Doppler technology is not just the stuff of … doctors and scientists! Raymarine’s new pulse compression CHIRP Quantum 2 radar detects targets with great accuracy at both long (up to 24 miles) and very short range (5 meters!).
Using Doppler processing, the system immediately highlights radar contacts and differentiates them with colors to indicate whether they are approaching (red) or receding (green). Target tracking can be done in ARPA mode (in automatic) or MARPA mode (manual).Raymarine’s MARPA target tracking technology is the same as that relied upon by the U.S. Coast Guard. TrueTrails adjustable target history shows the movement history of moving contacts, and interference rejection eliminates disturbances caused by radar transmissions from other vessels. Prices from 2,433 euros including VAT. www.raymarine.it
HOW DOPPLER RADAR WORKS
Energy microwaves bounce off a distant target, just as in a conventional radar.
Moving targets return an echo whose frequency is higher or lower than what was originally transmitted.
For approaching targets, the frequency increases, as the rising front of return echoes is received more frequently as the distance to the target decreases.
For receding targets, the frequency decreases, as the return echoes distribute as the distance increases.
Doppler radars are designed to detect these small changes in wave frequency and to use them to classify moving targets.
TARGET DOPPLER PROCESSING
Doppler radar is specifically adjusted to detect the frequency change of echoes returned by moving and stationary targets.
The Quantum 2 then distinguishes moving targets with colors to indicate whether they are approaching or receding.
- Approaching targets are colored red.
- Receding targets are colored green.
Color-coded targets make it easier to detect moving traffic among other stationary targets such as land, aids to navigation, and stationary or anchored vessels.
