Should I be using low bandwidth mode for rtcm with Lora radios. My first try with it the age was very high like up to 90 seconds and then would drop to dgps. This was in my backyard about 40 feet apart. Baud and airspeed default rate. Facet and postcard.
Yes, lowering the data across the link will help it. RTK doesn’t need 1 update per second… 1 successful RTCM packet every few seconds is sufficient, with many RTK receivers lasting 60 seconds or more before losing RTK Fix if RTCM is not present (you’re seeing 90 seconds).
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Perfect slowly trying to perfect base rover setup in times I do not have cell service. Still need to master static. Then I think I can truly do it all with my sparkfun gear.
One could also reduce bandwidth by strategically slewing the constellations and satellites., across messages and time. The receivers don’t really facilitate this, but could be done in the transport layer.
I was mainly wondering if the amount of data versus the Lora was why rtk was dropping in and out, went to the manual and saw low bandwidth mode so my thought was maybe that would fix it.
LoRa has some ridiculously low bandwidth methods if you push the spreading factor out, ie several seconds for a few dozen byte, but a throw of >15 KM LoS with relatively low effort.
The LoRa methods at 10kbps have a throw of a couple of KM LoS. High physical placement of antenna at the Base, high gain, receive only at the Rover(s)
As RTCM3 is about fresh/timely delivery, I’d go with the higher bandwidths, and send more frequently. You ideally want sub-second latency, but once the carrier lock / ambiguity is determined, it can carry for 60s with maintained carrier lock