True Terrain-Following Systems.

Where the surface of the terrain is too hazardous or inaccessible, sensor-carrying drones come into play. But how can you fly drones at a precise height – a very, very precise height? 

Magnetometers and Ground Penetrating Radars (GPR) provide the ability to see below the ground. This useful feature has seen them gain wide use in mining, engineering, construction, and many other industries – even in archaeology.  

However, data this precise requires flying very close to the ground and maintaining a consistent height regardless of terrain. 

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 accurate enough to fully realize the benefits of these technologies. 

For example, one of the best available commercial DEM data (WorldDEM) has a vertical precision of three metres. but if  your mission the sensor needs to be two or even one metres above ground level, this data is simply of no use. 

LiDAR seemingly offers a solution - creating extremely accurate terrain maps with a precision level of up to one centimetre. While the accuracy of the data sounds ideal, for a drone mission it also means a lot of wasted time. Missions based on LiDAR data have too many waypoints (we’re talking hundreds and hundreds). Therefore following a LiDAR-mapped area of terrain precisely would involve flying over the area time and time again. And that’s without mentioning the drain on the batteries.

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.

Adding a radar/laser altimetry unit 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 (up to 1 meter) without the need to import precise Digital Elevation Model (DEM) height-map.