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CN-120908838-B - GPS deception signal ranging and speed measuring method for improving carrier synchronization loop compensating Doppler

CN120908838BCN 120908838 BCN120908838 BCN 120908838BCN-120908838-B

Abstract

The invention provides a GPS deception signal ranging and speed measuring method for improving carrier synchronization loop compensation Doppler, which firstly utilizes square spectrum to carry out Doppler coarse estimation on a medium-frequency echo signal; then, the accurate Doppler frequency is obtained by using a phase-locked loop, the target speed is estimated, doppler compensation before matching filtering is carried out, the influence of autocorrelation loss caused by Doppler sensitivity on the matching filtering effect is avoided, and finally, the distance measurement precision of the matching filtering is improved by an interpolation method. Simulation experiments show that the method can effectively improve the distance measurement and speed measurement accuracy on the premise of not improving the sampling rate.

Inventors

  • ZHU XUEFEN
  • FENG CHI
  • SHU GUOLIANG
  • TU GANGYI

Assignees

  • 东南大学

Dates

Publication Date
20260505
Application Date
20250804

Claims (4)

  1. 1. The GPS spoofing signal ranging and speed measuring method for improving carrier synchronization loop compensation Doppler is characterized by comprising the following specific steps: (1) Receiving an echo signal, performing down-conversion treatment on the echo, and stripping a modulated carrier wave to obtain an intermediate frequency signal S (t); (2) Dividing the intermediate frequency signal into two channels for processing, respectively measuring the speed and the distance, and obtaining the speed measuring channel by utilizing square spectrum frequency estimation For and re pair Performing Doppler coarse estimation to obtain estimated value ; (3) Determining whether Doppler coarse compensation is needed according to the Doppler coarse estimation result, if the Doppler coarse estimation value is larger than or equal to 1000Hz, carrying out Doppler coarse compensation, and then carrying out Doppler frequency fine estimation by using a phase-locked loop; the step (3) specifically comprises: (3.1) if the Doppler coarse estimation value is more than or equal to 1000Hz, constructing a Doppler frequency offset coarse compensation function according to the estimation value: Multiplying the compensation function with the signal yields: ; Wherein, the Representing the Doppler frequency estimation error; a residual error representing the compensated phase; (3.2) further constructing a carrier synchronization loop based on a phase-locked loop to realize accurate estimation of echo Doppler frequency, wherein the compensated signal is expressed as follows by applying an Euler formula: Wherein, the ; (3.3) To further increase the energy of the signals, respectively And Proceeding with Integration over time, then The individual integration results are: ; ; (3.4) the phase discriminator adopts a four-quadrant arctangent algorithm to perform phase discrimination, and then: , wherein, Is a four-quadrant arctangent function; (3.5) obtaining the Doppler frequency estimation result of the phase-locked loop according to the carrier synchronization result of the phase-locked loop Final if echo signal doppler frequency estimation ; (3.6) If the Doppler coarse estimation value is less than 1000Hz, the Doppler frequency estimation is directly carried out by using the phase-locked loop without FFT Doppler coarse compensation, and the final intermediate frequency echo signal Doppler frequency estimation is carried out at the moment Namely the Doppler frequency estimation result of the phase-locked loop I.e. The expression is: ; (3.7) target speed estimation results The calculation formula is as follows: ; (4) Doppler compensation is carried out on the intermediate frequency echo signals according to the accurate Doppler frequency obtained from the speed measuring channel, and frequency domain zero filling operation is carried out before matched filtering; The step (4) specifically comprises: (4.1) Doppler compensating the received intermediate frequency echo signals, the compensated signals Expressed as: ; (4.2) assume a Doppler-compensated intermediate frequency echo signal Discretized expression as Performing FFT operation on the sample, and then performing zero filling processing on the frequency domain, wherein the zero filling of the frequency domain is equivalent to the intermediate interpolation of the original sampling interval on the time domain; let the discretized matched filter coefficient signal be After FFT processing, the same frequency domain zero filling processing is carried out to ensure that the lengths of the input signal and the matched filter are consistent, the transformed data are correspondingly multiplied, and inverse Fourier transform is carried out to obtain the matched filter processing result And, moreover; ; Wherein, the And Respectively input signals Matched filter coefficients Finally, peak detection is carried out on the incoherent accumulation result to obtain a pseudo code phase, and relatively accurate time delay is obtained according to the pseudo code phase ; (5) And finally, estimating the pseudo code phase through matched filtering, obtaining time delay and calculating a target distance R.
  2. 2. The method for GPS spoofing signal ranging and velocity measurement with improved carrier synchronization loop compensation Doppler of claim 1 wherein step (1) comprises down converting the intermediate frequency echo signal The method comprises the following steps: 。
  3. 3. the method for improving carrier synchronization loop compensation Doppler GPS spoofing signal ranging and velocity measurement of claim 1 wherein in step (2), 。
  4. 4. The method for improving carrier synchronization loop compensation Doppler GPS spoofing signal ranging and velocity measurement of claim 1 wherein in step (5), 。

