Research On Cooperative Acoustic Beacon Signals Processing Under Doppler Conditions And Engineering Implementation

The underwater high-speed moving target measurement system usually installs the cooperative acoustic beacon on the target.When the target is sailing,the cooperative acoustic beacon transmits the signals according to the specific signal system,and accomplishes the measurement task of the target’s trajectory with other measuring units.For the detection of cooperative acoustic beacon signals,the copy correlation method with good robustness and stable signal-to-noise ratio gain is often used in engineering.However,for high-speed moving targets,Doppler effect is very serious.The adoption of copy correlation algorithm will not only lead to the decrease of signal processing gain and affect signal detection,but also the deviation of correlation peak location will lead to biased time delay estimation.Therefore,the subsequent target positioning accuracy is affected.In view of the problems existing in the above copy correlation method,this paper studies the core algorithm of cooperative acoustic beacon signal processing under severe Doppler influence,and uses DSP software for engineering implementation,and tests the performance of DSP software of this system through laboratory and lake tests.Aiming at the Doppler problem of underwater moving targets,a Doppler model is constructed,the Doppler estimation technology based on broadband signal fuzzy function and double pulse delay difference is studied,and the Doppler estimation algorithm based on narrowband pulse frequency is mainly studied,including the frequency estimation algorithm based on FFT interpolation and the frequency estimation algorithm based on phase difference correction,the principle of the algorithm is analyzed in detail,and the performance simulation is verified.Aiming at the detection and delay estimation of pulse signals in Doppler environment,this paper studies the principle of copy correlation algorithm and performs performance simulation,and analyzes the influence of Doppler on the performance of signals detection and delay estimation.In this paper,a signal detection and delay estimation algorithm based on Doppler correction is proposed,the acoustic beacon signal system is first designed,and then the specific implementation process of the algorithm is given,and the performance simulation verification is carried out,the influence of signal-to-noise ratio and multipath effect on the performance of Doppler estimation is discussed,and the performance of signal detection and delay estimation before and after Doppler correction is compared and analyzed.The simulation results show that the modified algorithm proposed in this paper can effectively improve the performance of the signal detection and delay estimation algorithm in Doppler environment.On the basis of theoretical analysis,the algorithm designed in this paper is engineering and implemented on DSP signal processing software.The signal processing software is based on the TL-5728 development board,mainly including inter-core communication,control instructions and signal processing three functional modules,which can realize data interaction with the underwater data acquisition cabin and the display and control platform,and can process the received signals in real time and execute the instructions issued by the display and control platform,and upload the signal processing results and the execution of the instructions.Finally,after laboratory joint debugging and lake test tests,it is verified that the real-time signal processing software designed in this paper can realize the robust detection and accurate delay estimation of cooperative acoustic beacon signals under the severe influence of Doppler,and has engineering practicability.