Cobham Technical Services has designed and built vehicle-mounted multi-channel radar systems specifically for mine detection. The low-power ultra wideband (UWB) time-domain radar technology can detect buried metallic and minimum metal anti-tank mines in realistic conditions. The architecture of the system is based around 16 receivers, each of which sequentially sample the signal incident on receive antenna elements. The transmitters are synchronised by adjacent receivers and a central master clock.
A 32-channel ground-penetrating radar (GPR) system, for example, must maintain calibration of both start time and time linearity for all channels to within demanding limits. In addition, the relative gain and, if used, time varying gain profile must also match to within close tolerances. Where the antenna array is spaced off the ground, there may also be the need to compensate for variations in surface topography.
A further aspect to be considered is the antenna element spacing. This needs to be adequate to provide proper resolution of the wanted target and it can be shown that the probability of detection with respect to small targets is closely related to the density of the elements of the antenna array.