INS/CNS Deeply Integrated Navigation Method of Near Space Vehicles.

Rongjun Mu,Naigang Cui,Yuntian Li,Hongchi Sun

doi:10.3390/s20205885

Abstract

Celestial navigation is required to improve the long-term accuracy preservation capability of near space vehicles. However, it takes a long time for traditional celestial navigation methods to identify the star map, which limits the improvement of the dynamic response ability. Meanwhile, the aero-optical effects caused by the near space environment can lead to the colorization of measurement noise, which affects the accuracy of the integrated navigation filter. In this paper, an INS/CNS deeply integrated navigation method, which includes a deeply integrated model and a second-order state augmented H-infinity filter, is proposed to solve these problems. The INS/CNS deeply integrated navigation model optimizes the attitude based on the gray image error function, which can estimate the attitude without star identification. The second-order state augmented H-infinity filter uses the state augmentation algorithm to whiten the measurement noise caused by the aero-optical effect, which can effectively improve the estimation accuracy of the H-infinity filter in the near space environment. Simulation results show that the proposed INS/CNS deeply integrated navigation method can reduce the computational cost by 50%, while the attitude accuracy is kept within 10” (3 ). The attitude root mean square of the second-order state augmented H-infinity filter does not exceed 5”, even when the parameter error increases to 50%, in the near space environment. Therefore, the INS/CNS deeply integrated navigation method can effectively improve the rapid response ability of the navigation system and the filtering accuracy in the near space environment, providing a reference for the future design of near space vehicle navigation systems.

Highlights

Near space refers to the airspace 20 to 100 km above the surface [1]
Simulation results show that the proposed INS/CNS deeply integrated navigation method can reduce the computational cost by 50%, while the attitude accuracy is kept within 10” (3 σ)
The Smithsonian Astrophysical Observatory (SAO) catalog was used for simulation validation, first-order corrections, and polar shiftwere correction was by the International where precession and nutation compensated forprovided by the IAU1980 model, aberration only Earth Rotation first-order corrections, and polar shift correction was provided by the International Earth

Summary

Introduction

Near space refers to the airspace 20 to 100 km above the surface [1]. Near space vehicles can cruise at a high speed in both the atmosphere and space. Near space vehicles have been widely applied in space transportation, remote penetration, and so on, due to their advantages relating to launch costs and re-usability, among others [2,3]. Near space vehicles fly so fast that attitude errors can greatly affect their position accuracy [6,7]. As the most accurate navigation method [8,9,10], celestial navigation is helpful for improving the long-term accuracy preservation capability of near space vehicles [11]. Celestial navigation calculates the attitude of aircraft by measuring stars which are firmly fixed in the inertial space, such that navigation error does not accumulate with time. Star sensors are widely used in modern celestial navigation systems, which capture images of stars and calculate the attitude according to the star point locations [12].

Methods

Results

Conclusion