Hi all,
I have a site up in a forested, hilly area where I have logged and recorded two Base Station locations. With my know base coordinates, I input those manually into my base, and then walk around with my Rover recording different tree point locations in survey mode. Both of my Base and Rover are logging at the same time. I am getting a both float and fix on different points. My questions are:
Should my Rover be in static mode for this type of survey?
Is survey mode accurate enough with the exported .csv and shapefile to use these points or does further post processing need to be done?
If I need to do more post processing on my points, how do I export the ppk’d points to a csv from RTKpost?
My thoughts were that survey mode is a great way to keep a timestamp for every point taken, and if further post processing needed to be done I could reference those times to tease out my trees with better precision.
I’m not very familiar with using RTKLIB, but dmitriy.ershov and Michael Lambert are seen here on the forum a good bit. I use my M2 for static work only and PP with commercial software.
I don’t see any problem with your methodology. If it’s just basic tree location, you’ll probably be good to go with PP the points. If you have a short baseline to the base, you should log maybe at least 5 minutes per tree. That should give you at least sub meter accuracy and would verify the fixed solution if you get one.
Thanks for your reply Bryan. I’m not entirely sure how I can PP my points with RTKLib but I am scouring the Emlid Community for answers. @dmitriy.ershov What do you think?
That entirely depends on what your needs are? Can you tell us more?
There are multiple ways:
The manual: insert the start/stop times RTKPlot
The smart: use some of the provided community made tools like this one: PPK point extractor software
The paid: use EZSurv feeding it the raw files and the original csv, and magic happens.
Here’s a very good price for commercial PP software. A whole lot cheaper than the others we’ve got. Good videos also for learning. GPS, GLONASS, Galileo and BeiDou static, kinematic and Stop-and-Go data. $620
The data you download in csv format would depend on how the points were saved. If all your data is fixed, you’re good and csv file can be used immediately. If you’ve got a mix of fix and float values from the observations, the float points would have to be PP. I’d collect at least 3 minutes on each point if you have a short baseline and no fixed solution, then PP.
The non-fixed or float values could be a meter or more in error.
Thanks Christian,
I will continue my survey in static mode. As far as my survey goes, I am trying to collect every tree location, with tree id, species, diameter, and notes on whether they are alive, diseased, etc. I would like the location as accurate as possible, but I have over 2k trees in this plot, and don’t want to spend over 5 mins per tree. I have shown a fix within 1 min per tree, is that enough?
Thank you for the resources for ppk software. I will definitely look into those possibilities.
Thanks for the resource Bryan,
I have more fixed points than anything, but definitely have float values in there. Good point on staying longer for a float point.
My baselines can vary from very short (2-20meters) but also over 60m. For this I have logged 2 different base station locations within my plot to give me a shorter baseline on different sides of my plot. I’m thinking I might have to go log 1-2 more base station locations now.
Mannie
I think you’ll be fine with the small baselines. I’d collect at least 1 minute of data. Even if you get a fixed solution, you’ll have the data to PP. Keep in mind though, most commercial PP software will probably need at least 3-5 minutes data. Our software, usually requires a minimum of 5 minutes based on the collection rate, i.e. 10-20 hz. You can change some parameters, but you’ll lose accuracy. In your case, probably 0.5 meter would suffice
Hi Manuel… I haven’t had a chance to experience the new R3 software yet, I’m planning on buying two LoRa units soon for testing the M2’s for RTK.
I was glad I had my M2’s running the other day. Cell service is pretty marginal in some places around here and I found one ! I had good cell coverage in the a.m locating some property corners, but after lunch for whatever reason, I guess the weather maybe, I had no coverage. I PP my baselines with the M2’s and everything was good. I was in some very thick woods, sky mostly blocked by foliage. I used my Javad T2 with Victor LS controller for the rover. I occupied each property corner (6) 15 minutes per point. Baseline lengths were about 1200’ to 2500’ each, polygon closures for the loops were 1: 100K +, position accuracy was +/- 0.02’. I was amazed using just GPS and GLONASS sats.
I use the controller for all my COGO. Javad has some neat routines in their system.
