Radar performance evaluated by range, accuracy, target detection, and availability. Maximum range depends on transmitter power and antenna size. Some radars have antennas up to 100 feet diameter
Heinrich Hertz proved radio waves were reflected by metallic objects in 1886-1888. Christian Hülsmeyer developed first ship detection device in 1904. Rudolf Kühnhold pioneered pulsed radar development in Germany in 1930s
Doppler radar uses the Doppler effect to measure target velocity by analyzing signal frequency changes. The Doppler effect is the difference between observed and emitted frequencies for moving objects. Frequency increases during approach, equals at pass, decreases during recession
Radar uses radio waves to detect objects' distance, direction, and velocity. System consists of transmitter, antenna, receiver, and processor. Radio waves reflect off objects and return to receiver for detection
X band spans 7.0-11.2 GHz in communication engineering. IEEE specifies radar range as 8.0-12.0 GHz
Position fixing interval determines maximum time between position fixes. Position fixing interval should allow time for course correction. GPS is primary method, radar fix secondary in open sea