Topographic special point positioning method for three-antenna interference delay Doppler radar altimeter

Abstract

The invention discloses a topographic special point positioning method for a three-antenna interference delay Doppler radar altimeter, and mainly solves a problem that a conventional method is lower in height measurement precision and ground resolution. The method comprises the steps: establishing an echo signal model of the three-antenna interference delay Doppler radar altimeter; calculating a noise power estimation and detection threshold of an echo signal; delineating an interference window, and obtaining all ground units whose amplitude values are greater than the detection threshold; selecting a special point, and selecting a ground unit without aliasing; extracting an interference phase, and obtaining an inclined angle of the ground unit relative to the normal of an antenna array; and estimating the three-dimensional coordinates of the special point according to a distance corresponding to the special point in the interference window, the inclined angle of the ground unit relative to the normal of the antenna array and an inclined angle between the center of a Doppler channel where the special point is located and the heading direction. The method improves the height measurement precision of the radar altimeter and the resolution in a direction perpendicular to the heading direction, can obtain more special points and gives the three-dimensional coordinate information, and can be used for locating a target during topographical 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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