Radar altimeter assistance method aiming to inertial navigation

Abstract

The invention provides a radar altimeter assistance method aiming to inertial navigation. In the method, a measurement quantity is constructed in the manner of calculating earth core altitude of an air vehicle according to position vectors outputted by the inertial navigation, calculating earth core altitude minus earth ellipsoidal radius to obtain the calculated altitude height of the air vehicle, obtaining observed altitude height by means of a measurement value from the radar altimeter with other algorithms, and calculating altitude height minus the observed altitude height to obtain a difference as the measurement quantity, and finally deriving a total differential equation of the measurement quantity. The invention provides a particular embodiment, wherein a strapdown inertial navigation / radar altimeter combined navigation system is formed on the basis of the measurement quantity. Estimation on position error status quantity is achieved, diffusion of position error is inhibited and positioning precision is increased through an indirect method Kalman filtering with feedback compensation.

Description

(1) Technical field [0001] The invention provides a radar altimeter auxiliary method for inertial navigation, belongs to the field of navigation, and provides an effective method for improving the navigation and positioning accuracy of aircraft. (2) Background technology [0002] As a completely autonomous navigation system, the basic principle of inertial navigation is to use the rotation and translation information of the sensitive carrier of the gyroscope and accelerometer, and complete the calculation of the attitude, speed and position of the aircraft through formula programming. It has continuous output, strong reliability, It has obvious advantages such as high short-term accuracy, but it also has the disadvantage that the error diverges with time. [0003] A radar altimeter is an active distance sensor. Radar has different systems, such as lidar or radio radar, to measure the distance between the aircraft and a target object. With the rapid development of guidance, ...

AI Technical Summary

Problems solved by technology

[0004] How to improve navigation accuracy during autonomous flight has always been a hot research issue. The combination of inertial navigation and star sensors is a commonly used autonomous navigation solution. Improving the accuracy of the reference coordinate system of the inertial navigation system and reducing the cross-coupling effect of the accelerometer can reduce the speed and position errors caused by the acceleration integration method to a certain extent, but it cannot fundamentally solve the divergence problem of the speed and position errors

Inertial navigation can also be combined with GPS. GPS positioning results have no drift error, but GPS is usually not considered to be a completely autonomous navigation method, and the combination of the two is not a completely autonomous navigation method.

Images