CN109541650B - Long-period pseudo-random sequence local synchronization code generation method and device - Google Patents
Long-period pseudo-random sequence local synchronization code generation method and device Download PDFInfo
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- CN109541650B CN109541650B CN201811523389.2A CN201811523389A CN109541650B CN 109541650 B CN109541650 B CN 109541650B CN 201811523389 A CN201811523389 A CN 201811523389A CN 109541650 B CN109541650 B CN 109541650B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
- G01S19/13—Receivers
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/30—Acquisition or tracking or demodulation of signals transmitted by the system code related
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/7075—Synchronisation aspects with code phase acquisition
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Abstract
The invention discloses a method and a device for generating a long-period pseudo-random sequence local synchronous code, which solve the problem of long synchronization time of a long code. The method comprises the following steps: acquiring satellite external input data comprising local time, local position and ephemeris parameters; obtaining satellite position coordinates of satellite signal receiving time as receiving positions through local time and ephemeris parameters; obtaining a transmitting position from the receiving position; calculating according to the transmitting position and the local position to obtain satellite signal propagation time, and calculating according to the satellite signal propagation time and the local time to obtain satellite on-board time; respectively inputting satellite time to a clock generation unit and a long code generation unit to obtain a long code stream extraction clock and a long code initial phase; and inputting the long code stream extraction clock to the long code generation unit to obtain a local long code signal. The device comprises a processor, a clock generation unit and a long code generation unit. The invention has short synchronization time of long code, simple equipment and easy realization.
Description
Technical Field
The invention relates to the field of satellite navigation, in particular to a method and a device for generating a long-period pseudo-random sequence local synchronization code.
Background
GPS and Beidou satellite navigation systems are spread spectrum communication systems based on code division multiple access, and signals of the system are transmitted to the ground after being modulated by a data code, a pseudo-random sequence code (also called pseudo code below) and a carrier wave in a three-level mode. GPS, big dipper signal all contain two kinds of forms's pseudo-code: a normal ranging code with a short period of 1ms and a long code with a long period of 7 days. The long code rate is 10.23Mcps, the repetition period is 7 days, and when a local synchronization code is generated, if chip shifting is performed every 1ms, pseudo code synchronization can be achieved only after 10.23e6x 7x0.001 is 71610 days. The source of satellite time in the existing long code pseudo code synchronization technology comprises internal data calculation and external data direct calculation, and the method obtained by internal data calculation has the defects of long calculation time, long capture time and incapability of meeting the rapid time requirement of navigation positioning; in the existing method for directly obtaining satellite time through external data, the external data is complex and difficult to obtain.
Disclosure of Invention
The invention provides a method and a device for generating a long-period pseudo-random sequence local synchronous code, which solve the problem of long code synchronization time of the conventional method and device.
A long-period pseudo-random sequence local synchronization code generation method comprises the following steps: acquiring satellite external input data comprising local time, local position and ephemeris parameters; obtaining a satellite position coordinate at the satellite signal receiving moment as a receiving position according to the local time and the ephemeris parameters and a satellite orbit calculation method; obtaining the satellite position coordinate of the satellite signal transmitting time from the receiving position as a transmitting position; calculating according to the transmitting position and the local position to obtain satellite signal propagation time as the difference between the transmitting position and the local position and dividing the satellite signal propagation time by the light speed; calculating according to the satellite signal propagation time and the local time to obtain satellite on-satellite time as the difference between the local time and the satellite signal propagation time; inputting the satellite time to a clock generating unit and a long code generating unit respectively to obtain a long code stream extraction clock and a long code initial phase; and inputting the long code stream extraction clock to the long code generation unit to obtain a local long code signal.
Preferably, the transmitting location and the receiving location are equal in value.
Preferably, the ephemeris parameters are GPS ephemeris parameters or beidou ephemeris parameters.
