General constraints on influential error sources for super-high accuracy star tracker

TL;DR

This paper develops a theoretical framework using CRLB to estimate the minimum error constraints for star tracker accuracy, considering various error sources and enabling pre-launch error margin analysis.

Contribution

It introduces a general theory for quantifying minimum error constraints on star tracker measurements, including position, intensity, and scale, based on CRLB analysis.

Findings

Analytical error margins for in-flight star tracker accuracy.

Constraints on motion and focal length drift impact.

Pre-launch error estimation methodology.

Abstract

Though in-orbit calibration is adopted to reduce position error of individual star spot down to 0.02pixel on star tracker, little study has been conducted on the accuracy to what extent for some significant error sources which often leads to in-orbit correction inefficiency. This study presents the general theory and estimates of the minimum error constraints, including not only on position but also on intensity and scale of Gaussian shaped profile based on Cramer Rao Lower Bound(CRLB) theory. By imposing those constraints on motion, drift in focal length and so on, margins of in-flight error sources and the final accuracy of star tracker can be analytically determined before launch.