Indeed.... swingwing is great but maintenance challenges.
Good points. I cannot comment regarding the specifics of radar signal processing (RSP) employed to mitigate the sea clutter at low grazing angles, as I have not studied that myself. However, the clutter can be statistically modeled and catered for during the tracking stage. There are well established multi-target tracking (MTT) algorithms that can be employed e.g. MHT and JPDA family of algorithms and the RFS based approaches like PHD, GLMB filters etc. Also, its true that fusing disparate sensors could lead to a significant improvement in the tracking performance. For instance, in the automotive industry ADAS and AD systems base their working on fusing atleast two different sensors e.g. the radar (good slant range, poor azimuth estimation) and the camera (good cross range, poor slant range estimation) for MTT purposes. Though I have never worked with the airborne systems, I believe similar arrangements are made there on RSP(pre-detection/detection) and/or information processing (tracking) stages to increase the statistical knowledge.
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Friend, RF engineering is a huge field, propagation is just one entire field of study which is still evolving. DSP and others can only help to some extent but there are multiple challenge areas one has to content with.Good points. I cannot comment regarding the specifics of radar signal processing (RSP) employed to mitigate the sea clutter at low grazing angles, as I have not studied that myself. However, the clutter can be statistically modeled and catered for during the tracking stage. There are well established multi-target tracking (MTT) algorithms that can be employed e.g. MHT and JPDA family of algorithms and the RFS based approaches like PHD, GLMB filters etc. Also, its true that fusing disparate sensors could lead to a significant improvement in the tracking performance. For instance, in the automotive industry ADAS and AD systems base their working on fusing atleast two different sensors e.g. the radar (good slant range, poor azimuth estimation) and the camera (good cross range, poor slant range estimation) for MTT purposes. Though I have never worked with the airborne systems, I believe similar arrangements are made there on RSP(pre-detection/detection) and/or information processing (tracking) stages to increase the statistical knowledge.
Lastly, yes, signal waveforming can be used to combat the ill effects introduced by the physical channel. I have some background in communications too, and I know that orthogonal transmission together with channel coding and equalization can be used to that effect; OFDM straightaway comes to the mind. Though, the ranging systems are different from the communication systems in terms of their pursued objectives, the physical channel affects the working of both in a similar way. Hence, the transmission techniques which are used the in end to end communication systems can be adapted for the radar as well.
Just a minor correction, I guess you meant frequency (transmission) orthogonality not the statistical one, as the later is a concept in statistics and is actually related to the estimation theory not the communication
How about a better understanding of the process than you do?
Multipaths propagation affects all types of radars. But the most affected are when there is a low grazing angle, not steep like the altitude of an AWACS.
As long as there is a receiver or a reception mode, there is a vulnerability to multipaths propagation.
That is your opinion. But essentially -- so what? How does that invalidates the fact that there are still problems with multipaths propagation?
Yeah...Proving that multipaths propagation exists within the system with sufficient strength that we can use the effects.
No one said multipaths propagation cannot be compensated. But what I pointed out was that environmental factors changes and to date, we can only compensate for some and only to some degrees.
The only thing you 'advanced' is your ignorance, even in the face of evidence.
Why do you think that tactics persists in the first place? Because it worked in the past. Whether that tactic is effective against the radar systems in the F-22/35, I will not say. But the core of the issue is that multipaths propagation CONTINUES to plague radar systems today.
Clutter cannot be 'avoided'. It can only be compensated. The error in terminology reveals your technical ignorance of the issue.
That is a terrible argument.
This is not a luxury for any aircraft, especially in hostile territory.
You are not living up to your forum handle.
Tell that to Russian the maker of.your mki who failed to intercept a single cruise missile with su or s400
Yes, but the multipath effects compensation does not primarily rely on this. E.g. in GSM a mobile phone can keep the track of signal levels of multiple base stations but its for the purposes of handover (during a call) from one cell to another and for cell re-selection (idle). A new connection is made when the phone user reaches the cell boundary based on the RF signal levels and quality measurements. There are other methods, namely the channel coding and equalization, which are used to mitigate the multipath phenomena. Thank you.
I didn't accuse you of being ignorant. I accused you of being intellectually dishonest. And you continue to be so.
Let me spell this out for your benefit. I am asserting that multipath is not the type of radar limitation that makes investment in the strategy of low flying aircraft beneficial. To the contrary, modern (airborne, or those that benefit from multi-sensor fusion, or have alternate sources of ground truth etc.) radars pose a serious threat to all aircraft, whether low or high flying. Modern multipath detection and cancellation algorithms can be augmented to solve this problem. Modern techniques of SEAD/DEAD involve EM warfare, cyber warfare, radar avoidance using range or terrain. But no modern aircraft is optimized for low level flight, and no airforce bets a major portion of air war on low flying bomb trucks. In response to that, you presented a paper in an attempt to show that multipath is a current research topic and thus modern radars are susceptible to it. This paper turns out to be irrelevant to the logical chain of argumentation that I have been presenting. This shows that instead of actually understanding what I am saying, you are googling for search terms and pasting results. Pretty amateurish.
Presenting low quality research has never proven anything but the incompetence of the presenter. Stand in a corner and cry with shame.
No! Proving that you are a copy/pasting amateur fanboy. This paper is exactly proving my point: by using terrain mapping data, it is possible to solve the multipath problem. Go and actually read what you are pasting @gambit.
And you are completely wrong. See above.
Don't act like a jerk. I thought you were better than that.
No it does not. You have proven yourself wrong with the third paper above.
With augmented data, clutter is not the huge performance limitation you are making it out to be. Don't flog a dead horse.
Yes, and another irrelevant presentation in the context of this discussion. There are geometries where multipath becomes a limitation. The paper is proposing to entiely avoid those geometries. Low level flight against AWACS is NOT one of those geometries.
You failed to understand what I was saying. Multipath effects in the receiver are treated as constructive composition of multiple random variables, and using the Central Limit Theorem, the normal distribution is used to model them. This exact same theory carries over to basic clutter detection in radars. Modern algorithms then go on to determine sources of non-gaussian clutter and compensate them as well.
To summarize, I am saying that modern airborne radars are not hampered significantly by clutter, whereas you repeatedly bring the discussion to the specific cases where clutter does cause a large problem. And the paper you yourself presented as proof suggests that such geometries should be entirely avoided. What a waste of time!
Hi
Agree sir
