KR100539604B1 - Dual Band Global Positioning System Receiver - Google Patents

Abstract

The present invention relates to a GPS receiver, and more particularly, to a GPS receiver capable of minimizing and minimizing a distance error of a target by improving the structure of the GPS receiver.

A receiver of a dual band Global Positioning System (GPS) for receiving L1 and L2 carrier signals transmitted from a satellite according to the present invention comprises a first low noise for amplifying while minimizing a noise figure of the L1 and L2 carrier signals. An amplifier and a second low noise amplifier; A summer for outputting each of the amplified L1 and L2 signals from the first low noise amplifier and the second low noise amplifier in one path; A radio frequency (RF) mixer for frequency converting the L1 and L2 carriers inputted through the summer to an intermediate frequency; An intermediate frequency (IF) mixer for frequency converting the intermediate frequency converted from the RF mixer to a final intermediate frequency; A composite band pass filter controlling the gain of the signal converted from the IF mixer and selecting a frequency band; An analog to digital (AD) converter for converting a signal filtered from the complex band pass filter into a digital signal; And a phase locked loop providing a local oscillation frequency corresponding to each of the RF mixer, the IF mixer, and the AD converter, wherein the RF mixer includes an intermediate frequency having the same frequency value of each of the L1 and L2 carriers inputted through the summer. It is characterized in that it is set to output.

Description

Dual Band Global Positioning System Receiver

The present invention relates to a GPS receiver, and more particularly to the structure of a dual band GPS receiver.

In general, the Global Positiong System (hereinafter referred to as 'GPS') is a system for reading a position on the earth, which is composed of a space part, a user part, and a control part. The space sector is at the heart of the GPS system, and satellites belonging to the US Department of Defense are distributed across six orbital planes, approximately 20,200 km high.

In addition, the user part receives a message from the satellite to calculate the current position and use the data for the purpose. The control part consists of Master Control Station (MCS) and Monitor Station (MS). It analyzes each satellite signal, controls the position of satellites and checks the status.

GPS satellites transmit L1 band (f _L1 = 1575.42MHz) and L2 band (f _L2 = 1227.6MHz) signals modulated with a binary phase shift keying (BPSK) signal. The satellite signal is subjected to respective modulation processes through P (Precision) code and Coarse / Acquisition (C / A) code, which are spread spectrum. In this case, in the L1 band signal, the P code and the C / A code exist simultaneously, and the P2 code exists in the L2 band signal.

The P code is encrypted because it is used for military purposes, and commercially uses an L1 band signal including a C / A code. The L1 band signal has a frequency of 1575.42 MHz, a bandwidth of 2.046 MHz, and a received power of -130 dBm. The GPS signal of the L1 band transmitted from the GPS satellite may be expressed by Equation 1 below.

Here, the parameters of Equation 1 will be described.

-D ( t ) represents a 50bps navigation message such as orbital information, location information and time information transmitted from a satellite.

C ( t ) denotes the C / A code which is one of pseudo random noise codes for direct sequence among Code Division Multiple Access (CDMA). Indicates.

- P (t) represents the P code.

A _c , A _p represent power magnitudes of the C / A code and the P code.

- Denotes the phase delay.

- Denotes the frequency difference due to Doppler.

At this time, the P code has a chip rate of 10.23 MHz, and the C / A code has a chip rate of 1.023 MHz.

1 is a block diagram schematically showing the structure of a general GPS receiver. As shown in FIG. 1, the GPS receiver includes an antenna 101, a preamplifier 102, a frequency synthesizer 103, a basic oscillator 104, and a down converter in order to process received satellite signals into data desired by a user. 105, an IF unit 106, a signal processing unit 107, and an application processing unit 108 are provided.

The antenna 101 receives satellite signals from the satellites while eliminating multipath and interference signals.

Preamplifier 102 consists of burnout protection, filtering, and low-noise amplifier, removes signals outside the frequency band, and determines the noise figure.

The frequency synthesizer 103 generates a clock and local oscillators for use in the GPS receiver.

A reference oscillator 104 supplies an alternating frequency to the frequency synthesizer 103. Since the measurement of the GPS receiver is based on the phase of the pseudo noise code, the phase of the received carrier, and the arrival time of the frequency information, the basic oscillator 104 plays an important role in the GPS receiver.

A down-converter 105 converts a radio frequency (RF) signal into an intermediate frequency (IF) signal using the local oscillation frequency.

