Radar or Laser Altimeter for UAS
Adding a radar or laser rangefinder to a drone enables it to precisely follow the terrain during the flight, based on the data received from the altimeter.
In True Terrain Following mode, the drone flies at low and constant AGL altitudes (starting from 0.5m) without the need to import precise Digital Elevation Model (DEM) height-map into UgCS.
How It Works
The integrated system that enables the drone to fly in True Terrain Following consists of:
- UAV
- DJI M350 RTK
- DJI M300 RTK
- DJI M600/M600 Pro (incl.RTK)
- DJI M210/M210 v2 (incl.RTK)
- DJI A3 (custom built)
- Pixhawk with ArduCopter
- Radar or laser altimeter
- SkyHub onboard computer
- UgCS ground control software
One of the main components of the integrated system, enabling efficient survey planning is UgCS - flight planning software providing tools for easy creation and calculation of flight paths, and interpretation of acquired data in a user-friendly manner.
Flying low. Accurately so
Magnetometers and Ground Penetrating Radars (GPR) have an extremely useful ability — they can see below the ground. For this very reason, they are widely used in mining, engineering, construction, and many other industries – even in archaeology. As usual, where the surface of the terrain is too dangerous (or fragile) for humans to walk on, sensor-carrying drones come into play. But there is one problem with this: how can you fly drones at a precise height – a very, very precise height?
Too little
Usually, digital elevation model (DEM) data that represents the surface of the terrain is used for such purposes. However, this kind of data is not available for many remote areas, and when it is, it is often not sufficiently accurate. For example, one of the best available commercial DEM data (WorldDEM) has a vertical precision of three meters. If for your mission the sensor needs to be two or even one meters above ground level, this data is simply of no use.
Measuring on the go
Why not use actual terrain information instead of relying on sub-optimal pre-existing data? That was the game-changing thinking behind a new integration solution brought onto the market by SPH Engineering, which provides unmanned systems integration services and software development.
By adding a proprietary onboard computer SkyHub and a radar altimeter to the drone carrying a sensor (the feature is currently available for DJI M350 RTK, DJI M300 RTK, DJI M600/M600 Pro, and M210/M210 v2 drones and can also be used with custom drones based on DJI A3 autopilot) SPH Engineering makes it possible to follow the terrain accurately without crowding the mission with too many waypoints and thus making it inefficient.
First, the altimeter gathers an uninterrupted data flow by measuring the distance to the surface of the terrain. Second, the onboard computer adjusts the drone flight height accordingly. As it uses actual data, rather than pre-existing information, this mode is called True Terrain Following.
True terrain-following with one click
All of this, combined with a special add-on of SPH Engineering’s UgCS software, allows for hassle-free drone mission planning with immaculate flight height precision. True Terrain Following mode requires no more than two waypoints on each survey line, thus sparing you from unnecessary interruptions to missions. The operator just needs to set the desired flight height and speed and activate the True Terrain Following mode. The rest of the work will be done automatically.
In addition to mining, engineering, and archaeology, this new solution is useful in situations where sensors like magnetometers and GPRs are not used, but flying over objects or following the surface at a particular height is required for other reasons. This could include spraying plants in agriculture and many other situations where accuracy is a priority.
Case Studies
GPR+UAV+Laser altimeter integrated system for archaeological investigation of Inca ruins
The system integrates a Ground Penetrating Radar (GPR) and a drone equipped with a laser altimeter, allowing the drone to fly in the True Terrain Following mode. The golden rule for GPR surveys is: to fly as slow and low as possible. The adding of the laser altimeter enables the drone to fly in the True Terrain Following mode without requiring Digital Elevation Model (DEM) data to guarantee the delivery of accurate survey results.
GPR-Integrated system with laser altimeter for true terrain following
By adding a proprietary onboard computer SkyHub and a laser altimeter to the drone carrying a GPR SPH Engineering makes it possible to follow the terrain accurately without crowding the mission with too many waypoints and thus making it inefficient.
Ground penetrating radar flying at 60cm AGL
DJI M600 drone equipped with Zond-12e Drone 500A ground penetrating radar (GPR). The adding of the onboard computer SkyHub and a laser altimeter to this integrated system enables the drone to fly on 60cm altitude in the True Terrain Following mode - the drone adjusts itself according to sensor's data to keep at an exact altitude above ground level.
UgCS for flight planning and control
One of the main components of the integrated system, enabling efficient survey planning is UgCS - flight planning software providing tools for easy creation and calculation of flight paths, and interpretation of acquired data in a user-friendly manner.
