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.

• GSS8000The GSS8000 Multi-GNSS Simulator provides up to 3 constellations (GPS/SBAS, GLONASS, BeiDou-2 and Galileo) in a single chassis. GPS configurations can also support QZSS.
• GSS6700The GSS6700 supports any combination of GPS/SBAS/QZSS, GLONASS, Galileo L1 and BeiDou-2 signals and provides accurate, repeatable combined multi-GNSS signals.
• GSS6400The market’s leading record and playback system, from the experts in GNSS Testing
• TestDrive GNSSProvides SimGEN™, SimREPLAYplus and SimREPLAY customers with an integrated test solution that automates the testing process by configuring the instruments in the system, stepping through the test sequences, and processing and storing the results, removing much of the burden of manual test setup and configuration.

Testing GNSS on the Railway

Issue

• Need to test the integrity of the system under test, including operation in a range of safety cases
• Need to understand the performance of the system in difficult environments (eg. cuttings, tunnels, bridges) and error conditions

Solution

• GSS6700 with SimGEN
• Optional GPS/inertial package to simulate IMU and/or distance indication (eg. wheel pulses)

Benefit

• Save time and improve performance through lab-based test approach, using representative scenarios
• Introducing errors in a controlled way enables system level confirmation that these will be flagged and/or rejected appropriately according to the requirement

DLR Institute of Space Systems

The DLR institute required a GPS simulation platform that was flexible and easy to use. They needed to hit the ground running. Find out more

DLR Institute of Communications and Navigation

The DLR Institute of Communications and Navigation required a specialised solution that wasn’t available off the shelf. Find out more.

ipi-Institut

The IPI-institute had a very specific simulation requirement for end user testing within the automotive marketplace. Find out more.

LOCOSYS

LOCOSYS needed a flexible GPS platform for their own, and their customers testing requirements, they chose Spirent. Find out more.

Septentrio 

When Septentrio were looking for a new way to characterise their new algorithms, they turned to Spirent. Find out more.

ST-Ericsson Case Study

ST Ericsson was looking to reduce time and travel costs incurred during extensive testing and development phases of their GPS and GNSS receiver chipsets. Find out more.