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Integration of Reach RS3 with Aplitop TcpGPS for Android


This guide is also available in Spanish.

This tutorial shows how to integrate your Reach RS3 with the TcpGPS app for Android devices over Bluetooth to collect and stake out data in the field in RTK mode.


Aplitop TcpGPS is a mobile app for Android devices that allows you to collect and stake out data in the field in RTK mode.

To integrate your Reach with the Aplitop TcpGPS app, you'll need the following:

  • Reach RS3
  • A device on Android OS v7.0+
  • Emlid Flow v9.2+
  • Aplitop TcpGPS v2.6+


To integrate your Reach RS3 with the Aplitop TcpGPS app follow the steps below.

Configuring Reach RS3 settings in Emlid Flow

First you need to configure correction input, enable tilt compensation, and set up position streaming in the NMEA format on your Reach RS3 in the Emlid Flow app. Follow the steps below:

  1. Open the Emlid Flow app and connect to your Reach using Wi-Fi.

  2. Go to Correction input and select Bluetooth.

  3. Go back, tap Settings and tap the IMU option.

  4. Tap the TURN ON IMU button.

  5. Wait until the "Waiting for FIX" message appears in the status bar.

  6. Go to the main menu. In Settings, select Position Streaming 1.

  7. Select Bluetooth and tap the Edit button.

  8. Select NMEA as format.

  9. Tap NMEA settings. Select GGA, GSA, GST, EBP, and ETC messages with 5Hz frequency and GSV message with 0.5Hz frequency. Then, tap the Apply button.

Configuring communication between Aplitop TcpGPS and Reach RS3


Make sure Bluetooth is enabled on your Android device.

  1. Open the Aplitop TcpGPS app and tap the receiver icon next to Device type.

  2. On the opened screen, select the following:

    • GNSS External Receiver (Bluetooth) for Device type
    • EMLID for Brand
    • Reach RS3 for Model
  3. Tap the Receiver button and select the Bluetooth device. If the receiver is not on the list, tap the Search button.

  4. Tap the Connect button and wait for the configuration of Reach.

  5. Tap the forward arrow button and on the opened Working mode screen, tap the Rover button.

  6. Configure NTRIP to send RTK corrections over Bluetooth.

  7. To set up the NTRIP server, tap the three dots button and specify the following parameters:

    • Name of the profile
    • IP
    • Port
    • User name
    • Password
    • Mountpoint

    After that, tap the OK button.

  8. Tap the Connect button and check that the number of bytes sent and received grows.

  9. Go back to the Working mode screen and tap the Tilt button.

  10. Enter the antenna height and tap the Activate tilt button.


Antenna height can be changed in the status bar after activating the tilt compensation and creating a project.

  1. Follow the instructions until Compensating status is shown.
  1. Tap the forward arrow button and select or create a project.
  1. Tap the survey button to start working with TcpGPS and Reach RS3.