국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	Estimating Thruster Impulses From IMU and Doppler Data
저자	Lisano, Michael E.;; Kruizinga, Gerhard L.
Keyword	MATHEMATICAL MODELS;; MOMENTS OF INERTIA;; INERTIAL PLATFORMS;; THRUST;; ESTIMATING;; DOPPLER RADAR;; CATALYSTS;; COMPUTER PROGRAMS;; CENTER OF GRAVITY;; ALGORITHMS;; COVARIANCE;; SPACECRAFT CONTROL;; REACTION CONTROL;;
URL	http://hdl.handle.net/2060/20090032101
보고서번호	NPO-45825
발행년도	2009
출처	NTRS (NASA Technical Report Server)
ABSTRACT	A computer program implements a thrust impulse measurement (TIM) filter, which processes data on changes in velocity and attitude of a spacecraft to estimate the small impulsive forces and torques exerted by the thrusters of the spacecraft reaction control system (RCS). The velocity-change data are obtained from line-of-sight-velocity data from Doppler measurements made from the Earth. The attitude-change data are the telemetered from an inertial measurement unit (IMU) aboard the spacecraft. The TIM filter estimates the threeaxis thrust vector for each RCS thruster, thereby enabling reduction of cumulative navigation error attributable to inaccurate prediction of thrust vectors. The filter has been augmented with a simple mathematical model to compensate for large temperature fluctuations in the spacecraft thruster catalyst bed in order to estimate thrust more accurately at deadbanding cold-firing levels. Also, rigorous consider-covariance estimation is applied in the TIM to account for the expected uncertainty in the moment of inertia and the location of the center of gravity of the spacecraft. The TIM filter was built with, and depends upon, a sigma-point consider-filter algorithm implemented in a Python-language computer program.