Abstract:

For the detection of the weak bearing line in the bearings vs. time record in passive sonar system, the distribution of the measurements is derived under the noise only and target present conditions respectively. Then a bearing only trajectory detector based on the hidden Markov model (HMM) is given. Meanwhile, two methods based on sequential detection are proposed to automatically decide the start point and the end point of the trajectory. These two methods fully use the distribution characteristic of the measurements and the continuity of the trajectory and performe much better than the conventional energy detection. The detection performance is improved by about 3 dB, the estimating precision of the trajectory is improved and the probability of the false alarm is low. The real experiment data verify the effectiveness of the detector when there is a single target.