A long-period pseudo-random sequence local synchronization code generation device is used for the method and comprises the following steps: the device comprises a processor, a clock generation unit and a long code generation unit; the processor is used for receiving the external input data of the satellite and calculating to obtain the satellite on-board time; the clock generating unit is used for receiving the satellite time and generating the long code stream extraction clock; the long code generating unit is used for receiving the satellite time and long code stream extraction clock and outputting the local long code signal.
Further, the processor is realized by an ARM or a DSP.
Further, the clock generation unit is implemented by a programmable logic device.
Preferably, the long code generating unit is implemented by using a dedicated chip.
The beneficial effects of the invention include: the long-period pseudo-random sequence local synchronous code generation method provided by the invention adopts an external data input mode to calculate the on-satellite time, and further generates the local synchronous code, so that the pseudo code synchronization time is greatly shortened; compared with other pseudo code time synchronization modes adopting external data, the method adopts the current local time, the local position and the GPS ephemeris parameters as the external data, can be obtained by other satellite observation equipment, is simple and feasible in implementation method, and can be used for quickly capturing the GPS and Beidou satellite signal long codes by a satellite navigation receiver.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a flowchart of an embodiment of a method for generating a long-period pseudo-random sequence local synchronization code;
fig. 2 is an embodiment of a long-period pseudo-random sequence local synchronization code generation apparatus.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
GPS and Beidou satellite navigation systems are spread spectrum communication systems based on code division multiple access, and signals of the system are transmitted to the ground after being modulated by a data code, a pseudo-random sequence code (also called pseudo code below) and a carrier wave in a three-level mode. The pseudo code belongs to the second level of GPS and Beidou signals, and the satellite navigation receiver can obtain the data code only after carrier and pseudo code synchronization is carried out, so as to carry out navigation positioning calculation. GPS, big dipper signal all contain two kinds of forms's pseudo-code: a normal ranging code with a short period of 1ms and a long code with a long period of 7 days. The common ranging code consists of 1023 chips, the code is repeated every 1ms, and if chip movement is carried out every 1ms when the local synchronization code is generated, the pseudo code synchronization can be realized for 1.023s at the longest, and the short-time satellite signal searching process can be accepted for navigation positioning application. The long code rate is 10.23Mcps, the repetition period is 7 days, when a local synchronization code is generated, if chip shifting is performed every 1ms, pseudo code synchronization can be realized only after 10.23e6x 7x0.001 ═ 71610 days, and the navigation positioning application cannot wait for the long-time signal search process.
The technical solutions provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.
Fig. 1 is a flow embodiment of a long-period pseudo-random sequence local synchronization code generation method, which is used to implement local synchronization of a long-period pseudo-random sequence code, and as an embodiment of the present application, a long-period pseudo-random sequence local synchronization code generation method includes the following steps:
In step 101, the ephemeris parameters are GPS ephemeris parameters or beidou ephemeris parameters. It should be noted that the ephemeris parameters may be GPS ephemeris parameters or beidou ephemeris parameters in the embodiment of the present invention, or ephemeris parameters of other navigation systems, which is not limited herein.
And step 102, obtaining a satellite position coordinate at the satellite signal receiving moment as a receiving position according to the local time and the ephemeris parameters and a satellite orbit calculation method.
In step 102, the satellite orbit calculation method is prior art and is not specifically described here.
And 103, obtaining the satellite position coordinate of the satellite signal transmitting time from the receiving position as a transmitting position.
In step 103, the transmitting position and the receiving position are equal in value, i.e. the receiving position is equal to the transmitting position.
In step 103, since the orbit height of the satellite is higher than 2 kilometres, the propagation speed of the satellite signal is about 3 × 108And m/s, the time delay of the satellite signal reaching the local satellite navigation receiver is less than 100 milliseconds according to the formula that the time is equal to the distance divided by the speed. Since the maximum satellite motion speed is about several kilometers per second, and the signal propagation delay caused by the satellite position coordinate change is less than 4 microseconds in 100 milliseconds, in the calculation of the transmitting position in the embodiment of the present invention, the change amount of the satellite position coordinate in the propagation delay from the transmitting time of the satellite signal to the time when the satellite navigation receiver receives the satellite signal is ignored.
