MiG-31 Avionics

Evidence from the Fedesov book on air defence:

еализован режим КНИ высокой частоты повторения импульсов с частотой следования порядка 200 кГц;

KNI mode of high pulse repetition frequency with a repetition rate of about 200 kHz is implemented;

введено двухпороговое обнаружение цели (вальдовское различение гипотез), в среднем вдвое сокращающее время ее обнаружения;
• использована комбинированная временная диаграмма обзора пространства, дискретного сопровождения до 10 целей и непрерывного подсвета до
четырех атакуемых целей;
• по дискретно сопровождаемым целям реализована проводка в зоне прозрачности отраженных сигналов цели с точным определением дальности;
• введена моноимпульсная пеленгация в дискретные моменты сопровождения цели, характеризуемая высокой точностью определения углового положения цели.

introduced two-threshold target detection (Waldian hypothesis discrimination), on average, halving the time of its detection;
• used a combined timing diagram of space survey, discrete tracking up to 10 targets and continuous illumination up to
four attacked targets;
• for discretely tracked targets, tracking was implemented in the zone of transparency of the reflected signals of the target with an accurate determination of the range;
• introduction of monopulse direction finding at discrete moments of target tracking, characterized by high accuracy in determining the target's angular position.


So its a very high PRF pulse-doppler radar, but I couldn't find definitive proof it uses FM ranging.
 
Maybe you could find the Pulsewidth used in that mode, from there we could glean information on duty cycle. FMICW Radar may operate in excess of 50% duty cycle, while more "conventional" pulse doppler implementation with multiple range gates are in lesser duty cycle e.g 3% to as high as 25-30% Optimized to reduce eclipsing loss.

AFAIK in high or very high PRF it's usually impossible to do a typical Pulse delay ranging so it's either FM ranging is used or range is simply not measured thus such mode is referred as VS or Velocity Search.
 
Aldrich Ames turned over a document on Zaslon that Tolkachev provided the CIA. I believe this was used in the prosecution against Ames. If I get a chance to I’ll see if I can get any court records
 
I'm actually leaning towards Zaslon being similar as AWG-9 or AN/APG-63 in terms of processing namely a "conventional" pulse doppler radar. Instead of FMICW one.

As previously mentioned in Foxhunter thread FMICW Radar only have single range gate, while "conventional" pulse doppler have multiple gates. This have effects on the number of doppler filters and related equipment which in turn drive the weight of the radar set. I believe had Zaslon resorts to FMICW it wont have over 700 Kg of LRU's beside it's 300 Kg Phased array antenna.
 
Disagree, you can't make that argument. AN/ASG-18, ancestor of AWG-9, weighed close to the same as Zaslon despite a much lighter antenna design and was FMICW - it was built with older computing hardware. AWG-9 is still large and bulky, if lighter than Zaslon.

Nice article on the Argon computers used in Zaslon here:

 
FLIGHT TESTS SUV "ZASLON" - Vladimir Ilyin (Аэрокосмическое обозрение №05 2005)

The weapon control system (SV) "Zaslon", developed for the MiG-31 fighter-interceptor, is a unique product, many of whose characteristics have not yet been surpassed by foreign counterparts. The extremely high characteristics of the complex for its time were largely achieved through numerous, sometimes very large-scale (both organizational and financial) flight tests and experiments. Some of these experiments are still unique.

It should be noted that such experiments aimed at improving the capabilities of the aviation complex were also carried out after the MiG-31 was put into service. Let us dwell only on the individual, most significant stages of the development of the complex, carried out by the NIIP. V.V. Tikhomirova and OKB A.I. Mikoyan during flight tests of the MiG-31.


Target acquisition range
NumberTarget acquisition and automatic tracking range, kmTarget flight altitude, m
1141.31400
2162.29000
3136.52000
4124.81700
5131.52600
6137.89300
7144.38700
8121.59600
9112.22300
10115.48400


On February 15, 1978, Akhtubinsk hosted a flight experiment that has not been repeated by any foreign aviation complex so far for the simultaneous detection, capture and tracking of 10 air targets flying in a wide front (about 150 km) at various altitudes.

The MiG-31 interceptor flew at an altitude of 5000 m. The targets were divided into two groups. The first group flew at altitudes from 8400 m to 9600 m, the second - from 1400 m to 2600 m, flying (relative to the interceptor) against the background of the underlying (terrestrial) surface. The maximum target detection range (having an EPR of the order of 16 m2) was 210 km.

