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I didn't understand this. How would the GPS system allow the US to know the location of Pakistani soldiers? GPS satellites only transmit and GPS receivers only

I didn't understand this. How would the GPS system allow the US to know the location of Pakistani soldiers? GPS satellites only transmit and GPS receivers only receive - there is no return path that would disclose the location. What am I missing?

nacnud 9y ago
Only a guess, but at that time wasn't the GPS signal intentionally degraded for non-US-military use, with reduced accuracy? Perhaps they're talking about the more precise signal, which the US didn't let them use.
- andyjohnson0 9y ago
  Yes, "selective availability" was still in use then - but I can't see how its use or not would disclose a GPS user's position.
  - Arnt 9y ago
    "I need a missile strike. My position according to GPS is x and the Pakistani you should hit are 920m straight north of me according to my rangefinder."
rajeshpant 9y ago
Its not about location of foot soldiers. Although the article highlights about GPS, it is mapping in general. India wanted terrain and altitude data for making strategy.
hshehehjdjdjd 9y ago
https://m.timesofindia.com/home/science/How-Kargil-spurred-India-to-design-own-GPS/articleshow/33254691.cms https://m.timesofindia.com/home/science/How-Kargil-spurred-I... This seems to have moderately more information. It seems like maybe they wanted to use GPS capabilities in their guided weapons systems, and the US would not permit it or perhaps threatened to disable the system in that theater? It’s a bit confusing and fuzzy.
stedaniels 9y ago
There are many scenarios, but here's a simple one. Boots on the ground. You have men on the ground who can see the enemy position, they need to know exactly where they are to be able to know exactly where the enemy is. Without GPS you are relying on visual points of reference against maps of shaky providence.
- bluGill 9y ago
  Boots on the ground don't need to be accurate to within 1cm. If a normal human is within 10 meters they can nearly always figure things out. In fact if humans are that close it is because you don't actually know where the enemy is and you need the humans to find them - otherwise you would have a plane drop a bomb on them. Where you need more accuracy is when you want something at a long distance to do something - drop a bomb or something.
michaelt 9y ago
As far as I can tell, all the online reports have been written 15+ years after the fact, and they all just quote one another; I suspect the journalists may be mistaken. It's worth bearing in mind the Kargil War took place in 1999, and GPS Selective Availability wasn't turned off until May 2000. It might be that India asked for the SA seed key so their own forces/missiles could navigate more accurately, but were denied?
- chiph 9y ago
  IIRC, with SA on, accuracy was to within 100 meters. And that's enough for troop movements but not accurate enough for missiles and artillery. So using it for land navigation would have been fine. It's sounding like it was a case of "We want it because we want it"
  - rdsubhas 9y ago
    Kargil is one of the highest battlefields on Earth. I don't think I'd compare Himalayan warfare to "land navigation". https://en.wikipedia.org/wiki/Kargil_War https://en.wikipedia.org/wiki/Kargil_War https://en.wikipedia.org/wiki/Mountain_warfare#Kashmir_conflicts https://en.wikipedia.org/wiki/Mountain_warfare#Kashmir_confl... > The most dangerous and volatile of all mountain conflicts involves the ongoing one between India and Pakistan over the Kashmir region.
    - chiph 9y ago
      It's a generic term meaning "How do I get my troops from here to there" either by vehicle or marching, such that they don't get lost and arrive when needed. This is the classic way with map + compass. GPS just makes it easier. https://www.youtube.com/watch?v=xSNohNPqWlU https://www.youtube.com/watch?v=xSNohNPqWlU
SoulMan 9y ago
Also because swearing-in ceremony of Barack Obama as US President in January 2009 had a disastrous impact on the test-firing of the BrahMos supersonic missile https://www.thehindubusinessline.com/news/national/how-obama-swearing-in-scuttled-brahmos-missiles-test-flight/article23103459.ece https://www.thehindubusinessline.com/news/national/how-obama...
- sdhgaiojfsa 9y ago
  > But an apprehensive US official turned down the request and told Kalam: “Sorry Dr Kalam, we will give you good lunch and dinner, but no Craig computer.” > Kalam came back empty-handed, but went on to develop the Pace Plus computer with help from the Indian Institute of Science and others in two years. And, Pace Plus proved to be 20 times faster than Craig! This type of thing sounds incredibly childish and jingoistic to my American ears. Does it read better to folks who learned to speak English in India, or is it just really awful writing? Also, as best I can tell, there is no "Craig" super computer. Does the author mean Cray? And if so, why was the scientist asking the USG? You would normally want to get such computers from the manufacturer, not a foreign government, however friendly.
  - dilawar 9y ago
    That's the usual state of news reporting. People just love discourse of conspiracy over here.
    - shripadk 9y ago
      It's not a conspiracy. The sale of Cray supercomputers was indeed blocked by the US Government. Just because the article is badly written doesn't negate the facts on the ground.
  - shripadk 9y ago
    http://www.rediff.com/computer/dec/18super.htm http://www.rediff.com/computer/dec/18super.htm I agree that it is awful writing. I hope the article above is written better. > Does the author mean Cray? And if so, why was the scientist asking the USG? You would normally want to get such computers from the manufacturer, not a foreign government, however friendly. It's not possible to directly purchase from manufacturers if the US Government is going to block the purchase on various grounds. Don't forget that there was a period where sanctions and arms embargo was also imposed on India. It's a different thing that today the US considers India a "strategic partner" but it wasn't always the case. As far as Cray goes, they even setup an award in the name of the scientist mentioned in the article (who also served as the President of India from 2002 to 2007 [1]): https://www.cray.com/blog/cray-hpc-awards-honor-achievements-india/ https://www.cray.com/blog/cray-hpc-awards-honor-achievements... [1] https://en.wikipedia.org/wiki/A._P._J._Abdul_Kalam https://en.wikipedia.org/wiki/A._P._J._Abdul_Kalam
inglor 9y ago
GPS broadcasts several signals, the higher precision ones are encrypted - until 1999 GPS was encrypted at much lower resolution but the army and armies it shares its tech with still operate at a higher resolution. The US can lock countries out of higher resolution GPS at will - this (and GLONASS) make sense because of it.
jhayward 9y ago
I would speculate that India wanted access to the encrypted military GPS signal, which would have given them 10-1000 times more accurate guidance for precision weapons.

