The assumption is that the Chinese have AESA technology comparable to that of older versions of the F-22. Using the same technology, and scaling it up to the aperture size of the Flanker (the F-22 has an aperture around 900mm, the F-15 and Flankers have an aperture size of about 1000mm), you should get roughly 10% more detection range. The official detection range is 240km+, which I assume means 300km in practical use, adding 10% range via aperture size grants about 330 km range. You are right, the declared range is a bit high for Gallium Arsenide, but it's possible with GaN technology and higher power outputs.
When a customer is looking to purchase a radar system, civilian or military, he would normally say something like: 'I want a system that have an %X odds of detecting any target at Y distance.'
Maximum range is always greater than effective detection range so if I say: 'I want a system that will have a %75 certainty (odds) of any target at 200 km.', the maximum reach of this system will be around 300 km. The percentage figure will be the threshold upon which the system will flag the system to display the target on the scope. The %75 figure means that a body became reflective at around 300 km, but the system have not been able have consistent target resolutions of:
- Altitude
- Speed
- Heading
- Aspect angle
As this body approaches, the system must have those target resolutions at %75 intensity by the time it reach that 200 km marker. If a supplier/competitor have only %70 intensity of those target resolutions at 200 km, it means he will have %75 at 180-190 km. Am just playing with rough numbers here to illustrate a point. Anyway, this supplier will be disqualified from competition.
The customer -- me -- specified a distance and target intensity combination for a reason.
If I am an air traffic control designer, 200 km (or whatever) will be the distance where I will begin to manage traffic and order aircrafts around. Beyond 200 km, those aircrafts can self manage.
If I am an air defense specialist, 200 km will be where I need to have %75 certainty so I do not send my forces chasing ghosts. But if you can give me %75 certainty at 300 km, I will move you to the top of the list and if you can prove to me that you can acquire %75 certainty at 500 km, I will buy your product on the spot.
I can specify %50 certainty at whatever distance and the lower that threshold, the more suppliers/competitors I will get.
Now when we add low radar observable bodies into the mix, it gets problematic for air defense systems, whether that system is a SAM station or a fighter aircraft. If the system is designed to flag at %75 certainty at 200 km, against an F-117 class body, it will flag %75 at visual range. Or may be a little bit further out. Again, am just using rough numbers to illustrate the relationship between target intensity and distance to produce that 'effective detection range' that everybody casually throws around.
If you want to know what an F-117 class body look like on a typical fighter-class radar, then look at this article...
http://www.acc.af.mil/news/story.asp?id=123041725
Pilots from the 65th and 64th AS, including exchange pilots from the Royal Australian Air Force and Royal Air Force, of Australia and England respectfully, expressed their frustration related to flying against the stealthy F-22.
"The thing denies your ability to put a weapons system on it, even when I can see it through the canopy," said RAAF Squadron Leader Stephen Chappell, F-15 exchange pilot in the 65th AS. "It's the most frustrated I've ever been."
Chappell was able to acquire visual ID of the F-22 but his radar was unable to acquire that %X threshold necessary for weapons lock. If both fighters are at fixed distance from each other, then most likely Chappell would be able to have those target resolutions, but most likely he failed because his adversary was maneuvering, creating high levels of
radar target scintillation (keywords search), as in high-low reflectivity with no discernable pattern, for his radar to calculate those target resolutions at %X certainty.
Scintillation (radar) - Wikipedia, the free encyclopedia
Scintillation is a fluctuation in the
amplitude of a target on a
radar display. It is closely related to
target glint, or
wander, an apparent displacement of the target from its
mean position. This effect can be caused by a shift of the effective reflection point on the target, but has other causes as well. The fluctuations can be slow (scan-to-scan) or rapid (pulse-to-pulse).
People who do not understand the crucial relationships between target resolution, threshold certainty, and distance usually focus on sales brochure 'maximum' and 'effective' target detection ranges, how large is the array, etc...etc...And for those of us who know, we just shrugs those figures off.
What I presented above I presented them here before -- many times. I know more precise figures but people here know I will not reveals them for reasons am sure you can understand.
The APG-77v1 is obsolete, however. I believe that the US is in the process of upgrading the APG-77v1 to the APG-77v2 with technology from the F-35. It means that the APG-77v1 is no longer state of the art and that later versions should exceed it in performance and resolution.
Again...Obsolete based upon whose standards? If the -77 is still the desirable system for most of the world's forces out there, and most American arms that became 'hand-me-downs' for other countries are still formidable systems, then the criticism that the -77 is 'obsolete' is meaningless.