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