Base and Rover setup
This tutorial will show how to set up two Reach RS/RS+ units as rover and base and how to make them work over LoRa radio in RTK mode.
For setting NTRIP base corrections, follow the steps from "Working with NTRIP service" guide.
Renaming Reach devices¶
By default, every Reach has the same name, and the first thing we will do is renaming them so it’s easier to distinguish base and rover in the field.
How to define Reach?
There’s an easy way to understand which unit you are connected to. Just open the menu and tap the lamp-shaped button. All LEDs will blink simultaneously.
Connect to Reach RS/RS+ you want to use as a base
Go to settings and change the name to reach-base. This name will also be used as a Wi-Fi network label when Reach RS is in hotspot mode
Use a special sticker from a package to mark the unit.
Do the same with the second Reach RS/RS+. However, use reach-rover name instead of reach-base.
Setting up base station¶
Now we’ll configure RTK settings and communication between base and rover. Let’s start with the base.
Connect to the base unit
Open RTK Settings tab and check that GPS, GALILEO and either GLONASS or BeiDou are enabled. Remember the selection of the satellites on your base, you will need to enable the same systems on the rover unit
Choose which one to use depending on your location. While GLONASS covers most of the world, BeiDou might be more efficient in the Asia-Pacific region.
- Set the update rate at 1 Hz
Now we’ll set up LoRa radio on Reach RS/RS+ base to broadcast RTK corrections.
Go to Base mode tab and in the Corrections output section select LoRa
In the list of RTCM3 messages select to output GPS L1 observations at 1 Hz, ARP station coordinates at 0.1 Hz, GLONASS L1 observation at 1 Hz and GALILEO or BeiDou at 1 Hz
Set the output power to 20 dBm and air rate at 9.11 kb/s
Make sure to select appropriate output power and frequency according to your local regulations.
- Apply settings and wait until base averages its position in Base coordinates box
Setting up rover¶
Connect to the rover unit
Go to RTK settings tab
Set the positioning mode to Kinematic, GPS Ambiguity resolution mode to Fix-and-hold and GLONASS Ambiguity resolution mode to ON
Select the same GNSS systems as for the base, set 5 Hz update rate and press Apply
Now we’ll configure LoRa radio on the rover unit to receive the corrections.
Go to Correction input tab
In the Base correction pick LoRa
Frequency and air rate settings must match what was configured on the base
Apply changes and you will see rover is connected to the base
To make sure that corrections are passing from base to rover, you can put both receivers by the window for a few minutes to provide the sky visibility. Go to the status tab on the rover unit. Colorful bars are standing for available satellites. If LoRa is configured correctly, they’ll be accompanied by grey bars. These are standing for the corrections received from the base station.
Placing Reach RS/RS+ module¶
Once the units are configured, we can move to the field. For the field works, you’ll need a tripod and survey pole. You can also use a photo tripod and monopod.
To mount Reach RS/RS+ on the survey grade tripod or pole use an adapter that comes with Reach RS/RS+. Also, attach the LoRa antenna.
Mount Reach RS/RS+ base and accurately level the tripod. Put the rover on the pole. Turn on the devices.
There should be no obstacles near the antenna that could block the sky view higher than 30 degrees above the horizon. Do not test the device indoors or near buildings, do not cover the sky view for the antennas with laptops, cars or yourself. RTK requires good satellite visibility and reception.
A guide on how to properly place the antennas is available in Reach RS/RS+ placement section.
Let’s set up the base station.
Connect to the base
Go to Base mode tab
In the Base coordinates section select Average single and set averaging time. The longer you choose to accumulate data, the more accurate base position you get. Don’t move the base while Reach RS is accumulating data
Once the position is calculated, press Apply
Go to the Status tab on the base station to assure ReachView shows plenty of green satellites
Connect to the rover and check the status tab. If everything is configured correctly, you’ll see a lot of green satellites accompanied by grey bars.
Go to the Status tab of the app on the rover device.
Below the SNR chart, you’ll see the current solution status.
Single means that rover has found a solution relying on its own receiver and base corrections are not applied. Precision in standalone mode is usually meter-level
Float means that the base corrections are now taken into consideration
Fix status means all ambiguities are resolved and RTK solution is centimeter-level accurate
After a short period of time, the rover gets a fixed solution and you'll see AR ratio is growing. In good environments, it will take around a minute to get a fixed solution. In tough conditions, it may take a little longer. Once rover gets fix status, we’re all set for work.
Scroll the status tab down to see your location in the real-time.