Multi-chip DSP System for Active Sonar Detecting Low-speed Small Targets

The active sonar equipped on underwater moving platform such as autonomous undersea vehicle(AUV) is easily affected by clutter when it works in shallow water, which makes it hard to detect low-speed small targets. In this paper, the detecting system uses binary phase-shift keying(BPSK) waveform to reduce the clutter. To conquer the high computing burden of BPSK waveform, a signal processor composed of 6 high performance digital signal processor(DSP) chips is used in this paper, and a processing algorithm suitable for the hardware platform is designed, and the software is optimized in real time. Real-time test result shows that the system can complete the processing of one frame of echo data within 160 ms when the pulse width is 200 ms. Lake test verifies that the system can detect the transponder which is pre-arranged at 1 360 m, with a speed of 1 kn and a target strength of 3 dB. Test results show that the detecting system can effectively detect low-speed small targets in complex underwater environment in real time.