Autonomous Optical Navigation for Spacecraft in Earth Departure Phase

This thesis looks at the effectiveness of using nanosatellite class star trackers to perform optical navigation. Although star trackers used for these missions lack the accuracy and sensitivity of sensors employed on larger spacecraft, they offer great resolution relative to its compact size. Two Extended Kalman Filter-based navigation filters illustrate the applications of this class of sensor. The first filter looks at horizon-based techniques using observations of Mars and its moons to assist the navigation filter in a hyperbolic approach. Results show low position (< 300 m) and velocity (< 0:15 m/s) errors as spacecraft reaches periapse. The filter formulation serves as a basis for a design case study exploring different possible sensor configurations for this mission type. The second filter looks at landmark-based techniques using absolute and relative landmarks as observations. Measurement frequency appears as a key parameter in this study, simulation results show position errors in the order of tens of kilometers, or better even if absolute landmarks are only available every 30 minutes. The accuracy of the results are validated through series of Monte Carlo simulation.

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Ground Calibration System Design of High-Precision Star Sensor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.694-697.1068 ◽

2013 ◽

Vol 694-697 ◽

pp. 1068-1073

Author(s):

Jie Duan ◽

Zhi Yong An ◽

Xiang Yang Sun

Keyword(s):

High Precision ◽

Optical Transmission ◽

Angular Distance ◽

Star Sensor ◽

Optical Navigation ◽

Calibration System ◽

Large Size ◽

High Magnitude ◽

Design Plan ◽

Ground Calibration

In order to meet the high precision calibration requirements of precision angular distance and high magnitude to the optical navigation sensor, A new style of high precision star simulator with large caliber, and long-focus, is presented. And then the main compositions of this simulator are designed in detail referring to the simulator, the steering mirror, the standard simulated targets and so on. According to the simulator characteristics of large size lens and multi lens, the structural of lens cone uses the tube sleeve and inner sleeves fixed together means. To eliminate the mirror deformation, the design plan based on the tiny stress is applied in steering mirror. In order to achieve a high magnitude, the light targets are simulated by optical transmission from OLED to high precision drone with fibers. Its degree ≤1〞,simulated magnitude≥5 that meet calibration requirements of the current high-precision optical navigation sensor.

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