I have built a rover using an APM 2.7, Sabretooth 2x32 speed controller, 12V brushed motors.
This youtube video gives a quick demonstration of what it is. It still needs a lot of work! I operate a vineyard on Australia and I hope to develop my machine to be accurate and reliable enough to drive between rows of vines spaced about 3 metres apart. The maximum range of the rover from a base station would be no more than 1000 metres.
The next stage of development is to upgrade to a Pixhawk controller and use a relatively low cost RTKGPS.
I was wondering if anyone would have any advice on which RTKGPS would be the best to try?
I am considering 4 options. (just because these are the low cost systems I am aware of)
Piksi from Swift Navigation
Reach from Emlid
RTKite from North Surveying
Precis from Tersus
I would be interested an anyone’s feedback and experience with these systems.
Thanks for your time and for the help this forum has already given me.
Hi Stephen. I’ve had limited experience only using the Piksi. My thoughts are:
An RTK fix takes a bit of time to get i.e. when you’ve turned everything on and are ready to go be prepared to wait 10-20 minutes to get an RTK fix.
A dual/multi frequency GPS i.e. (L1, L2 and L5) will be more accurate because the multi frequencies allow the “math” to handle atmospheric disturbances but they are more expensive. A single frequency GPS may be accurate enough for your needs.
When vendors say they get mm accuracy they are lying
I think the weaving is occurring probably because your NAVL1 is too high. The vehicle can’t corner hard like an RC car so it needs to be higher - say 14 or so.
Thanks for your comments and advice Grant, much appreciated.
I have implemented a tracked vineyard rover based on ardurover/pixhawk. I will post some video next week but I am able to get 20mm positioning accuracy and after some weeks of tuning have got the 900 Kg vehicle to drive perfectly. It now navigates the rows and can perform autonomous spraying. I tried many rTK solutions but the RTKite from North works the best. I use a ground station for correction over UHF link because cellular coverage (CORS) was not reliable. Good luck. Juan at North tech support is excellent and he helped get the RTKite to work with version 3.
PS the RTKite gets RTK lock within 1 to 3 minutes. You will lose fixed lock if you are of line of sight of the ground station antenna and also if you go under heavy tree cover but this is not so likely in a vineyard environment. My next task is for the rover to perform autonomous inspection of the grapes, measuring grapes per cluster, clusters per meter and also color. I also use it to scare birds by driving along with a speaker shouting recorded obscenities. The birds here only seem scared of yelling people !
Thankyou Heliboy for your comments, they are very much appreciated. I am looking forward to the video
Swift is aware of these issues and is planning new products to address these concerns. Stay tuned at Intergeo.
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