion points are all equal to f_MSynchronization, t ∈ [ n/f_M,(n+1)/f_M) N is an integer greater than or equal to zero, s is in the t period_iSymbol s of (t)_i,n∈ { +1, -1} remains unchanged;

at a frequency f_P＝(f₁+f₂) Driven by carrier driving clock of/2, two paths of carriers cos (2 pi f) with mutually orthogonal phases are generated by a carrier generator_Pt) and sin (2 π f)_Pt) and multiplying and adding the multi-path compounded in-phase baseband waveform I (t) and the multi-path compounded quadrature baseband waveform Q (t) respectively to obtain a radio frequency signal S meeting the constant envelope condition_RF(t) wherein f₁Is s is₁(t) and s₂(t) center frequency point in constant envelope composite signal finally modulated onto radio frequency, f₂Is s is₃(t) and s₄(t) at the center frequency point in the constant envelope composite signal that is finally modulated onto the radio frequency.

21. The constant-envelope multiplexing method of navigation signals of claim 20, wherein the multiplexed in-phase baseband waveform i (t) and the multiplexed quadrature baseband waveform q (t) are:

in the above formula, f_s＝(f₁-f₂) Sgn is a sign function

While

Wherein, c_i(i ═ 1,2,3,4) power parameters for i baseband signals, a andrespectively representing the amplitude and phase, A 'and A', of a locally reproduced in-phase baseband waveformRespectively representing the amplitude and phase of a locally reproduced quadrature baseband waveform;

atan2 in the formula is a four-quadrant arctangent function

7