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Today, drone mappers prefer to use an RTK setup of a GNSS base station and an RTK drone to achieve centimeter-level precision when mapping areas. Reach receivers integrate seamlessly with your RTK drone and are designed to handle all possible setups.
Elevating drone precision with GNSS base station
The drone alone typically achieves a positional precision of only a few meters. Various factors negatively affect satellite signal quality, leading to inaccuracies in determining the drone’s exact position.
GNSS base station allows you to improve your RTK drone’s precision to a few centimeters. When located at a known position, a base station receives the same satellite signals as the drone and can calculate the errors, which are then transmitted to the drone for real-time correction.
The Reach RS2+/RS3 GNSS base station can be easily integrated with the RTK drone to provide real-time correction data and ensure centimeter-precise data. The Reach receivers have two connectivity options that depend on the availability of an Internet connection. If you have internet access, you can stream corrections from your base to the drone via Emlid NTRIP Caster. In the areas with no internet coverage, you can adopt the Local NTRIP option in Emlid Flow, Reach’s companion app.
The Reach RS2+/RS3 GNSS base stations can also log raw data in RINEX format. Sometimes, the pictures from your drone may be taken in the Float or even Single solution. This can happen when RTK communication between a base and a drone is lost due to electromagnetic interference, obstacles, or an exceeded baseline. Thanks to the recorded logs, you can update the photos with precise coordinates in our free post-processing software Emlid Studio.
Ensuring reliable base station setup
Apart from the coordinate system setup, the way you place and specify your Reach base position in the Emlid Flow companion app determines the resulting accuracy of your project. The drone’s position is measured relative to the RTK base, so even with centimeter precision, the rover’s coordinates are only as accurate as the base’s placement.
If you don’t need to tie your coordinates to a true geographical position, such as when measuring distances between objects, averaging your base’s position in SINGLE mode is sufficient. However, if you need accurate results in a specific coordinate system, as it is often required in aerial surveying, the base should be placed over a point with known coordinates. To learn more about GNSS base station setup methods, explore our series of guides in the documentation.
After setting up the base’s position, ensure you are in an open area with a clear view of the sky for optimal signal reception and satellite availability.
Aligning your map with the real world using ground control points
For drone mapping, you’ll need a few ground control points (GCPs). These are large, visible markers with known coordinates placed in the surveyed area, used to stitch together images taken during the flight. Using GCPs improves precision and ensures correct scale and orientation in the photogrammetry software. When surveying with RTK drones, ground control points also serve as checkpoints validating the resulting model’s precision.
To measure GCPs for aerial mapping, you can use any of the field-ready Reach receivers—Reach RS2+, Reach RS3, or Reach RX. In this case, Reach will serve as a rover. The choice will depend on the project’s conditions.
If you have good internet coverage in the surveyed area and want something light and compact, Reach RX is your choice. This network rover requires no pre-configuration—simply enter the credentials for your correction network (NTRIP) and start surveying.
If the surveyed area has a lot of hard-to-reach points, pick Reach RS3. With tilt compensation, it enables precise measurement even in tough environments. Plus, this versatile model offers solutions for any area independent of internet coverage.
If tilt compensation isn’t necessary and conditions in the surveyed area are not challenging, the Reach RS2+ is your choice. It offers the same features as the Reach RS3, except for tilt compensation and the built-in UHF radio.
We’ve prepared a comparison table for you to ease your choice:
Reaching hidden places with Reach RX and Pix4D
Some sites have areas that are inaccessible to drones, making it difficult to obtain a complete orthophoto or digital model. Now, you can quickly capture these hard-to-reach areas, such as under trees or near buildings, and merge aerial and terrestrial data to create highly detailed digital models. All you need is a smartphone with LiDAR, the Reach RX rover, and Pix4D photogrammetry software.
With the Pix4D & Emlid Scanning kit, you can handle a complete field-to-office workflow:
- Capture on-the-ground assets with PIX4Dcatch integrated with Reach RX for RTK precision.
- Bring your data to PIX4Dcloud or transfer it to PIX4Dmatic right away.
- Merge terrestrial and aerial data in PIX4Dmatic and/or PIX4Dsurvey.
For information about setup, check the guide in our Docs.
Choose your Reach option for drone mapping
Completing your drone mapping setup with the Reach receiver allows you to cover the entire mapping workflow. Choosing your specific mapping setup will depend on the availability of the internet connection in the surveyed area. Here are your options:
- With internet access: Opt for the Reach RS3 plus Reach RX or the Emlid x Pix4D Scanning kit for seamless connectivity and advanced features.
- Without internet access: Choose the Reach RS3 Survey Kit for reliable performance even offline.
Select the best option for your needs and ensure efficient, precise mapping every time!