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India Launches World's First Stereo Imaging Satellite
sgups writes "India will tomorrow inaugurate a new launch pad at its Satish Dhawan space port near Chennai, on the south-east coast, by putting the world's first stereographic mapping satellite into orbit.
The most innovative feature of the 1.6-tonne Cartosat-1 is its pair of cameras, which will give stereo images of the earth's surface that can distinguish features down to 2.5 metres across. They will directly generate three-dimensional maps that have until now been achievable only indirectly, by combining data from a large number of satellite passes over the same place.
"Such a stereographic imaging system does not exist in the civil sector anywhere else," says Mr Nair, chairman of the Bangalore-based Indian Space Research Organisation (Isro). "It will give information about heights that will be very useful in applications such as planning power lines."
Cartosat-1 will join what is already the world's largest cluster of non-military remote sensing satellites. Six Indian spacecraft are already observing the earth with a wide range of instruments."
Six Indian spacecraft are already observing the earth with a wide range of instruments."
Though probably none are currently tracking CowboyNeal.
A feeling of having made the same mistake before: Deja Foobar
But HIFI stereo, which means it has the highest level of fidelity available. It also sports an 8-track.
...will be off-shored to China.
Religion is for people afraid of going to hell.
do the cameras have to be to get a proper parallax?
Uh, can't they already determine heights to high degree of accuracy with GPS or other radio wave methods? How would a picture be more accurate?
I don't get. If it's not a geosync, then it's going to be moving, so they could just use 2 images from a few seconds apart to get the required images. No?
...probably had this ability in the late 60s or early 70s.
Stereoscopic imagery is great for mapping geology. Most stereo photos are not shot at a small enough scale to do regional mapping so this could be wonderful. Hopefully the data will be easily obtainable and the coverage will be suitable to do broad-scale work.
I'm going to assume the satellite designers knew what they were doing and there is some good reason for this.
:-), I'm looking for something a little more informed.)
That said, given the resolution with which we know the position of a given satellite, and the low resolution of the source image in this case, what advantage does using two cameras give you, vs. taking one camera and snapping two pictures in quick succession?
Maybe they can't be snapped quickly enough? But then, you'd think the larger parallax would be helpful, not harmful.) I know consumer cameras have the basic tech now to take a snapshot of the CCD state and process it later, that tech ought to scale right with the CCD resolution, whatever it is.
Maybe this is so you can choose the parallax direction, instead of the orbit forcing your choice? Does the image processing need the parallax to show up in some particular direction relative to the light source to work?
Honest questions; knowledgeable answers appreciated. (As you can see, I can talk out of my ass too
Weather Radar on birds with ISAR can do this.
0 49193.Ph.r.html
http://www.madsci.org/posts/archives/2004-09/1094
I've exchanged email with NOAA about hurricane photos and have been told that some of them are inface ISAR radar images that have been colored.
The blurb there for the story sounds like a Press Release there from Mr Nair, chairman of the Bangalore-based Indian Space Research Organisation (Isro).
This is just supposition, based on the fact that two cameras on a satellite would not be far enough apart to generate parallax.
Share. Until it becomes uncomfortable. Or at least a little.
I knew they were big into offshoring but...
Over the summer and last semester I worked in a nano-satellite lab at ASU. The most recent satellite of ours that was launched was Three Corner Sat and one of its primary mission objective was sterio imaging.
g e=3CS
http://threecornersat.jpl.nasa.gov/
http://nasa.asu.edu/
https://spacegrant.colorado.edu/tiki-index.php?pa
Unfortunately, the two of our satellites that got launched were released at 50,000 km instead of 100,000 km so they burnt up before they could power up.
http://www.spacetoday.net/Summary/2737
-- James
Any truth to the rumor that they're going to oursource their call center to a US firm?
I'm kidding!
"If god did not exist, it would be necessary to invent him" --Voltaire
... hopefully with Dolby!
--- Attorneys Assisting Citizen-Soldiers & Families -
Um...right. Like decades if not centuries of maps can't help there. Besides, I would think that in a country as large as India, they'd be focusing on localized power generation.
