Doppler Marine Radar

Doppler technology can help boaters quickly and easily recognize targets that pose a collision risk.

Doppler Marine Radar
Doppler Marine RadarGarmin

Solid-state marine radars from Furuno and Garmin now feature Doppler technology to help boaters quickly and easily recognize targets that pose a collision risk. Both radar systems automatically change the color of a target if it’s moving toward your boat, making for safer navigation in fog or darkness.

To understand how Doppler works, think of the differences in sound from a siren on a fire truck speeding toward you, then away. The processors in the Furuno DRS4D-NXT and Garmin Fantom series sense such dynamic ­differences in the radar returns to identify and highlight approaching targets.

Furuno calls the Doppler system in its new NXT dome radar Target Analyzer. A similar feature in Garmin’s Fantom open-array radar series is known as MotionScope. In both systems, targets moving toward your boat at 2 knots or more are painted in a contrasting red color.

“With the Furuno ARPA (automatic radar plotting aid) on, the red targets also get an echo trail, and an audible alarm is sounded,” says Eric Kunz, senior product manager for Furuno USA. “There’s no need to set an acquisition zone; the ARPA automatically shows the vector, closest point of approach and time to closest point of approach.”