If Japanese ships actually locked their own weapons radar onto PLA ships,...
without any evidence, it is very biased when you said you believed JP had not done so. that is why whatever you told us is just BS and hypocrisy. we never believe in such biased person.
Here is why, on a purely technical basis, Japan's accusation is more credible than China's denial...
China denies putting radar-lock on Japanese warship - CNN.com
Hong Kong (CNN) -- China on Friday denied accusations by Japan that a Chinese navy vessel had put a radar-lock on a Japanese warship near a group of disputed islands at the heart of a bitter feud between the two Asian nations.
First...
The above is not to scale, of course. It is meant to illustrate the difference in wavelengths.
Second...
In order to have target resolutions and updates of these resolutions:
- Altitude
- Speed
- Heading
- Aspect angle
We must uses pulses as in the second illustration. It does not matter if the target is at ground level or at 100,000 ft. Most radar systems will produce altitude resolution anyway, especially if weapons systems such as missile that flies above sea/ground level, depends on target altitude, even if it is zero, as guidance through data links. And since the missile flies above sea/ground level, its perspective will be different than that of the ship that is providing said guidance. So it will need altitude information about the target.
Each pulse has two timestamps: pulse start and pulse end. This is called 'finite pulse length'.
The longer the duration between these two timestamps, the less fine grain target resolution updates. It make sense because the leading edge of the transmitted pulse will also be the leading edge of the returned (echo) pulse, and if the duration between the return pulse leading edge and trailing edge is long, it will take longer for the radar computer to assess where is that target regarding those four main resolutions. Timing is everything in radar detection.
So if we want high resolution updates, even for a ship moving far slower than an aircraft, we must use shorter pulses. This in turn will make the inter-pulse periods, those 'silent' or no energy pauses, also shorter. It is the 'pulse repetition freq' (PRF) or some would call it 'interval' (PRI). The PRF is usually measured from leading edge to leading edge, or from trailing edge to trailing edge.
To resist countermeasures (ECM), we usually transmit in pulse trains, which is like 100 pulses with uniform finite pulse length and equally uniform PRF. Then we pause and transmit another pulse train of another 100 pulses. Except this time we change this pulse train with regards to amplitude, freq, and PRF. On the next pulse train of 100 pulses, we change those three pulse characteristics again. And again. And so on...
RADAR *PULSE *CHARACTERISTICS
PULSE REPETITION FREQUENCY(PRF).PRF is the rate at which pulses are transmitted (per second). It controls a radars maximum effective range by dictating the duration of its listening time. Increased PRF speeds the rate at which targets are repeatedly radiated. This increased sampling results in greater target detail, but the maximum range of the radar is reduced because of the shorter periods between pulses. The WSR-88D can emit anywhere from 318 to 1304 pulses per second. It has a maximum range of approximately 250 nautical miles (nmi).
Not only that, if it is a moving target, we must sweep our beam, but not in a 360 deg or 180 deg or even 90 deg. We sweep or 'paint' the target only within its dimensions, which we established with the initial scan. In other words, if the ship is 50 meters long, we sweep our beam in approximate to that electrical length. There is no need to overscan the ship. So what this mean is that our scan or 'paint' of the target will be rapidly back and forth.
The problem for China's denial is that the Japanese Navy is fully capable of analyzing any radar scan of its ships and such analysis is completely automatic to distinguish general volume search transmissions, which would be long duration between 'hits' and probably with longer wavelengths, from targeting transmissions, which would be high PRF and with shorter wavelengths, and because of the necessity of high target resolutions update, those 'hits' will be quick in between.
All typical characteristics of weapons targeting radar transmissions.
Japan considers disclosing evidence on China radar lock ? Japan Today: Japan News and Discussion
TOKYO
The Japanese government said on Saturday it was considering disclosing evidence to bolster its claim that a Chinese frigate locked its weapon-targeting radar on a Japanese ship, after Beijing rejected the charge.
Japan
SHOULD NOT reveal those technical data. Japan have nothing to gain and much to lose in terms of revealing vital technical capabilities to the PLA. The military and engineering communities, which includes China, know that Japan's accusation has valid technical merits. It is within these communities, not the public, that Japan should focus her attention and they do not need to see those data.
To all the Chinese members here, you can get away with being China's mouthpieces and support that denial elsewhere on the Internet.
But not here.
i hope next time, china fire real missile at japan, i will see how fussy you are, hahaha
