Until the 60’s era, the experts of water power still lulled, because it focuses the idea of water superiority on the creation of the ability to maneuver and attack aircraft. No wonder at the time of the air war, so many aircraft fell due to weakness of defense devices. Even radar technology that developed since 1941, the design is already identical as an attacking tool (intercept radar), located in the muzzle of the plane and only able to detect objects that are in the front. Other areas that cannot be reached radar-back, up, down, side – eventually become a deadly hell, especially after created sophisticated missile types released beyond visual range, which are increasingly difficult to detect by radar intercept.
The changes began in the 60s, when US AU and Navy bombers had to face the North Vietnamese hanud system. Although radar remains the primary system, US aircraft must be equipped with missile-suppression systems. So was born the first generation of missile detector that is warning receiver and defensive jammer. An air-to-air missile (SAM) missile guided by Russia’s latest radar system and large US air power, made Vietnam’s war the longest “electronic war” in war history. The strength of US Aircraft AU which has been equipped with RWR and jammer at that time is EB-66, F-100F and F-105G, while from AL US is EA-6A, EA-6B, A-6B, and F-4F. The jammer used is ALQ-75, 77 and 87 (AU) and ALQ-76 and 81 (AL), while the RWR used is APR-25 and ALR-46. This is then called electronic warfare (EW), which literally means the use of electromagnetic energy to determine, exploit, reduce or prevent the use of the electromagnetic spectrum of opponents. EW is divided into two groups, namely Warning Receiver and ECM (Electronic Counter Measure).
Passive Deterrent “Warning Receiver”
The most popular warning receiver and widely used in all types of military aircraft or helicopters is the Radar Warning Receiver (RWR). The principle works against the radar. If the radar of the aircraft emits radar waves toward the front, then RWR serves as a radar catcher from any direction that leads to the plane. RWR can detect radar emissions coming from all directions because the antenna is mounted in 4 positions, i.e. 2 on the left-right of the aircraft’s muzzle and 2 in the left-right part of the tail.
How just by capturing radar jets, make RWR a reliable missile deterrent? This cannot be separated from the use of aircraft radar, ship or missile battery, as the main device to guide air missiles. The performance of air missile systems that are sliding into air targets – either surface-to-air (SAM) or air-to-air missiles (AAM) – are essentially the same, i.e. radar aircraft, boats, or SAM batteries will search for targets, , The height and angle position of the selected target (acquire / track), lock (lock on) and then the missile is fired (launch). Air-missile performance is usually differentiated based on the tracking system used. Now, when radar detection is detected by RWR antenna, RWR processor performs comparation between radar jets captured and matched radar data in RWR data bank (library). RWR must be filled with radar data of aircraft, ships, SAM batteries or missiles used around the world, so that when capturing radar emissions, monitors directly display the name of the radar source according to the data bank. The library will compile the radar type, so the pilot can conclude “friend, enemy or unknown”. If RWR does not have complete radar data then the monitor only displays unknown target (target unknown). The most serious problem for RWR service users is the high price set by RWR producers to fill and update radar data banks.
Until now RWR has not been able to localize the position of the opponent or display the position of the source of the radar beam precisely. The distance shown is only the relative distance obtained from the strength of the jet. Thus a stronger emission is assumed to be from a source that is closer to position. RWR can recognize that the aircraft is being locked on or not by a missile, based on the intensity of the radar’s radar. When the radar condition does not lock on a target (searching), the intensity of the received jets is still weak. When the radar is locked, the radar angle is locked and continuously leads to the target in high intensity to guide the missile. Well, the intensity of the continuous and larger emission is what turns on the “lock on missile” alarm on the RWR. Pentagon coding of RWR is ALR (A = piloted Aircraft, L = Countermeasure, R = Receiver), e.g. ALR-69 for F-16, ALR-91 for F-5, ALR-67 for F-18 and so on. Russia uses RWR with SPO codes, such as SPO-15 Beroza for MiG-29, SPO-29 Pastel for Su-27 …