GPS/INS integration: A performance sensitivity analysis

Inertial Navigation System (INS) and Global Positioning System (GPS) technologies have been widely used in a variety of positioning and navigation applications. Both systems have their unique features and shortcomings. Therefore, the integration of GPS with INS is now critical to overcome each of their drawbacks and to maximize each of their benefits. The integration of GPS with INS can be implemented using a Kalman filter in such modes as loosely, tightly and ultra-tightly coupled. In all these integration modes the INS error states, together with any navigation state (position, velocity, attitude) and other unknown parameters of interest, are estimated using GPS measurements. In a high performance system it is expected that all these unknown states will be precisely estimated. Although it has been noted that both the quality of the GPS measurements and the trajectory and/or manoeuvre characteristics of the problem will have impacts on system performance, a systematic sensitivity analysis is still lacking. This paper will address this issue through real data analyses. The performance analysisresults are very relevant to system design and platform trajectory and/or manoeuvre optimisation.