Can I use a Labsat 3 Wideband Record & Replay System to test to ETSI EN 303 413?
LabSat is Racelogic’s GNSS Signal replicator, which gives you the ability to record and replay real GPS/GLONASS/BDS/Galileo RF data, as well as user generated SatGen scenarios.
The advantages of using the LabSat as a GNSS simulator comes primarily from the fact that each time you replay a scenario it will be the same, and therefore consistent, repeatable signals are provided to the system under test. This is not the case with using live-sky testing alone, where satellite position, multipath, and atmospheric conditions are constantly changing. This makes for highly cost-effective testing, as you will have credible, unambiguous results with a reduction in travel and testing time often associated with repeating live-sky GPS tests. Recording GNSS scenarios with LabSat means that you can reduce the amount of live-sky testing associated with GPS/GLONASS/BDS receiver testing, by recording a test once, and then playing back the recorded scenario on the test bed as many times as you require. All LabSat products are manufactured with an anodized aluminium casing that ensures that the devices will survive the knocks experienced in field testing.
LabSat 3 Wideband is capable of recording each of the signals required for these tests but can only record with a maximum bandwidth of 56MHz. SatGen Software is capable of simulating the signals required excluding SBAS. However, when using SatGen the signal bandwidths are not user configurable, the software calculates what bandwidth to use based on the signals selected for simulation.
If LabSat 3 Wideband was used for this testing, we would recommend using SatGen to simulate the required signal as it produces a consistent signal level across all satellites. The LabSat 3 Wideband internal attenuation or amplification can be used along with either external attenuators or external amplifiers if required to achieve the desired signal level.
LabSat/SatGen maintain a constant total power per channel but this standard is on a per satellite/signal basis so if you have different numbers of satellites for each signal/system then you would need to compensate for that, but if you keep the same number of satellites for each signal/system then no compensation is needed. Please note it is possible to limit the number of satellites used for a constellation in SatGen by editing the almanac, this could be done for each constellation to ensure the same number of satellites per system/signal. I have included a link here to our knowledge base article that describes this process.
If each signal is on a different LabSat channel then it is possible to easily change the relative levels. If the signals are in the same band, it will be dependent on how SatGen generates the signals which can vary dependent on which signals are selected for simulation.
You can download the ETSI EN 303 413 standard PDF here.
