Necessary and sufficient conditions for the observability of linear motion quantities in strapdown navigation systems

Navigation Systems are a key element of a large variety of mobile platforms, whether manned or unmanned, autonomous or human-operated. This paper dwells on the observability of linear motion quantities (position, linear velocity, linear acceleration, and bias), in 3-D, of mobile platforms, and presents necessary and sufficient conditions, with physical insight, for the observability of these variables. The analysis provided is based on kinematic models, which are exact and intrinsic to the motion of a rigid-body, and different cases are presented depending on the assumptions made on the sensor suite installed on-board.