Height Measurement Simulation Research On Interference Delay Doppler Radar Altimeter

The radar altimeter was originally used to measure the height of the ground.After many years of development,the altimeter was also widely used in other fields,one of which was used in terrain-aided navigation systems.Aircrafts such as cruise missiles have made increasingly higher demands on inertial navigation systems.In order to improve its positioning accuracy,the using of terrain aided navigation to modify the inertial navigation system has become the research emphasis in many countries,and it is the key core to obtain the terrain height information.Therefore the measurement accuracy and resolution of radar altimeter are given a higher demand.However,in some areas with complex terrain,the altitude measurement and resolution of conventional methods have a lower precision,and the accuracy of terrain matching cannot be met.Therefore,a new interferometric delay doppler radar altimeter is proposed to improved its measurement accuracy and ground resolution.The research work of this thesis mainly includes the following: firstly,in the basis of existing delay doppler radar altimeter,this thesis proposes to add two receiving antennas in the direction of its vertical heading,and a vertical heading one-dimensional interferometric delay doppler radar altimeter is formed.So that it has the ability to measure the interferometric angular.By interfering the echo signals of the three antennas,the lateral angle measurement capability of the receiving antenna array can be used to obtain the angle information of the ground unit with respect to the vertical heading,and then the position and height information of the ground unit can be obtained.The accuracy of altitude measurement and the resolution of vertical heading were improved,and the three-dimensional location method of terrain feature points was given.Then,in the basis of vertical heading one-dimensional interferometric altimeter,this thesis adds another receiving antenna along the heading direction to form a two-dimensional interferometric delay doppler radar altimeter,so that the angle of the ground unit with respect to the heading direction can be obtained.And then,using these two angles of information,the 3D coordinate information of the ground unit can be accurately calculated.This further improves the altimeter's resolution along the heading and the high accuracy and this thesis gives the specific terrain feature point at this time three-dimensional coordinate positioning method.Finally,this thesis introduces some radar parameters which can influence interference delay doppler radar altimeter such as vertical heading resolution,heading resolution,and measurement accuracy,at the same time,an example of system parameter design of interferometric delay doppler radar altimeter based on the terrain matching accuracy is given in the thesis.Through computer simulation experiments,the correctness of the vertical heading one-dimensional interferometric delay doppler altimeter topography method and the two-dimensional interferometric delay doppler altimeter topography measurement method are verified,and the altimeter measurement performance under complex terrain conditions is improved.The measurement performance lays a good theoretical foundation for the engineering research of terrain matching navigation system based on interferometric delay doppler altimeter.