Reach M+ and M2. (Photo: Emlid)
Emlid is offering two positioning modules for mapping with unmanned aerial vehicles (UAVs). Both the Reach M+ and Reach M2 provide centimeter-level accuracy in real-time kinematic (RTK) and post-processed kinematic (PPK) modes, enabling precise UAV mapping with fewer ground control points.
The Reach M+ single-band receiver has a baseline up to 20 kilometers in PPK. The Reach M2 is a multi-band receiver with a baseline up to 100 kilometers in PPK.
Usually autopilot triggers the camera and records the coordinate it has at that moment. When the drone is flying at 20 m/s and GPS works at 5 Hz, the UAV autopilot will have position readings only every four minutes, which is not suitable for precise georeferencing. In addition, there is always a delay between the trigger and the actual moment the photo is taken.
Reach solves this problem by connecting directly to the camera’s hot-shoe port, which is synced with the shutter. The time and coordinates of each photo are logged with a resolution of less than a microsecond. Reach captures flash sync pulses with sub-microsecond resolution and stores them in a raw data RINEX log in the internal memory. This method allows ground control points to be used only to check accuracy.
The Reach RS2. (Photo: Emlid)
The Reach M2 PPK UAV mapping kit consist of the Reach M2 multi-band GNSS receiver onboard the aircraft that records the location of each photo at a frequency of 20 Hz. It is combined with the Reach RS2 GNSS multi-band receiver on the ground, drastically reducing the number of ground control points and simplifying the setup process on site, while maximizing the accuracy to centimeter levels even in remote areas.
The M2 tracks GPS/QZSS (L1, L2), GLONASS (L1, L2), BeiDou (B1, B2), Galileo (E1, E5) and SBAS (L1C/A), and receives a fixed solution almost instantly.