Sorry, but this sounds like a really lame excuse for lobbing a satellite up there to spy on Pakistan, with a happy-go-lucky PR spin so the average citizen thinks "oh, another satellite that will be useful!" Yessir, routing power lines.
Not like the US hasn't done the same thing- the majority of shuttle missions were for either admitted, or "disguised-as-scientific-experimentation" military satellites.
Please help metamoderate.
Due to spacecraft (or aircraft) motion, stereo pairs are generated along the flightpath if sequential images overlap. In many systems, each image n generates overlap with both image n+1 and n+2. Given the ability to launch two cameras, why not launch a single camera with more capabilities? Another minor, and common, error is that the Cartosat-1 has a 2.5m pixel on its CCD, which does not transalate into a 2.5m "resolution." CCD resolution corresponds to Ground Sampled Distance (GSD), or the amount of ground sampled on one pixel. Ground resolved distance, (GRD), measures the highest frequency visible in the image and is what we normally think of as "resolution." As a result, for electro optical systems, GRD = 2 x GSD.
Perhaps you ought to RTFA (or at least TFS)...
____
~ |rip/\/\aster /\/\onkey
Perhaps I'm not understanding how the submitter is using the term "non-military", and not to wave Uncle Sam's flag too much, but offhand I can think of more than six US RS platforms/sensors:
EOS/Terra/MODIS http://modis.gsfc.nasa.gov/
Landsat ETM+ http://landsat.gsfc.nasa.gov/
Landsat MSS (yes still going)
AVHRR http://daac.gsfc.nasa.gov/data/dataset/AVHRR/
GOES http://www.goes.noaa.gov/
ASTER http://asterweb.jpl.nasa.gov/
Not to mention US based commercial satellites:
IKONOS http://www.spaceimaging.com/
Quickbird URL:http://www.digitalglobe.com/
There is no such thing as 1st, 2nd and 3rd world nations any more. There are only developed and developing nations, India being of the developing kind.
Jonathanjk.com
Getting proper parallax from 620 km is a bit tricky. The cameras would need to be many km apart to get good stereo (31 km camera baseline is equivalent to the parallax that human eyes have at 1 meter).
Instead, I suspect that the parallax is achieved by having two cameras that point slightly different angles. One points down and forward along the track of the satellite, the other points down and backward. Thus, as the satellite passes overhead, the same spot on the ground is seen by the two cameras in succession from different parts of the orbit.
For purposes of get topo data on fixed objects, its more than adequate. Given that the satellite is moving about 8 km/sec, it traverses the needed baseline for stereo in only a few seconds. This is not enough time for the scene to have changed that much.
Two wrongs don't make a right, but three lefts do.
The spacecraft is configured with the Panchromatic cameras which are mounted such that one camera is looking at +26 deg. w.r.t. nadir and the other at -5 deg. w.r.t. nadir along the track. These two cameras combinedly provide stereoscopic image pairs in the same pass.
I have something of a hard time seeing the utility of this new system.
People who think they know everything really piss off those of us that actually do.
There's probably TWO cameras, one for visible light, one for infrared. Not two cameras for binocular vision. The two "eyes" would be too close together for any usable stereoscopic effect.
India has been doing VERY good in applied sciences and technology in spite of limited resrouces.. mainly because of huge techi population. Its one of the 5 nations to launch PSLV, is working on intercontinetal ballistic missles, one of 5-6 nuclear nations. So, as far as space research is concerned i wouldn't call it 3rd world country :-)
And, at least in space research, there is virutally no coperation between US and India after Indian nuclear test in 1998.
This sig doesnt exist.
This isn't the first stereographic satellite that's accessible to the general public; that would be MISR - NASA's Multi-angle Imaging Spectroradiometer, built by JPL, with nine cameras pointed in different directions along its direction of travel in polar orbit, ranging from nadir (straight down) to 70 degrees in either direction. Compared to India's new high-resolution satellite, MISR seems very low resolution - 275 meters per pixel - however, it covers the entire surface of the Earth every few days and all of the data is available for free at this resolution, while India's satellite is "targeting"; it only images a particular area when it is programmed to do so. MISR is used primarily to study clouds and aerosols.
