Passive radar

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Hobbes

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Silentium Defence announced its first Space Situational Awareness radar station is now operational.

The Oculus Observatory is a new kind of observatory that will deliver the widest field of view and most cost-effective monitoring of objects in orbit anywhere in the world.

Located in South Australia’s Mid-Murray region, the Oculus Observatory is the first in the company’s planned network of wide-field-of-view observatories set to be deployed around the world.

Based off Silentium’s unique radar technology, the observatory’s sensors use Megawatts of transmitted power from pre-existing transmitters, meaning these surveillance radars can be built and commissioned rapidly worldwide in a more cost-effective manner than ever before.

CEO of Silentium Defence, Dr James Palmer, said this generation of space observatory will offer high quality data for more informed decision making, traffic management and collision avoidance in space.

“Unlike traditional space surveillance technologies that provide a narrow view of debris and objects in orbit, the sensors at our observatory provide coverage of an area the size of South Australia,” Dr Palmer said.

“For customers, this means we will detect and track objects they expect to see, like satellites and catalogued debris, as well as new and unknown objects that may pose a threat to critical services or assets in space.
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Silentium builds passive radar systems: systems that don't have a transmitter of their own, but rely on radar signals broadcast elsewhere. Unlike bistatic radar, those radar sources don't have to be linked to the receiver.
They're offering this system both for space surveillance and for defence purposes, where it would be a gamechanger - finally there's a way to run a radar system without having to worry about ARMs.
 
I'd be curious to know what bandwidths does it uses. That would determine what its primary sources end up being. I'm going to go out on a limb and say probably TV/radio broadcasts; I can't think of anything else sufficiently strong enough to create signals across that wide of an area.
 
Josh_TN said:
I'd be curious to know what bandwidths does it uses. That would determine what its primary sources end up being. I'm going to go out on a limb and say probably TV/radio broadcasts; I can't think of anything else sufficiently strong enough to create signals across that wide of an area.
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The MWA is using FM radio frequencies, so roughly centered around 100 MHz.
 
There are several of such a systems, here Leonardo has developed AULOS but other (Thales, Hensold) have also.
Those of Silentium seems me oriented toward space but majority of them are used mainly into detecting planes well into the atmosfere.
It a VERY promising technology but has some obvious limitation.
Bystatic and cooperative radars didn't as an example are not exempt by the risk of ARM launch, knowing that those particular radio emission is linked to an AD system would mean to be targeted anyway.
Non cooperative i.e. using the normal civilian emissions is much more better but suffer from the non control of emitting source, it depend from where you put such a system, in a desert you have only a few emission, maybe not ideal for detection, in an heavily urbanized area you get a lot of interferences.
Advantages, in case of a non cooperative, multistatic radar, however surpass by large the drawbacks: system is absolutely discrete, use no expensive components (although it need a lot of software development but it is an one off), can be masked with normal antennas AND is totally impervious to stealth features of a plane due to blank screen effect.
It need just a little maturation ,and some attention from the various MoD or aerial transport.
 
Just to add to the drawbacks; clearly such a system is all but unworkable over open ocean.
 
Have a series of drawback and limitations.
Certainly it have to be conceived as a part of a larger system and not as a stand alone thing.
Probably it is also a reason because at a certain points those systems seem to proceed and in others they seem to reach a standstill.
They are EW systems and are strictly defensive in nature, so until now in the west they were not be considered so necessary due to a convinction (or better illusion) of having still an air dominance and in Russia and China they are actually in competition with other more mature EW technology, like metric band and OTH radars.
 
Marcellogo said:
Have a series of drawback and limitations.
Certainly it have to be conceived as a part of a larger system and not as a stand alone thing.
Probably it is also a reason because at a certain points those systems seem to proceed and in others they seem to reach a standstill.
They are EW systems and are strictly defensive in nature, so until now in the west they were not be considered so necessary due to a convinction (or better illusion) of having still an air dominance and in Russia and China they are actually in competition with other more mature EW technology, like metric band and OTH radars.
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In war time, then, we have to turn off the TV transmitters......
 
...or the power grid that feeds them, which is probably a more centralized target. Would most TV station have back up diesels or would it be considered a non essential service in most countries?
 
The contrary , the more we broadcast the more our own system would get data, problem can arise from non regular transmissions in deeply crowned areas but on open fields it will work most of time. problem is also what is the content of trasmission itself: it was founf that signals are better when you broadcast heavy metal than classical music as an example...
 
Josh_TN said:
...or the power grid that feeds them, which is probably a more centralized target. Would most TV station have back up diesels or would it be considered a non essential service in most countries?
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You can also use transmission for nearby countries... I didn't think someone would bomb a neutral country but even to attack national ones they would need to enter national airspace first...
 
Fluff said:
Marcellogo said:
Have a series of drawback and limitations.
Certainly it have to be conceived as a part of a larger system and not as a stand alone thing.
Probably it is also a reason because at a certain points those systems seem to proceed and in others they seem to reach a standstill.
They are EW systems and are strictly defensive in nature, so until now in the west they were not be considered so necessary due to a convinction (or better illusion) of having still an air dominance and in Russia and China they are actually in competition with other more mature EW technology, like metric band and OTH radars.
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In war time, then, we have to turn off the TV transmitters......
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TV is still transmitted over the air? How quaint...
 
Paid for infrastructure with low cost of ownership. I don't think there's any country that stopped using transmitters, though in the eastern US (my region) I can't imagine who's actually receiving the signal.
 
Hobbes said:
TV is still transmitted over the air? How quaint...
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Josh_TN said:
Paid for infrastructure with low cost of ownership. I don't think there's any country that stopped using transmitters, though in the eastern US (my region) I can't imagine who's actually receiving the signal.
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Even in the US, close to 20% of households rely on OTA television signals. (A figure that is actually going up as cord cutters use broadcast TV for local channels.)
 
Leading to situation where, 'SHTF Scenario', civilian transmitters shut down for their own protection as soon as shooting starts. And never mind their locations are already 'dialled in' for GPS attack...

Presumably, this is why during 'Gulf #x', those TV stations were whacked, due use of 'bistatic' radar ?? Not just the morale hit...
 
One can use Star (one can google RAND Study on "Stellar Radar" back in 1963) or GPS emission for this non cooperative Bistatic radar or the more proper term "PCL" (Passive Coherent Location). Starlink Emission can also be a good candidate and the neat thing is there would be over 40000 Of them littering the sky one will Never runs out of emitters.

But of course one make sacrifice e.g Loss control to emitted power. Potentially resolution problem. as one may need to receive multiple frequencies.. this precludes use of large high gain antenna. Which is why that operational system claiming such are also double up as ESM like Czhech Republic Tamara, Vera and Ukrainian Kolchuga.

Also your method of angle determination.. may require multiple receivers placed in some baseline distance. e.g Triangulation at least 2 receiving stations are needed for DTOA angle finding methods, 3 works best and do have enough accuracy for weapons delivery.
 
TomS said:
Hobbes said:
TV is still transmitted over the air? How quaint...
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Josh_TN said:
Paid for infrastructure with low cost of ownership. I don't think there's any country that stopped using transmitters, though in the eastern US (my region) I can't imagine who's actually receiving the signal.
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Even in the US, close to 20% of households rely on OTA television signals. (A figure that is actually going up as cord cutters use broadcast TV for local channels.)
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20% in total, but I suspect it is highly regional and not evenly distributed - more remote areas probably tend to use broadcasts more.
 

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