4 ms·

A new way to detect secret nuclear tests: GPS

43 points by Sandman 15y ago

mturmon 15y ago
This is a cool application of GPS radio occultation. For a simple overview, see: http://www.atmo.arizona.edu/~kursinsk/GPS_RO_overview.htm http://www.atmo.arizona.edu/~kursinsk/GPS_RO_overview.htm The same idea has recently been used to improve weather forecasts for a few years now (http://en.wikipedia.org/wiki/GPS_meteorology http://en.wikipedia.org/wiki/GPS_meteorology). Differences in atmospheric gas density affect the propagation speed of the GPS radio signal. Peering thru the edge of the atmosphere at the constellation of GPS transmitters allows you to get a bunch of density/temperature profiles in a way that's immune to some instrumental artifacts of other instruments. One of the inventors of the idea formed a company to cooperatively launch small satellites to do these retrievals: http://geooptics.com/?page_id=35 http://geooptics.com/?page_id=35
wickedchicken 15y ago
"GPS might at first seem like an unlikely source for nuclear test detection." Actually, it makes total sense. So much sense that the creators of GPS put sensors in the satellites to do this... "GPS satellites carry a set of nuclear detonation detectors consisting of an optical sensor (Y-sensor), an X-ray sensor, a dosimeter, and an electromagnetic pulse (EMP) sensor (W-sensor), that form a major portion of the United States Nuclear Detonation Detection System" http://en.wikipedia.org/wiki/Global_Positioning_System http://en.wikipedia.org/wiki/Global_Positioning_System
- mturmon 15y ago
  That's interesting, I did not know that. The approach in the article is in fact quite novel, though. They're actually detecting the shock wave in the atmosphere. Not even something "easy" like the seismic shock wave.
maaku 15y ago
If the data is accurate enough to detect a kiloton blast deep underground, what about conventional weapons on the surface? Could this be used to detect and track the use conventional explosives deep inside the territory of oppressive regimes?
alex_h 15y ago
Somehow I don't think this is the main sticking point preventing the US from ratifying the nuclear test ban treaty, as the article seems to suggest.
- caf 15y ago
  Page Van der Linden has posted the first two parts of a multipart series on the domestic arguments around US ratification of the CTBT, if you're interested: http://vanderlinden.armscontrolwonk.com/archive/205/secrets-in-the-sand http://vanderlinden.armscontrolwonk.com/archive/205/secrets-... http://vanderlinden.armscontrolwonk.com/archive/225/we-should-retain-the-option-to-test http://vanderlinden.armscontrolwonk.com/archive/225/we-shoul...

43 points by Sandman 15y ago

This is a cool application of GPS radio occultation. For a simple overview, see: http://www.atmo.arizona.edu/~kursinsk/GPS_RO_overview.htm http://www.atmo.arizona.edu/~kursinsk/GPS_RO_overview.htm The same idea has recently been used to improve weather forecasts for a few years now (http://en.wikipedia.org/wiki/GPS_meteorology http://en.wikipedia.org/wiki/GPS_meteorology). Differences in atmospheric gas density affect the propagation speed of the GPS radio signal. Peering thru the edge of the atmosphere at the constellation of GPS transmitters allows you to get a bunch of density/temperature profiles in a way that's immune to some instrumental artifacts of other instruments. One of the inventors of the idea formed a company to cooperatively launch small satellites to do these retrievals: http://geooptics.com/?page_id=35 http://geooptics.com/?page_id=35

wickedchicken 15y ago

"GPS might at first seem like an unlikely source for nuclear test detection." Actually, it makes total sense. So much sense that the creators of GPS put sensors in the satellites to do this... "GPS satellites carry a set of nuclear detonation detectors consisting of an optical sensor (Y-sensor), an X-ray sensor, a dosimeter, and an electromagnetic pulse (EMP) sensor (W-sensor), that form a major portion of the United States Nuclear Detonation Detection System" http://en.wikipedia.org/wiki/Global_Positioning_System http://en.wikipedia.org/wiki/Global_Positioning_System

mturmon 15y ago
That's interesting, I did not know that. The approach in the article is in fact quite novel, though. They're actually detecting the shock wave in the atmosphere. Not even something "easy" like the seismic shock wave.

maaku 15y ago

If the data is accurate enough to detect a kiloton blast deep underground, what about conventional weapons on the surface? Could this be used to detect and track the use conventional explosives deep inside the territory of oppressive regimes?

alex_h 15y ago

Somehow I don't think this is the main sticking point preventing the US from ratifying the nuclear test ban treaty, as the article seems to suggest.

caf 15y ago
Page Van der Linden has posted the first two parts of a multipart series on the domestic arguments around US ratification of the CTBT, if you're interested: http://vanderlinden.armscontrolwonk.com/archive/205/secrets-in-the-sand http://vanderlinden.armscontrolwonk.com/archive/205/secrets-... http://vanderlinden.armscontrolwonk.com/archive/225/we-should-retain-the-option-to-test http://vanderlinden.armscontrolwonk.com/archive/225/we-shoul...