CN111694023A - Satellite navigation anti-interference receiving processing method based on despreading and despreading - Google Patents
Satellite navigation anti-interference receiving processing method based on despreading and despreading Download PDFInfo
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- CN111694023A CN111694023A CN202010513931.7A CN202010513931A CN111694023A CN 111694023 A CN111694023 A CN 111694023A CN 202010513931 A CN202010513931 A CN 202010513931A CN 111694023 A CN111694023 A CN 111694023A
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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
- G01S19/21—Interference related issues ; Issues related to cross-correlation, spoofing or other methods of denial of service
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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
- G01S19/35—Constructional details or hardware or software details of the signal processing chain
- G01S19/37—Hardware or software details of the signal processing chain
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Abstract
The invention discloses a satellite navigation anti-interference receiving processing method based on despreading, which is characterized in that signal sampling and adaptive space-time filtering processing are carried out on signals to obtain optimal weight vectors aiming at different satellites, after the optimal weight vectors are respectively applied to carry out beam forming on the received signals, the main lobe of a directional diagram points to the corresponding satellite signals, so that high gain of expected signals is realized, and the suppression of interference signals and noise is completed. Then, each wave beam output by the multi-beam anti-interference module is respectively captured, tracked and resolved by a navigation message, and a despreading part is completed. And re-spreading the spectrum to generate baseband signals of each path of satellite according to the time delay of each satellite signal obtained by de-spreading, and finishing a re-spreading part, wherein the noise and the interference in the generated satellite baseband signals are suppressed. And finally, all the signals are synthesized into a comprehensive signal, so that the comprehensive signal can be conveniently input into a receiver module for positioning calculation, and the anti-interference receiving of the satellite navigation signal is realized.
Description
Technical Field
The invention relates to a satellite navigation anti-interference receiving processing method, and belongs to the technical field of array signal processing
Background
The global navigation satellite system utilizes an artificial satellite to transmit navigation signals, and a receiver realizes positioning by receiving a plurality of satellite signals, thereby providing all-weather high-precision timing positioning and navigation services. Due to the susceptibility of satellite navigation systems to interference, research on anti-interference techniques is actively being conducted in many countries. At present, the most effective interference suppression technology, i.e. the beam forming technology, also called as the spatial filtering technology, is to achieve the purposes of enhancing the desired signal and suppressing interference and noise by adaptively weighting the input signals of each array element on the basis of obtaining the signal space parameters.
The blind beamforming technology is a research hotspot in the technical field of radio anti-interference in recent years, because prior knowledge such as the arrival direction of a desired signal is not required to be known, and beamforming processing is performed on a received signal only by using sampling data and a known antenna array structure to achieve optimal reception of the desired signal. The beam forming algorithm based on the signal cyclostationarity characteristic and the beam forming algorithm based on the signal constant modulus characteristic are the most common, but because the satellite signal is very weak and the sample data size cannot tend to be infinite in practice, the performance of the two methods is greatly reduced. In 2005, m.g.amin et al proposed a SCORE algorithm based on a satellite period repetition characteristic, but the obtained array weighting vector is only suitable for the case where an array antenna receives 1 satellite signal, and cannot meet the actual requirement. 2013 Ludan et al propose an anti-interference algorithm based on single-channel single-delay cross-correlation processing and an improved algorithm thereof, the method can generate a plurality of beams pointing to satellite signals, but array manifold information is needed when estimating the direction of the satellite signals, and when the array has errors, the algorithm performance is affected. An improved de-despreading anti-interference algorithm based on the characteristics of satellite signals is provided by Wuren Biao in 2017, and the carrier-to-noise ratio of the satellite signals can be effectively improved.
Note that the above algorithms each separately calculate L satellite signals to obtain L weighting vectors, and the following processing mainly includes two ways: one is that the weighting vectors corresponding to L satellites are directly superposed to act on the received signal and sent to a rear-end satellite navigation receiving module to realize positioning, but in this way, because the weighting vectors are directly superposed, noise aliasing can be caused, and antenna gain brought by array signal processing is counteracted; and the other method is that the anti-interference module is embedded into the receiver, the L satellites are respectively captured, tracked and resolved according to the obtained weighted vectors, and then the resolved results are comprehensively transmitted to the positioning module to realize positioning. The method can not cause noise aliasing, but needs to be transplanted to the internal structure of the traditional receiver, and can not ensure the stability of the satellite navigation receiving system.
Disclosure of Invention
The invention overcomes the defects of the prior art and provides a satellite navigation anti-interference receiving processing method based on despreading.
The technical solution of the invention is as follows:
an anti-interference receiving processing method for satellite navigation based on despreading is characterized in that an anti-interference processing module is added between signals received by an antenna array and a positioning calculation receiver, wherein the anti-interference processing module comprises a multi-beam anti-interference algorithm module and a despreading and despreading module. Firstly, the optimal weight vector of beam forming is calculated for each satellite signal by using a multi-beam anti-interference algorithm, and the received array signals are respectively subjected to beam forming, so that each path of satellite signals with interference and noise suppressed can be obtained. Then, each path of satellite signal output by the multi-beam anti-interference algorithm is de-spread and re-spread, each path of regenerated satellite signal is superposed to synthesize a path of comprehensive signal, and the comprehensive signal is input to a subsequent satellite navigation receiving part to realize accurate positioning.
