scholarly journals Implementation of a Differential Geometric Filter for Spacecraft Formation Orbit Estimation

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Shu Ting Goh ◽  
Ossama Abdelkhalik ◽  
Seyed A. (Reza) Zekavat
Keyword(s):  
Kalman Filter ◽  
Convergence Rate ◽  
Extended Kalman Filter ◽  
Positioning System ◽  
Absolute Position ◽  
Spacecraft Formation ◽  
Stability Performance ◽  
Local Positioning System ◽  
The Absolute ◽  
Orbit Estimation

The differential geometric filter is implemented to estimate the absolute and relative positions of the spacecraft in a formation. The extended Kalman Filter is also implemented as a benchmark for the differential geometric estimation. Only relative positions between the spacecraft are measured. Relative positions are measured using a wireless local positioning system (WLPS) installed in all spacecraft. Two different scenarios are studied: (1) the observations include WLPS measurements only and (2) the observations include WLPS measurements in addition to measurements for the absolute position of one spacecraft made by a radar that takes measurements from the earth’s surface. Results show that the differential geometric estimation has better stability performance and a faster convergence rate compared to the extended Kalman filter.

scholarly journals Spacecraft Formation Orbit Estimation Using WLPS-Based Localization

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Shu Ting Goh ◽  
Ossama Abdelkhalik ◽  
Seyed A. (Reza) Zekavat
Keyword(s):  
Antenna Arrays ◽  
High Performance ◽  
Signal Transmission ◽  
Base Station ◽  
Position Estimation ◽  
Absolute Position ◽  
Coverage Area ◽  
Spacecraft Formation ◽  
Spacecraft Formation Flying ◽  
Local Positioning System

This paper studies the implementation of a novel wireless local positioning system (WLPS) for spacecraft formation flying to maintain high-performance spacecraft relative and absolute position estimation. A WLPS equipped with antenna arrays allows each spacecraft to measure the relative range and coordinate angle(s) of other spacecraft located in its coverage area. The dynamic base station and the transponder of WLPS enable spacecraft to localize each other in the formation. Because the signal travels roundtrip in WLPS, and due to the high spacecraft velocities, the signal transmission time delay reduces the localization performance. This work studies spacecraft formation positions estimation performance assuming that only WLPS is available onboard. The feasibility of estimating the spacecraft absolute position using only one-dimensional antenna array is also investigated. The effect of including GPS measurements in addition to WLPS is studied and compared to a GPS standalone system.

scholarly journals Underwater Positioning Using Near Surface Long Baseline Transponder’s Induced by Wave Motion

2017 ◽  
Author(s):  
Stian S. Sandøy ◽  
Ingrid Schjølberg
Keyword(s):  
Kalman Filter ◽  
Extended Kalman Filter ◽  
Wave Motion ◽  
Weather Conditions ◽  
Sea Surface ◽  
Positioning System ◽  
Motion Model ◽  
Near Surface ◽  
Long Baseline ◽  
Underwater Positioning

This paper presents a filter for underwater positioning in an aquaculture environment with demanding weather conditions. The positioning system is based on acoustic transponders mounted at a net pen on the sea surface. The transponders are exposed to oscillations due to wave disturbance. This will have an impact on the accuracy of the positioning system. An extended Kalman filter (EKF) solution has been proposed including a wave motion model integrated with the pseudo-range measurements from the transponders. Simulations show that the proposed filter compensates well for the disturbances.

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