Coherent navigation radar target enhancement technology based on Doppler processing

Abstract

The invention relates to a coherent navigation radar target enhancement technology based on Doppler processing. Based on a coherent receiver, a reasonable signal processing flow is designed, under thepremise of not changing the working mode comprising an antenna rotating speed and pulse repetition frequency of the existing navigation radar, Doppler processing is performed by using a data buffer area and by using a sliding window FFT method to form a distance-Doppler two-dimensional map, and present ship motion compensation is performed, so that a stationary target is located at a zero Dopplerchannel; then adaptive clutter suppression is performed, such as dynamic clutter of sea clutter and rain clutter; the stationary target and a moving target are respectively extracted and stored according to Doppler characteristics, and finally, echo images of the stationary target and the moving target are adjusted separately and displayed comprehensively by using double threshold detection and overlapping two-color maps. According to the coherent navigation radar target enhancement technology provided by the invention, the target detection capability under the condition of sea clutter is greatly improved by automatically suppressing the clutter, and the high-threat moving target is highlighted to give full play to the superior performance of coherent navigation radars.

Description

Technical field: [0001] The invention relates to the technical field of radar, in particular to a coherent navigation radar signal processing technology. Background technique: [0002] Marine radar is mainly used for detection and tracking of maritime targets, assisting ship navigation and collision avoidance, and ensuring navigation safety. With the increasing complexity of the ship's navigation environment, the performance of marine radar, especially the ability to detect surrounding targets under sea clutter conditions, is directly related to the safety of ship navigation and the safety of people on board. Since 2004, the International Maritime Organization (IMO) began to encourage the use of coherent radars to improve target detection capabilities in severe sea clutter conditions. [0003] Coherence means that the initial phase between radar transmission pulses is deterministic, which is the premise of using the Doppler effect. In order to give full play to the superio...

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Problems solved by technology

However, the prior art marine radar adopts a mechanical scanning antenna with a fixed rotational speed of 24 or 48r / min, and cannot perform beam dwell at a certain position. Due to the need for distance measurement range, the pulse repetition frequency (PRF) is mostly 500 to 2000Hz, and The antenna beam is narrow (usually 0.8° or 1.3°), and the coherent processing is directly performed with N pulses as a group, which will greatly reduce the azimuth scanning accuracy

[0004] The clutter situation faced by marine radar is complex and changeable. Taking sea clutter as an example, the distribution of sea clutter energy along the distance dimension and Doppler dimension is different under different sea conditions, wind speeds, and incident angles. There are literature records, According to Stokes' calculation, the maximum possibility is that the crest of a steady wave is at an angle of 120°. If more energy is supplied to the wave, for example, under the blowing of a strong wind, they will start to break (spray), which is It makes the situation of clutter more complicated and anisotropic, so it is difficult to adopt empirical formula

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