The GEM-3R is a cart-mounted GEM-3 with a rectangular transmitter. It is specifically designed for UXO survey by single operator on foot. This new model features a large transmitter (1 m x 0.75 m) for deep penetration, real-time screen display on a PDA, and rugged construction for rough ground conditions. Everything, including electronics and battery, is selfcontained on the cart, leaving the operator completely free of external luggage or tangled cables.

The sensor produces inphase and quadrature data at each frequency. Inphase data is sensitive to earth's electrical conductivity and magnetic susceptibility. Over highly conductive or magnetic soil, the inphase data is often too sensitive to motion-induced noise to be a stable detection indicator. The quadrature data, however, are insensitive and, thus, provide reliable detection. The sum of all quadrature data, called the Q-sum, is an excellent detector in conductive or magnetic geology, with minimal false alarms.