Certification of GNSS Devices
Traditionally, civilian use of GPS was seen as free and to a large extent “at your own risk”. The typical performance one might expect was stated in the relevant Interface Control Documents (ICD’s) but no guarantee of service was given. The reason for this was the historical remit of GPS as a system to satisfy US military requirements, the civilian use of the coarse acquisition (C/A) ranging code being essentially a by-product of its primary use, which was to provide classified receivers a ‘first step’ towards fast acquisition of the precise ‘P(Y)’ code.
With the increasing number of GNSS services that will offer certain guarantees of service scheduled to be available over the coming years, there is an increasing requirement for certification of these services and the GNSS devices that use them.
To facilitate these requirements, new performance standards are being written which are dictating the tests to be performed.
Test integrity is essential
All proper testing must have good integrity – that’s a given, however, it is especially so with certification, verification and type approval testing, particularly when the device and / or application is safety critical. This is why using quantifiable, traceable and accurate test methods are important. Accredited test laboratories use precision test equipment which is calibrated to standards traceable to National references for all certification and type approval testing. The same must therefore apply to GNSS testing. This is why using calibrated precision RF constellation simulators is the only way to perform this kind of testing. The inherent uncertainty and variability of using other methods (such as real GNSS signals) rules them out completely.
Spirent’s pedigree in producing high-fidelity, precision test equipment is well proven over more than 25 years. Spirent has supplied equipment into critical test programmes across the world. These equipments have often been put through rigorous certification and validation programmes to ensure they are themselves fit for certification testing. The most recent examples of this are;
- The certification by the European Space Agency and Galileo Supervisory Authority of the world’s first Galileo RF constellation simulator—Spirent’s GSS7800 for the Ground Receiver Chain (GRC) and Test User Segment (TUS) receiver developments in the IOV phase of the Galileo programme.
- The certification of Spirent’s GLONASS implementation by the Russian authorities
So, to ensure your testing is up to standard, make sure you select test equipment from Spirent, the world’s leading and most proven simulator provider.