GTT adds GNSS to enhance its signal priority system


Global Traffic Technologies (GTT) announced today that it has added the Global Navigation Satellites System (GNSS) to its Opticom solutions, to enhance the reliability of the signal-priority connected vehicle services. This collection of satellites transmits positioning and timing data to GNSS receivers, which use this data to determine location.

Though we might not realize it, most of us have used the Global Positioning System – ie, GPS – before. In fact, many connected vehicle applications, including emergency vehicle preemption and transit signal priority, rely on GPS to determine the real-time location of vehicles. But while that single satellite system employs 31 satellites, GNSS utilizes 89 satellites from four different satellite navigation systems around the world, including GPS (America), Galileo (European Union) and either GLONASS (Russia) or China’s BeiDou (GTT is using GLONASS).

“It’s well-documented that urban canyons and multipath effects can negatively impact the accuracy and overall performance of GPS-based locating,” says GTT VP of product development Ravi Shah. “The advantage of adding GNSS is that it gives our customers access to multiple satellite networks, thereby reducing interference and increasing accuracy while providing reliable redundancy and availability.”

Adding GNSS will enable more consistent, reliable priority control in dense urban areas with obstructions such as bridges, tunnels and tall buildings. It will reduce the kind of performance issues that can diminish priority control’s effectiveness by helping ensure the correct intersection receives the request for a green light as priority vehicles approach intersections. Better location services will minimize disruptions to traffic, and help fire and emergency personnel, bus drivers and light rail train conductors navigate dense urban areas in safer and faster.

Even with access to more satellites, communication to these satellites can be lost temporarily in areas with tall buildings, tunnels or multi-level roads. To address this, GTT has also added the ability to more effectively determine vehicle position in these areas with software-based “dead reckoning.” If satellite communication is lost, dead reckoning can calculate a moving vehicle’s position by estimating its direction and distance traveled from its last known geo-location. GTT’s software-based dead reckoning solution functions with sensors built into the Opticom devices, with no additional vehicle wiring required.

“Opticom, like other connected-vehicle applications, relies on accurate vehicle position to deliver high performance solutions,” says Chad Mack, GTT’s director of product management. “Incorporating GNSS and software-based dead reckoning into our Opticom portfolio is a testament to GTT’s commitment to creating best-in-class solutions for our customers.”



Share this story:

About Author


Tom has edited Traffic Technology International (TTi) magazine and its Traffic Technology Today website since May 2014. During his time at the title, he has interviewed some of the top transportation chiefs at public agencies around the world as well as CEOs of leading multinationals and ground-breaking start-ups. Tom's earlier career saw him working on some the UK's leading consumer magazine titles. He has a law degree from the London School of Economics (LSE).