Research on joint calibration and compensation of the inclinometer installation and instrument errors in the celestial positioning system

Abstract

The application of celestial navigation based on inclinometer to aircraft in nearearth space and planetary rovers is a significant development direction. Due to the installation and instrument errors of the inclinometer, it is difficult for tilted platforms to obtain high-precision positioning results. But the installation error of the inclinometer is coupled with the error of the instrument itself, and there is no effective way to measure the two errors separately. To improve the positioning accuracy of the tilted platform, a joint calibration and compensation algorithm of the inclinometer's installation and instrument errors is proposed.First, based on the principle of celestial positioning, the influence analysis model of the inclinometer error on the positioning accuracy is built according to the definition of inclinometer installation error and instrument error, which indicates the traditional algorithms are not suitable for tilted platforms. Then, a joint calibration and compensation algorithm for the inclinometer installation and instrument errors is presented based on coordinate transformation relationship and error propagation characteristics. Finally, a ground test platform is built and the experimental verification of the joint calibration and compensation algorithm of inclinometer error is accomplished. Experiment results show the root mean square errors of the longitude and latitude are 0.00309 ∘ and 0.00283 ∘ , and the mean distance error is 397.46 m, which is far less than the mean distance error 3629.27 m of the traditional calibration algorithm.

Optical system design method of the all-day starlight refraction navigation system

“…For the star sensor, the FOV is divided into two parts, namely the non-refracted region and refracted region, which meet the needs of attitude calculation and position calculation respectively, as shown in Figure 3. In Figure 3a, the subscript t represents the northeast coordinate system, and the solar zenith angle is 0°in this paper [20]. The tangent height of the refracted star ranges from 20 km to 50 km.…”