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Showing 1 to 16 of 16 for “"star tracker"”.
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Lunar Surface Navigation Using Gravity and Star Tracker Measurements
… analyzes a method that uses measured gravity and starlight vectors to provide position and attitude estimates, given a predefined high-fidelity lunar gravity field. The gravity field uses provided values for the surface gravity magnitude and the East-West (EW) and North-South (NS) deflections of …
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Autonomous Artificial Neural Network Star Tracker for Spacecraft Attitude Determination
… to solve the ""lost-in-space"" problem for this star tracker prototype is on average 9.5 seconds. This is an improvement over the 60 seconds needed by the current off-the-shelf autonomous star tracker by Ball Aerospace, the CT-633. Initial acquisition after launch as well as recovery from a loss …
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Development of a low-cost multi-camera star tracker for small satellites
The student, Hongrui Zhao, accepted the attached license on 2020-07-20 at 13:59.
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Fast star tracker centroid algorithm for high performance CubeSat with air bearing validation
… stabilization. The optical sensor provides star images from which a centroiding algorithm estimates the star locations on the optical focal plane. The star locations are used for both the optical control loop and satellite attitude determination. The centroiding algorithm requires a short …
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Kalman Filter Implementation to Determine Orbit and Attitude of a Satellite in a Molniya Orbit
… magnetometer, Earth sensor, sun sensor, and star tracker. A controlled altitude path was chosen to test the accuracy of each of these cases and it was shown that the algorithm using star tracker measurements was three hundred times more accurate than that of the magnetometer algorithm.
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Designing star trackers to meet micro-satellite requirements
Star trackers provide numerous advantages over other attitude sensors because of their ability to provide full, three-axis orientation information with high accuracy and flexibility to operate independently from other navigation tools. However, current star trackers are optimized to maximize …
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Skymark selection algorithm for a space-based navigational concept
… from an observer to a skymark using a modified star tracker, and then making use of triangulation to estimate the observer's location. A Kalman filter is used to update the observer's knowledge of its state, and the uncertainty concomitant with that knowledge can then be determined. This thesis …
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Linear covariance analysis trade study of autonomous navigation schemes for cislunar missions
… levels of flight readiness: MIMU IMU, LN200 IMU, star tracker, Inertial Stellar Compass (ISC), lunar orbiting beacon (Navsat), lunar ground beacons (Navsites), LIDAR, known lunar landmarks, SkyMark, TDRS, and GPS. A complete formulation of the linear covariance tool (LINCOV) dynamics and …
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On-orbit inspection of a rotating object using a moving observer
… that the inspector satellite be equipped with a star tracker, an inertial measurement unit, and a dense 3D visual sensor such as stereo cameras or LiDAR. The inspector trajectory is estimated in a manner which is independent of target motion, using a factor graph approach. Here, star tracker …
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Analyzing and monitoring GRACE-FO star camera performance in a changing environment
… attitude determination sensors are the three star cameras on board each GRACE-FO satellite, and errors in their measurements stem from star tracker performance, on-ground measurement of the alignments between them and the spacecraft, and how stable that alignment is over the course of the …
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A Systems Framework for Multi-Messenger Astronomy
… and electromagnetic detection of neutron star mergers — cosmological standard sirens. This case study predicts [formula] joint detections by the end of the 2020s, likely sufficient to measure the Hubble parameter with 4% uncertainty. Furthermore, 𝒪(10⁵) instrument networks are simulated. …
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Portable optical ground stations for satellite communication
… station has a 28 cm aperture and utilizes a star tracker for automated calibration. The ground station reduces mass by at least 10x and cost by at least 100 x over existing optical ground stations. We present a ground station architecture that enables deployment in less than one hour and that …
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Control and Sensor Development on a Four-Wheel Pyramidal Reaction Wheel Platform
… Furthermore, the system will incorporate a star tracker in conjunction with a Simulated Star Field (SSF) to better estimate the PRWP orientation. For the sake of this document, however, the goal is to implement a gyroscope, wheel rate sensors, and a make-shift accelerometer—to the PRWP—and …
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Attitude Determination & Control System Design and Implementation for a 6U CubeSat Proximity Operations Mission
… sensors include an angular rate gyro and star tracker (STR), supplemented by the payload optical array cameras.</p> <p>The dynamic simulation of the satellite includes extensive environmental models and analyses that show how the satellite attitude is affected by aerodynamic drag, solar …
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Robust Adaptive Estimation for Autonomous Rendezvous in Elliptical Orbit
… consisting of accelerometers and gyroscopes, a star tracker, and a horizon sensor are utilized to provide measurement data to the navigation filters so that the chaser vehicle can estimate its relative state during the rendezvous maneuver. Several filters are implemented for comparison, …