Dynamic Testing of a DGPS System Used As a Truthing Mechanism For Collision Avoidance Radar Evaluation

John W. Sisak, Paul K. Zoratti

Abstract:	The ERIM Intelligent Transportation System test- bed vehicle will be used to evaluate radar-based collision warning sensors. The testbed vehicle will host the radar sensor under test. A secondary vehicle will jointly stage test scenarios with the primary vehicle that are representa- tive of typical roadway driving. A Differential GPS (DGPS) system is being proposed as a truthing mechanism for assessing the range and range rate accuracies of for- ward-looking automotive radars, or other range, range rate measurement systems, when the automobiles undergo dy- namic maneuvers. The proposed DGPS system will pro- vide an independent measurement of the “truth” trajectory, that is, the true range and range rate, between the primary and secondary vehicles. The proposed DGPS system must provide an accurate trajectory during vehicle accelerations in order to thoroughly assess the effects of vehicle dynam- ics on the radar signal. This paper describes a test sequence for evaluating the accuracy of the proposed DGPS system during vehicle dynamics. Three GPS receivers were selected for the test and installed on the ERIM ITS testbed van. The reference tra- jectory (i.e. “truth” trajectory of the van) during periods of vehicle acceleration is provided by the ERIM Motion Mea- surement System (MMS). The MMS consists of an F-15 Ring Laser Gyro (RLG) Inertial Navigation System (INS) and a high accuracy strapdown navigation/Kalman filter software package. Experimental data were collected for three maneuvers: 1) linear acceleration/deceleration up to 0.75g; 2) lane change with lateral acceleration up to 0.3g and 3) a hard 90 degree turn. The DGPS data were pro- cessed in several modes using various combinations of the GPS observables. The position and velocity results from DGPS processing under vehicle acceleration are presented and compared to the position and velocity derived from in- ertial data. The paper concludes with a comparison of DGPS performance for the various combinations of ob- servables relative to the truthing system requirements.
Published in:	Proceedings of the 1997 National Technical Meeting of The Institute of Navigation January 14 - 16, 1997 Loews Santa Monica Hotel Santa Monica, CA
Pages:	709 - 716
Cite this article:	Sisak, John W., Zoratti, Paul K., "Dynamic Testing of a DGPS System Used As a Truthing Mechanism For Collision Avoidance Radar Evaluation," Proceedings of the 1997 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1997, pp. 709-716.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In