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Integration of Reach RX2 with Mergin Maps for Android

This tutorial provides step-by-step instructions on how to integrate your Reach RX2 with Mergin Maps for Android via Bluetooth.

Overview​

Mergin Maps is a mobile app for Android devices that allows you to collect, share and publish geodata and collaborate with teams using instant sync with QGIS.

To integrate your Reach RX2 with Mergin Maps via Bluetooth, you will need the following:

  • Reach RX2
  • A device on Android
  • Mergin Maps mobile app installed on your Android device
  • Mergin Maps account

Workflow​

To integrate your Reach RX2 with Mergin Maps follow the steps below.

Configuring corrections in Emlid Flow​

note

Reach RX2 uses Bluetooth and streams its position in the NMEA format by default. No pre-configuration is needed.

tip

For more information on how to receive corrections on your Reach RX2, refer to the Quickstart section.

To achieve centimeter-level accuracy when surveying with Reach RX2, set up your receiver to receive NTRIP corrections in the Emlid Flow app. Do as follows:

  1. Open Emlid Flow and connect to your Reach.

  2. Go to Correction input and tap NTRIP over Bluetooth.

  3. Tap the Edit button to configure receiving corrections from the NTRIP base.

    note

    To start receiving corrections, make sure that your receiver has satellite visibility.

Enabling tilt compensation​

Reach RX2 supports IMU-based tilt compensation, allowing you to collect and stake out points even when the survey pole is tilted. The software calculates the tilt angle and distance to determine the pole tip position on the ground. To enable tilt compensation, follow the How to enable tilt compensation guide.

Setting up NMEA stream in Emlid Flow​

By default, Reach RX2 automatically streams the standard NMEA messages set. In this case, you need to set up your Reach receiver’s antenna height in your third-party software.

If you want to stream a compensated position of your Reach receiver, you need to enable it in Emlid Flow. In this case, the antenna height is included in the output, so you don’t need to set it up in your third-party app. To set up compensated NMEA messages, do as follows:

  1. In Emlid Flow, open Settings and go to Integration with external software.

  2. Turn on the toggle to enable streaming compensated position.

  3. Set the antenna height. You only need to enter the pole height. Emlid Flow automatically applies the antenna phase center offset and adjusts the measurements accordingly.

    tip

    If you use a quick release, turn on the toggle to include its height in the antenna height calculation.

    caution

    When sending compensated NMEA messages, set the antenna height only in Emlid Flow. Setting it in third-party apps as well may cause discrepancies.

Paring Reach RX2 and Android device​

To find your Reach RX2 in the list of devices in Mergin Maps, you need to pair it with the Android device as follows:

  1. Navigate to the Bluetooth configuration screen on your Android device and enable Bluetooth.

  2. Wait for your Reach RX2 to be listed as an available device.

    tip

    Keep Reach within a few meters from the device.

  3. Tap the name of your Reach in the list of available devices on the Android device.

    note

    If your device requires a PIN code, enter 123456.

  4. Pair Reach with the Android device.

Configuring communication between Mergin Maps and Reach RX2​

  1. Open the Mergin Maps app and create an account if you don’t have it yet to access the app.

  2. Open or create a new project.

  3. On the opened screen in the lower right corner, tap More and Settings.

  4. In Settings, tap Select GPS receiver.

  5. Tap Connect new receivers.

  6. Choose your GPS receiver from the list of Bluetooth devices and wait until it's connected.

  7. Go back to Settings and set the antenna height. For Reach RX2, the antenna height is the distance from the mark on the ground to the center point on the Reach’s bottom, antenna reference point (ARP), plus the height of the receiver to the antenna phase center (APC), antenna height offset. The antenna height offset equals to 145 mm.

  8. Go to the GPS tab and check the RTK status and accuracy on the map. To check the detailed GPS info, tap the tab one more time.

Now you are ready to start collecting data!