Description

GPS deception signal ranging and speed measuring method for improving carrier synchronization loop compensating Doppler Technical Field The invention relates to the technical field of wireless communication, in particular to a GPS spoofing signal ranging and speed measuring method for improving carrier synchronization loop compensation Doppler. Background With the continuous development of aircraft system technology, various low-altitude aircrafts grow exponentially in number, and the occurrence of potential safety hazards caused by black flight of unmanned aerial vehicles frequently occurs. In order to cope with the threat of illegal use of unmanned aerial vehicles to public security and personal privacy, the development of anti-unmanned aerial vehicle systems has become a very important research field. The method is used for interfering with the GNSS navigation system of the unmanned aerial vehicle, and is one of research hotspots for unmanned aerial vehicle reaction. GNSS interference mainly includes jamming and spoofing. The pressed interference mainly transmits high-power interference signals to directly cause the target receiver to be out of lock, and normal capturing, tracking and positioning resolving functions cannot be realized. The deception jamming mainly is to forward satellite navigation signals or generate counterfeit satellite navigation signals, so that a target receiver cannot distinguish real signals from jamming signals, and the power advantage is utilized to mislead the target receiver to obtain wrong position information according to the deception jamming signals. The suppressed interference is easily found because the signal transmission power is high and the receiver is directly unlocked. In contrast, rogue interference is more covert. In the navigation interference detection integrated system based on the GNSS deception signal, detection of the target is realized mainly by receiving the deception signal echo and performing signal processing. Since GNSS signals are not converted into detection signals designed by a radar, it is necessary to study a ranging and speed measuring algorithm suitable for detecting GNSS spoofed signal targets. In a low-altitude detection scene, strong clutter interference often exists in the environment, and the target speed is quite low and the echo is quite weak in many cases, so that a clutter suppression algorithm suitable for low-speed weak target detection under the condition of low signal-to-clutter ratio needs to be researched. When the GNSS deception signal is used for ranging and speed measuring, the ranging and speed measuring precision is mainly limited by the signal sampling rate. In addition, if the moving target speed is high, a large autocorrelation loss is brought, and a matching filter mismatch problem is generated, so that accurate ranging cannot be performed. In practical engineering application, due to factors such as hardware performance and operand, it is often difficult to improve accuracy by increasing the sampling rate. Disclosure of Invention In order to solve the technical problems, the invention provides a GPS spoofing signal ranging and speed measuring method for improving carrier synchronization loop compensation Doppler, which can improve the ranging and speed measuring precision without increasing the sampling rate, and the ranging error and the speed measuring error are obviously smaller than those of the conventional method. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the GPS spoofing signal ranging and speed measuring method for improving carrier synchronization loop compensation Doppler comprises the following specific steps: (1) Receiving the echo signal, performing down-conversion treatment on the echo, and stripping the modulated carrier wave to obtain an intermediate frequency signal S (t); (2) Dividing the intermediate frequency signal into two channels for processing, respectively measuring the speed and the distance, and obtaining the speed measuring channel by utilizing square spectrum frequency estimation For and re pairPerforming Doppler coarse estimation to obtain estimated value; (3) Determining whether Doppler coarse compensation is needed according to the Doppler coarse estimation result, if the Doppler coarse estimation value is larger than or equal to 1000Hz, carrying out Doppler coarse compensation, and then carrying out Doppler frequency fine estimation by using a phase-locked loop; (4) Doppler compensation is carried out on the intermediate frequency echo signals according to the accurate Doppler frequency obtained from the speed measuring channel, and frequency domain zero filling operation is carried out before matched filtering; (5) And finally, estimating the pseudo code phase through matched filtering, obtaining time delay and calculating a target distance R. Further, in step (1), the intermediate frequency echo signal after down-conversionTh