scholarly journals Relative Velocity Measurement with Spectrometer and Its Integrated Navigation

2018 ◽  
Author(s):  
Zhonghua Wang ◽  
Yiming Peng ◽  
Jiu Liu
Keyword(s):  
Velocity Measurement ◽  
Relative Velocity ◽  
Large Error ◽  
Formation Flight ◽  
Time Of Arrival ◽  
Relative Navigation ◽  
Integrated Navigation ◽  
Satellite Links ◽  
Navigation Method ◽  
Pulsar Navigation

In order to enhance the accuracy of the relative velocity measurement for the Mars explorer formation flight, we develop a relative velocity measurement method. In this method, the spectrometers at two Mars explorers are adopted to measure the starlight frequency shift and to estimate the velocity with respect to the star. Unfortunately, the instantaneous velocity of star can not be predicted accurately, which results in a large error in the velocity measurement. The difference of these two velocities, which does not include the proper motion of star, is the relative velocity between a pair of Mars explorers at the direction of the star. However, this navigation method can not work alone because of unobservability. To make the navigation system observable and improve the accuracy of both absolute and relative navigation for the Mars explorer formation flight, we combine it with X-ray pulsar navigation and the inter-satellite links, and propose an autonomous integrated navigation method with observability. In this integrated navigation scheme, the extended Kalman filter is adopted to deal with the relative velocity, the inter-satellite links and the pulse time-of-arrival, and estimate the absolute and relative navigation information for the Mars explorer formation flight. The simulation results demonstrate that both absolute and relative navigation accuracy of the proposed method are higher than that of the pulsar navigation, especially the relative one.

Extended Kalman Filtering and its Application to Intelligent Missile Formation Flight Mechanics

2013 ◽  
Vol 387 ◽  
pp. 193-196
Author(s):  
Xu Zhang ◽  
Nai Gang Cui ◽  
Xiao Gang Wang
Keyword(s):  
Formation Flight ◽  
Flight Mechanics ◽  
Line Of Sight ◽  
Relative Navigation ◽  
Extended Kalman Filtering ◽  
Vision Navigation ◽  
Simulation Results ◽  
Navigation Equipment ◽  
Navigation Information ◽  
Navigation Method

Aimed at the needs of intelligent missile cooperative engagement mission, a relative navigation method based on INS/Vision is presented, and the relative inertial equation between leader missiles and attack ones is derived. The line of sight measurement is acquired by observing the beacons on the attack ones using the vision navigation equipment on the leader missiles. The extended Kalman filter is used to estimate the relative attitude, relative velocity and relative position by fusing the inertial navigation information and the line of sight measurement. Simulation results verify the effectiveness of the relative navigation method. Improve the estimated accuracy of missile in formation flight mechanics.

Closed-loop EKF-based Pulsar Navigation for Mars Explorer with Doppler Effects

2014 ◽  
Vol 67 (5) ◽  
pp. 776-790 ◽  
Author(s):  
Jin Liu ◽  
Jiancheng Fang ◽  
Xiaolin Ning ◽  
Jin Wu ◽  
Zhiwei Kang
Keyword(s):  
State Estimation ◽  
Prior Information ◽  
Closed Loop ◽  
Estimation Error ◽  
Measurement Model ◽  
Time Of Arrival ◽  
X Ray ◽  
Doppler Effects ◽  
Navigation Method ◽  
Pulsar Navigation

To eliminate the impact of the Doppler effects caused by the motion of the Mars explorer, a novel X-ray pulsar navigation method based on a closed-loop filter is proposed. In the pulsar signal observation period, the Doppler velocity predicted by the orbit dynamic model and the prior information is utilised to compensate the X-ray photon time-of-arrival (TOA). However, because of the error in prior information, there is a bias caused by the Doppler compensation in the pulse time-of-arrival. The pulse TOA bias and the Mars explorer's state estimation error are correlated, which results in the decline of the Kalman filter performance. To deal with this problem, we build the TOA measurement model with respect to the state estimation error, and utilise the closed-loop extended Kalman filter (EKF) as the navigation filter, where the predicted state error is adopted as the state estimation. The simulation results demonstrate the feasibility, real-timeliness and effectiveness of the proposed navigation method. The navigation method based on the closed-loop EKF using the measurement model with the Doppler effects is more accurate than the traditional one.

scholarly journals MEMS Based SINS/OD Filter for Land Vehicles’ Applications

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Huisheng Liu ◽  
Zengcai Wang ◽  
Susu Fang ◽  
Chao Li
Keyword(s):  
Navigation System ◽  
Velocity Measurement ◽  
Microelectromechanical Systems ◽  
Low Cost ◽  
Detection Algorithm ◽  
Measurement Unit ◽  
Integrated Navigation ◽  
Integrated Navigation System ◽  
Land Vehicles ◽  
Mems Imu

A constrained low-cost SINS/OD filter aided with magnetometer is proposed in this paper. The filter is designed to provide a land vehicle navigation solution by fusing the measurements of the microelectromechanical systems based inertial measurement unit (MEMS IMU), the magnetometer (MAG), and the velocity measurement from odometer (OD). First, accelerometer and magnetometer integrated algorithm is studied to stabilize the attitude angle. Next, a SINS/OD/MAG integrated navigation system is designed and simulated, using an adaptive Kalman filter (AKF). It is shown that the accuracy of the integrated navigation system will be implemented to some extent. The field-test shows that the azimuth misalignment angle will diminish to less than 1°. Finally, an outliers detection algorithm is studied to estimate the velocity measurement bias of the odometer. The experimental results show the enhancement in restraining observation outliers that improves the precision of the integrated navigation system.

scholarly journals VISUAL-BASED INTEGRATED NAVIGATION SYSTEM APPLIED TO A SIMULATION OF LUNAR MODULE LANDING

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 305-313
Author(s):  
C. T. Kuo ◽  
Y. T. Tien ◽  
K. W. Chiang
Keyword(s):  
Lunar Surface ◽  
Navigation System ◽  
Poor Performance ◽  
Initial Position ◽  
Relative Navigation ◽  
Integrated Navigation ◽  
Space Technology ◽  
Integrated Navigation System ◽  
Lunar Landing ◽  
Landing Module

Abstract. With the development of space technology, more and more lunar researches are performed by different countries. For the lunar landing mission success, the lunar landing module should equip with advanced Positioning and Orientation System (POS) for the navigation requirements. For the pinpoint landing mission formulated by NASA, a good POS with error less than 100 meters is needed in order to make the lunar module land safely at the exact destination on lunar surface. However, the existing technologies for lunar navigation, such as satellite positioning and star tracker, have poor performance for the navigation requirements. The visual-based positioning technology is an alternative way to make sure a lunar landing module reaches the destination. There are two types of visual-based positioning technology, absolute and relative navigation. The relative navigation system can provide the solution at a higher rate, but the error would accumulate over time. On the contrary, the absolute navigation could provide an initial position or updates of position and attitude for relative navigation. Thus, the integrated navigation system from those two methods can take advantage of both stand-alone systems. On the other hand, the Inertial Navigation System (INS) can help it overcome the disadvantage that the images much closer to the lunar surface are not available. This study shows an integrated navigation system that integrates a visual-based navigation system and an INS, which is implemented in a simulated lunar surface.

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