I’ve been using Sparkfun Reference Station as a VRS. Generally the way I’m communicating with VRS is by sending GGA message to VRS if there’s no NTRIP data. But I constantly see a fix 2 when using sparkfun Reference Station, compared to using CORS mountpoints where I see a fix of 4. I also noticed the number of satellites in view drastically changes as well. when connecting to Reference Station, I see 1 to 2 satellites in view. But the number jumps to 8 or more when connected to a CORS mountpoint. Has this been an issue for you? Is there a way to achieve a fix of 4 using the reference station?
The quality of the GNSS antenna can affect the number of satellites in view and the quality of the fix. you have to use a high-quality, multi-frequency GNSS antenna.
Are you running in a classic RTK Base/Rover setup, with the Base utilizing an NTRIP Caster for corrections transport? Just want to make sure we are on the same page about your VRS configuration. If so, which device are you using for Base, which for Rover, and what NTRIP Caster platform?
I’ve never seen less that 15 satellites in view with any of our devices (given clear skyview, and a proper antenna). If you see 2, something is wrong with either your physical setup or your device configuration.
I would verify that the following settings are correct under the “Configure GNSS Receiver” menu in the reference station:
4) Set Constellations 6) Minimum elevation for a GNSS satellite to be used in fix (degrees): 10 7) Minimum satellite signal level for navigation (dBHz): 6
These three settings will conduct filtering of satellite tracking; were you to set option 6 to 60, for example, you’d significantly limit the number of tracked satellites reported by GGA.
From my understanding, RTCM should have no effect on SIV for either Base or Rover; the GGA messages generated by the receiver indicate the number of satellites it is tracking, not the number tracked by the correction source or sink.
What receiver and antenna are you using for your Base?
What receiver and antenna are you using for your Rover?
How are corrections getting from the Base to the Rover?
Which CORS mountpoint are you using?
When you say “where I see a fix of 4”, what do you mean? Is that the fix quality, is that the number of satellites used, the type of fix (like 3D Point, DGPS, RTK Float, RTK Fix).
I think there are some terms being confused, so clear descriptions will really help troubleshoot the issue you are seeing.
When you say “where I see a fix of 4”, what do you mean? Is that the fix quality, is that the number of satellites used, the type of fix (like 3D Point, DGPS, RTK Float, RTK Fix).
using the following chart as a matrix for fix quality:
So when I’m talking about a fix of 4, I mean RTK fix. I am aware that the receiver needs to see 5 satellites to get the RTK fix. But with the base mentioned in number 1, my receiver outputs satellites in view of 1 or 2. When connecting the same receiver to the NY CORS, it outputs the number of satellites seen ranging from 8 to 12.
Also checked the GNSS receiver configuration. This is what I have:
Set Constellations: GPS, SBAS, GLONASS, BeiDou, and Galileo.
Minimum elevation for a GNSS satellite to be used in fix (degrees): 10
Minimum satellite signal level for navigation (dBHz): 6
The Base sees 42 satellites in survey-in mode and then goes into casting mode. That’s when I’m connecting to it and getting NTRIP data where the receiver is outputting bad fix quality(2, Differential GPS Fix )