The antenna array receives the satellite navigation signal and transmits the satellite navigation signal to the radio frequency circuit.
The radio frequency circuit sequentially amplifies, filters and down-converts the signals, and then transmits the generated intermediate frequency signals to the anti-interference processing part.
Firstly, signal sampling and adaptive space-time filtering processing are carried out on signals by using a multi-beam anti-interference receiving algorithm to obtain optimal weight vectors aiming at different satellites, after the optimal weight vectors are respectively applied to carry out beam forming on the received signals, the main lobe of a directional diagram points to the corresponding satellite signals, so that high gain of expected signals is realized, and meanwhile, the suppression of interference signals and noise is completed. Then, each wave beam output by the multi-beam anti-interference module is captured, tracked and resolved by a navigation message, and a despreading part is completed. And re-spreading to generate baseband signals of each satellite according to the information of time delay, Doppler frequency offset, navigation messages and the like of each satellite signal obtained by despreading, and completing a re-spreading part, wherein noise and interference in the generated satellite baseband signals are suppressed. And finally, synthesizing all the signals into a comprehensive signal, and facilitating the subsequent input into a receiver module for positioning calculation.
And sending the re-expanded synthesized satellite signal to a satellite navigation receiver part, and outputting a positioning result. Therefore, the anti-interference receiving of the satellite navigation signals is realized.
(1) The anti-interference receiving processing method designed by the invention is independent from the satellite navigation resolving part, the anti-interference processing is not required to be embedded into the navigation positioning resolving in the receiver, intermediate frequency digital signals are transmitted among modules, the integrity and the stability of the satellite navigation resolving part of the subsequent receiver are ensured, and meanwhile, the anti-interference receiving processing part also has better transportability.
(2) The anti-interference processing module applies the output result of the multi-beam algorithm, respectively applies the corresponding optimal weight vectors to the L satellite signals for beam forming, respectively performs de-spreading and re-expanding processing, and compares the mode that a plurality of optimal weight vectors are directly superposed to perform beam forming on the array signals, so that the problems of noise superposition and carrier-to-noise ratio reduction are avoided, and the carrier-to-noise ratio performance improvement obtained by the anti-interference algorithm is effectively reserved.
(3) According to the invention, the optimal weight vector of the L satellite signals is calculated respectively, and each satellite signal is captured and tracked according to the calculation result, so that interference can be effectively inhibited, gain is formed in the direction of an expected signal, a good anti-interference effect is still achieved when a certain satellite is exactly positioned in the same direction as the interference signals of other satellites, and the performance of an anti-interference algorithm of a receiver is improved.
Drawings
FIG. 1 is a schematic diagram of a complete receiving system according to the present invention
FIG. 2 is a design structure diagram of the anti-interference processing part of the present invention
FIG. 3 is a detailed view of the design of the re-expanded portion of the present invention
Detailed Description
As shown in fig. 1, the complete schematic diagram of the receiving system specifically includes: the system comprises an antenna array, a radio frequency module, an anti-interference processing module and a satellite navigation receiving module. The anti-interference processing module consists of a multi-beam anti-interference algorithm module and a de-spreading and re-spreading module. The anti-interference processing module and the subsequent satellite navigation receiving module are mutually independent.
The antenna array is responsible for receiving satellite navigation signals and transmitting the satellite navigation signals to the radio frequency module. The radio frequency module sequentially amplifies, filters and down-converts the signals, and then transmits the generated intermediate frequency signals to the multi-beam anti-interference module. The multi-beam anti-interference receiving module performs signal sampling and adaptive space-time filtering processing on signals to obtain optimal weight vectors aiming at different satellites, after the optimal weight vectors are respectively applied to beam forming of the received signals, the main lobe of a directional diagram points to the corresponding satellite signals, high gain of expected signals is achieved, and meanwhile suppression of interference signals and noise is completed. Then, in the de-spreading and re-spreading module, each wave beam output by the multi-beam anti-interference module is respectively captured, tracked and resolved by a navigation message, and a de-spreading part is completed. And re-spreading to generate baseband signals of each satellite according to the information of time delay, Doppler frequency offset, navigation messages and the like of each satellite signal obtained by despreading, and completing a re-spreading part, wherein noise and interference in the generated satellite baseband signals are suppressed. And synthesizing the baseband satellite signals subjected to the L-path re-expansion into a path of comprehensive signal, inputting the path of comprehensive signal into a satellite navigation receiving module, carrying out capturing, tracking and positioning resolving on the satellite navigation signal again inside the satellite navigation receiving module, and outputting a positioning result to realize anti-interference receiving of the satellite navigation signal.
