Good insight about the coax. Am I asking for trouble by thinking I can get away with two telemetry (RFD900s) and a GPS cable running 10m along side each other going to the roof peek?
Most of the Chinese ā915ā antennas are tuned for 868, and fall off a lot at 915, so its a crapshoot. The ones I bought were tested by a commenter and peaked at 915. So Iām hopeful, but its been a month. I have no good way to mount antennas high and outside. Even lifting my PC-side stock antenna up a couple feet inside the house gets me from 70% to 85% in MP.
Likely not ideal but I think youāll be fine. Let us know the results! Good luck!
If you only have a 1/4 acre (or did I miss something about more acreage?), you will have no problem with any of the suggested radios and antennas. I expect the cheapest 100mW units with stock antennas would work. I am very confident that the the RFD900 pair with stock antennas will work.
If you improve the antennas a little, you will certainly be fine.
I would try to separate the GPS coax from the telemetry radio coax by a fiot or so if easy to do. You may have no trouble with your current configuration, but it would be best practice to separate them.
As @Swebre2023 stated, it will likely be fine.
Thanks guys, itās the combination of big canopy trees and my dense head Iām most worried about. Figured Iād go big on my first attempt and fail fast if Iām gonna. Iāll make a separate thread for my progress.
1 Like
RFD900ās assuming RFD900x but brilliant little units either way.
Gotchaās are needing their own power as they will brownout your Flight computer when turned up to high power. Iāve got 20km easily on these, but mowing sections that slope off so no line of sight gets a bit iffy.
1 Like
Choose the Ideal Mower System Control
Iāve assembled a short table of possible systems I am considering based on the leading hardware and would appreciate your view of which (or none) is best for a mower running Mission Planner. Iāll post the results in a week or so.
A B C Other
CubeOrange+ x
Pixhawk6C x x
Other Autopilot?
SimpleRTK2B (x2) x
H-RTKF9P (x2) x
UM982 x
Other GPS?
Cost $$$ $$ $
Time to Set Up?
Programming Skill?
Field Reliability?
Iāve assumed a compatible base station (e.g., H-RTKF9P Base), telemetry set and power management are included. This is all for upgrading my SODAR-controlled mower to RTK.
Thanks for your thoughts!
1 Like
Sorry, the table got garbled in translation.
System A = CubeOrange+, SimpleRTK2B (x2), $$$
System B = Pixhawk6C, H-RTKF9P (x2), $$
System C = Pixhawk6C, UM982, $
Your methodology is flawed.
The Cube Orange+ and Pixhawk 6C are, for all intents and purposes, equivalent hardware. The Cubeās heated and damped IMUs are largely irrelevant for the slow-ish inner control loop utilized by and lack of 6DOF stabilization required by Rover firmware.
The only difference between SimpleRTK2B performance and any other Zed-F9P based system is antenna choice, which you have not specified in the case of the SimpleRTK2B. Practically speaking, though, you could expect identical performance.
Additionally, youād be hard pressed to note a real, practical difference between UM982 performance and Zed-F9P performance in a Rover use case.
Essentially, given the options presented, choose the price point and form factor that most appeals to you. If you feel you have the skillset to eek every last drop of performance from your system, the Cube Orange+ and pair of SimpleRTK2Bs coupled with survey grade antennas would be VERY slightly preferable.
And why not just continue the conversation youāve already started here?
Thanks much for your insights. I couldnāt figure out the differences between these choices given the reading I have done, and you have answered that question in detail. My reading also suggested that the UM982 was difficult to use. I hoped to solicit answers to the three questions at the bottom from the experience of others in this thread, and you hit on an important one. My skill set in AP is negligible since I havenāt used it yet, and the learning curve appears to be pretty steep. While Iām fluent in C, I hoped to not have to re-develop what I already have in a different environment. Price point for me is last since the time spent debugging eats up the differences pretty fast. With that said, have you found substantial differences in this aspect of getting my straw-men examples to work?
Thanks again!
The CUAV C-RTK 2HP and Holybro H-RTK Unicore UM982 are probably the easiest to configure amongst anything discussed here, and both offer excellent value.
You shouldnāt need to write any source code to get a mower running via ArduPilot Rover.
Thank you, sir! Just what I needed.