nacnud 9y ago

Only a guess, but at that time wasn't the GPS signal intentionally degraded for non-US-military use, with reduced accuracy? Perhaps they're talking about the more precise signal, which the US didn't let them use.

andyjohnson0 9y ago
Yes, "selective availability" was still in use then - but I can't see how its use or not would disclose a GPS user's position.
- Arnt 9y ago
  "I need a missile strike. My position according to GPS is x and the Pakistani you should hit are 920m straight north of me according to my rangefinder."

rajeshpant 9y ago

Its not about location of foot soldiers. Although the article highlights about GPS, it is mapping in general. India wanted terrain and altitude data for making strategy.

hshehehjdjdjd 9y ago

https://m.timesofindia.com/home/science/How-Kargil-spurred-India-to-design-own-GPS/articleshow/33254691.cms https://m.timesofindia.com/home/science/How-Kargil-spurred-I... This seems to have moderately more information. It seems like maybe they wanted to use GPS capabilities in their guided weapons systems, and the US would not permit it or perhaps threatened to disable the system in that theater? It’s a bit confusing and fuzzy.

stedaniels 9y ago

There are many scenarios, but here's a simple one. Boots on the ground. You have men on the ground who can see the enemy position, they need to know exactly where they are to be able to know exactly where the enemy is. Without GPS you are relying on visual points of reference against maps of shaky providence.

bluGill 9y ago
Boots on the ground don't need to be accurate to within 1cm. If a normal human is within 10 meters they can nearly always figure things out. In fact if humans are that close it is because you don't actually know where the enemy is and you need the humans to find them - otherwise you would have a plane drop a bomb on them. Where you need more accuracy is when you want something at a long distance to do something - drop a bomb or something.

