Distributed passive radar target detection method under direct wave-free condition

Abstract

The invention discloses a distributed passive radar target detection method under a direct wave-free condition, and belongs to the technical field of distributed passive radar target detection. A conventional passive radar target detection method is based on the classical matched filtering theory, and approximately optimal detection properties can be achieved on premise that a direct wave with a relatively high signal-to-noise ratio can be acquired in real time and an emitted signal can be estimated with high quality by using a direct wave signal received by a reference channel. To solve the problem of detecting a target which cannot receive the direct wave signal in practical, the invention discloses the distributed passive radar target detection method under a direct wave-free condition, and a concentrated target detector under the direct wave-free condition is established, so that target detection can be implemented when the signal-to-noise ratio of the direct wave signal is relatively low or the direct wave signal cannot be received in a multiple-input multiple-output geometric structure, and meanwhile the target matching problem which is very hard to solve among different receiving stations of a distributed passive radar is indirectly avoided.

Description

technical field [0001] The invention belongs to the technical field of distributed passive radar target detection, in particular to a method for distributed passive radar target detection under the condition of no direct wave. Background technique [0002] Many experiments at home and abroad have proved that the passive radar based on the third-party non-cooperative radiation source has good detection potential, and can realize the detection and positioning of small air targets and low-altitude flying targets. In order to further improve target detection stability and tracking continuity, many research institutions in Europe and the United States have carried out research on distributed passive radar technology based on multiple transmission and multiple reception systems of FM, DAB, DVB-T, and GPS signals. [0003] At present, the target detection method of distributed passive radar is based on the classic matched filter theory, that is, using each transmitter-target-receiv...

AI Technical Summary

Problems solved by technology

[0005] However, in distributed passive radar, if the signal-to-noise ratio of the direct wave signal is relatively low, the transmitted signal cannot be estimated with high quality, which will cause a mismatch with the real transmitted signal, the detection performance will decrease, and even the target cannot be detected

Although the effect of mismatch can be mitigated to some extent by channel equalization, it is impossible to completely eliminate the mismatch

In addition, due to the influence of complex terrain environment in practice, if there is physical occlusion in the line-of-sight propagation path between the non-cooperative radiation source and the receiver, the passive radar will not be able to receive the direct wave signal from the non-cooperative radiation source. The target detection cannot be completed by using the classical matched filter theory

Therefore, the target detection method by calculating the cross-ambiguity function or generalized cross-correlation between the received signals of the reference channel and the monitoring channel is not suitable for the situation where the direct wave signal-to-noise ratio is very low or the direct wave signal is not received at all.

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