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ORAC
26th Oct 2018, 07:13
Alert 5 » Patriot?s C-band PESA radar is showing up on SAR satellite images - Military Aviation News (http://alert5.com/2018/10/26/patriots-c-band-pesa-radar-is-showing-up-on-sar-satellite-images/)

Patriot’s C-band PESA radar is showing up on SAR satellite images

https://medium.com/@HarelDan/x-marks-the-spot-579cdb1f534b

X Marks The Spot: Identifying MIM-104 Patriot Batteries From Sentinel-1 SAR Multi-temporal Imagery

There are two main types of remote sensing satellites: optical and radar. Each type can be subdivided further into sub-categories based on aperture, orbit, and bands. One of the most used is ESA’s Copernicus program Sentinel 1 (https://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-1/Introducing_Sentinel-1) pair of satellites, S1A and S1B, giving a combined average revisit time of 1.5 days in a best case scenario. Such a high-resolution and high revisit time, as well as the open access approach, has made the data these satellites provide essential in many fields of study, from emergency response, marine monitoring, vegetation analysis, wildfire quantification, and urban planning.

The data can be freely downloaded and analysed on many platforms, including Copernicus Open Data Hub (https://scihub.copernicus.eu/), Sentinel EO Browser (https://apps.sentinel-hub.com/eo-browser/) and Google Earth Engine (https://earthengine.google.com/),........

Two paragraphs ago I mentioned that most of the noise can be removed by some forms of image aggregation, or multi-temporal analysis, where for each image pixel the lowest value is selected. When I attempted such a feat in Google Earth Engine, I accidentally selected the maximum value, and the results were staggering. Displaying a combination of VH and VV polarizations, these lines, the result of overlapping ascending and descending orbit interferences, consistently converge. What is it?

Long story short, some of these are AN/MPQ-53/65 phased array radars that form a Patriot missile battery (https://en.wikipedia.org/wiki/MIM-104_Patriot) C². Looking at official documentation, the military G-band (https://en.wikipedia.org/wiki/G_band_%28NATO%29) is the civilian C-band. Sentinel-1 central frequency is 5.405 Ghz, well within this range, hence my working hypothesis is that there is some sort of ground based interference with the Sentinel-1 signal.

So anywhere in the world these artifacts appear, they may point to a location of a patriot battery, or other early warning system, as I shall show........

https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/1366x768/1_dhy45s6l3cqh82nmgwhgww_70f5dd0b5dbd6559c8d666e487f4ea8eb23 c2f3e.png

glad rag
26th Oct 2018, 08:02
Cue the inevitable "it can't happen here" die hards :lmfao:

Now then what about great big grey carriers? I seem to remember being dissed about JUST THIS CAPABILITY on the grey funnel line thread.

have another couple :lmfao::lmfao::lmfao:

Bing
26th Oct 2018, 11:22
Cue the inevitable "it can't happen here" die hards :lmfao:

Now then what about great big grey carriers? I seem to remember being dissed about JUST THIS CAPABILITY on the grey funnel line thread.

have another couple :lmfao::lmfao::lmfao:

You understand that this is achieved using multiple passes of the satellite which are 1.5 days apart yes? You understand why this is therefore a poor way to attempt to track a carrier, or more likely a destroyer escort yes?

Pontius Navigator
26th Oct 2018, 11:39
Bing, what was impossible becomes the improbable. This then becomes the possible, probable before becoming a certainty.

You can never say never.

Bing
26th Oct 2018, 12:57
Bing, what was impossible becomes the improbable. This then becomes the possible, probable before becoming a certainty.

You can never say never.

