3 ms·
The problem is, COCOM says: GPS devices should disable themselves when at an altitude above 60,000 feet AND a speed faster than 1,000 knots Whereas some vendo
by Florin_Andrei 13y ago
The problem is, COCOM says:
GPS devices should disable themselves when at an altitude above 60,000 feet AND a speed faster than 1,000 knots
Whereas some vendors read it:
GPS devices should disable themselves when at an altitude above 60,000 feet OR a speed faster than 1,000 knots
Which effectively disables your cheap GPS dongle in your home-made stratospheric balloon, which is quite capable of reaching 30 km, above the COCOM altitude spec.
Sometimes it's quite tricky to figure out if a given receiver is an AND or an OR.
- shabble 13y agoYou could maybe beg/steal/borrow a GPS simulator[1] and test your candidate receivers with it. Best do it in a Faraday cage though, unless you want to upset some Very Serious Important Things[2], and (likely government) owners thereof. Probably way out of budget range for hobby stuff though [1] One is the WelNav GS720: http://www.t-e.com.tw/GS-720.pdf http://www.t-e.com.tw/GS-720.pdf [2] A Simple Demonstration that the Global Positioning System (GPS) is Vulnerable to Spoofing: http://www.ne.anl.gov/capabilities/vat/pdfs/GPS-Spoofing-%282002-2003%29.pdf http://www.ne.anl.gov/capabilities/vat/pdfs/GPS-Spoofing-%28...