Emlid

Community Forum

RS+ Base / Reach M+ Rover (add LORA?)


(Stuart Stacey) #1

Has anyone experienced an EMLID RS+ base transmitting correction data to an EMLID Reach M+ on a drone for PPK (EDIT: RTK) mapping?


(Michael Lambert) #2

No corrections are being sent in a PPK scenario. That’s what the post-processing does. RTK or Real Time sends the corrections. You can get a LoRa antenna for an M+ though. I actually have one that I am going to test by putting it on my vehicle instead of the magnet mount and RS+ rover that I normally use. I thought about trying it on my drone, but without the ability to tag the images in real time it’s kind of a waste. I’m hoping that this is what the a-shot does. Not associated with this thread.


(Christian Grüner) #3

Experienced, nop, but is it possible? Yep!

But if you are doing ppk, why would you need Lora and an rtk solution? For navigation?


(Timd1971) #4

I guess the LoRa radio add-on would be handy for RTK for a future multi-frequency M++ receiver like the new RS2.


(Christian Grüner) #5

But only if the image files can get the coordinates at save time, with the same precision as usual.
I have not yet seen a non-integrated solution, that can do that.

Or of course to get rid of PPK all together, but that has is it drawbacks.


(Stuart Stacey) #6

Sorry Michael… You’re right. I should have said RTK. We do everything PPK for our sites … slip of the finger. :slight_smile:


(Stuart Stacey) #7

Christian, I agree. We fly with GCP’s and process PPK. However, its time consuming on a large construction site to replace GCP’s as earthworks takes place and digs existing ones out. We are currently exploring an M210 with a topodrone customized camera that is connected to a Reach M+. This is still a PPK process, as we take the logs from the base and rover, perform the corrections, update the EXIF image tags with the corrected data and then perform a final process on the cloud. I guess I started asking myself, could we not add a lora antenna to the reach M+, send corrections from the base… But as previously discussed, if we hit a FLOAT, which we have, then data is not good and you have to rerun. and yes, wouldn’t it be nice if the updated metadata were written directly to the images, rather than the steps needed.


(Michael Lambert) #8

This should not be the case with PPK. I previously used 10-15 GCP’s at 50 acres and then incrementally went up as size increased, but I have not used more than 5 or 6 since I have started using PPK. All the GCP’s are doing at this point are keeping the model in check and localizing. I do agree with @timd1971 statement above that if we can get a multi-frequency M+ then paired with the RS2 is a valid RTK solution. This is how the Phantom 4 RTK works, but I still would not trust a pure RTK solution on a drone. Especially if you are in any level of adverse conditions.


(Stuart Stacey) #9

Thanks Michael. I agree with the 5 or 6. We maintain many due to the number or rock trucks and excavators performing work and stockpiles being moved. I’m a fan of PPK but still testing our RTK solution with Reach M+. We have found float shortly after take off and fix is established on the first few turns and then back to fix, but that just means I continue tweaking with RTK while we maintain PPK for our work. Hence the thought of a Reach M and Lora antenna, connected to an RS2.


#10

IF a M2+ is used in RTK, it would most likely perfom better then M+ in terms of float vs fix but the PPK will also be better.
Unless there is a need for the RTK feature i would still pick PPK over RTK with a M+/M2+ unit.
As of now you would still need a ok link between base and rover for the RTK and from what i have seen, a small banking (depends on the situation) in turns will drop a connection, a M2+ would not save you there other then regaining a fix faster ones the connection is up again.
Until SSR is up and running and if the accuracy is good enough, refrence data is crucial in both RTK and PPK.


(Michael Lambert) #11

Theory of the number of GCP’s is from setting GPS control networks. The site needs to be “boxed” in with 4 and one in the center. One more may be needed if the site configuration is odd or the points get too far apart. It use to be about 600-800ft, but with PPK 1600-1800ft works fine. You can verify this with midpoint checkpoints.