The mass of the airborne radar is 1% of the take-off mass, but it is the characteristics of the radar that determine the capabilities of modern fighters. The statistics of combat use over the past 15 years gives a clear picture: all air battles in which the fourth generation fighters took part took place at a long distance (100% of victories were won using medium and long-range air-to-air missiles).
Radar is the main element of the aircraft sighting and navigation system. Modern multifunctional stations provide effective search, detection and tracking of air and ground targets, remotely program the autopilots of launched missiles, measure altitude and allow mapping of the terrain. The most "advanced" models are used as transmitters in high-speed data exchange systems, perform the functions of electronic warfare and electronic warfare systems - up to the implementation of the principle of "beam" weapons!
At the heart of modern airborne radar are three essential technologies:
Phased array radars (PAR). The use of a group of antenna emitters (instead of a single "dish") made it possible to realize a whole range of advantages, the main one of which was fast scanning of the selected area of space (within 1 millisecond). Electronic beam control has eliminated the cumbersome drives and gimbals needed to mechanically control conventional antennas. Efficiency. Reliability. Multifunctionality. Better sensitivity and noise immunity.
MiG-31 surprises the audience with its huge Zaslon radar (LeBourget-91 air show)
Aperture synthesis technology. The aperture (linear dimension of the antenna) determines the beamwidth (beamwidth). To obtain a high azimuth resolution, antennas with the largest possible aperture are required, while the limiting dimensions of a fighter airborne radar antenna cannot exceed 1.5 meters.
Synthesized (artificial) aperture is a technique based on sequential reception of signals at different positions of a real antenna in space. In that split second, while the radar pulse lasted, the plane managed to fly 10 meters. As a result, the illusion of a huge antenna with an aperture of 10 meters was created!
The advent of synthetic aperture radar made it possible to survey and map the earth's surface with a resolution comparable to the quality of aerial photographs. Modern fighter-bombers have received unique capabilities for striking ground targets - in any weather and time of day, from a great distance, without entering the zone of action of enemy air defense.
Radar with an active phased antenna array (AFAR)
N010 "Zhuk-A" radar for the MiG-35 fighter
An array of thousands of individual transmit-receive modules (TPM) that do not need a single high-power emitter. The advantages of the technology are obvious:
- antenna modules can simultaneously operate at different frequencies;
- smaller weight and dimensions: due to the smaller size of the antenna itself, the absence of a high-power lamp and the associated cooling system and high-voltage power supply unit;
Notice how small the nose of the F-35 is compared to our "dryers" and MiGs.
- increased reliability: failure / damage of one element will not lead to loss of performance of the entire radar (however, the presence of a complex cooling system for thousands of AFAR modules largely negates this advantage);
- high sensitivity and resolution, the ability to scale and work in the "magnifying glass" mode (ideal for work "on the ground");
- due to the large number of transmitters, the AFAR has a wider range of angles to which the beams can be deflected - many of the restrictions on the geometry of the arrays inherent in the HEADLIGHTS are removed;
- high transmitting capacity of AFAR made it possible to integrate it into the communication and data exchange system:
In 2007, tests by Northrop Grumman, Lockheed Martin and L-3 Communications allowed the Raptor's AFAR to operate as a Wi-Fi hotspot, transmitting data at 548 megabits per second, 500 times faster than NATO's standard Link 16 link. …
Dassault Rafale
Currently, seven serial multi-role fighters can take advantage of all the advantages of AFAR technology: five modernized fourth-generation fighters and two machines of the "5" generation.
Among them: French "Rafale" (RBE-2AA radar), export F-16E / F "Desert Falcon" of the UAE Air Force (these fighters are equipped with AN / APG-80 radars), export F-15SG fighter-bomber military -Singapore Air Force (equipped with AN / APG-63 (V) 3), while the American "Strike Needles" are also being upgraded with the installation of AN / APG-82 (V) 2 radars. In addition, radars with AFAR AN / APG-79 received upgraded deck F / A-18E / F "Super Hornet".
All of the above-mentioned radar models for generation 4+ fighters represent the evolutionary stages of conventional radars. For example, the APG-63 (V) 3 and APG-82 (V) 2 are improvisations based on the old APG-63 radar of the F-15 fighter. Therefore, despite the new antenna and updated processor, the end result was not very impressive.
The APG-79 shows a slight performance increase over the APG-73. The results of practical tests did not reveal any noticeable advantages of F / A-18E / F fighters equipped with AFAR radars over vehicles with conventional radars.
From Director of Test & Evaluation (DOT & E), 2013.
This is despite the fact that the cost of the new radar has increased markedly. Even in the digital age, when the cost of manufacturing each AFAR module has dropped to several thousand dollars, the final cost of a lattice of thousands of MRPs is many millions. Of course, the price is not an argument for the United Arab Emirates, where the sheikhs wanted to equip their F-16 fighters with the coolest radar possible.
