Railways world-wide demand a great deal of maintenance and cash to keep rolling stock up-to-date, signalling systems operating smoothly and thousands of miles of track in good repair. Budgets are under constant scrutiny and the balance between efficient operation and safety is critical. Many operators are investigating how GPS/GNSS systems could be used to reduce infrastructure costs and improve performance over traditional approaches.

Providing a rail infrastructure that is based on GNSS approaches presents many opportunities but also many challenges. Often the candidate approaches will include some compliment to GNSS, such as inertial sensor or dead reckoning technology or track-side infrastructure.

But how do you manage and plan your testing when the GPS satellites are constantly moving making controlled, repeatable measurements impossible. How do you account for multipath effect when signals are being bounced off tall buildings or when trains are in narrow gullies, tunnels or sidings and have limited exposure to satellite signals.

Testing in the laboratory using GPS/GNSS constellation simulators is the proven standard for all GNSS based applications, but especially for those demanding the highest performance, such as the railways.

Introducing certification testing is an aim of many rail bodies and Spirent GPS and GNSS rail simulation systems are being evaluated around the world. GNSS simulation is the only test methodology that can be fully certified and the benefits of GPS/GNSS simulators to enable controlled testing under a wide range of conditions can contribute positively to the certification of GNSS systems.

SPIRENT'S VALUE FOR GNSS TESTING ON THE RAILWAYS

In a sector where there are little or no standards available that define how and what to test in a GNSS system, Spirent can help. Our experience in helping customers with GNSS systems and applications can assist you to make the right decisions. Spirent simulation systems range from simple to sophisticated and cover GPS and Multi-GNSS testing. However, all share our commitment to technical excellence, quality and reliability so that you can rely on the results you get while benefiting from Spirent’s 20 plus years as specialists in GNSS testing.