The IF unit 106 removes the signal outside the frequency band and amplifies the signal to a level capable of signal processing. In addition, the IF unit 106 includes a VGA (Variable Gain Amplifier) circuit that controls the signal to always be at a constant level even if the magnitude of the input signal is not constant.

The signal processing unit 107 may be a core part of a GPS receiver, and has various functions such as dividing a signal into several channels to simultaneously perform signal processing of multiple satellites. The output signals of the signal processor 107 are code phase, carrier frequency, carrier phase, SNR, and local receiver timetable.

The application processor 108 controls the signal processor 107 and processes the signal input from the signal processor 107 into appropriate data corresponding to each component of the GPS system.

On the other hand, the GPS receiver should be able to minimize the distance error of the target to provide navigation data to facilitate the informational azimuth work about the user's location.

GPS receivers are also integrated or portable in other large devices in many areas. Accordingly, in order to facilitate the user's portability, there is an urgent need for lower power consumption due to miniaturization and miniaturization. In this regard, there is a patent for a dual band GPS receiver capable of receiving the L1 and L2 carrier signals at the same time, and research on dual band GPS has been actively conducted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a GPS receiver capable of minimizing a distance error of a target by improving the structure of the GPS receiver.

Another object of the present invention is to provide a GPS receiver that can be miniaturized and low power by improving the structure of the GPS receiver.

In order to achieve the above object, the present invention provides a receiver of a dual-band global positioning system (GPS) for receiving L1 and L2 carrier signals transmitted from satellites. A first low noise amplifier and a second low noise amplifier for minimizing amplification; A summer for outputting each of the amplified L1 and L2 signals from the first low noise amplifier and the second low noise amplifier in one path; A radio frequency (RF) mixer for frequency converting the L1 and L2 carriers inputted through the summer to an intermediate frequency; An intermediate frequency (IF) mixer for frequency converting the intermediate frequency converted from the RF mixer to a final intermediate frequency; A band pass filter controlling the gain of the signal converted from the IF mixer and selecting a frequency band; An analog to digital (AD) converter for converting the signal filtered from the band pass filter into a digital signal; And a phase locked loop providing a local oscillation frequency corresponding to each of the RF mixer, the IF mixer, and the AD converter, wherein the RF mixer includes an intermediate frequency having the same frequency value of each of the L1 and L2 carriers inputted through the summer. It is characterized in that it is set to output.

According to a feature of the invention, the phase locked loop provides a local oscillation frequency having an intermediate value of the frequencies of the L1 and L2 signals input through the adder to the RF mixer, thereby providing the L1 and L2 output from the RF mixer. The intermediate frequency will have the same frequency value. At this time, the frequency having the intermediate value of the frequency of the L1 and L2 signal is fixed to 1401.51MHz. Thus, the GPS receiver of the present invention can receive both L1 and L2 bands.

In addition, the GPS receiver of the present invention is provided with a divider for providing a local oscillation frequency corresponding to each of the IF mixer and the AD converter. At this time, by configuring the frequency divider with a frequency divider having a 1/2 frequency division ratio, the size of the GPS receiver can be reduced, and power consumption can be reduced.

Hereinafter, with reference to the accompanying drawings, a specific embodiment according to the present invention will be described in detail the configuration and operation.

2 is a block diagram schematically showing the structure of a GPS receiver according to an embodiment of the present invention. First, referring to the configuration according to the present invention, as shown in Figure 2, the GPS receiver 200 of the present invention, the first low noise amplifier 201, the second low noise amplifier 202, summer 203, RF Mixer 204, IF mixer 205, band pass filter 206, AD converter 207, and phase locked loop 208.

The first low noise amplifier 201 and the second low noise amplifier 202 amplify while minimizing the noise figure of each of the L1 and L2 carrier signals.

The summer 203 outputs each of the amplified L1 and L2 signals from the first low noise amplifier 201 and the second low noise amplifier 202 in one path.

An RF mixer 204 frequency-converts the L1 and L2 carriers input through the summer 203 to an intermediate frequency. According to one embodiment of the invention, the RF mixer 204 is set to output an intermediate frequency having the same frequency value of each of the L1 and L2 carriers. A more detailed description thereof will be described later.

An intermediate frequency (IF) mixer 205 frequency converts the intermediate frequency converted from the RF mixer 204 to the final intermediate frequency. Here, since the IF mixer 205 needs an I / Q (In-phase, Quad-phase: 90 degree phase difference) signal for channel selection and image signal removal, two IF mixers 205 are preferable.

