Operation Manual

ULTRASONIC SPEED SENSOR
5
1.4 Operation
The Ultrasonic Speed Sensor uses ultrasonic pulses to collect echoes from
small particles in the water as they pass under the two transducers embedded
in the unit (refer to figure 1.1).
These transducers monitor the particles in their respective beams. As the boat
travels through the water, both transducers ‘view’ the same stream of particles.
Because it takes time for the particles to travel between the two transducers,
the aft transducer detects the particles later than does the forward transducer.
By measuring this time lapse, the instrument processor is able to calculate the
speed of the boat through the water.
Figure 1.1 - Monitoring particles in the water