Quick Answer
Setting up an Emlid Reach base and rover involves positioning the base over a known point or letting it average its own position, connecting it to a NTRIP caster or radio link, then configuring the rover to receive corrections. With a proper RTK fix, you achieve centimetre-level positioning accuracy for surveying and mapping work.
What You Need
An RTK setup requires two Emlid receivers: one acts as the base station and the other as the rover. The base stays fixed at a known location and sends correction data to the moving rover. You also need a way to link them: either a radio connection for local use, or an NTRIP service over a mobile data connection for network RTK. A telescopic tripod with spirit level is recommended for the base to ensure a stable, level setup.
The Emlid Reach RS4 Pro is the latest model and works well as either base or rover. For a lighter, more portable rover, the Emlid Reach RX2 is pocket-sized and ideal for walking surveys.
Step 1: Set Up the Base Station
Mount the base receiver on a tripod over a known survey point. If you have coordinates for the point, enter them manually in the Emlid Flow app. If not, let the receiver average its position over several minutes to establish a base location. The longer you let it average, the more accurate your base coordinates will be. For professional survey work, averaging for at least 15 to 30 minutes is standard practice.
In the ReachView app, navigate to the Base mode settings. Select "Average single" for automatic averaging, or enter your known coordinates if you have them. Set the correction output format: RTCM3 is the standard and works with most rovers and NTRIP services.
Step 2: Choose Your Correction Link
The correction data from the base needs to reach the rover. There are two main approaches.
| Method | Range | Best For |
|---|---|---|
| LoRa radio (built-in or external) | Up to 10km+ | Local surveys, no mobile signal |
| NTRIP over mobile data | Unlimited (network dependent) | Urban work, VRS networks |
| Wi-Fi hotspot | 50-100m | Very short range, office setup |
For most field work in the UK, a LoRa radio link between base and rover is the simplest approach. Emlid receivers have built-in LoRa radios, so no extra hardware is needed. Just set both units to the same radio channel. If you need longer range or want to use an existing NTRIP service, connect the base to a mobile phone hotspot and configure it as an NTRIP caster.
Step 3: Configure the Rover
On the rover receiver, open ReachView and set it to Rover mode. Under the correction input, select the same method you chose for the base output: LoRa radio for a direct link, or NTRIP client if connecting to a caster or network service.
When connecting via NTRIP, you need the caster address, mount point, port, username, and password. These are provided by your NTRIP service. In the UK, services like Ordnance Survey's OS Net and various commercial providers offer correction data.
Step 4: Verify Your Fix
Once the rover starts receiving corrections, it will attempt to achieve an RTK fix. Watch the status indicator in ReachView: "Float" means corrections are being received but the solution is not yet fully resolved, while "Fix" means you have centimetre-level accuracy. A Fix status is what you want before collecting any survey points.
Common reasons for failing to achieve a fix include: insufficient satellite visibility, radio link issues, incorrect base coordinates, and multipath interference from buildings or trees. Move to a more open sky location if possible, and check that your base coordinates are entered correctly.
Using with Drones
RTK positioning is increasingly used in drone surveying. An Emlid receiver can provide centimetre-accurate position data to a flight controller running ArduPilot or PX4, enabling precision mapping without ground control points. Our telemetry radios guide covers the radio side of connecting RTK corrections to a drone. The Pixhawk guide explains how flight controllers process RTK data for autonomous missions.
Tips for Reliable Results
Always set up the base with a clear view of the sky. Avoid placing it near buildings, large trees, or metal structures that cause multipath interference. Keep the rover antenna vertical and avoid tilting the pole. Use the Emlid Flow app on your phone or tablet for point collection and stakeout, which integrates directly with Reach receivers. Browse the GPS navigation systems collection for compatible receivers and accessories.