Band pass filter 206 controls the gain of the signal converted from IF mixer 205 and selects a frequency band. At this time, the summer of the output terminal of the band pass filter 206 outputs the I / Q signal in one path.

An analog to digital (AD) converter 207 converts the signal filtered from the band pass filter 206 into a digital signal. The digital signal converted by the AD converter 207 is transmitted to a signal processor (not shown).

A phase locked loop 208 provides a local oscillation frequency corresponding to each of the RF mixer 204, IF mixer 205 and AD converter 207. Here, the phase locked loop 208 divides the oscillation frequency into a local oscillation frequency input to the IF mixer 205 and the voltage adjusting oscillator 209 and the oscillation frequency which are controlled according to a voltage value to provide an oscillation frequency. The apparatus further includes first, second, third and fourth dividers 210, 211, 212, and 213 which divide at the sampling frequency of the converter 207.

At this time, the RF mixer 204 is directly input the oscillation frequency from the voltage regulation oscillator 209, the IF mixer 205, the first and second dividers (210, 211) from the voltage regulation oscillator 209 The oscillation frequency is input through the reference signal, and the oscillation frequency is input to the AD converter 207 through the first, third, and fourth dividers 210, 212, and 213 from the voltage adjusting oscillator 209.

In addition, the first divider 210 has a division ratio of 1/4, the second divider 211 has a divide ratio of 1/2, and the third divider 212 has a 1/32 ratio. The fourth frequency divider 213 has a division ratio of 1/2.

The dispenser according to one embodiment of the present invention is preferably configured as a divider having a dividing ratio of 1/2. Since the frequency divider having a division ratio of 1/2 can be implemented with a simpler circuit than other frequency dividers such as 1/3, 1/5, etc., and power consumption is small, the size of the GPS receiver 200 can be miniaturized. Low power can be achieved. Here, the first divider 210 having a dividing ratio of 1/4 may be implemented by connecting two dividers having a dividing ratio of 1/2 ((1/2) ^ 2 = 1/4). . The third divider 212 may be simply implemented by connecting five dividers having a division ratio of 1/2 ((1/2) ^ 5 = 1/32).

In a variant of the embodiment of the present invention, the phase locked loop is controlled in accordance with a voltage value to provide an oscillation frequency, and a sampling of the oscillation frequency input to the IF mixer and the local oscillation frequency input to the AD converter. First and second dispensing means for dividing at a frequency may be provided.

In this case, the first dispensing means may be composed of first and second dividers, and the second dispensing means may be composed of first, third and fourth dividers.

The first divider has a division ratio of 1/4, the second divider has a divide ratio of 1/2, the third divider has a divide ratio of 1/32, and the fourth divider Has a division ratio of 1/2. The frequency dividers are preferably configured with a frequency divider having a division ratio of 1/2 described above.

Here, the oscillation frequency is directly input from the voltage regulation oscillator to the RF mixer, the oscillation frequency is input to the IF mixer from the voltage regulation oscillator through a first division means, and the AD converter is input from the voltage regulation oscillator to the second. The sampling frequency is input through the dispensing means.

Next, the operation of the GPS according to the present invention will be described. First, the GPS satellite signal is received from the antenna 214, and the band pass filter 215 passes through an L1 band signal having a frequency of 1575.42 MHz and an L2 band signal of 1227.6 MHz. And jamming signals other than the L1 and L2 signals are eliminated.

Thereafter, the L1 and L2 signals filtered through the band pass filter 215 are amplified through the first low noise amplifier 201 and the second low noise amplifier 202, respectively, and then output through a summer 203 through one path. .

Thereafter, the L1 and L2 signals output through the one path are mixed in the RF mixer 204 with an oscillation frequency of 1401.51 MHz output from the voltage adjusting oscillator 209 of the phase locked loop 208 and 173.91 MHz (1575.42-). 1401.51, 1226.7-1401.51).

The converted 173.91 MHz intermediate frequency signal is a 175.189 MHz local oscillation frequency provided from the voltage adjust oscillator 209 of the phase locked loop 208 through a first divider 210 and a second divider 211. And are mixed in the IF mixer 205 and converted to a final intermediate frequency of 1.279 MHz (175.189-173.91).

Thereafter, the gain is controlled in the band pass filter 206 to obtain an output signal of a constant magnitude regardless of the magnitude of the input signal of the final intermediate frequency signal, and at the same time the frequency band is selected.

