Patent ID: 9243931
Filing Date: 2016-01-26
CPC Classification: G01C

Claim Text:
1. A method for calibrating a gimbal assembly, the method comprising: providing a gimbal assembly having a non-rotatable base and a steerable section, the steerable section having portions configured to rotate around a nominal azimuth axis and a nominal elevation axis; steadying the gimbal assembly base; measuring locations of a first single point affixed to the steerable section at different rotation angles of the steerable section around the nominal azimuth axis; measuring locations of a second single point affixed to the steerable section at different elevation angles of the steerable section around the nominal elevation axis; calculating an actual azimuth axis from the measurements at the different rotation angles of the steerable section around the nominal azimuth axis; calculating an actual elevation axis from the measurements at the different rotation angles of the steerable section around the nominal elevation axis; determining an azimuth axis error between the actual azimuth axis and the nominal azimuth axis; determining an elevation axis error between the actual elevation axis and the nominal elevation axis; storing information representing the azimuth axis error and elevation axis error; steering the steerable section of the gimbal assembly to point to a direction in space; acquiring a nominal pointing vector of the steerable section from a rotation angle around the nominal azimuth axis and a rotation angle around the nominal elevation axis; and transforming the nominal pointing vector to a corrected pointing vector using the stored information representing the azimuth and elevation axis errors.