Research

Developing GPS Antenna Error Models For Improved Centimeter Level Positioning

Principal Investigator:

  • Rhonda Franklin, Professor, Electrical and Computer Engineering

Co-Investigators

  • Demoz Gebre-Egziabher, Professor, Aerospace Engineering & Mechanics
  • Robert Sainati, Adjunct Professor, Electrical and Computer Engineering

Project Summary:

A 2017 study of vehicles with lane-departure/keeping systems involving 25 states found that crash rates and injuries declined by 11 percent and 21 percent, respectively. These systems have been available on high-end vehicles since 2000. A key feature is a positioning system 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, but the high cost (> $10,000) and cumbersome size hinder suitability for automotive applications. Currently, video, laser, radar, and infrared sensors- used to determine car location relative to visible lane markings- are less costly. Integration into the vehicle 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 research shows 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 normally in view send GPS signals that arrive from different directions, which introduces time-varying error. The overall objective is to develop a methodology for characterizing error and subsequently develop mathematical algorithms to compensate for RTK GPS receiver error.

Project Details:

  • Start date: 03/2018
  • Project Status: Completed
  • Research Area: Transportation Safety and Traffic Flow

Reports or Products:

"Characterizing Phase-Center Motion of GNSS Antennas Used in High-Accuracy Positioning" (2019)


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