Ozair wrote:YIMBY wrote:Give me a couple of millions and I will build you a demonstration system.
So the answer is no system exists.
Before radars were invented - and long after that, in many parts of the world even today - the air defence uses human surveillance network. That is, there is a man in a tower, looking around and listening carefully, and when he sees or hears something he makes a call to the command centre that builds the actual situation in the air space using all information it gets.
Today you can replace the man with a machine, in this case a microphone which is much cheaper, more sensitive and more reliable.
Ozair wrote:YIMBY wrote:I am not aware of a sound sensor that is able to identify that, but a grid of cheapest available microphones will give remarkable accuracy. If such costs less than a dollar, and military pays ten dollars, then with a cost of one radar you can buy one million sensors, to have 2 sensors per square kilometre over Germany and you still have a couple of hundred thousand left to be hidden over the borders.
So again the answer is no system exists and despite that it apparently will take you no time at all to build and develop this no other nation or company in the world, who faces the very real prospect of facing a stealth aircraft it will struggle to identify on radar, has developed this system it clearly is possible…
There may be a good reason why your country do not have any surveillance network, but that does not mean that others do not have. Russian will certainly not open the details of their air defence to potential aggressors and USA would keep very silent of possible weaknesses of its fighters it wants to sell at a good price.
Ozair wrote:YIMBY wrote:I would bet my life for a 1 km resolution, my balls for 100 m, my hair for 10 m and my reputation for 1 m. It is less accurate for high altitudes and more accurate for low altitudes (below radar horizon).
A claim that you can not support nor have you provided any technical or mathematical evidence.
Tracking is a very well-known technique in physics and engineering with ample applications. Existing tracking software can be modified for this purpose in a few days.
You place a set of sensors in a suitable formation. You have a moving target that emits some kind of pulses, like sound, em radiation or surface waves. The sensors measure the pulses, i.e. recording the arrival time and the strength (often the full time profile to get more information). Then you just make best fit for a test track (e.g. maximum likelihood method).
The ultimately limiting factor is the time resolution of the sensor. The 8 kHz sampling rate of the cheapest wireless microphones or telephones would correspond to 0.13 ms or 4 cm with sound speed. The actual resolution may be worse due to variations in sound speed due to temperature and pressure and wind, reflections and error in the position of the microphone itself. Some of that can be mostly eliminated with accurate environmental measurements or statistics, i.e. combining the data of multiple sensors. The final resolution depends on the configuration of your system, number of sensors, quality of the microphone and amount of real-time environmental measurements made.
Reaching sub metre accuracy for the track of a low-flying supersonic aircraft is completely reasonable. The largest uncertainty is caused by the random movements of the plane after the last tracked point.
It is also possible to distinguish separately all aircraft in a formation. That may be challenging for a radar. With a good sound analysis system you can define the type of the plane, at least the engine and its thrust and get some hint of its weight.
Ozair wrote:YIMBY wrote:With the sonic boom, we will talk about centimetres, at least low altitudes. That is enough to hit it with one bullet, if it just goes straight ahead (assuming a gun with such an accuracy in the right place, not always possible). How fast and often you turn when supercuising?
Yimby, when the respective airframe is travelling towards you at a speed faster than the speed of sound, how do you expect to identify where it is before it reaches you?
First, how do you know where I am to drop the bomb in my head?
Second, the signal can be transmitted wirelessly or wired almost with the speed of light from the most remote corner of the sensor net which can be thousands of kilometres away. I do not have to wait that the sound reaches me.
Yes airframes turn when they are going supersonic, whether supercruising or using burner…
If I force you to make continuous random turns I make you to lose your energy. Such movements may help the radar detection also as you cannot keep in the most optimal attitude for radar reflectivity.
Ozair wrote:YIMBY wrote:The time delay from highest altitudes may be up to a minute. Rotating radars also have a limited time delay, up to 15 seconds typically. Of course, you can lift the sensors to 15 km if you want, though you may not be able to make a dense and symmetric grid in the air.
It keeps getting better… So given the quality of a radar track from an EW radar, which will provide you with a hit every 10-15 seconds at the speed of light, is so low you cannot use it to cue weapons, apparently a sound sensor that has a delay of one minute is satisfactory?
That is the worst case, a high flying plane. High-flying fighters are rather good targets for radars as there is less background.
We never rely on one sensor system but always combine all available information.
Ozair wrote:YIMBY wrote:Note that the sound sensors are practically undestroyable and unjammable.
Of course no one has ever invented a system that outputs audio noise into the spectrum…
Here we agree, though theoretically that is possible.
Ozair wrote:Yimby, when you want to have an intelligent, logical and fact based discussion on this I will participate. If you want to enter fantasy land, make claims that are not only illogical but completely technically unsupported I have better things to do with my time.
If you want to have an intelligent discussion, please do not throw arrogant insults.