I’m considering using 2 facets (base and rover) for the RTK capability. The Facets will be fix mounted within 40 feet of each other… I would like to hardwire the radio comms… Is hardwiring and option with existing connectors? The project will be used outside cellular coverage.
Can I setup the RTK at my workshop on simply turn it on once it is onsite at final destination?
Hoping for some guidance on this topic… What’s the best way to get technical support? This is an active project and the interconnect is being designed.
You have a few options.
As of firmware v2.4 you can use the devices themselves with no external radios. The ESP32 can be used point to point to broadcast data up to ~800ft line of sight. See the docs: https://docs.sparkfun.com/SparkFun_RTK_ … nu_radios/
Is hardwiring and option with existing connectors?
Yes. The Radio ports would need to be wired to each other with only two pins: The TX pin of the base needs to go to the RX pin of the rover. The GNDs between the two units needs to be connected. However, the serial coming out of the units is 3.3V TTL which means the data will degrade over a series of feet. I suspect >20 ft it will have problems. 40ft might work. You will likely need to convert the TTL to RS-485 or some other industrial or differential pair type signal.
The project will be used outside cellular coverage.
I personally would use a 100mW telemetry radio (https://www.sparkfun.com/products/19032) or the internal ESP-Now radios. But note we just added support for the internal ESP-Now radios last week so, while it’s been thoroughly tested, it is still new. One of the major limitations is that Bluetooth SPP does not work at the same time as ESP-Now. If your rover’s data collector supports Bluetooth BLE (ie, SW Maps) it works great.
Can I setup the RTK at my workshop on simply turn it on once it is onsite at final destination?
Mostly yes. I recommend lots of practice setting up an RTK system where it’s easy (ie, the parking lot, near a computer, etc) before heading out into the field. But the antennas really need a clear view of the sky to complete a survey in and obtain RTK fix.
Thanks sparky, the facets are slated to be mounted subsurface inside a steel frame with the antennas at the surface with unobstructed sky view. I am planning on a shielded twisted pair for the hard wire setup. I’ll let you know how it goes.
I’ll try the point to point first to see if the steel frame hinders comms.
Once the base / rover are setup at the shop I shouldn’t need my phone to do any setup in the field right? Likely no cellular reception in many cases.
Once the base / rover are setup at the shop I shouldn’t need my phone to do any setup in the field right?
It’s hard to say. Are you doing a temporary base setup? If so, you’ll need access to the base unit to power it on, and press the setup button a few times. That should be all you need. The base will start transmitting RTCM out the RADIO port, the rover will receive it, and very quickly (1 to 2s) get RTK fix (assuming both units have good SIV).
You certainly won’t need cellular connectivity but I always seem to need to pull out my phone, put the device into config mode, and configure some setting over WiFi AP config mode.
Certainly come back and let us know if 40 ft of twisted pair is good enough for RTCM. I suspect it will work but now I’m curious 
Are you permanently mounting these? I wondered when I read your statement “Facets will be fix mounted…”
In case you are, SparkFun doesn’t recommend the Facets for permanent outdoor mounting. You might want to see the “Important” note at the bottom of the Facet product page. Sparkfun has other products for external outdoor permanent mounting.
Sorry for the delay, I’ve been on the road… The end application is for permanent outdoor fixed mounting. These facets are being used for proof of concept only and will probably die for a just cause. We’ll do some weatherproofing but hopefully the proof of concept testing will only have them outdoors during “nice” weather.
Thanks for the heads-up!
sparky:
Once the base / rover are setup at the shop I shouldn’t need my phone to do any setup in the field right?
It’s hard to say. Are you doing a temporary base setup? If so, you’ll need access to the base unit to power it on, and press the setup button a few times. That should be all you need. The base will start transmitting RTCM out the RADIO port, the rover will receive it, and very quickly (1 to 2s) get RTK fix (assuming both units have good SIV).
You certainly won’t need cellular connectivity but I always seem to need to pull out my phone, put the device into config mode, and configure some setting over WiFi AP config mode.
Certainly come back and let us know if 40 ft of twisted pair is good enough for RTCM. I suspect it will work but now I’m curious
I’ll keep you in the loop!