Military Avionics Systems

Moir, Ian; Seabridge, Allan

doi:10.2514/4.478338

Cited by 57 publications

(45 citation statements)

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“…1 for rendezvous operates as follows. The target is first acquired with an imaging sensor using some acquisition methodology [3]. Whereas the required pointing accuracy for the imaging sensor is not stringent, that for the collimated LRF is 75 rad per axis (1) at a 10 km distance.…”

Section: Overall Architecture Of Autonomous Inertialmentioning

confidence: 99%

“…1, the integrated sensors may be sufficiently accurately pointed at the client satellite so that the collimated laser beam would impinge upon the client and determine its relative range. The required pointing accuracy is about 10-100 rad (1) [3,26], depending on the relative range. The noisy range measurement is modeled as…”

Section: Focal Plane Angles and Range Measurementsmentioning

confidence: 99%

“…The sensor suite considered here is based on the scenario that the client spacecraft is passive, disabled, or noncooperative, and so there is no cross-link communication between the two satellites nor are there any optical reflective geometry on the client satellite. As such, following [2,3], the selected sensor suite is an integrated sensor system composed of an imaging sensor with wide, medium, and narrow fields of view for relative angle measurements, a coboresighted (or collimated) laser range finder (LRF) for range measurement, and the space-integrated Global Positioning System/inertial navigation system (SIGI) for the active chaser satellite. A new autonomous relative navigation algorithm that this sensor ensemble facilitates is formulated in an inertial frame using a continuous-discrete extended Kalman filter (EKF).…”

Section: Introductionmentioning

confidence: 99%

“…A three-axis attitude controller stabilizes the imaging sensor's sight line and coboresighted LRF at the client satellite within the pointing-accuracy requirements. Whereas the field of view of an imaging sensor is large (4 4 deg for medium and 1 1 deg for narrow fields of view), the laser beam width is merely 0:25 mrad (0.014 deg) and has very low divergence (0:25 mrad) [3]. Therefore, whereas the pointing requirement to avoid jitter of the imaging sensor is loose, that for the LRF is stringent (15-30 rad).…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, whereas the pointing requirement to avoid jitter of the imaging sensor is loose, that for the LRF is stringent (15-30 rad). For accurate pointing, the imagingsensor boresight and the coboresighted LRF must be aligned very carefully [2,3]. Because achieving this degree of alignment and pointing stability is expensive, a secondary objective of this study is to show that it is not necessary to measure the range for a midrange (20-1 km) rendezvous, because it can be estimated from the angle measurements under certain observability conditions [4,5].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Autonomous Inertial Relative Navigation with Sight-Line-Stabilized Sensors for Spacecraft Rendezvous

Hablani

2009

Journal of Guidance, Control, and Dynamics

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This paper presents a novel autonomous inertial relative navigation technique with a sight-line-stabilized integrated sensor system for midrange (20-1 km) spacecraft rendezvous. A continuous-discrete six-state extended Kalman filter is developed for this purpose. The integrated sensor suite onboard an active chaser satellite comprises an imaging sensor, a coboresighted laser range finder, the space-integrated Global Positioning System/inertial navigation system, and a star tracker. For high accuracy of the relative navigation, the Kalman filter state vector consists of the inertial position and velocity of the client satellite governed by a high-fidelity nonlinear orbital dynamics model. The error covariance matrix is formulated in terms of the estimation error in the relative position and velocity of the client satellite, consistent with the sensor measurements. Inertial attitude pointing and rate commands for tracking the client satellite are determined using the estimates of the client's inertial relative position and velocity. To estimate the inertial attitude of the chaser satellite outside the space-integrated Global Positioning System/inertial navigation system, a new three-axis steady-state analytical attitude estimator is developed that blends the gyro-and the star-tracker-measured attitudes. The simulation results of a midrange spacecraft rendezvous using glideslope guidance validate this new six-state autonomous inertial relative navigation technique. The simulation results show that the imaging sensor's sight line can be stabilized at the client satellite in midrange accurately enough to enable the laser range finder to measure the range occasionally, but these measurements are not necessary for the midrange rendezvous phase, because the extended Kalman filter can estimate the range with the angle measurements of the imaging sensor.

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Section: Overall Architecture Of Autonomous Inertialmentioning

confidence: 99%

Section: Focal Plane Angles and Range Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%