Thereafter, the 1.279 MHz analog signal output from the band pass filter 206 is first, third and fourth dividers 210, 212 and 213 from the voltage-regulated oscillator 209 of the phase locked loop 208. It is sampled in the AD converter 207 and converted into a digital signal by a sampling frequency of 5.475 MHz provided through.

Here, the digital signal is a signal MAG having magnitude information and a signal SIGN having phase information, and the digital signal is transmitted to a signal processor (not shown).

As such, the technical configuration of the present invention described above can be understood by those skilled in the art that the present invention can be implemented in other specific forms without changing the technical spirit or essential features of the present invention.

Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the detailed description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

As described above, the present invention improves the structure of the GPS receiver to reduce the distance error of the target to a minimum, and has the effect of miniaturizing and lowering the GPS receiver.

1 is a block diagram schematically showing the structure of a general GPS receiver.

2 is a block diagram schematically showing the structure of a GPS receiver according to an embodiment of the present invention.

***** Explanation of symbols for main parts of drawing *****

101, 214: antenna 102: preamplifier

103: frequency synthesizer 104: basic oscillator

105: down converter 106: IF section

107: signal processor 108: application processor

200: GPS receiver 201, 202: low noise amplifier

203: summer 204: RF mixer

205: IF mixer 206, 215: band pass filter

207: AD converter 208: phase locked loop

209: voltage controlled oscillator 210, 211, 212, 213: divider

Claims (10)

A receiver of a dual band Global Positioning System (GPS) for receiving L1 and L2 carrier signals transmitted from satellites, A first low noise amplifier and a second low noise amplifier for amplifying while minimizing a noise figure of the L1 and L2 carrier signals; A summer for outputting each of the amplified L1 and L2 signals from the first low noise amplifier and the second low noise amplifier in one path; A radio frequency (RF) mixer for frequency converting the L1 and L2 carriers inputted through the summer to an intermediate frequency; An intermediate frequency (IF) mixer for frequency converting the intermediate frequency converted from the RF mixer to a final intermediate frequency; A band pass filter controlling the gain of the signal converted from the IF mixer and selecting a frequency band; An analog to digital (AD) converter for converting the signal filtered from the band pass filter into a digital signal; And A phase locked loop providing a local oscillation frequency corresponding to each of the RF mixer, the IF mixer and the AD converter; Including, And the RF mixer is configured to output an intermediate frequency having the same frequency value of each of the L1 and L2 carriers inputted through the summer. The method of claim 1, The phase locked loop A voltage regulated oscillator controlled according to a voltage value to provide an oscillation frequency; And First, second, third, and fourth dividers which divide the oscillation frequency into a local oscillation frequency input to the IF mixer and divide into the sampling frequency of the AD converter; Dual band GPS receiver, characterized in that it further comprises. The method of claim 2, The oscillator frequency is directly input to the RF mixer from the voltage regulation oscillator, The oscillator frequency is input to the IF mixer through the first and second dividers from the voltage regulated oscillator, And the oscillation frequency is input to the AD converter through the first, third and fourth dividers from the voltage adjusting oscillator. The method of claim 2, The first divider has a division ratio of 1/4, The second divider has a division ratio of 1/2, The third divider has a division ratio of 1/32, And the fourth divider has a division ratio of 1/2. The method according to any one of claims 1 to 4, Dual frequency GPS receiver, characterized in that the oscillation frequency output from the voltage-controlled oscillator is 1401.51MHz. The method of claim 1, The phase locked loop A voltage regulated oscillator controlled according to a voltage value to provide an oscillation frequency; And First and second dividing means for dividing the oscillation frequency into a local oscillation frequency input to the IF mixer and a sampling frequency input to an AD converter; Dual band GPS receiver, characterized in that it further comprises. The method of claim 6, The first dispensing means is composed of first and second dividers, And said second divider means comprises first, third and fourth dividers. The method of claim 7, wherein The first divider has a division ratio of 1/4, The second divider has a division ratio of 1/2, The third divider has a division ratio of 1/32, And the fourth divider has a division ratio of 1/2. The method of claim 6, The oscillator frequency is directly input to the RF mixer from the voltage regulation oscillator, An oscillation frequency is input to the IF mixer from the voltage adjusting oscillator through a first division means, And a sampling frequency is input to the AD converter from the voltage adjusting oscillator through a second frequency divider. The method according to any one of claims 6 to 9, Dual frequency GPS receiver, characterized in that the oscillation frequency output from the voltage-controlled oscillator is 1401.51MHz.