Hello, We manufacture GNSS Frequency Standards, both Rubidium based and OXCO based. When comparing the frequency and phase outputs of two GNSS Rubidium Disciplined units, that are connected to the same antenna and receiving the same satellite systems, we get very low frequency difference and phase change over seconds to weeks. My customers asked me how good two of our units will be when placed about 1 km apart. They need two units to remain in phase are two different locations, as I said about 1 km apart. The customer wants to know how the phase stability of the sinewave outputs will suffer or degrade, when receiving slightly different satellites with two separate antennas. Our units can pick up GPS, Galileo, Beidou and Glonass. We usually have them receiving GPS and Galileo and Beidou and not GLONASS. I'm trying to simulate a worst-case scenario by having one unit receive GPS only and the other Galileo only, while still using a common antenna. Does anyone have an idea how the performance may degrade at 1 km apart but both units receiving GPS+Galileo+Beidou? It will take many weeks of testing for me to draw conclusions, so I'm hoping someone already have done this experiment. Best Regards Martyn Smith

Hi Martyn, we touch the topic in one of our publications: https://arxiv.org/abs/2210.07168 We employed the SRS FS740 for synchronization of spatially distributed SDR receivers for the purpose of RF emitter localization. My best guess is that your mileage will vary depending on the GNSS receiver in question. For the purpose an RTK timing receiver, e.g., u-blox ZED-F9T, may offer better performance, but we haven't gotten around to testing that. Best regards, Carsten On 31.08.23 18:16, Martyn Smith via time-nuts wrote: > Hello, > > > > We manufacture GNSS Frequency Standards, both Rubidium based and OXCO based. > > > > When comparing the frequency and phase outputs of two GNSS Rubidium > Disciplined units, that are connected to the same antenna and receiving the > same satellite systems, we get very low frequency difference and phase > change over seconds to weeks. > > > > My customers asked me how good two of our units will be when placed about 1 > km apart. > > > > They need two units to remain in phase are two different locations, as I > said about 1 km apart. > > > > The customer wants to know how the phase stability of the sinewave outputs > will suffer or degrade, when receiving slightly different satellites with > two separate antennas. > > > > Our units can pick up GPS, Galileo, Beidou and Glonass. We usually have > them receiving GPS and Galileo and Beidou and not GLONASS. > > > > I'm trying to simulate a worst-case scenario by having one unit receive GPS > only and the other Galileo only, while still using a common antenna. > > > > Does anyone have an idea how the performance may degrade at 1 km apart but > both units receiving GPS+Galileo+Beidou? > > > > It will take many weeks of testing for me to draw conclusions, so I'm hoping > someone already have done this experiment. > > > > Best Regards > > > > Martyn Smith > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com