Method for designing MINS/GPS ultra-tight integrated navigation system

Abstract

The invention provides a MINS / GPS ultra-tight integrated navigation system design method. The method comprises the following steps of carrying out time-space difference by using carrier phase measurement to obtain a measurement equation, calculating Doppler frequency shift, assisting a GPS carrier tracking loop PLL, smoothing a pseudo-range outputted by a GPS by using carrier phase measurement, and carrying out Taylor expansion of the pseudo-range; and taking the obtained pseudo-range difference and speed difference as measurement of a system model, designing a combined Kalman filter to estimate a system state, correcting inertial device errors and the strapdown inertial navigation calculation navigation information by utilizing a state estimation result outputted by the Kalman filter, andtaking the corrected strapdown inertial navigation calculation information as the navigation positioning result. The method is advantaged in that the Doppler auxiliary errors caused by low-precisionSINS are avoided, correlation between GPS measurement errors and SINS speed errors is avoided, dynamic performance, the anti-interference capability and the navigation positioning precision of the system are enhanced, and non-linear errors introduced by linear pseudo-range measurement are overcome.

Description

technical field [0001] The invention relates to the technical field of combined navigation, in particular to a design method of MINS / GPS ultra-tight combination. Background technique [0002] Global Positioning System (GPS) and Strapdown Inertial Navigation System (SINS) are highly complementary. The SINS / GPS integrated navigation system has the advantages of both systems, and can overcome the shortcomings of each system at the same time. It is one of the main forms of integrated navigation technology at present and plays a very important role in aviation, space navigation and weapon guidance. Compared with the SINS / GPS loose and tight integrated navigation system, the SINS / GPS ultra-tight integrated navigation system adds assistance to the GPS receiver, has higher dynamic performance and anti-interference ability, and is gradually becoming the first choice of SINS / GPS integrated navigation. The main research direction. [0003] According to the different implementation fo...

AI Technical Summary

Problems solved by technology

[0005]The main problem of the SINS / GPS ultra-tight combination system based on SINS-assisted GPS is that if a low-level SINS is used, the When there is interference, the Doppler auxiliary error introduced by SINS will increase rapidly. When the Doppler auxiliary error is large and the tracking loop does not have enough bandwidth margin to track it, the GPS measurement error will be related to the SINS error. This kind of correlation will lead to the reduction of the estimation accuracy of the combined filter, the loss of the tracking loop, and even the instability of the system

In addition, the system uses pseudo-range and pseudo-range rate as measurements, and the measurement error is relatively large. In a highly dynamic or strong interference environment, a large number of model errors will be introduced, resulting in the decline or even divergence of navigation results.

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