This report discusses the continuing efforts of the study and development of Deeply Integrated (DI) GPS/INS navigation. The intended goal resulting from the collaborative efforts of AMRDEC and the Auburn GPS and Vehicle Dynamics Laboratory (GAVLAB) is to build and implement a Deeply Integrated GPS/INS test bed for performance analysis of the navigation solution.
GPS suffers from a fundamental weakness - low received signal power. This low signal power makes GPS receivers extremely susceptible to RF interference, both intentional and unintentional. This weakness is further exacerbated by platform dynamics which can cause a GPS receiver’s signal tracking subsystem to “unlock.” Through simulation, and eventually implementation, the performance of deeply-integrated GPS/INS is examined as an improved technique for use under high platform dynamics in environments with high levels of RF interference.
The figure below gives an overview of the proposed DI test bed. Section (i) is the software correlator. Section (ii) is the GPS RF Front End that yields the digitized intermediate frequency processed by the software correlator. Section (iii) is the IMU from which the INS data is updated in the extended Kalman filter (iv) using GPS measurements.
Deeply Integrated Block Diagram