Error Sources In Four-Point Attitude Calculations

A practical system for computing attitude angles from the image of four rectangular, coplanar points has a number of potential error sources that degrade the accuracy of the attitude computation. An error analysis is presented for the Robot Locating System (RLS), which is a multisensor laboratory testbed that seeks to compute attitude angles from an image of four points. This paper discusses potential error sources and their relative effects for the RLS system. The error sources are discussed from a physical point of view and expected error characteristics are described. These error sources are then evaluated using a software simulation of the RLS system.