Gaofen 4: World's most powerful GeoSpy Satellite continues China's leap in Space.

[Beidou2020]

=GT at China Defense Forum

Journey's Start

The Gaofen 4 was launched on December 28, 2015 from Xichang in central China, on a CZ-3B/Long March 3 rocket, to a geosynchronous orbit 22,000 miles above the Earth.

On December 28, 2015, a Long March 3B/G2 rocket launched from Xichang and lofted into space the 4.6 ton Gaofen-4 imaging satellite.

Nasaspaceflight.com

Gaofen 4 Orbit

The GEO orbit of Gaofen 4 means that it can maintain continuous coverage of Chinese territory and surrounding areas. It's also the most powerful GEO satellite, good enough to track aircraft carriers in near real time from space.

Billed as a disaster relief satellite, the Gaofen 4 was placed in Geosynchronous Orbit (GEO). GEO satellites constantly stay above a patch of Earth, thus providing constant 24 hour surveillance of a geographic area. By contrast, low earth orbit (LEO) satellites such as the U.S. KH-11 spy satellites are closer to the Earth, so their speed exceeds that of the Earth's rotation (meaning that they cannot maintain continuous surveillance over specific locations). In the Gaofen 4's case, its range of view is a 7,000km by 7,000km box of 49 million square kilometers of Asian land and water in and around China.

CCTV 13

Gaofen 4

The 4.6 ton Gaofen 4 is the most powerful GEO spy satellite, with a imaging resolution of under 50 meters in color, and 400 meters for thermal imaging.

The Gaofen 4 is the world's most powerful GEO spy satellite. It has a color image resolution of slightly less than 50 meters (which is enough to track aircraft carriers by their wake at sea) and a thermal imaging resolution of 400m (good for spotting forest fires). It may also have a lower resolution video streaming capacity. Because of its round-the-clock coverage of Chinese territory and near aboard, Gaofen 4 can provide instant coverage of earthquake or typhoon hit areas to support humanitarian relief. It will also allow China to monitor strategic foreign sites such as WMD facilities and naval bases inside its observation box.

ChinaSpaceflight.com

The High Ground

As a high orbiting GEO satellite, the Gaofen 4 would be very difficult to attack with anti-satellite weapons.

Jilin Provincial Government

Jilin Constellation

When the Jilin satellite constellation is completed in 2030, it will have 138 small satellites that provide a snapshot of any place on Earth every ten minutes.

The satellite is part of the dual use China High-Resolution Earth Observation System (CHEOS), which already has five other satellites (Gaofen 1, 2, 3, 5 and 8). This fits within a larger program of radar, imaging, hyperspectral and atmosphere monitoring satellites that will support Chinese civilian missions like agriculture, construction, disaster relief and climate change monitoring. Of course, the Chinese Aerospace Force (a new branch of the PLA following its December 2015 reorganization) could easily make use of such satellites during Chinese military operations. Also of interest is the Jilin LEO imaging satellites (sponsored by the Jilin Provincial government); the first four Jilin satellites launched in October 2015 and already have 80cm imaging resolution. By 2030, the Jilin constellation will have 138 imaging, high-resolution small satellites that provide all weather coverage of any point on Earth, at 10 minute intervals.

xyz via China Defense Forum

GEO Spy Satellite

This scientific article by Beijing Institute of Space Mechanics and Electricity's Zhang Yue, Wang Chao, Su Yuan and Jiao Jianchao, describes temperature control on a 20+ meter diameter mirror made of optical membrane foil (a smaller satellite can unfold the optical membrane foil to create a larger lens to enable higher resolution). DARPA is also looking at similar concepts to meet American IMINT needs.

With a lifespan of 8 years, the Gaofen 4 will likely be superseded by future GEO observation satellites with higher resolution imaging capabilities. One intriguing possibility is revealed in a study from a Chinese engineering journal. Enterprising scientists propose that a future GEO spy satellite could deploy a foldable telescope lens of over 20 meters diameter, which could be powerful enough provide sub 1-meter resolution (similar to Ball Aerospace and DARPA's Membrane Optics program). Such a futuristic GEO spy satellite wouldn't just be able to find interesting targets like aircraft carriers and missile launcher trucks, it could beam back real time video streams of enemy forces underway.

http://www.popsci.com/gaofen-4-worl...ontinues-chinas-great-leap-forward-into-space

 

[Beidou2020]

China's first high orbit remote sensing satellite, Gaofen-4, went into use after six months of in-orbit testing, the State Administration of Science, Technology and Industry for National Defense (SASTIND) announced Monday.

China's first high orbit remote sensing satellite, Gaofen-4, was launched on Dec 29, 2015. [Photo/chinanews.com]

Gaofen-4 is China's first geosynchronous orbit high-definition optical imaging satellite and the world's most sophisticated.

Unlike from Gaofen-1 and Gaofen-2 in low orbits around the earth, Gaofen-4 is orbiting at 36,000 kilometers. High orbit satellites have the advantage of being able to snap "grand scenarios." Low orbit satellites, in contrast, can see more detail at faster speed.