The total time of detection and capture was 153.5 s. At the same time, the first seven targets were detected and captured in 69.5 s. The time spent directly on the procedure for capturing seven targets was 24.3 s, and 10 targets - 49.05 s.

To avoid multiple capture of the same target and, as a result, "looping" of the system, a comparison of the coordinates of newly captured targets and a ban on their re-capture was introduced.

It should be noted that the possibility of multiple acquisition and tracking of the same target in one flight experiment made it possible to estimate the load of computational processes and collect statistics on the observation of target signals (mode for experimental work) without organization in the future of expensive flights of 10 targets.

The creation of a phased antenna array (PAR) for the SUV "Zaslon" made it possible not only to implement the multi-purpose operation of the radar complex, but also to work out the use of the so-called "sequential detector" mode to increase the range.

In this case, the analysis is carried out within two to four elementary time cycles (the position of the PAR beam remains unchanged). The lower and upper thresholds are different for each measure. When the upper threshold is exceeded in each of the 180 sections of Doppler frequencies, a “target” signal is generated.

The sequential detector made it possible to obtain a gain in the detection range of air targets, which is approximately 20-25%. In this case, the entire procedure for sequential detection is implemented in a special analog-to-digital processor. The implementation of this mode in modern digital signal processors is problematic due to insufficient speed and the need to organize a special computing process.

On August 28, 1978, the MiG-31 successfully hit four radio-controlled air targets with four simultaneously fired R-33 missiles.

On August 18, 1993, a series of flight experiments was carried out to intercept a target at maximum range. During the first of them, a radio-controlled target flying at an altitude of 10.300 m at a speed of 189 m / s was captured by a MiG-31 interceptor (flight altitude 8480 m, speed - 669.3 m / s) at a distance of 319.5 km. The R-33 missile (which successfully hit the target) was launched at a range of 228 km.

Perhaps the most spectacular flight experiment, which fully demonstrated the capabilities of the aviation complex, was the experiment conducted on April 21, 1994, on the simultaneous firing of four air targets. As the latter, specially equipped MiG-21 fighters (controlled from ground command posts) were involved, which had a relatively low EPR and high maneuverability.

The first target flew at an altitude of 7100 m, the second - 1720 m, the third - 2470 m, the fourth -6230 m. The sequence of target firing was determined by the program of the MiG-31 computer system: 4-2-3-1. All targets maneuvering along the course were destroyed a few tens of kilometers from the interceptor fighter.

Thus, SUV "Barrier" in conditions as close as possible to real, confirmed its unique characteristics. It should be noted that even today the MiG-31 aviation complex, created back in 1968-1981, has not exhausted its evolutionary possibilities. Its modernization will significantly increase its combat potential and give it characteristics that meet the requirements for fighter-interceptors of the 21st century.

For the creation of the SUV "Barrier" and its modifications, 196 employees of NIIP were awarded orders and medals of the USSR.
And the development of the SUV "Barrier" began in 1968. At first, it was difficult and difficult to move forward. All technical solutions were new: phased array, quasi-continuous radiation, multi-purpose work, group actions, etc. Now, 37 years later, they have become
familiar, understandable and, as a matter of course, indispensable in every new development. At the same time, it is important to note that the main technical solutions were immediately chosen correctly, but their practical implementation was an extremely difficult task.
In the process of working on the SUV "Zaslon", a creative association of specialists from different organizations was formed.

Involvement in solving a priority problem, the scale of work and the highest level of scientific and technological tasks brought together the specialists of the developer's firm - the Research Institute of Instrument Engineering, the Leninets serial plant and many enterprises and services of science, industry and the customer.

But the most important result of the development of the Zaslon SUV was the creation at the NIIP of a scientific and technical school for the development of antenna systems and radars with electronic beam control, which today is capable of carrying out the most complex and advanced developments for both aviation and anti-aircraft missile systems
 
Disagree, you can't make that argument. AN/ASG-18, ancestor of AWG-9, weighed close to the same as Zaslon despite a much lighter antenna design and was FMICW

Wait AN/ASG-18 is FMICW ?

Well looking at the pulsewidth.. you could glean that the duty cycle is 25% for 1 microsecond of pulse and 250 KHz PRF. While the FMICW is duty cycle of some 50% or even higher.
 
It uses fm modulation of a very high PRF pulse doppler radar for ranging. As does AWG-9. At this stage I don't see any clear distinction.
 
