Multispectral GPR: Stage 2
Project Number: P1187A
Status: Open to sponsors
Amira Program Manager: Dr Silvia Black
Deeper, smaller and faster GPR
Amira’s Project P1187 developed a 30 cm long magnetic radar receiver that significantly outperformed traditional electrical field dipoles which are 20 times their length. The magnetic sensors are designed for low frequency (< 40 MHz applications) for deep penetration in challenging radar environments. In a trial at a mineral deposit in Western Australia overlain by conductive aeolian sands, the new magnetic sensor was able to nearly double the penetration of deepest conventional GPR system, as confirmed by extensive drilling.
Unlike electric dipole antennas, whose length needs to roughly half the GPR wavelength, which wavelength varies between the ground and air and is inversely proportional to frequency, magnetic sensors operate identically on the ground or in the air. This suggests that such miniature GPR receivers can easily be mounted on UAVs for large scale aerial coverage.
The magnetic sensor is much wider bandwidth than electric dipoles, and P1187a aims to develop a magnetic transmitter dipole to enable ultrawideband GPR from a miniature transmitter. This would lead to the development of multistatic GPR with an array of sensors, which could be used for mapping moisture, or potentially phased array beamforming in future developments. Several successful key lab tests have significantly reduced the risk associated with this electronic development. With its much smaller size than electrical dipoles, P1187a should provide the key missing step to enable operation of GPR systems in the low MHz to tens of MHz bandwidth, both on the ground or on a UAV.
