Very Low-Frequency (VLF) systems for airborne / UAV surveys. The VLF survey technique is a passive electromagnetic method that utilizes distant, globally positioned transmitters to induce secondary responses in conductive geologic units.

A dedicated towed-bird UAV VLF system with dual VLF sensors.
A towed-bird combined UAV VLF and magnetometer system available with single or dual VLF sensors.
An airborne VLF system with dual VLF sensors. Designed for surveys with manned aircraft.