Search results
Results From The WOW.Com Content Network
Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. [4] Acoustic location in air was used before the introduction of radar. Sonar may also be used for robot navigation, [5] and sodar (an upward-looking in-air sonar
Modern radar systems are generally able to smoothly change their PRF, pulse width and carrier frequency, making identification much more difficult. Sonar and lidar systems also have PRFs, as does any pulsed system. In the case of sonar, the term pulse-repetition rate (PRR) is more common, although it refers to the same concept.
These generally use navigational radar frequencies, but modulate the pulse so the receiver can determine the type of surface of the reflector. The best general-purpose radars distinguish the rain of heavy storms, as well as land and vehicles. Some can superimpose sonar and map data from GPS position.
Lidar is a sort-of acronym that may or may not be capitalized when you see it, and it usually stands for "light detection and ranging," though sometimes people like to fit "imaging" between the ...
RADAR and LiDAR are examples of active remote sensing where the time delay between emission and return is measured, establishing the location, speed and direction of an object. Illustration of remote sensing. Remote sensing makes it possible to collect data of dangerous or inaccessible areas.
In radar or sonar applications, linear chirps are the most typically used signals to achieve pulse compression. The pulse being of finite length, the amplitude is a rectangle function . If the transmitted signal has a duration T {\displaystyle T} , begins at t = 0 {\displaystyle t=0} and linearly sweeps the frequency band Δ f {\displaystyle ...
The radar mile is the time it takes for a radar pulse to travel one nautical mile, reflect off a target, and return to the radar antenna. Since a nautical mile is defined as 1,852 m, then dividing this distance by the speed of light (299,792,458 m/s), and then multiplying the result by 2 yields a result of 12.36 μs in duration.
When it is exactly zero the radar is a monostatic radar, when it is close to zero the radar is pseudo-monostatic, and when it is close to 180 degrees the radar is a forward scatter radar. Elsewhere, the radar is simply described as a bistatic radar. The bistatic angle is an important factor in determining the radar cross section of the target.