Complex Environment Of A Small Target Signal Detection And Tracking Technology

Targets detected by radars are mostly moving objects, such as aircrafts and ships; and around them are often varieties of clutters cause by ground objects, clouds and rain, sea waves, and sometimes chaffs sent by enemies.Studies are made on the technologies of detecting weak signals of small targets in the background of strong sea clutters, as well as the ways of tracking highly maneuverable targets with small SNR and low detection probability, so as to facilitate reliable detection and stable tracking of small, maneuverable targets in strong sea clutters.The grid method is adopted as the algorithm for target detection. The result of CFAR processing is achieved through the setting of the factor of the CFAR. Flags are given to those CFAR cells that satisfy the threshold requirement and the cells are forwarded for the follow-up range and bearing detections in which the M/N start and end criteria are employed.Three algorithms, which are respectively theα-βalgorithm, the Kalman filtering algorithm, and the Interactive Multiple Mode (IMM) algorithm, are studied; and comparisons are made among them. Results show that the decisions of theαand theβare not easily made for theα-βalgorithm; whereas the Kalman filtering algorithm is capable of providing the filtering covariance matrix and the maneuverability that are not possessed by the a-p algorithm. Besides, for the IMM algorithm, the varieties of the dynamic system can be precisely described by one of the M different models within a given period.Simulations are carried out through Matlab for the three algorithms; and comparisons are made between the results of filtering processing and prediction. It is found that relatively big error exists between the filtered point and the predicted one for theα-βalgorithm; the typical Kalman filtering algorithm also has the weak points as difficulties in factor optimization and criteria judgment for maneuvers; and the IMM algorithm features to be robust, capable of making automatic judgment for maneuvers and fusions for judgment results, and having less parameters that need to be adjusted, making the tracking results better.