Oh I'm certain if you wanted to invest in an actual spy satellite to do the job you could do that today, you're just listening out for transmissions in certain areas of the frequency spectrum which is what a radar warning receiver does. Orbital mechanics makes it difficult trying to maintain 24/7 coverage but you wouldn't need to faff around looking for weird interference patterns building up. I just don't think being able to do it with several days worth of open source data is anything to worry about.

glad rag
26th Oct 2018, 14:56
Oh I'm certain if you wanted to invest in an actual spy satellite to do the job you could do that today, you're just listening out for transmissions in certain areas of the frequency spectrum which is what a radar warning receiver does. Orbital mechanics makes it difficult trying to maintain 24/7 coverage but you wouldn't need to faff around looking for weird interference patterns building up. I just don't think being able to do it with several days worth of open source data is anything to worry about.



https://www.space.com/34324-cubesats.html

CubeSats are miniature satellites that have been used exclusively in low Earth orbit for 15 years, and are now being used for interplanetary missions as well. In the beginning, they were commonly used in low Earth orbit for applications such as remote sensing or communications. As of mid-2018, a pair of CubeSats has been deployed on a mission flying to Mars, and other CubeSats are being considered for the moon and Jupiter.

The CubeSat design was first proposed in the late 1990s by two professors: Jordi Puig-Suari of California Polytechnic State University and Bob Twiggs of Stanford University. They were trying to help students gain engineering experience in satellites, which are traditionally expensive to build and launch. The idea for the CubeSat came in part from the miniature toy craze of the day, Beanie Babies, according to Spaceflight Now (http://www.spaceflightnow.com/news/n1403/08cubesats/). Inspired by the individualized stuffed animals, Twiggs' idea was to allow students to build their own miniature satellites.

The basic design of a CubeSat is a 10-centimeter (4-inch) cube with a mass of less than 1.33 kilograms (2.93 lbs.), the article added. But variations on the theme are possible. CubeSats can also be designed to encompass two, three or six 10-centimeter units for more complicated missions.

CubeSats reduce launch costs in two fundamental ways. They don't weigh that much, which means a rocket doesn't need a lot of fuel to heft them. In most cases, they also share a rocket with a larger satellite, making it possible to get to space on the coattails of the heavier payload.

There are some design challenges with CubeSats, however. The electronics are smaller and are therefore more sensitive to radiation. Because they are small, they cannot carry large payloads with them. Their low cost also means they are generally designed to last only a few weeks, months or years before ceasing operations (and for those in low Earth orbit, falling back into the atmosphere.) ....

glad rag
26th Oct 2018, 15:00
Bing, what was impossible becomes the improbable. This then becomes the possible, probable before becoming a certainty.

You can never say never.


PN your pm inbox is "full".....

Bing
26th Oct 2018, 16:26
Thanks, I know what a cube sat is. I also have a reasonable idea what you'd need to track the RF emissions from a radar. The two things would not seem to be currently compatible.

ORAC
26th Oct 2018, 17:27
Bing,

Without getting dragged into the argument, if you do a search on fractal antenna, Koch etc, you will find WLAN Tx/Rx antenna for Cubesat applications in the 5Ghz band are available,

Bing
26th Oct 2018, 18:41
ORAC,

Granted, but how are you getting bearing discrimination? You'd need multiple receivers with a reasonable distance between them to get a decent number of cross fixes, i.e. a multi-static system the same as sites like flightradar use to track Mode C aircraft, except the receivers are also moving. So the problem then is you'd need to know the exact position of the cubestat and time of receiving a particular pulse from the transmitter. GPS might work for that if you've got access to receivers that work at orbital speeds* but I suspect if you've already got plans for a standard spy satellite it's just as easy to launch more of those?
Of course you can always just turn the radar off.

*COTS ones don't as I understand it.

ion_berkley
26th Oct 2018, 21:59
ORAC,

Granted, but how are you getting bearing discrimination? You'd need multiple receivers with a reasonable distance between them to get a decent number of cross fixes, i.e. a multi-static system the same as sites like flightradar use to track Mode C aircraft, except the receivers are also moving. So the problem then is you'd need to know the exact position of the cubestat and time of receiving a particular pulse from the transmitter. GPS might work for that if you've got access to receivers that work at orbital speeds* but I suspect if you've already got plans for a standard spy satellite it's just as easy to launch more of those?
Of course you can always just turn the radar off.

*COTS ones don't as I understand it.

Yeah, not a problem.
HawkEye 360 - Satellite-based GEOINT Technology, AIS Ship Tracking RF (http://www.he360.com/)

VinRouge
27th Oct 2018, 05:07
Or, just this.

https://en.m.wikipedia.org/wiki/Naval_Ocean_Surveillance_System