FACTORS AFFECTING ACCURACY IN A HYBRID DEAD-RECKONING/SIGNPOST SYSTEM FOR URBAN VEHICLE LOCATION. NAV 85 - LAND NAVIGATION AND LOCATION FOR MOBILE APPLICATIONS - PAPERS PRESENTED AT THE 1985 CONFERENCE OF THE ROYAL INSTITUTE OF NAVIGATION, YORK, 9-11 SEPTEMBER 1985

By reference to an automatic vehicle location system using electronic signposts which transmit by infra-red signalling to an on-board dead-reckoning system, an examination is made of factors affecting accuracy. The dead-reckoning system uses a speedometer transducer for the scalar component and a geomagnetometer for the azimuth component. Distance transducer errors are found to be less than 0.1%. Static azimuth errors in the urban area give a root-mean-square of less than 1 degree, the exception being in proximity to underground or British rail electric lines where it can be 8 degrees. A greater contributor to azimuth errors arises from dynamic effects on the measurement platform due to e.g. Vehicle pitch, hills, road camber. A fixed magnetometer is found to have an overall standard deviation of 2.6 degrees. A gimballed magnetometer is affected by acceleration, deceleration and turns with positional errors up to 50 metres. Practical experience shows that position errors increase at the rate of 5% of distance travelled from the last beacon. An increase in the number of beacons will improve accuracy. With knowledge of the dead-reckoning accuracy and the total road length to be covered, the optimum number of beacons can be calculated. This is described on a 'security application' and 'despatch application' basis. (TRRL)

• Corporate Authors:

  Royal Institute of Navigation

  1 Kensington Gore
  London,   England 
• Authors:
  • Ewen-Smith, B M
• Publication Date: 1985

Media Info

• Pagination: 4 p.

Subject/Index Terms

• TRT Terms: Accuracy; Automatic vehicle location; Conferences; Electronics; Errors; Infrared radiation
• ITRD Terms: 3882: Automatic; 8525: Conference; 6965: Electronics; 6440: Error; 6797: Infrared; 9061: Location; 1255: Vehicle
• Subject Areas: Highways; Planning and Forecasting;

Filing Info

• Accession Number: 00491621
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Mar 31 1990 12:00AM