As shown in fig. 2, the anti-interference processing module performs multi-beam anti-interference processing, performs beam forming on the L satellite signals according to the calculation result, respectively captures, tracks, and re-expands each beam output, and finally outputs a re-expanded baseband signal, specifically:
taking the ith satellite as an example for explanation, the optimal weighting generated after the signal is processed by the multi-beam anti-interference algorithm is assumedVector is WoptThe signal vector received by each array element at a certain time is Xi(k) Then, the output signal after beamforming is:
at this time, a main lobe is formed in the direction of the desired signal, and nulls are formed in the directions of the noise and the interference, so that the desired satellite signal is preserved and the interference signal and the noise component are suppressed.
And sequentially capturing and tracking the output signals, and solving the corresponding Doppler frequency offset, time delay and navigation message data codes. And sent to the signal re-expansion link.
As shown in fig. 3, a corresponding C/a code is generated according to the PRN code of the received satellite signal and the navigation message value demodulated accordingly, and the C/a code is delayed according to the delay information so as to be consistent with the received phase. Meanwhile, due to relative motion between the satellite and the receiver, Doppler frequency shift and code phase drift exist in the signal actually received by the receiver, so the Doppler frequency shift is added when the carrier wave is generated, and the code phase drift is considered when the C/A code is generated. And multiplying the three sampling points to obtain the baseband signal of the satellite.
The above operations are performed on L satellites, and the obtained baseband signals of the satellites are added to generate a combined satellite signal from which interference and noise are removed.
And transmitting the generated baseband satellite signal to a subsequent satellite navigation receiver part, respectively capturing, tracking and positioning the conventional satellite navigation signal, and outputting a positioning result.
Example (b):
the antenna array adopts an 8-element uniform linear array, after 8 paths of radio frequency signals are received, the amplification, filtering and down-conversion of the signals are completed through a radio frequency channel, and 8 paths of digital intermediate frequency signals are formed after high-precision AD sampling. The FPGA carries out multi-beam anti-interference calculation on the received signals, the number of satellites in the received signals is set to be 4, 4 sub-beams are respectively generated for 4 satellites after a multi-beam anti-interference link, 4 paths of intermediate frequency digital signals are generated after beam forming is respectively carried out, despreading processes of capturing and tracking are respectively carried out, and time delay, Doppler frequency offset and navigation messages corresponding to 4 satellite signals are solved. And then, respectively carrying out re-spreading according to the information to obtain baseband signals from which noise and interference components are removed. And adding the baseband signals generated by the 4 satellites together to obtain satellite signals for positioning, inputting the satellite signals into a subsequent satellite navigation receiving module, and finally outputting a positioning result through capturing, tracking and positioning resolving.
The anti-interference processing method designed by the invention is independent from satellite navigation receiving calculation, the integrity and stability of the satellite navigation receiving module are ensured, and meanwhile, the anti-interference receiving module also has stronger transportability. By applying the calculation result of the multi-beam anti-interference output, the despreading and despreading module respectively performs weighting and beam forming on the optimal weight vectors of the L satellite signals, so that the problems of noise superposition and carrier-to-noise ratio reduction caused by direct superposition of the weighted vectors of a plurality of beam forming are avoided, and the carrier-to-noise ratio performance improvement obtained by an anti-interference algorithm is effectively reserved. Meanwhile, when the incoming direction of a certain satellite is exactly the same as the incoming direction of an interference signal of another satellite, if the signals after beam forming are directly superposed, the main lobe and the null are superposed, so that the interference suppression effect is greatly weakened.
Claims (3)
1. A satellite navigation anti-interference receiving processing method based on despreading is characterized in that an anti-interference processing module is added between signals received by an antenna array and a positioning calculation receiver, wherein the anti-interference processing module comprises a multi-beam anti-interference algorithm module and a despreading and despreading module, the multi-beam anti-interference algorithm is firstly used for calculating the optimal weight vector of beam forming for each satellite signal, the received array signals are respectively subjected to beam forming, so that each path of satellite signals with interference and noise suppressed can be obtained, then each path of satellite signals output by the multi-beam anti-interference algorithm are respectively subjected to despreading and despreading, and the regenerated satellite signals are superposed to synthesize a path of comprehensive signal, and then the comprehensive signal is input to a subsequent satellite navigation receiving part to realize accurate positioning.
2. The method of claim 1, wherein the antenna array receives the satellite navigation signal and transmits the satellite navigation signal to the radio frequency circuit.
3. The satellite navigation anti-interference receiving processing method based on despreading according to claim 1, wherein the radio frequency circuit sequentially performs amplification, filtering and down-conversion of the signal, and then transmits the generated intermediate frequency signal to the anti-interference processing section.
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| CN117452446A (en) * | 2023-12-26 | 2024-01-26 | 中国人民解放军国防科技大学 | Anti-interference processing architecture based on satellite navigation signal bi-component fusion application |
| CN113433575B (en) * | 2021-07-16 | 2024-05-31 | 广东省南方航天港科技有限公司 | Method, device, equipment, system and storage medium for positioning radiation source |
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