Low orbit satellites cannot always follow natural disasters, but Gaofen-4 can continuously observe a disaster because it moves synchronously with the earth. It improves the response to disasters like earthquakes, landslides and typhoons with its high-precision sensors.

Gaofen-4, which was launched in December 2015, has a designed lifespan of eight years, compared to other remote sensing satellites which remain in service for less than three to five years.

During the in-orbit test, Gaofen-4 has been used to collect imageries of flood-hit areas in south China and monitor fires that occurred in southwest China's Sichuan Province and in Russia.

China started the Gaofen project with the launch of Gaofen-1 in April 2013. It aims to launch seven high-definition observation satellites before 2020, designed for disaster prevention, surveillance of geological disasters and forest disasters and weather forecast.

Gaofen-3 is set to be launched in August 2016, according to the SASTIND.

http://www.china.org.cn/china/2016-06/14/content_38661184.htm

 

[Tiqiu]

Gaofen-3 is a phased array satellite. I wonder what it does.

GF-4 was officially put in use on June 13.

It covers 1/3 of the earth, can track ANY VESSEL FLEET REAL TIME AROUND WEST PACIFIC AND INDIAN OCEAN 24/7.

 

[jhungary]

It covers 1/3 of the earth, can track ANY VESSEL FLEET REAL TIME AROUND WEST PACIFIC AND INDIAN OCEAN 24/7.

This is just wrong........

That satellite can monitor traffic 24/7 over an area, it cannot track said traffic 24/7.

You do understand the different between TRACK and MONITOR, right?

 

[Indika]

I do not understand the different between TRACK and MONITOR.
I do understand the difference between TRACK and MONITOR.

What is the difference?

Track -> follow the object in real time.
Monitor-> observe the activities periodically in specific time intervals.

Monitor becomes tracking when periodic time interval equals 0. Monitor is more of passive while tracking is actively following/pursuing.

 

[Tiqiu]

Track -> follow the object in real time.
Monitor-> observe the activities periodically in specific time intervals.

Oh, you mean this difference. Literally speaking, there is no difference according to the English I learned

Monitor verb
observe and check the progress or quality of (something) over a period of time; keep under systematic review.
"equipment was installed to monitor air quality"
synonyms: observe, watch, keep an eye on, keep track of, track, keep under observation, keep watch on, keep under surveillance, surveil, check, keep a check on, scan, examine, study, record, note, oversee, supervise, superintend;

Monitor becomes tracking when periodic time interval equals 0. Monitor is more of passive while tracking is actively following/pursuing.

If you were trying to infer that GF-4 can't actively pursue large vessel fleet, then you should first search at what time interval it takes optical and infrared images. I know the answer already but I guess you don't.

 

[chauism]

Track -> follow the object in real time.
Monitor-> observe the activities periodically in specific time intervals.

Monitor becomes tracking when periodic time interval equals 0. Monitor is more of passive while tracking is actively following/pursuing.

I am speechless, next time read more carefully.

 

[jhungary]

I do not understand the different between TRACK and MONITOR.
I do understand the difference between TRACK and MONITOR.

What is the difference?

Tracking is to follow a certain object into and out of an area. where as monitoring or surveying is to keep an eyes on a certain area. In military term. Tracking is not the same as Monitoring.

A CCTV camera on a motorway monitor traffic in and out of the camera range, and the direction is general, so that it record indiscriminately on any target going in an out of a certain area.

Can you tell me from this CCTV feed, where is the white van on the bottom of the photo will go next?

To track something, you need to have to first Identify the target first, and unless you are claiming Geofan can identify your target automatically by any means, you have to have someone study the target on your feed and pan or pix on the target.

Now, by the time you have studied and locate your target, there are already lag in the system and will not be real time. And to track something, you have to be able to point out track the target in real time.

Tracking can be done by surveillance, however, you will need more than 1 surveillance camera to track a target, that is the basis of tracking.

And, don't be a smartarse when you don't know how ISR works. You watched too much TV

And no, Track and Monitor are different in English

Monitor in Oxford Dictionary

http://www.oxforddictionaries.com/definition/english/monitor

Observe and check the progress or quality of (something) over a period of time; keep under systematic review: equipment was installed to monitor air quality

Maintain regular surveillance over:

Listen to and report on (a foreign radio broadcast or a telephone conversation): listening devices were used to monitor conversations

Check or regulate the technical quality of (a radio transmission or television signal):

Track in Oxford Dictionary

http://www.oxforddictionaries.com/definition/english/track

Follow the trail or movements of (someone or something), typically in order to find them or note their course:

As you can see, monitor is for a general area, track is for a specific something.

