A Time-Space Difference GPS/Sins Ultra-Compact Integrated Navigation Method

Abstract

The invention belongs to the technical field of integrated navigation, and relates to a time-space difference GPS / SINS supercompact integrated navigation method. The time-space difference GPS / SINS supercompact integrated navigation method comprises the steps that output information of a strapdown inertial navigation system is used for forecasting a time-space difference observed value of a carrier angular speed error and a time-space difference observed value of an initial phase error; output information of a GPS receiver is used for calculating a time-space difference observed value of the carrier angular speed error and a time-space difference observed value of the initial phase error; subtraction is carried out on the time-space difference observed values of the carrier angular speed error and the time-space difference observed values of the initial phase error obtained in the first step and the second step to serve as measurement of a system model; a kalman filter is used for estimating the state of the system, and an inertial element error and navigation information resolved by the strapdown inertial navigation system are corrected through the estimation result; Doppler shift is calculated through the corrected navigation information, is input to the receiver and is corrected. The time-space difference GPS / SINS supercompact integrated navigation method improves the navigation accuracy of the system, and reduces the calculation amount and complexity of the system.

Description

technical field [0001] The invention belongs to the technical field of integrated navigation, and relates to a GPS / SINS ultra-tight combination method of time-space difference. Background technique [0002] The integrated navigation system composed of Global Positioning System (GPS, Global Positioning System) and Strapdown Inertial Navigation System (SINS, Strapdown Inertial Navigation System), has become an important branch of integrated navigation system due to its good complementary advantages. GPS / SINS integrated navigation system can be divided into: loose combination, tight combination and super tight combination according to the combination method. Compared with loose combination and tight combination, ultra-tight combination is a deeper fusion of GPS and SINS information. The fusion result can not only correct the inertial device, suppress the accumulation of errors, but also correct the parameters of the receiver and improve its ability to track satellite signals. ...

AI Technical Summary

Problems solved by technology

[0005] (1) There is a model error: when using the expectations of I and Q as the modeling bridge, the model does not reflect the functional relationship between I, Q itself and the error parameters, so the model cannot accurately describe the relationship between the receiver and SINS

[0006] (2) Poor real-time performance: I and Q are sine / cosine functions, so that the measurement equation contains sine / cosine function items, and the system model has strong nonlinearity

Such a model has higher requirements on the filtering algorithm, and the amount of calculation increases, which makes the system lose its real-time performance.

[0007] (3) There is a time error residual: the signal from the satellite to the receiver not only propagates at the speed of light in a vacuum, but also passes through the ionosphere and troposphere, resulting in a delay error, and there is also a clock error between the satellite and the receiver

The existing ultra-tight combination model compensates these errors by modeling them, but the compensation results are not ideal, and there are still error residues, which will lead to a decrease in positioning accuracy

At the same time, this part of the error residual is affected by atomic clock frequency drift, sunspot activity and meteorological changes, and cannot be accurately obtained through measurement or modeling, which increases the uncertainty of the system

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