F-16 with AN / APG-68 radar
F-16 Block 60 with radar with AFAR
Well, while the "majors" are having fun with their "toys", real work is in full swing in serious scientific centers.
The greatest success in the development of radars with active phased array systems was achieved by the teams working on avionics for the F-22 and F-35 fighters. For these machines, a new generation radar was created, where high computing power made it possible to realize the full potential of the AFAR technology.
F-22 and its radar AN / APG-77
What is the Raptor fighter's radar capable of that the other airborne radars cannot?
At first glance, nothing special. According to the military reference book "Jane", the "Raptor" radar has an operational detection range of 193 km, which provides 86% of the probability of detecting a target with RCS = 1 sq. m. on one pass of the antenna beam. For comparison: the domestic radar N035 "Irbis", according to the developers, sees air targets at a distance of 300-400 km (EPR = 3 sq. M.). By and large, these values should not be taken seriously - in combat conditions, under the influence of various interference and situational restrictions, the actual detection range will be significantly reduced. With regard to energy capabilities, APAR, for all its advantages, has greater energy dissipation and lower efficiency than PFAR.
In theory, this could equalize the chances of the Raptor and the Su-35. But it is worth remembering that the range of mutual detection in air combat depends not only on the energy capabilities of the airborne radar and EPR of the air target.
The Raptor's radar has a special LPI mode (low probability of interception), which is especially important for a stealth aircraft. Unlike conventional radars, the Raptor emits low-energy pulses over a wide range of frequencies. This negates the effectiveness of the enemy's electronic warfare and electronic warfare systems - the enemy does not even know that the F-22 is close and has already begun an attack. The only one who is able to understand the random stream of signals at different frequencies is the processor of the AN / APG-77 radar itself, which gradually accumulates data and, according to the theory of probability, finds the true position of the target.
The second most important advantage of the Raptor radar is the ability to simultaneously operate in the air-to-air and air-to-surface modes. It is difficult to overestimate the importance of this moment for the pilots of fighter-bombers who search in the folds of the relief of an enemy tank column in the presence of a threat from enemy aircraft.
According to widespread data, the AN / APG-77 with a synthetic aperture can detect targets with an RCS of 30 square meters. m. (tank) at a distance of 50 km, and a bridge or large ship (1000 sq. m.) at a distance of up to 400 km! However, do not forget that the max. the resolution of the radar is achieved by no means in the entire field of view, but only in the form of a narrow "searchlight" beam. In addition, high-resolution mapping imposes certain restrictions on the flight profile and is possible only in the absence of active opposition from enemy aircraft and air defense.
In addition to the functions of detection means, AFAR, in theory, is capable of itself becoming a formidable weapon. By focusing radiation in the form of narrow "death rays", such a radar can "burn" the electronics of incoming enemy missiles. What would be the real effectiveness of the Raptor radar as an electromagnetic weapon is a difficult question. Nevertheless, the topic has gone beyond the confines of secret laboratories and is now actively discussed in the circle of aviation specialists.
It remains to add that, in addition to sci-fi properties, AN / APG-77 has all the usual advantages of AFAR technology: relative compactness and increased reliability. The use of radar with AFAR, oddly enough, had a favorable effect on reducing the EPR of the Raptor itself (due to the absence of mechanical drives and mirror surfaces under the nose cone + reduction in the size of the nose). Beginning with the Block 32 version, the APG-77 was able to fire directional electronic jamming, including against several targets at the same time. Finally, do not forget about the potential for integrating the radar into high-speed data networks.
The conclusion is obvious: with all its limitations and disadvantages (the main one being cost!), The AN / APG-77 system represents a real breakthrough in the field of radar. The potential is so high that even two decades later, the radar continues to bring surprises and open up new opportunities.
Even greater success was achieved by the research team that created the radar for the F-35 multirole fighter. The scientific community is convinced that the developers of the system, which received the designation AN / APG-81, could seriously qualify for the Nobel Prize in Physics - and, perhaps, will receive their award when their developments lose the secrecy label.
In comparison with the mighty Raptor radar, the APG-81 electronic miracle has modest dimensions and lower power capabilities. Nevertheless, it provides the pilot with almost a lot of information. It's all about the unique mathematical algorithms for signal processing: for example, extracting useful information from the noise reflected from the "side lobes" of the AFAR.
But the main capabilities of the F-35 radar are revealed when working on ground targets: the creators of the APG-81 managed to achieve mines in incomprehensible ways. terrain resolution within 30 x 30 centimeters. This allows, literally, when viewed from stratospheric heights, to distinguish a tank from an infantry fighting vehicle!
If earlier there was only a mark on the screen, nowadays the software and hardware capabilities of the radar make it possible to reconstruct the type of target.
What awaits us in the near future? The main development trend is already known today - the creation of a mathematical apparatus for a three-dimensional radar model.
