I was talking about bearing accuracy, where incertitude and calculation error weigh more at shorter range than at longer. .
Iam talking abour bearing ( angular ) accuracy too
a 20% angular error at 5 km distance is alot better than 20% angular error at 100 km distance
While elements are on the same platform their radial distances and motions relative to the emitter are different.
Technically speaking if you have 2 receiver on the wing tips , and you keeping yaw left and right , you can have that kind of Doppler shift different , however, i can own see this method working again a stationary emitters , because if you known the emitter is stationary , you know your own speed and you know your yaw rate then technically speaking you will know how much Doppler shift will be induced due to motion of each wing tip. All of these estimation go out of windows if the emitters also moving at an unknown speed ( even worse if it is accelerating or decelerating ).
And to be fair , you probably need several platforms (long baseline) if you want high accuracy for this method ( kinda similar to TDOA )
The Doppler phase interference method ( I think it is its name, or something alike ) exploit the differential in Doppler shift resulting from difference in radial motion relative to emitter, between the elements of the array to compute the range .
Iam quite certain that what you thinking about is Doppler difference of arrival
I disagree, going superfast will indeed result in a very high IR signature, flying at about mach 1.4 would not,
It really up to your definition of very high
No . The technic I am talking about yields an instantaneous direction and more or less accurate range, via measurement of the incident signal instantaneous phase differences at each antenna elements (Delta PHI) of a phase interferometry antenna array.
The phase interferometry Direction Finding method give the incident signal Angle of Arrival using the phase differences measured at each antenna elements and some trigonometric (AOA= f(Delta Phi)) .
From there , the Doppler shift at each elements is calculated and used to compute the differential in radial distance to emitter (Delta r), between each antenna elements (Delta r=f( Delta Phi, AOA, ReceiverElementSpeed )).
The combination gives both direction: AOA and the radial distance to emitter :r on a single measurement (r=f(Delta r, AOA)). .
I know how an inferormetry work , finding direction with it should be simple , monopulse radar use the same principle to improve their angular accuracy
But i dont see how you can deduce range to target through doppler processing at difference receivers , given that all receivers are on the same platform , they would literally move at the same speed , hence create same Doppler shift. Unless you are talking about long baseline Interferormetry with receiver on different aircrafts several miles apart. In which case , shouldnt triangulation be a simpler solution ?. Moreover, if you dont know the transmitted frequency ( before Doppler shift ) then how can you deduce emitter speed ?
Nevertheless the calculation error in AOA ,Doppler shift and ultimately range is related to wave length and the inverse of radial distance to emitter ( Hence it works better at longer rather than shorter range ). More significantly the calculation errors are independent of the emitter and receiver speed and direction or even changes in those.
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Iam honest dont see how that possible that Doppler processing could be independence of speed or direction
Well, its possible, but very debatable. I would be willing to accept a close couple canard would add to Clmax automatically, but on Typhoon, canards are just too far away to provide a meaningful vortex at high AOA.
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I been thinking about this for a bit , since we know that CL increase with AoA ( to a certain point )
Is there any chance the canard on Typhoon improve CLmax over Mirage design simply because it allow the Typhoon to be controlable at higher AoA ?
So MiG-21 has Clmax of 1,25
How come CL for Mig-21 wing configuration is so high compared to Mirage 2000? , they both use delta wing , both has tube body ?
Increase given by negative stability to calculate effective Clmax of entire airframe (not only the airfoil) is 3-5%
Shouldnt this depending on the size of their stabilizers and wing configuration as well ? , like for example i dont see the point of making canard aircraft negative stable
No I am talking about using the doppler changing rate equation, to measure the radial distance between emitter and receiver. .
You mean this one ( the last one ) ?
Iam quite certain that for this method you need the operating frequency of the threat radar to be constant for it to work ( and the threat platform need to move at a constant velocity too )
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