On a separate note, what is currently the newest/most powerful radar on Mig-31?. I recalled Zaslon-M was cancelled, so does that mean Mig-31 still use Zaslon-A and Zaslon-AM?. Do we have any data about detection range of Zaslon-AM?
 
According to official information, the combat effectiveness of the MiG-31BM has increased 2.6 times. For comparison, the MiG-31 exceeds the MiG-25 by 3.24 times in this parameter. At the same time, weapons and equipment were changed in the MiG-31BM, the aircraft itself remained the same
The MiG-31M surpasses the serial MiG-31 only 1.37 times. At the same time, the MiG-31M could carry 6 - 8 long-range R-37 missiles

Combat effectiveness concerns only air-to-air operations
 
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It is possible to compare the effectiveness of the earliest version of the MiG-31 without in-flight refueling and the latest version of the MiG-31BM with an electro-remote control system. This is the only way to explain such significant numbers
 
It is possible to compare the effectiveness of the earliest version of the MiG-31 without in-flight refueling and the latest version of the MiG-31BM with an electro-remote control system. This is the only way to explain such significant numbers
That doesnt tell us anything about Zaslon-AM range though
 
  • The energy capabilities of the Zaslon-AM radar have been increased by about 2 times in comparison with the usual Zaslon 8B: the target detection range with an RCS of 1m2 reached 200-230 km, the inconspicuous F-35A fighter reached about 140 km; the number of escorted targets reached 24 units, and the speed of the intercepted target reached 6,300 km/h. In addition, the new station can control air-to-air missiles of the R-77 family, including the 180-PD Product, due to which the MiG-31BM became capable of fighting highly maneuverable enemy aircraft, to which the conventional MiG-31B was not adapted. But this does not mean that the modernization potential of the MiG-31BM as a whole has been exhausted.
 
  • The energy capabilities of the Zaslon-AM radar have been increased by about 2 times in comparison with the usual Zaslon 8B: the target detection range with an RCS of 1m2 reached 200-230 km, the inconspicuous F-35A fighter reached about 140 km; the number of escorted targets reached 24 units, and the speed of the intercepted target reached 6,300 km/h. In addition, the new station can control air-to-air missiles of the R-77 family, including the 180-PD Product, due to which the MiG-31BM became capable of fighting highly maneuverable enemy aircraft, to which the conventional MiG-31B was not adapted. But this does not mean that the modernization potential of the MiG-31BM as a whole has been exhausted.
Where is this from?
 
The energy capabilities of the Zaslon-AM radar have been increased by about 2 times in comparison with the usual Zaslon 8B: the target detection range with an RCS of 1m2 reached 200-230 km, the inconspicuous F-35A fighter reached about 140 km;
So the F-35 headon RCS is about 0.25 sq m. Okay.
 
That's significant improvement over original Zaslon-A. Though why does it mention R-77 with ramjet, which went into nowhere and long-range engagements are bread and butter of R-37M and it's izd.810 derivative (assuming it an derivative and not entirely new project).
 
That's significant improvement over original Zaslon-A. Though why does it mention R-77 with ramjet, which went into nowhere and long-range engagements are bread and butter of R-37M and it's izd.810 derivative (assuming it an derivative and not entirely new project).
I think that site took the reference number from the "Mikoyan MiG-31: Famous Russian Aircraft" book written by Yefim Gordon and Dmitriy Komissarov. But the site added the "RCS = 1 m2" which is their guess and didn't came from the book.
This is data from the book:
Zaslon-A range:
zaslon A.PNG
Zaslon-M range:
Mig-31M.PNG

Zaslon-AM range:
Mig-31BM3.jpg

The reference RCS for 320 km detection range of Zaslon-AM should be 16 m2 (same standard they used for Zaslon-A).
Zaslon-AM is basically Zaslon A with new processor
 
Pit said:
The article is funny to translate due to extensive use of slang, unless you know what they are talking about.
1. They are saying the OEPS-27 is cooled by a compressed gas (it use to be a dryed nitrogen gas which cooles the IR sensor to -196deg of Celsius). It is called "kryogen" sometimes.
2. The RLPK-27 is cooled with the "antifriz", a toxic mixture. Note: Usually, radars/targeting systems are designed to run without cooling for some minutes,
Can you give the source for this?
 
I bought an old book on the Fs-x and it used this as an example of a phased array scan pattern. I wonder were it’s from.
 

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