Ground radar provides a wide area coverage, which will also include the perimeter of the park. The radar systems we are considering, have typically a detection range of 5km for humans and big animals, and 10 km for vehicles. These ranges are indicated with different circles on the map illustration below. The radar is here placed on a centrally located cliff, where it can overlook the flat area of Ngulia with line of sight conditions.
That is, radar provides both border protection and area surveillance capabilities. It can sort out moving objects (by the Doppler shift), and delivers position as well as speed and size (measured in radar reflectivity). High-end radars also provide the micro Doppler spectrum, see an example below for a human approaching the radar.
The experiment illustrated below shows radar detections of a human and a number of savannah animals, including a rhino. A video camera is placed on top of the radar to illustrated the current bearing. The raw detections are marked with green dots, and the human is manually highlighted with yellow in both the radar and camera view.
The micro-Doppler spectrum is a promising way to classify different animals and humans, based on the envelope of the different body parts. The theory for tracking using micro-doppler is described in:
This work is documented in Millimeter-wave radar micro-Doppler signatures of human motion. S. Björklund, H. Petersson, A. Nezirovic, M. Guldogan and F. Gustafsson. Radar Symposium, 2011.
Recent field tests have provided much more data for research. The image below illustrated both the setup and the resulting micro-Doppler from the radar, now in staring mode (not scanning).