Seamless and reliable personal navigator

The primary objective of the project presented here, sponsored by the National Geospatial-Intelligence Agency (NGA), is to develop a prototype of a personal navigator to support navigation and tracking of ground military and rescue personnel. This research aims at forming the theoretical foundations for such a system by developing the algorithmic concept of a basic GPS-based, Micro-electro-mechanical inertial measurement unit (MEMS IMU)-augmented personal navigator system with an open-ended architecture, which would be able to incorporate additional navigation and imaging sensor data, extending the system's operations to the indoor environments. The accuracy requirement is considered at 3-5 m CEP (circular error probable). In the current system design and implementation, the following sensors are integrated in the tightly coupled Extended Kalman Filter GPS carrier phase and pseudorange data, Crossbow MEMS IMU400C, PTB220A barometer, and KVH Azimuth 1000 digital compass. This paper presents the design architecture of the integrated system and the preliminary performance analysis, with a special emphasis on the navigation during the loss of GPS signal. Individual sensor calibration, as well as sensor inter-calibration are presented, and the impact of the calibration on the final navigation results is demonstrated. Simulated and real data are used. The system's architecture is currently designed to incorporate a simplified dynamic model of human locomotion. The system is trained during the GPS signal reception and is subsequently used to support navigation under no GPS signal. The calibrated model of stride parameters (step frequency and length) extracted from the GPS data and impact switches during the system calibration period, and heading information from the compass and the IMU, offer dead reckoning navigation, facilitating bridging of GPS gaps. This paper offers only a brief overview of the system design and preliminary performance analyses, while a journal paper, currently in preparation, will provide the details on the design architecture and performance assessment.