Radar Aided INS Navigation Filter with Magnetometer Based Attitude Measurements

Abstract

This thesis presents a method for GPS-free navigation using a radar-aided inertial navigation filter with a magnetometer based attitude measurement. GPS has become the popular tool of choice when considering navigation solutions today, however, GPS is a low-power signal that can be easily blocked by large structures or jamming. Previous work has been done on attitude and heading reference systems which use magnetometers and accelerometers to determine the attitude of a vehicle. The magnetometer and accelerometer attitude measurement can be incorporated into the measurement update of an Extended Kalman Filter (EKF). The EKF presented in this thesis propagates the inertial navigation solution in the time update, while the measurement update uses the radar and attitude measurements to correct the inertial navigation system propagation errors. In this thesis, magnetometer calibration will fi rst be discussed. A magnetometer calibration routine will be selected then verified though simulated and experimental tests. Then, an attitude determination algorithm that uses magnetometer and accelerometer measurements will be reviewed and tested in simulation and with experimental data. Next, inertial navigation system propagation errors will be discussed and how radar-aiding in an Extended Kalman Filter can reduce propagation errors. Radar target determination is overviewed next, and finally, a new fi lter called the Radar-Aided INS (RAINS) filter is proposed and tested in simulation. The results of RAINS fi lter analysis show the possibility of navigation completely independent of GPS. The radar used in this thesis is a Delphi Electronically Scanning Radar which provides measurements of range, range rate, and azimuth.