I’m coming to this forum for some help because I know there is lots of knowledge here. I built an RTK basestation this summer to used with my Trimble Autosteer systems in my tractors. I’m using a Mosiac X5 board and the system works absolutely perfectly under all scenarios but one. For two of my rovers I have NTRIP clients that feed serial RTCM data to the device by connecting to a hotspot. One device is an RTKonnect from Back 40 Precision and the other is a WIFI NTRIP Master on a serial board from Ardusimple. Both work absolutely perfect and the RTK age stays between .6 and 2 seconds.
My other option is a 4G NTRIP Master from Ardusimple and the same serial board. All basestation settings are the same but with this board my RTK age often goes past 10 seconds and sometimes disappears for up to a minute. The light on the board shows a steady cellular connection and my SNIP server does not show a disconnect. I’ve had it running on my desk for several days at a time without a disconnect. I’ve also tried different SIM cards. Where do I start?
Probably start by analysing the data received and the latency.
It’s a continuous stream, with new / current data provided immediately.
TCP/IP probably overkill as it forces the transport to keep trying, and acknowleging, potentially pushing out latency further.
Use HIGH baud rates the rate too/from the modem can reduce latency there. Less hops the better, including in-out of various MCUs in the chain of custody.
Data needs to arrive within the current second, ie tending toward 200 ms rather than 1000, end-to-end. The receivers aren’t looking to dig into the distant past to align observations.
WIFI is likely to provide higher bandwidth/speed, although it’s throw is very limiting.
Perhaps 2 Hz, UDP ? It’s ultimately a One-Way broadcasts of data, the rovers don’t need to be interacting, though NTRIP is often pushing GLL to confirm it’s alive, and within the service area.
I’ll try to add a little bit more. When I say WIFI, I really mean iPhone/iPad delivered WIFI. The difference being that my phones use Verizon and the 4G NTRIP Master can only use T-mobile (i’m using a reseller SIM). A friend is using the same reseller SIM in a different system with perfect results as well so I don’t think its a SIM issue. Also, I have a different tractor with built in cellular NTRIP on Verizon and it works perfectly as well.
Both the WIFI and 4G systems are configured at 115,200 baud. My RTCM stream is only 6 messages being sent at 1hz.