NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: How likely is a GPS shutdown?
From: Richard B. Langley
Date: 2000 Jan 25, 10:24 AM
From: Richard B. Langley
Date: 2000 Jan 25, 10:24 AM
PPS uses the encrypted P-code on both the L1 (same as civilian SPS) and the L2
carrier. However, there are DoD single-frequency (L1) receivers and these
also have SA and A/S decryption capability.
-- Richard Langley
Professor of Geodesy and Precision Navigation
On Tue, 25 Jan 2000, Rodney Myrvaagnes wrote:
>This is not quite right, although the rest of RBE's post is
>right on. The military receivers that can get the encrypted
>(long) word get it over another carrier than that used by
>the C/A word decoded by civil receivers. There is no way
>for your Walmart gps to use the military code.
>
>
>During the Gulf War, SA was turned off because the military
>had to use civilian receivers. SA was an afterthought,
>applied because the civil receivers turned out to work much
>better than expected.
>
>On Mon, 24 Jan 2000 19:09:42 -0500, Richard B. Emerson
>wrote:
>
>> >
>> > I suspect that the military has its own encrypted version
>> > of GPS although this is simply a guess on my part.
>>
>>One of the absurdities of GPS is that during Desert Storm and Panama,
>>GPS' selective availability was turned off. Thus, for a short period,
>>the normally encrypted data segment (it's already there and used
>>routinely) was available unencrypted. Consider, too, the error even
>>with S/A enabled. A fuel-air bomb (or ammonium nitrate bomb) could
>
>
>
>Rodney Myrvaagnes J36 Gjoa
>Senior Editor Electronic Products
>My oyster knife is Y2K compliant
>
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Richard B. Langley E-mail: lang@unb.ca
Geodetic Research Laboratory Web: http://www.unb.ca/GGE/
Dept. of Geodesy and Geomatics Engineering Phone: +1 506 453-5142
University of New Brunswick Fax: +1 506 453-4943
Fredericton, N.B., Canada E3B 5A3
Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/
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