Improving the Strapdown Airborne Vector Gravimetry by a Backward Inertial Navigation Algorithm.

Ruihang Yu,Meiping Wu,Minghao Wang,Juliang Cao,Kaidong Zhang,Shaokun Cai

doi:10.3390/s18124432

Ruihang Yu, Meiping Wu + Show 4 more

Open Access

https://doi.org/10.3390/s18124432

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Abstract

Strapdown airborne gravimetry is an efficient way to obtain gravity field data. A new method has been developed to improve the accuracy of airborne vector gravimetry. The method introduces a backward strapdown navigation algorithm into the strapdown gravimetry, which is the reverse process of forward algorithm. Compared with the forward algorithm, the backward algorithm has the same performance in the condition of no sensor error, but has different error characteristics in actual conditions. The differences of the two algorithms in the strapdown gravimetry data processing are presented by simulations, which show that the two algorithms have different performance in the horizontal attitude measurement and convergence of integrated navigation filter. On the basis of detailed analysis, the procedures of accuracy improvement method are presented. The result of this method is very promising when applying to an actual flight test carried out by a SGA-WZ02 strapdown gravimeter. After applying the proposed method, the repeatability of two gravity disturbance horizontal components were 1.83 mGal and 1.80 mGal under the resolution of 6 km, which validate the effectiveness of the method. Furthermore, the wavenumber correlation filter is also discussed as an alternative data fusion method.

Highlights

The information of Earth’s gravity field is important in geophysics, geodesy, resource exploration, etc. [1]
The classical optimal smoothing mainly improves the convergence of filtering, while the forward backward fusion in the proposed method improves the accuracy of filtering, and takes advantage of the different characteristics between forward and backward inertial navigation algorithms to improve the accuracy of attitude measurement [29]
Using the method of strapdown vector gravimetry shown in the former section, we could get the result of airborne gravimetry

Summary

Introduction

The information of Earth’s gravity field is important in geophysics, geodesy, resource exploration, etc. [1]. The information of Earth’s gravity field is important in geophysics, geodesy, resource exploration, etc. In order to accurately determine the information of the gravity field, there are several methods, such as satellite gravimetry, airborne gravimetry, shipborne gravimetry and ground gravimetry [2]. The satellite gravimetry can achieve the task of determination high precision global gravity field, but it cannot obtain the gravity information in the high frequency band. The ground gravimetry is the initial and the most classical method to survey the gravity field, the shortcoming of which is inefficiency and confined to the terrain. Just as its name, uses a ship to measure the gravity field information. Among all the gravity measurement methods, airborne gravimetry is an effective method to collect high precision and high resolution large areas gravity field datum [3]

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Discussion

Conclusion