Monitoring traffic flow and congestion with sub-metre positioning.

  • The system had to provide sub-metre positioning sufficient to correctly identify probe-vehicles travelling in a high traffic volume motorway network and interchange system
  • Vehicle velocity had to be given with an accuracy of 0.1 miles/hr or better
  • Vehicle position and velocity data was passed by cellular communications using SMS and GPRS data structures
  • The probe cars are run by a highways authority to monitor managed roadway contractor invoices for payment approval. The system had to run continuously without being affected by vehicle use
  • Our CPUpak-4 was modified to include a cellular telecoms card and built-in battery backup to maintain the 24/7 heartbeat services
  • Using remote cell phones, the watch-keepers and maintainers were able to monitor the system through the use of QA messages
  • Any problem would be reported by SMS or GPRS immediately it occurred with location, vehicle ID and the nature of the fault
  • For advanced debugging a full fault history could be downloaded to a computer with NAVPak quality control software.
  • Recently we upgraded this system with the CORE-1 GNSS system, bringing the technology up to date and improving the communications