Science & Health6/10
Defence Analyst Debunks Claim US Denied GPS to India in Kargil
Arun Golaya explains that GPS is a passive system and that civilian signals remained globally available during Kargil, subject only to the worldwide Selective Availability degradation. He argues that India was not selectively denied GPS and that military-grade P(Y) code was unavailable due to US sanctions.
Original post · 2 min read
Another myth just like the story about the US denying GPS to India during Op Vijay (Kargil).
GPS is a purely passive system. It works on pseudo ranging. The receivers receive data from multiple satellites (4 satellites for resolving 3D position and time) and work out their own position. No transmission by the user is needed.
Another statement I have read many times (including in some reputed defence journals) is that the US “denied” GPS to India during Kargil thus making us initiate the case for NAVIC. I’m not sure how this story came about.
Non military (US / NATO) GPS sets (till May 2000) operated under the US Selective Availability (SA) policy, which deliberately degraded civilian accuracy *worldwide* to roughly 100 meters horizontal (versus the much higher military precision). India was not uniquely singled out. SA was a standing global feature of GPS (including for US based civilian users) from the early 1990s until President Clinton ordered it turned off in May 2000.
Even during Kargil, civilian GPS signals remained available globally. Indian forces too used commercial/handheld GPS receivers (including units fitted into some aircraft).
I’m not sure if India ever asked for the precision code for targeting during Op Vijay. It is highly unlikely as at that time, India was under US sanctions (after India’s 1998 nuclear tests. Under the Glenn Amendment), which restricted military sales, equipment and technical assistance to India. So at best, Military-grade GPS (encrypted Precise Positioning Service / P(Y) code) was not provided to India. I’m not sure how the stories about GPS being “denied” to India came about. Selectively denying GPS to a particular user / group of users is also not technically feasible. It can be denied (by the US) or even jammed / spoofed (by anyone not just the US) with the right equipment *over an area*…but that again cannot be country specific.
GPS is a purely passive system. It works on pseudo ranging. The receivers receive data from multiple satellites (4 satellites for resolving 3D position and time) and work out their own position. No transmission by the user is needed.
Another statement I have read many times (including in some reputed defence journals) is that the US “denied” GPS to India during Kargil thus making us initiate the case for NAVIC. I’m not sure how this story came about.
Non military (US / NATO) GPS sets (till May 2000) operated under the US Selective Availability (SA) policy, which deliberately degraded civilian accuracy *worldwide* to roughly 100 meters horizontal (versus the much higher military precision). India was not uniquely singled out. SA was a standing global feature of GPS (including for US based civilian users) from the early 1990s until President Clinton ordered it turned off in May 2000.
Even during Kargil, civilian GPS signals remained available globally. Indian forces too used commercial/handheld GPS receivers (including units fitted into some aircraft).
I’m not sure if India ever asked for the precision code for targeting during Op Vijay. It is highly unlikely as at that time, India was under US sanctions (after India’s 1998 nuclear tests. Under the Glenn Amendment), which restricted military sales, equipment and technical assistance to India. So at best, Military-grade GPS (encrypted Precise Positioning Service / P(Y) code) was not provided to India. I’m not sure how the stories about GPS being “denied” to India came about. Selectively denying GPS to a particular user / group of users is also not technically feasible. It can be denied (by the US) or even jammed / spoofed (by anyone not just the US) with the right equipment *over an area*…but that again cannot be country specific.
Aviator Anil Chopra @ChopsyturveyOur fighter jet pilots bombed US bases without GPS, used paper maps: Iran
inshorts.com/en/news/8cnvvmxm-1?utm_source=new…
-via inshorts
♥ 87 · ⟲ 16 · 👁 18.1KView on X ↗
