Method and system for improving isolation degree of long-distance echo and short-distance clutter of harmonic radar

Abstract

The invention provides a method and a system for improving the isolation degree of long-distance echo and short-distance clutter of a harmonic radar. The method comprises the steps: employing frequency and time coding modulation, and forming an excitation signal according to a designed code element sequence for amplification and transmission; carrying out frequency mixing and filtering on the harmonic receiving signal by using a reference signal, suppressing a carrier frequency and digitalizing, and obtaining a vector reflecting a target distance by using the harmonic channel; recovering a phase sequence of elements in the vector according to a frequency sequence corresponding to a designed code element sequence, and performing power spectrum estimation; and performing weighting according to the power spectrum, and using large weights for the pre-polymerization points exceeding the clutter map more; target information of the harmonic channel is obtained through power weighted target cluster aggregation; and each harmonic is respectively processed to finally obtain target multi-harmonic information. According to the method and the system for improving the isolation degree of the long-distance echo and the short-distance clutter of the harmonic radar, the isolation degree between the long-distance target echo and the short-distance clutter of the harmonic radar is greatly improved.

Description

Technical field[0001]The present invention relates to the field of near-field nonlinear target harmonic radar detection techniques, and in particular, to improving harmonic radar long-distance echo and close clutter isolation method, system.Background technique[0002]Harmonic radar first transmits a specially designed waveform, irradiated to a nonlinear target, and then detects the reclaimed harmonic signal characteristics after the nonlinear target after the waveform excitation, and realizes an internal nonlinear node containing a semiconductor node and a metal node. Features This type of objective detection and positioning. Harmonic radar has excellent anti-wire clutter performance than conventional linear radar. It can be widely used in defense, security, public security, transportation and urban construction.[0003]The long-distance target echoes received by the harmonic radar must have a certain isolation to separate the higher distance from the target from the near-range clutter...

AI Technical Summary

Problems solved by technology

[0006] 1. When the time-sharing technology of sending and receiving is applied to harmonic radar, it is constrained by the conversion speed of sending and receiving, and it is difficult to realize nonlinear target detection within tens of meters.

The propagation speed of electromagnetic waves in the air is close to 300,000 kilometers per hour, which is equivalent to a two-way delay of about 150 meters in 1 microsecond. In order to realize the time-sharing work of sending and receiving within tens of meters, it is necessary to realize the conversion of transmission and reception in the order of picoseconds. This presents great difficulties in engineering, thus limiting the application of this technology;

[0007] 2. When the time-sharing technology of sending and receiving is applied to harmonic radar, since the receiver is in a non-receiving state during the transmission period, it is impossible to achieve strong target detection within the corresponding distance of the transmission time window, resulting in a distance blind zone, and it is impossible to achieve close range Super clutter detection for strong target echo signals within range

[0008] In view of the related technologies mentioned above, the inventor believes that the method of improving the isolation between long-distance target echoes and short-distance clutter by using traditional time-sharing technology for sending and receiving is not applicable in the field of harmonic radar. Therefore, a technical solution needs to be proposed To improve the above technical problems

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