A Method for Initial Alignment of Aerial Mobile Base of Strapdown Inertial Navigation System

Abstract

The invention discloses a method for initial alignment of an aerial base of a strapdown inertial navigation system. The steps are: based on the difference between the calculated speed of the strapdown inertial navigation system and the speed measured by GNSS as a set of quantities, a speed measurement equation is established; The angular motion constraint model of the aircraft, based on the angular velocity calculated by the strapdown inertial navigation system, establishes the angular velocity virtual measurement equation, and during the air movement of the aircraft, the angular motion mode is discriminated in real time to determine whether it is in a non-angular motion state; When it is detected that the aircraft is in a state of non-angular motion, the established angular velocity constraint model is introduced, and the virtual measurement equation of angular velocity and the velocity measurement equation are combined for measurement update; when the aircraft is detected to be in a state of angular motion, only the velocity measurement equation is used. Measurement update. The present invention improves the comprehensive performance of the airborne strapdown inertial navigation system in air alignment accuracy, rapidity and the like under various maneuvering situations without adding auxiliary sensors.

Description

technical field [0001] The invention belongs to the technical field of inertial navigation, and in particular relates to a method for initial alignment of a movable base. Background technique [0002] For the carrier using GNSS / INS integrated navigation, if the GNSS information in the integrated navigation system can be fully utilized to initialize the inertial navigation system, the system's dependence on the carrier can be reduced and autonomous alignment can be achieved. Due to different carrier tasks and environments, it is often necessary to complete the initial alignment under different maneuvers: the initial alignment of some systems such as the targeting pod system needs to be achieved during the ground startup or take-off phase, and the maneuvering methods are strictly limited; some systems ( Such as aircraft) If a fault occurs during navigation and needs to be restarted, the initial alignment needs to be completed under high dynamic flight conditions in the air. I...

AI Technical Summary

Problems solved by technology

At present, the research on assisted navigation with kinematic constraints is mostly aimed at the situation where the carrier is moving on the ground. However, due to the existence of the angle of attack and sideslip angle of the aircraft flying in the air, even when the aircraft is flying straight, the lateral and vertical coordinates of the body coordinate The direction velocity is also not zero, and the conditions such as speed constraints and altitude constraints in ground motion are no longer applicable in the air

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