In step 103, since the propagation path delay caused by the ionosphere, the convection current, and the earth rotation is within 1 microsecond, the variation of the satellite position coordinates in the propagation path delay caused by the ionosphere, the convection current, and the earth rotation is ignored when calculating the transmitting position.
And 104, calculating according to the transmitting position and the local position to obtain satellite signal propagation time which is the difference between the transmitting position and the local position divided by the light speed.
In step 104, the difference between the transmit position and the local position is a distance between a satellite navigation receiver and a satellite.
And 105, calculating according to the satellite signal propagation time and the local time to obtain satellite on-satellite time as the difference between the local time and the satellite signal propagation delay.
And step 106, respectively inputting the satellite time to a clock generation unit and a long code generation unit to obtain a long code stream extraction clock and a long code initial phase.
In step 106, the clock generation unit is a programmable logic device, the long code generation unit is a dedicated chip, and a method for obtaining the long code stream extraction clock and the long code initial phase through the satellite time is the prior art and will not be described herein.
And 107, inputting the long code stream extraction clock to the long code generation unit to obtain a local long code signal.
In step 107, the local long code signal is generated by the long code generating unit under the action of the long code stream extraction clock, and the generation method is the prior art and will not be described repeatedly here.
In the method for generating the long-period pseudo-random sequence local synchronous code provided by the embodiment of the invention, the local code signal and the pseudo-random sequence in the satellite navigation signal adopt the same on-satellite time, so that the local code signal and the pseudo-random sequence are synchronous.
Fig. 2 is an embodiment of a long-period pseudo-random sequence local synchronization code generation apparatus, configured to generate a local synchronization code by using the long-period pseudo-random sequence local synchronization code generation method, where as an embodiment of the present application, the long-period pseudo-random sequence local synchronization code generation apparatus includes: processor 1, clock generation unit 2, long code generation unit 3.
The processor is used for receiving the external input data of the satellite and calculating to obtain the satellite on-board time; the clock generating unit is used for receiving the satellite time and generating the long code stream extraction clock; the long code generating unit is used for receiving the satellite time and long code stream extraction clock and outputting the local long code signal.
The long code generating unit receives the satellite on-satellite time and generates a long code signal, and the long code signal generates the local long code signal under the action of the long code stream extraction clock.
As an embodiment of the present invention, the long code generating unit is implemented by using a dedicated chip, and a process of generating the local long code signal by the long code generating unit is the prior art and will not be described herein.
As an embodiment of the present invention, the processor is implemented by an ARM or a DSP, and it should be noted that the processor is used for obtaining satellite time through calculation by inputting data from outside the satellite, and the processor may be the ARM or the DSP in the embodiment of the present invention, or may be other devices capable of performing calculation, such as a single chip, and is not limited herein.
As an embodiment of the present invention, the clock generation unit is implemented by using a programmable logic device, and it should be noted that the clock generation unit is used to generate a long code stream extraction clock, and the clock generation unit may be a programmable logic device in the embodiment of the present invention, such as an FPAG, or other devices, and is not limited herein.
The long-period pseudo-random sequence local synchronization code generation device provided by the embodiment of the invention realizes the long-period pseudo-random sequence local synchronization by adopting an external data input mode, and has the advantages of short code synchronization time, simple equipment and easy realization.