To see some 3-D images taken by MISR or some animations of its 9 cameras' views of different scenes, check out their gallery.
Plenty of orbiting satellites up there. What's amazing is this comes from a country with an average literacy rate of 52% (compared to 97% for the U.S.).
48% of their citizens can't read or write, but they're funding a space program to the equivalent of a few billion U.S. dollars. Amazing. I can only imagine what taxes must be like in India to pay for something so expensive when the per capita income is so low.
In the end they will lay their freedom at our feet and say to us, Make us your slaves, but feed us. - Fyodor Dostoyevsky
Do a Google search for Hipparcos, sometimes spelled Hiparcos. It's an ESA mission that's been taking high quality parallax data of hundreds of the nearest stars, for something like a decade now. Before that, Earth-based observers have been able to measure parallax to even closer stars. These distances are the most accurate measured in astronomy, and are used to calibrate distance scales based on other phenomena, like variable stars. The data, like many scientific endeavours, is publicly available, although you'd probably be hard pressed to do anything interesting with it. There are a number of programs available that let you visualize the local 3D starfield, if that's your interest.
1. The Indian economy happens to be the 12th largest in terms of GDP and 4th largest when adjusted for PPP (Purchasing Power Parity). I quote from the Wikipedia article:
With a GDP of 568 billion (B$) ($3.096 trillion (T$) at PPP) India has the world's 12th largest economy (and the 4th largest when adjusted for PPP). However, the large population means that per capita income is quite low. In 2003 the World Bank ranked India 143rd in PPP per capita income and 160th in real terms, among 208 countries and territories.
2. India has (through the Indian Space Research Organization) pursued a pretty widespread (and largely non-military space program) since the 60's. From this relevant Wikipedia article:
# 1962: Indian National Committee for Space Research (INCOSPAR); formed by the Department of Atomic Energy, and work on establishing Thumba Equatorial Rocket Launching Station (TERLS) near Trivandrum began.
# 1963: First sounding rocket launched from TERLS (November 21, 1963).
# 1965: Space Science & Technology Centre (SSTC) established in Thumba.
# 1967: Satellite Telecommunication Earth Station set up at Ahmedabad.
# 1972: Space Commission and Department of Space set up.
# 1975: First Indian Satellite, Aryabhatta, launched (April 19, 1975).
It's also fruitful to note that India was a British colony till 1947. IMHO, starting a space program in about 1.5 decades after gaining independence is a laudable achievement. The major problem which India faces today is it's large population, which pretty much negates all the economic advances, and causes it's perception as a "thirld world country" to continue.
It is also worth noting that India seems to be spending substantial amounts of money to improve it's people's lot and advancing education, science and research, rather than spending it instead on aggressive military tactics, which seems to be the trend nowadays. If you read up the history of the nation, you'll see that it's one of the few countries that has never pursued invasion/colonialism, and has instead been frequently invaded by conquerers (Mughals, British, etc) who looted the wealth of a formerly rich region and left it in a state that it's trying to dig itself out of now.
PS: Posted this because I perceived a derogatory slant in the Parent's use of the term "third world country". I find the practice of using wealth to rank nations (especially so when used to diss poor nations) quite abnoxious. I have nothing against using the term in a scientific/neutral sense.
An Indian-American Hindu committed to non-violent thought/speech/action alarmed by the global explosion of radical Islam
The stereo pair is not collected at the same moment. One image will be collect with a camera looking forward a few degrees and then once the satellite has pasted over the target, a second image will be taken looking back with the second camera. This technique is along-track stereo and has been used before. Cross-track stereo has also been used where an image will taken looking off to one side and then the second image will be taken on a subsequent orbit looking off to the other side. Along-track stereo has a big advantage in that the two images are taken within seconds of each other and will therefore have similar atmospheric and lighting conditions which improves analysis.
I'm going to act as if the poster was sincere and not a troll, therefore deserving of a thoughtful answer.
Every government is faced with the challenge of balancing the short term needs of the impoverished with the long term obligation to develop the national infrastructure and long term high paying jobs and therefore wealth of their economy.