1 Like
For those following this topic with interest in the UM982 based GPS modules, it appears that the CUAV C-RTK 2HP passes the rover antennaās position to the autopilot, which really threw me for a loop when I was setting up the GPS_POS* offsets.
Unlike the uBlox dual module config, you use the GPS1_MB* parameters to specify the relative positions of each antenna and establish the orientation for yaw/heading calculation.
Only one GPS instance is passed to the autopilot, and for best overall performance, you should still use the GPS_POS* parameters to specify its position relative to vehicle center (or pivot center, for skid steered vehicles). For this particular model, the rover antenna (which I usually set up as GPS2 with uBlox modules) is the reference.
I hope thatās clear as mud!
3 Likes
Yuri, very interesting. For the C-RTK2HP, it appears we have parameters GPS_POS1_X, _Y and _Z., and GPS_POS2_X, _Y and _Z. and GPS_MB1_OFS_X, _Y and Z. Seems like either way, we should set GPS_POS1ā¦ However, GPS_MB1_OFS and GPS_POS2_X, _Y, and _Z are redundant. You apparently set position of GPS 1 (Master), with reference to center of gravity (or pivot center for skid-steer), and then either the offset between the two antennas or the position of the second antenna wrt CG. You appear to be saying that setting position of Antenna 1 using POS1, and the relative position of the slave antenna via MB1_OFS. would get the best result? That is what CUAV recommends. They donāt apparently recommend using POS1 and POS2 to set the position of the two antennas on the rover. Also pretty muddyā¦
1 Like
There is no redundancy.
GPS_MB1_OFS* sets the position of the rover antenna relative to the moving base antenna.
GPS_POS* sets the position of primary GPS instance antenna relative to the vehicle.
2 Likes
There are a number of LoRa telemetry radios now available on Amazon. Has anyone used one of them? The price is attractive as is the claimed range and power. A couple of YTās claim success. Like: Amazon.com
OR https://www.amazon.com/REYAX-RYLR998-Interface-Antenna-Transceiver/dp/B099RM1XMG/ref=pd_bxgy_thbs_d_sccl_1/145-8977615-7971430?pd_rd_w=7kdN9&content-id=amzn1.sym.f7fa8b58-6436-47b8-8741-9e90c231669e&pf_rd_p=f7fa8b58-6436-47b8-8741-9e90c231669e&pf_rd_r=MBNZGQZ1B3QYYTC8PC41&pd_rd_wg=gST8Q&pd_rd_r=1fb37061-cf78-43aa-a184-fe6b2ba65689&pd_rd_i=B099RM1XMG&psc=1
range and power - excellent. Bandwidth - very low (0.3 Kb/s - 27 Kb/s) trading rate for range.
We use them for alerting purposes - with the very cool https://www.thethingsnetwork.org/.
Simple telemetry like gate open, or trap set works well for us.
Im guessing if you could define your telemetry requirements way way down, you could make it work.
Im thinking wifi6 and even bluetooth5 are getting very capable in range bandwidth and price.
Hello, again, I am working towards an RTK-implementation for a rover using a Pixhawk6c and a UM982 for yaw detection. It was recommended to me that I get a TX16s for manual control to/from the garage to the outdoor places for Mission Planner to take over. Can anyone please point me to setting up this transmitter for a rover? All the youtubes out there are for aircraft, and I have no idea what the difference is between one āflight modeā and another. Thanks!
For an RTK mower the main flight modes you need are manual and auto. Most of the time you are in one of those 2 modes and the transmitter is how you switch between the 2 modes normally. There are other modes that are used during tuning (like acro mode) and other less used modes you will get into later.
I have never set up a TX16s transmitter but I do know it is an advanced piece of equipment that can turn into a big learning curve.
We need one of our users who actually use that model of transmitter to offer advice.
I may have answered the wrong question but the basic information on setting up any transmitter for use with a rover is discussed in the radio Control Calibration section of the Ardupilot Rover WiKi Radio Control Calibration ā Rover documentation
The channel assignments for the transmitter switches and joy sticks are very important. For this information to be helpful, the transmitter has to be able to communicate with Mission Planner. When I connected mine it was pretty automatic, Mission Planner detected the receiver being connected. Mine is a very simple transmitter connected using SBUS. However, I am sure yours will be different.