It is to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (6)
1. A long-period pseudo-random sequence local synchronization code generation method is characterized by comprising the following steps:
acquiring satellite external input data comprising local time, local position and ephemeris parameters;
obtaining a satellite position coordinate at the satellite signal receiving moment as a receiving position according to the local time and the ephemeris parameters and a satellite orbit calculation method;
obtaining a satellite position coordinate of the satellite signal transmitting time from the receiving position as a transmitting position, wherein the receiving position is equal to the transmitting position;
calculating according to the transmitting position and the local position to obtain satellite signal propagation time as the difference between the transmitting position and the local position and dividing the satellite signal propagation time by the light speed;
calculating according to the satellite signal propagation time and the local time to obtain satellite on-satellite time as the difference between the local time and the satellite signal propagation time;
inputting the satellite time to a clock generating unit and a long code generating unit respectively to obtain a long code stream extraction clock and a long code initial phase;
and inputting the long code stream extraction clock to the long code generation unit to obtain a local long code signal.
2. The method for generating long-period pseudo-random sequence local synchronization codes according to claim 1, wherein the ephemeris parameters are GPS ephemeris parameters or beidou ephemeris parameters.
3. A long-period pseudo-random sequence local synchronization code generation device, for use in the method of any one of claims 1-2, comprising: the device comprises a processor, a clock generation unit and a long code generation unit;
the processor is used for receiving the external input data of the satellite and calculating to obtain the satellite on-board time;
the clock generating unit is used for receiving the satellite time and generating the long code stream extraction clock;
and the long code generating unit is used for receiving the satellite time and the long code stream extraction clock and outputting the local long code signal.
4. The apparatus of claim 3, wherein the processor is implemented using an ARM or DSP.
5. The long-period pseudo-random sequence local synchronization code generation apparatus of claim 3, wherein the clock generation unit is implemented using a programmable logic device.
6. The apparatus of claim 3, wherein the long code generating unit is implemented by a dedicated chip.
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| CN114252893B (en) * | 2020-09-21 | 2025-07-11 | 千寻位置网络有限公司 | Software receiver and positioning method for GNSS carrier phase differential positioning |
| CN113009527B (en) * | 2021-02-23 | 2024-09-27 | 湖南中森通信科技有限公司 | Universal satellite navigation pseudo code generation method |
| CN116318501A (en) * | 2022-12-29 | 2023-06-23 | 北京无线电计量测试研究所 | A method and system for calculating correlation peaks of long-code two-way time-frequency comparison signals |
| CN119828181A (en) * | 2024-12-30 | 2025-04-15 | 北京无线电计量测试研究所 | Processing method and system for low-orbit satellite opportunistic signal pseudo-range difference observed quantity |
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| US6188351B1 (en) * | 1998-08-13 | 2001-02-13 | Ericsson Inc. | Method for improving signal acquistion in a global positioning system receiver |
| US8660574B2 (en) * | 2008-04-02 | 2014-02-25 | Qualcomm Incorporated | Generic positioning protocol |
| US8334806B2 (en) * | 2009-10-15 | 2012-12-18 | Qualcomm Incorporated | Methods and apparatuses for responding to a request for satellite positioning system related information associated with a mobile station |
| CN102073053B (en) * | 2010-12-20 | 2012-10-03 | 东莞市泰斗微电子科技有限公司 | Pseudo random noise code generation unit of multi-mode GNSS (global navigation satellite system) receiver |
| CN102520423B (en) * | 2011-12-06 | 2013-06-19 | 成都金本华科技有限公司 | Rapid capturing method for Circuit for rapidly capturing long period pseudo random spread spectrum code of satellite navigation receiver and capturing method thereof |
| CN104460427B (en) * | 2014-10-31 | 2017-01-25 | 上海卫星工程研究所 | Integrated electronic system for modular microsatellite platform |
| CN104749588B (en) * | 2015-03-30 | 2017-02-01 | 北斗羲和科技发展（北京）有限公司 | Method for realizing realtime synchronization with Beidou system to generate pseudo satellite signals |
| CN106341361B (en) * | 2016-11-07 | 2019-09-27 | 杭州电子科技大学 | Multi-carrier synchronization method and system for nested cyclic PN sequence |
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