Location method of three-antenna interferometric delay Doppler radar altimeter topographical feature point

Abstract

The invention discloses a three-antenna interference delay Doppler altimeter terrain characteristic point positioning method, which mainly solves the problems of high measurement accuracy and low ground resolution of the existing method. The implementation steps are: establish the echo signal model of the three-antenna interferometric delay Doppler radar altimeter; calculate the noise power estimation and detection threshold of the echo signal; delineate the interference window, and obtain all ground units whose amplitude values ​​are higher than the detection threshold; Select the prominent point and select the ground unit without aliasing; extract the interference phase to obtain the angle between the ground unit and the normal of the antenna array; according to the distance corresponding to the prominent point in the interference window, the special point relative to the normal and the angle between the center of the Doppler channel where the prominent point is located and the heading, and estimate the three-dimensional coordinates of the prominent point. The invention improves the measurement accuracy of the radar altimeter and the resolution in the vertical course direction, can select more prominent points and provide three-dimensional coordinate information, and can be used for positioning the target during terrain matching.

Description

technical field [0001] The invention relates to the field of radar technology, in particular to a method for locating prominent topographic points of a delayed Doppler radar altimeter, which can be used for locating targets during terrain matching. Background technique [0002] The existing inertial guidance methods generally rely on other correction equipment because the accumulated errors will increase with the flight time, and there is no self-correction function. Therefore, using terrain matching navigation system to correct inertial navigation system is a research hotspot at present, and the core of terrain matching navigation system is the altimeter, so higher requirements are put forward for the measurement resolution and measurement accuracy of the altimeter. The measurement accuracy and ground resolution of the traditional radar altimeter are low, but after using delayed Doppler processing, the resolution along the heading direction is improved, but the resolution i...

AI Technical Summary

Problems solved by technology

However, the interferometric delay Doppler radar altimeter system developed by the United States is only a dual-antenna system. Since the echo signals of ground units with equal distances on the left and right sides of the route will overlap in one distance unit, this dual-antenna system is difficult to be effective. Extracting the angle information of the ground unit cannot distinguish the position information of the equidistant ground units on the left and right sides of the route, which in turn affects the improvement of the resolution of the radar altimeter in the direction perpendicular to the heading, resulting in low accuracy of matching and positioning, which cannot meet the requirements of terrain matching. need

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