Airborne distributed POS transfer alignment method based on relative strapdown calculation

Abstract

The invention discloses an airborne distributed POS transfer alignment method based on relative strapdown calculation, and aims to improve airborne distributed POS spatial motion information measurement precision in a dynamic environment. The method comprises the steps: a pseudo single subsample rotation vector is constructed by utilizing angular velocities output by gyroscopes at the current andprevious N sampling moments of a main subsystem and a rotation vector error compensation coefficient derived based on conical motion, and a relative attitude quaternion is solved in real time based onthe rotation vector to realize relative attitude updating; meanwhile, a relative speed and position updating algorithm is established according to the space position vector relation of the main subsystem, and relative speed and position updating is achieved through the output specific force and the relative posture of an accelerometer of the main subsystem; and finally, a transfer alignment statemodel and a measurement model are established based on the relative strapdown calculation error differential equation and the three-dimensional relative position and the three-dimensional relative attitude measured by a fiber bragg grating, and transfer alignment is carried out by adopting a linear Kalman filtering estimation method to obtain high-precision motion information.

Description

technical field [0001] The invention relates to an airborne distributed POS transfer alignment method based on relative strapdown calculation, which belongs to the field of aviation remote sensing, can improve the measurement accuracy of airborne distributed POS motion information and is applied to distributed imaging such as flexible baseline array antenna SAR Motion compensation of loads. Background technique [0002] The Distributed Position and Orientation System (DPOS) is an important device for airborne high-resolution earth observation systems to obtain motion parameters such as multi-node positions, speeds, and attitudes. The composition of distributed POS mainly includes a high-precision main position and attitude measurement system (main POS), multiple low-precision sub-inertial measurement units (Inertial Measurement Unit, IMU), a navigation computer and a set of post-processing software. The main POS is composed of high-precision main IMU and Global Navigation S...

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Problems solved by technology

[0004] The present invention aims at the technical problem of non-exchangeability error caused by flexible deformation of airborne distributed POS, and provides an airborne distributed POS transfer alignment method based on relative strapdown solution. The method does not increase the sampling frequency at the same time , can reduce non-exchangeability errors, improve relative strapdown solution accuracy, and improve measurement accuracy of multi-node motion parameters of distributed imaging loads such as flexible baseline array antenna SAR

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