michaelt 9y ago

As far as I can tell, all the online reports have been written 15+ years after the fact, and they all just quote one another; I suspect the journalists may be mistaken. It's worth bearing in mind the Kargil War took place in 1999, and GPS Selective Availability wasn't turned off until May 2000. It might be that India asked for the SA seed key so their own forces/missiles could navigate more accurately, but were denied?

chiph 9y ago
IIRC, with SA on, accuracy was to within 100 meters. And that's enough for troop movements but not accurate enough for missiles and artillery. So using it for land navigation would have been fine. It's sounding like it was a case of "We want it because we want it"
- rdsubhas 9y ago
  Kargil is one of the highest battlefields on Earth. I don't think I'd compare Himalayan warfare to "land navigation". https://en.wikipedia.org/wiki/Kargil_War https://en.wikipedia.org/wiki/Kargil_War https://en.wikipedia.org/wiki/Mountain_warfare#Kashmir_conflicts https://en.wikipedia.org/wiki/Mountain_warfare#Kashmir_confl... > The most dangerous and volatile of all mountain conflicts involves the ongoing one between India and Pakistan over the Kashmir region.
  - chiph 9y ago
    It's a generic term meaning "How do I get my troops from here to there" either by vehicle or marching, such that they don't get lost and arrive when needed. This is the classic way with map + compass. GPS just makes it easier. https://www.youtube.com/watch?v=xSNohNPqWlU https://www.youtube.com/watch?v=xSNohNPqWlU

SoulMan 9y ago

Also because swearing-in ceremony of Barack Obama as US President in January 2009 had a disastrous impact on the test-firing of the BrahMos supersonic missile https://www.thehindubusinessline.com/news/national/how-obama-swearing-in-scuttled-brahmos-missiles-test-flight/article23103459.ece https://www.thehindubusinessline.com/news/national/how-obama...

sdhgaiojfsa 9y ago
> But an apprehensive US official turned down the request and told Kalam: “Sorry Dr Kalam, we will give you good lunch and dinner, but no Craig computer.” > Kalam came back empty-handed, but went on to develop the Pace Plus computer with help from the Indian Institute of Science and others in two years. And, Pace Plus proved to be 20 times faster than Craig! This type of thing sounds incredibly childish and jingoistic to my American ears. Does it read better to folks who learned to speak English in India, or is it just really awful writing? Also, as best I can tell, there is no "Craig" super computer. Does the author mean Cray? And if so, why was the scientist asking the USG? You would normally want to get such computers from the manufacturer, not a foreign government, however friendly.
- dilawar 9y ago
  That's the usual state of news reporting. People just love discourse of conspiracy over here.
  - shripadk 9y ago
    It's not a conspiracy. The sale of Cray supercomputers was indeed blocked by the US Government. Just because the article is badly written doesn't negate the facts on the ground.
- shripadk 9y ago
  http://www.rediff.com/computer/dec/18super.htm http://www.rediff.com/computer/dec/18super.htm I agree that it is awful writing. I hope the article above is written better. > Does the author mean Cray? And if so, why was the scientist asking the USG? You would normally want to get such computers from the manufacturer, not a foreign government, however friendly. It's not possible to directly purchase from manufacturers if the US Government is going to block the purchase on various grounds. Don't forget that there was a period where sanctions and arms embargo was also imposed on India. It's a different thing that today the US considers India a "strategic partner" but it wasn't always the case. As far as Cray goes, they even setup an award in the name of the scientist mentioned in the article (who also served as the President of India from 2002 to 2007 [1]): https://www.cray.com/blog/cray-hpc-awards-honor-achievements-india/ https://www.cray.com/blog/cray-hpc-awards-honor-achievements... [1] https://en.wikipedia.org/wiki/A._P._J._Abdul_Kalam https://en.wikipedia.org/wiki/A._P._J._Abdul_Kalam

inglor 9y ago

GPS broadcasts several signals, the higher precision ones are encrypted - until 1999 GPS was encrypted at much lower resolution but the army and armies it shares its tech with still operate at a higher resolution. The US can lock countries out of higher resolution GPS at will - this (and GLONASS) make sense because of it.

jhayward 9y ago

I would speculate that India wanted access to the encrypted military GPS signal, which would have given them 10-1000 times more accurate guidance for precision weapons.