Patent ID: 8275193

Claim:
A method of three dimensional positioning of objects, comprising the steps of: (a) injecting raw measurements from two or more sensors into a data fusion system to derive relative position and attitude information of objects; (b) tracking at least four common GPS (Global Positioning System) satellites simultaneously by means of AERCam (autonomous Extravehicular Activity Robotic Camera) 1 ′ and ISS (International Space Station) 2 ′; (c) optimally blending multipath signal and GPS signal due to any intermittently fail of relative GPS-alone when said AERCam 1 ′ maneuvers into a proximity of said ISS 2 ′ because of occasional strong multipath signal and GPS signal blockage with IMU data including gyro and accelerometer measurements; (d) initializing an inertial navigation system when a GPS solution is available and using said GPS solution; (e) tracking position and attitude of said AERCam 1 ′ relative to said ISS 2 ′ by said inertial navigation system in close proximity; (f) estimating and resetting frequently for errors of said inertial navigation system growing with time; (g) aiding said inertial navigation system during close proximity operation with available GPS signals and at least two cameras installed on said AERCam 1 ′ to maintain accurate relative navigation, wherein range and range rate between said AERCam 1 ′ and said ISS 2 ′ are blended in multi-sensor fusion algorithm to compensate for IMU sensor drifts during GPS outage or unreliable GPS data; and (h) imaging said ISS 2 ′ by at least two cameras installed on said AERCam 1 ′ for images which are further processed via correlation and coordinate transformations techniques to derive range and range rate on-board of said ACRCam 1 ′ for image parameters which are able to be computed and transmitted said range and range rate back to said AERCam 1 ′.