The radar is one of the most utilized pieces of equipment in the nautical, aeronautical, and military world. This fantastic piece of equipment first came into existence in 1904 and since then it has rapidly evolved into an indispensible aid to improve navigation and collision avoidance.

The word radar is actually an acronym. It stands for Radio Detection and Ranging. A radar set works by transmitting and receiving electromagnetic pulses in frequencies of either 3 GHz (S-Band) or 9 GHz (X-Band). These electromagnetic pulses radiate outwards in all directions from the radar scanner. When the radar pulse strikes an object, a part of it is reflected back to the scanner. In this manner, the object is detected and displayed on the radar screen. By taking into account the time difference between when the pulse leaves the scanner and when the echo is received, the distance of the detected object can also be obtained. In addition to accurate ranges, radar sets also provide you with the bearing of detected objects. However, it must be borne in mind that a visual bearing is always far more accurate than any radar bearing.

Marine radars offer the dual functionality of coastal navigation and collision avoidance. Radar sets can be used to detect prominent navigational landmarks during coastal passages. The ranges, bearings, or a combination of both can be used to accurately determine the vessel’s position. Other techniques such as parallel indexing can be used to ensure that the vessel is not running into immediate danger.

Radars are also invaluable for collision avoidance. Systematic observation of detected objects can help you determine whether it will pass clear or come too close for comfort. Radar plotting is another method that can not only help you to determine a target’s range and bearing, but also its course, speed, closest point of approach (CPA) and the time to closest point of approach (TCPA). If your radar set is fitted with an Automatic Radar Plotting Aid (ARPA), you can obtain all this information at the push of a button. Although an ARPA is only mandatory for larger ships, it can prove invaluable on vessels of all sizes, particularly if you venture into areas that have a high traffic density.

Nowadays, radar sets are typically interfaced with the gyrocompass, GPS, speed log, and AIS. Modern day radar sets may also be interfaced with electronic charting systems to provide a radar overlay. With this sort of a system, you can easily identify and locate any possible dangerous targets, continuously track your ship’s position, and also identify any discrepancies in the position obtained by the GPS.