Survey Coordinate entry. RTK GPS and even drone, help...

Help, problems, suggestions about Waterski Homologation software
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Re: Survey Coordinate entry. RTK GPS and even drone, help...

Post by emmanuel » Wed Jun 20, 2018 1:06 pm

If you find such a tool, I am VERY interested in it, at least to check what I program...
or to use, if I don't success in that programming !

Not a lot of thought on that type of survey, as I am not surveying any waterski courses anymore.
It is surely one of the possibility for the future.


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Re: Survey Coordinate entry. RTK GPS and even drone, help...

Post by tjones99 » Sat Jul 14, 2018 11:46 pm

I was at the site today and wanted to redo the coordinates I had that were Float (less accurate) vs Fix from the original survey and it was really calm and things were working well so I just redid the survey completely. Attaching the CSV file.

There were issues with elevation in the previous survey, these seem to be very close in this survey.

At first glance I think this may be a good result!
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Re: Survey Coordinate entry. RTK GPS and even drone, help...

Post by tjones99 » Tue Jul 17, 2018 3:12 pm

Status update... if you have read this far then you are interested and I should follow through and keep things up to date...

Last Saturday I redid a survey at the lake. new data, better data (in RTK terms the data points were solution status FIX vs float meaning they should be cm accurate...)

Since then, lots of discussion with Emmanuel and lots of education on coordinate conversions from Lat Lon height to XYZ and UTM coordinates and short answer is I had no idea how to move from one to the other but I am piecing it together with help from many people like Emmanuel and a few people on the Emlid Reach forums (The GPS units are Emlid Reach units).

Epiphany was I needed to convert from LLH (Latitude Longitude height) that the GPS unit survey output produces to UTM coordinates (ie XY on a flat plat for a particular region on the globe) and I found NCAT by NOAA does that. Took the conversions and plugged them into the homologation software and got my first survey.

Here is a picture of the rover on the lake over a gate ball. The pink arrow shows where my Base unit is located on the top left corner of the steel shipping container.
Rover.jpg (261.78 KiB) Viewed 1972 times

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Re: Survey Coordinate entry. RTK GPS and even drone, help...

Post by tjones99 » Wed Jul 25, 2018 4:15 am

Just a further follow up post.

First, HUGE thanks to Emmanuel who did all the heavy lifting to integrate this new approach into the software! I was expecting this to be a long term project and it is already available.

Since it is now possible, a little more info is needed if anyone is interested in trying this approach.

First a warning... you can't just go out with your handheld GPS unit and survey your course. Regular GPS is nowhere near accurate enough. RTK or Real Time Kinematics reduce the GPS error by referencing a fixed location. Its still not as simple as it sounds... it takes two GPS units, one at a fixed location called the base and one that moves from ball to ball called the rover. The base unit communicates with the rover and they figure out where the rovers is by looking at where the GPS signals tell the base it is located and where the SAME GPS SATELLITES say the rover is... all this happens in real time using high end GPS receivers and a radio link.

The units I am using are Emlid Reach RTK units.
It looks like the original Reach units I am using have been replaced by a more "finished" unit called the Reach M+
You need two of these to survey, so that's $650US for the pair with antennas. You need radios that plug into them and those are about $50US a pair they are known as SIK radios or 3DR radios. So the emlid solution is a $700US solution. Not cheap, but not as expensive as a Total Station survey instrument with prism and tripod.

The big plus is this is a one person solution. Park the base unit on shore. Take the floating unit out and survey. All you do is place the rover over each ball, collect the position, move on to the next ball. The traditional Total Station survey is a minimum two person task and the instrument costs more. Another plus is that this can be relatively simple, you don't have to spend a lot of time trying to figure out how to use a Total Station. Additionally, I have found that the best time to view the iPad is NOT mid day in bright sunlight, so surveying late in the evening when its too dark to ski is ideal! The lake is usually calm and no skiers to make waves and mess up your survey!

The Emlid Reach units have a lot of "smarts" in them, they have their own wifi capabilities, all you need to do the survey is a wifi capable device with a web browser such as a laptop or a tablet or even a smartphone, though having a larger display like a tablet helps.

There is some DIY work required to get the whole setup wired. Radios have to be connected to each unit. The GPS antennas have to be mounted on metal "ground planes" and the rover is best if made pretty waterproof. Then there are the configuration settings on the Reach units themselves to turn one into the base and the other into the rover and to set up the radio communication for the GPS corrections to pass back and forth between the units.

Once set up, then you simply connect to the rover's wifi and using a web browser (Safari/Chrome/Edge etc) you connect ot the rover and us the built in survey tool.

In the survey, you collect a point at each ball. To use the drag and drop integration that Emmanuel added to the GPS input, you must name each point the same as the balls in the element you are surveying. ST1 St2 PG1 PG2 B1 B2 G1 G2 etc... The survey from the reach units is a CSV or comma separated value file and the header line identifies the name, latitude, longitude and height from the survey and these will import seamlessly into the Homologation software.

This is still just an overview... questions? Fire away.

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