Radar-Aided INS with Magnetometer Attitude Determination

GPS has become a popular measurement choice for navigation solutions today because of it long term stability and worldwide availability. However, GPS is a low-power signal that can be easily blocked by large structures or jamming. Without GPS, many consumer-grade sensors are unable to provide accurate navigation solutions because of noise and bias errors. This paper presents a method for a GPS-free navigation solution by using a magnetometer-aided, radar/INS coupled filter for vehicle navigation. Previous work has been done on attitude-heading reference systems which use magnetometers and accelerometers to determine the attitude of a vehicle. This attitude measurement can be incorporated in to the measurement update of an EKF. The main contribution of this paper is a radar aided INS EKF that will propagate the INS solutions in the time update, while the measurement update will use the radar measurement Jacobian and the attitude measurement to correct the INS propagations errors. Results in simulation and with real-world data show that this filter is capable of estimating the position, velocity, and attitude of a vehicle by constraining the error associated with pure INS propagation. The radar used in this paper is a Delphi Electronically Scanning Radar, and provides measurements for range, range rate, and azimuth.