 

[Tiqiu]

The Chinese GF-4 takes one optical picture and 3 infrared pictures in every X seconds(I know the X, but don't want to tell those who are pretending to know). At what speed has a large vessel fleet to travel in order to get out of the frame in that time interval? The answer: rockets

The Chinese Zhujiang Delta captured by the Chinese GF-4

The image of Shanghai Tower captured by the Chinese GF-2

 

[chauism]

Tracking is to follow a certain object into and out of an area. where as monitoring or surveying is to keep an eyes on a certain area. In military term. Tracking is not the same as Monitoring.

A CCTV camera on a motorway monitor traffic in and out of the camera range, and the direction is general, so that it record indiscriminately on any target going in an out of a certain area.

View attachment 314024

Can you tell me from this CCTV feed, where is the white van on the bottom of the photo will go next?

To track something, you need to have to first Identify the target first, and unless you are claiming Geofan can identify your target automatically by any means, you have to have someone study the target on your feed and pan or pix on the target.

Now, by the time you have studied and locate your target, there are already lag in the system and will not be real time. And to track something, you have to be able to point out track the target in real time.

Tracking can be done by surveillance, however, you will need more than 1 surveillance camera to track a target, that is the basis of tracking.

And, don't be a smartarse when you don't know how ISR works. You watched too much TV

And no, Track and Monitor are different in English

Monitor in Oxford Dictionary

http://www.oxforddictionaries.com/definition/english/monitor

Observe and check the progress or quality of (something) over a period of time; keep under systematic review: equipment was installed to monitor air quality

Maintain regular surveillance over:

Listen to and report on (a foreign radio broadcast or a telephone conversation): listening devices were used to monitor conversations

Check or regulate the technical quality of (a radio transmission or television signal):

Track in Oxford Dictionary

http://www.oxforddictionaries.com/definition/english/track

Follow the trail or movements of (someone or something), typically in order to find them or note their course:

As you can see, monitor is for a general area, track is for a specific something.

To end the arguement here, you and him are both right. You are correct that there is a difference in tracking and monitoring, and he is right that GF4 can indeed track a moving target such as aircraft carrier within its monitoring boundary which is actually quite large at 49 million kilometers^2. To put that into prospective, the total area of South China Sea is only 3.5 million km^2, less than 10% of what GF4's monitoring coverage is.

To us your traffic camera example, if there is a camera that can oversee the whole city while being stationary, then yes the people who monitor the camera can actively track the movement of all the cars within its city limits at least.

 

[jhungary]

To end the arguement here, you and him are both right. You are correct that there is a difference in tracking and monitoring, and he is right that GF4 can indeed track a moving target such as aircraft carrier within its monitoring boundary which is actually quite large at 49 million kilometers^2. To put that into prospective, the total area of South China Sea is only 3.5 million km^2, less than 10% of what GF4's monitoring coverage is.

To us your traffic camera example, if there is a camera that can oversee the whole city while being stationary, then yes the people who monitor the camera can actively track the movement of all the cars within its city limits at least.

.....

Actually, you have completely missed my point.

You need to know, in order for someone to track something, you need to:

1: Identify your target on your feed.
2. Identify your target track on your feed.

Only if you can do both in real time, then you are "Tracking" your target.

In a normal surveillance sense, the identification is made by human, you look at your feed and you call out your target. In Geofan case, it's would be quite hard to call out a target when you have a great area to cover, and the satellite cannot and will not ID your target for you, so to ID your target, you will have to have personnel looking up every inch of that feed, let's do a "For Instance"

Please Identify all the red car in this aerial surveillance picture. (notice that red car, not bus)

Now, time how long it take for you to ID all the red car in this picture?

Problem is, the above picture is only 1 block, and you are talking about general surveillance for 45 millions square kilometre. Even tho a carrier or carriers is a big target, it's not easy to spot it over a large piece of feed.

Then we move on to the next part, the tracking of the trail.

Now, can you tell me where is each red car is going and where does it come from?

You will need to know this answer to predict where your target is going to be next, given that you can only know from 1 feed to the other where that red car is going, and what if it changed direction? It means you will have to ID and locate the red car in all subsequent feed, and it takes time, which render real time tracking impossible.

The reason you assume you can do that is because you assume you can spot your target immediately from any feed *Like you did with the white van before, as it was right in front of you". But honestly do you expect to know where your target is immediately in that 45 millions sq km feed image of yours?

Unless you are claiming GF4 can Identify and locate each target you input automatically in real time, (like you put Nimitz Class Carrier in the control console and the feed generate result and locate the carrier by itself immediate.) Sat Image cannot be use to track target.

 

[GS Zhou]

Picture of Bohai Sea taken by Gaofeng 4. The distance between points A and B are 320km. Suppose the ship travels at 30knot, it needs about 6 hours to complete the 320km distance. So as long as <3hours required for taking pictures + data transmission + target identification, it is ok to say GF-4 is capable of "tracking" targets.

 

[Tiqiu]

So as long as <3hours required for taking pictures + data transmission + target identification,

Not hours, it is in second(s).

 

[grey boy 2]

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Keep up the good work guys

 

[21 Dec 2012]

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Keep up the good work guys

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