Marine RTK or PPK survey

I will be using 5 RS2s to collect positioning for an overwater geophysics survey in the coming months. Initially I’m thinking 1 RS2 on shore acting a base station and the other 4 as rovers placed at various locations along a ~ 500 foot long sensor cable that is towed behind a boat. We’d like to know the positions of the sensors on the cable as we move up/down river.

My questions are:
For data collection software/hardware, will I need anything other than the ReachView app and a tablet?

Secondly, the furthest roving RS2 unit will be ~500 feet from the boat where I will be with the tablet. And we may be up to 2-3 miles from the base station (likely only 1-2 miles). I know the base station won’t have a problem pushing corrections to the rovers over the radio at this distance. However, will this ~500 feet distance exceed the BlueTooth / Wifi capability of the rovers communicating with the tablet on the boat? If so, is my option to just collect and store the data on the units and not worry about seeing anything in ‘real-time’? The data aren’t to be used for navigation only locating where the sensors on the cable were during the survey so it’s not the end of the world if so. My concern is not knowing if a particular rover drops signal or lock, etc and then having a few hours of no position data.

Thanks,

I think BT limit is 200ft? Read that Sokkia GPS can communicate via BT up to 700m. But that was for sending corrections to the rover. Not sure if it applied to the controllers.
I think there are no advantages to having real time data. Like you said, if your rovers/base lost satellite signals, there is really nothing you can do to get it back. Best approach would be to do the boat survey.Process the data. See which sections have missing epochs. Rerun.

Hi @dpsprink,

For data collection software/hardware, will I need anything other than the ReachView app and a tablet?

You can manage all built-in features of Reach using ReachView on your tablet. There is no need for any additional software/hardware.

However, will this ~500 feet distance exceed the BlueTooth / Wifi capability of the rovers communicating with the tablet on the boat?

The internal Wi-Fi module wasn’t designed for such long distances.

So why do you need a real-time connection between base and rovers? Do you want to output Reach RTK position, or you only need its position track after the survey is done?

Use the RS232 port and extend via an RS232 to RS485 converter. Depending how much you want to spend on conversion this could be 1 four core cable for up to 32 (from memory) GPS units.

Agreed, thanks Juan!

Hi Gleb,

For now the real-time capability is not required. In the future we’d like to do the data inversions in real time which would require knowing the positions of our streamer sensors in real time as well.

Thanks for the info about ReachView.

Hi @dpsprink,

It’s possible to configure Reach to output the position data calculated in RTK via an external serial radio. However, you won’t be able to collect points remotely, I’m afraid.

Hi @tatiana.andreeva,

Thanks that’s good news about adding an external serial radio for outputting real time positions.

I’ve posted a problem I’m having with an unresponsive RS2 unit in another RS2 “getting started” thread. Is there someone from the Emlid team that can advise me on my options for getting that unit to work properly?

Hi @dpsprink,

It seems Dmitriy has answered you in this thread. If you need further help, let me know.