A radar transceiver observes an airplane by measuring the times of microwave pulses reflected from the plane. Suppose the plane is 15.97 km distant from the radar antenna. Determine the time delay between emission of a pulse and reception of the reflected pulse. Express the answer in microseconds (ms).
The speed of light (and all electromagnetic radiation, including microwave radiation) is 300,000 km/s.
So you need to find the time for the microwave radiation pulse to be emitted, reach the plane, and return to the receiver at the radar antenna. The total distance is then 2 * 15.97 km = 31.94 km.
Time = distance/speed = 31.94 km / 300,000 km/s = 0.000106s = 106.47ms
Hope this helps
Bill
November 26th, 2009 at 9:18 am
The speed of light (and all electromagnetic radiation, including microwave radiation) is 300,000 km/s.
So you need to find the time for the microwave radiation pulse to be emitted, reach the plane, and return to the receiver at the radar antenna. The total distance is then 2 * 15.97 km = 31.94 km.
Time = distance/speed = 31.94 km / 300,000 km/s = 0.000106s = 106.47ms
Hope this helps
Bill
References :
November 26th, 2009 at 10:03 am
0.000106s = 106.47ms
eh !! the right answer is 106.47uS
today cheap electronic counters can measure time delays with 1nS
resolution, giving you under 1m resolution !
good luck,
Thomas Scherrer
OZ2CPU webx.dk
References :