So I am using the RTCM3 format currently with Slingshot.
“The RTCM 10402.3 standards defined the messages for differential correction information. There are 64 types of messages. The message format is a sequence of 30 bits. The messages 1 to 17 are available in older RTCM versions, while messages 18-21 have been added in version 2.3 to made the standard applicable to RTK corrections.”
Diversity is a scheme where you usually have two antennas, and the device with antenna diversity will pick the best antenna of the two. That may change depending on which way the tractor is facing, etc.
…just came across a quote in their FAQ as well:
The way I read it, you have a base station somewhere (at your equipment dealer, or at your house) and that is connected to the Internet, so it can serve out RTK corrections (probably RTCM3). Then in your roving vehicle (tractor), you have a Slingshot field hub, which is basically a cellular modem with some extras. It has a GPS antenna, but that is not for RTK, only for reporting your location back to someone. The field hub must have some internal computer which can be set to log in to a NTRIP caster to get RTCM3 messages and then repeat them out the RS232 port. Your 750 must be taking those corrections in over RS232, and processing them against it’s own rover data.
Does that sound correct?
If so, then in the tractor, you would have:
Internet --> Cell modem --USB-cable–> Reach RS+ --RS-cable–> --Trimble-cable–> CFX-750
At the base station, you would have:
Reach RS+ --Wi-Fi–> Router --> Internet
(of course there could be a few variations on that)
Are you planning on having the Reach M+ act as your base, and then pipe corrections through to the Trimble CFX-750 (rover)?
If so I don’t want to burst your bubble, but I’ve run a similar setup with both Topcon and Leica receivers acting as rovers with Reach RS serving corrections from the base. Unfortunately it does not work.
On the other hand with an L1/L2 receiver at the base serving corrections to the Reach as rover then it should work, although we have found the fix to be a little slow and unreliable - although I don’t think this is what you are attempting to do.
Yes – I am planning to use one reach unit as the base station fixed in the farm yard. Planning on using a second reach unit in the tractors as the rover. Will pipe the corrections over to the CFX-750 via RS-232.
The current RTK system, the base stations stay on 24/7 but when you boot it up sometimes it can take upwards of 1/2hr to get a fix. But that doesn’t really matter as once it is up an running it should stay that way.
In your current system, your receivers on your rovers (tractors etc) should be getting an RTK fix within a few minutes if not well under a minute. Waiting 30 minutes to get a fix on a commercial RTK system, there is something very wrong there.
Secondly as pointed out above a Reach (base) to Reach (rover) connection will work fine, but I’ve yet to hear of a successful Reach (base) to third party L1/L2 receiver (rover) setup working. I’ve tried several different receivers now (TopCon, Leica, ComNav) and none of them remotely get a fix with Reach RS serving corrections from the base running ReachView 2.11.0. I’ve not yet tried with the new 2.14.0 stable release, but I’m not expecting any different results. So if you were to connect a Trimble/PacCrest radio to the Reach RS at your new base so it could serve corrections to your CFX-750 it in all likelihood won’t work.
Now for the second scenario with a ReachRS rover in conjunction with the CFX-750: as your CFX-750 has a full receiver built into the screen, if it’s unlocked for RTK you can feed it RTCM corrections directly via an NTRIP or via the internal/clip on Trimble UHF radio or serial port.
However connecting a Reach RS receiver to the CFX-750 will not help in this respect - the Reach will only be able to output an NMEA position/heading message stream serially. This is no use to the CFX-750 as it is already computing its own position (from its own GNSS antenna). Furthermore there is no facility to input an NMEA stream into the CFX-750 only for that unit output an NMEA stream. What it wants is RTCM (or CMR) based correctional messages - and as said if you feed it those from a Reach base it very likely won’t work.
Trimble can get corrections via NTRIP and via RS232 with Teltonika RUT955 router. We have developed this feature so that RUT955 can be used as a link (Over LTE) between navigation device (Trimble, etc) and RTK base station.
However I am not sure if it would work with your setup as I understand only half of what you guys are talking here about.