Developing GPS Antenna Error Models For Improved Centimeter Level Positioning
Rhonda Franklin, Professor, Electrical and Computer Engineering
- Demoz Gebre-Egziabher, Professor, Aerospace Engineering & Mechanics
- Robert Sainati, Adjunct Professor, Electrical and Computer Engineering
A 2017 lane departure/keeping systems' study involving 25 states found that crash rates and injuries reduced by 11% and 21%, respectively. These systems have been available, high-end vehicles since 2000. A key feature is positioning systems with centimeter level accuracy. Typical GPS receivers in vehicles today do not meet this requirement. Real Time Kinematic GPS (RTK GPS) systems do meet the performance requirements; however, their high cost (> $10,000) and cumbersome size hinder suitability for automotive applications. The current video, laser, radar, or infrared sensors that are used to determine car location relative to visible lane markings are less costly. Their car integration into the highly integrated electrical system, however, can only be done when the automobile is manufactured. If after-market systems with accurate positioning could be purchased for a reasonable cost, significant driver/road safety benefits could be achieved.
Prior work shows that a key factor limiting RTK GPS systems accuracy is the antenna measurement quality. Accurate (and expensive) GPS receivers have large uniform antennas and come with extensive factory calibration. On low-end receivers, the antenna dimensions are small with poor tolerances and lack extensive factory calibration. This creates inaccurate positioning data whose accuracy depends on the direction-of-arrival of signals transmitted by the GPS satellites. A minimum of 10+ GPS satellites are normally in view, which send GPS signals that arrive from different directions, thus introducing time varying error. The overall objective is to develop a methodology for characterizing error in order to subsequently develop mathematical algorithms that can compensate for RTK GPS receiver error.
- Start date: 03/2018
- Project Status: Active
- Research Area: Transportation Safety and Traffic Flow
- Topics: Safety