In the US from the 1960's onward, there were cries by some that the billions of dollars spent on our space program should have been spent on our poor. While we don't have the numbers of poor that are in India, a visit to American rural areas like Appalachia or any number of American Indian reservations or a visit to American inner city areas will tell you that we still have our own millions of people living in violent areas, without adequate food, medical care, education, or hope for improvement in these areas.
Even so, others will argue that much of American wealth created and shared by most of the population was helped by research in space and other military programs. (The reason we started our program was to maintain parity with the former Soviet Union.) If spin-offs from the Indian investments in space translate to private sector jobs, then an argument may be made that it has long term value.
If there is anything the Ronald Reagan taught us Americans (and no, I was NOT a big fan of Reagan's in many areas), it was that symbols, even costly symbols, can motivate millions to take actions toward better goals. (He followed Jimmy Carter. A man whose intelligence, sincerity and battles for human rights, were overshadowed during his presidency by American feelings of "malaise" and general helplessness felt during the hostage crisis, oil shortages, and resulting recession.)
Live Long and Prosper - Thanks Leonard. You are missed.
Ok, For those of you wondering why they use 2 cameras . . . Don't think of it as a typical camera CCD sensor, where you snap a picture, think of it a s a pushbroom. It is one long array(the broom) that, as the sattelite travels, collects information. So, like pushing a broom, you collect as it moves.By having a forward facing sensor (26)and rearward facing (-5) you have 2 "brooms" sweeping the sky, collecting the same information, but the large angle creates a paralax(31 I'll leave the math to someone else).
You can do this with 1 sensor by "pointing" in 2 directions, to gain paralax, but that requires moving the platform (sattelite) and doing this repeatadly is a real pain. Essentialy, this sattelite will capture the data in 1 pass, along the same track, in a manner that is easy and predictable for post-processing. I think its a very slick setup, a should provide alot of useful data.
The same rocket launch also put into place ham satellite for use in South Asia. There are other satellites available for personal use (AMSAT has several, including (Echo 51) but VUSat is focused on use from India and South Asia.
India doesnt receive much direct aid from the US . Indian poor do receive a large amount of money from US based evangelical groups trying to promote Christianity in India (pretty successfully too Already 2 Indian states have become Christian Majority over the last 50 years )
India keeps losing it best people to the US but now slowly more and more people are staying back and using their brains to run ISRO and DAE (department of Atomic Energy) instead of enriching the shareholders of IBM and Microsoft.
There is great emphasis on tech in India . Engineers are much more respected in society than doctors or lawyers in contrast to the US so a lot of the top brains go to Engineering.
**Life is too short to be serious**
..instead of people asking or commenting about the actual launch itself, most people are bothered about why India is not feeding its hungry people and launching satellites in space.
Doesnt it feel a lil daft asking these questions over & over again?!Is a developing country only expected to feed it hungry nad look after the poverty problem.I really fail to understand that point of view.
Lord of the Binges.
Its more like a technology demonstrator but given that ISRO runs on a shoestirng budget as the govt. has social priorities, the launch has to be justified using a socially usefull purpose. As for spying on Pakistan India already gets all it wants from its existing satellites as well as US owned satellites. The US is pretty friendly with India and more than happy to hand over imagery e.g. During the Kargill conflict the US provided satellite images of Pakistani intruders on Indian soil to the Indian air Force so they could better target their (US provided) smart bombs .
**Life is too short to be serious**
I'm not saying you're wrong about Pakistan though, just that you're wrong about archived maps of India...
[o]_O
Many people have posted almost the right answer for why two cameras are needed, one pointing slightly forward, one slightly back, for stereo. That's right, as far as it goes.
But what people are missing is that these are not cameras like you are used to. The pictures they take are not (say) 4k x 4k, they are 4k by 1 pixel. That one-pixel-high image is painted across the surface by the motion of the satellite, generating a very long strip image. Typically, the cameras run continuously.
So, that's why you can't just "snap a photo, move the camera, snap another one". These are not snapshots, they are long strip images taken a scanline at a time. Two fixed cameras are the right answer.
Thad Beier
I love Mondays. On a Monday, anything is possible.