From: "Powers Glenn" <Q101NOW@st.vse.cz>
Date: Fri, 12 Apr 1996 12:44:39 +0800
To: cypherpunks@toad.com
Subject: Re: No matter where you go, there they are.
Message-ID: <36B62659B@st.vse.cz>
MIME-Version: 1.0
Content-Type: text/plain


- It's called "S/A" (Selective Availability) which is the NWO term for adding 
- errors that "authorized" users can remove. (Not to be confused with A/S, or 
- anti-spoofing)   It was originally intended to be turned on in wartime to 
- deny the enemy accurate fixes, but during the Gulf War military GPS 
- receivers were so scarce that the soldiers had to use commercial products, 
- so the S/A actually was turned OFF then!
- 
- Since then, pressure has been building to turn off S/A, since its usefulness 
- is nearly zero.  Even so, the amplitude of S/A errors are only a little 
- larger than natural errors caused by satellite timing errors, atmospheric 
- propagation variations, etc.  The result is that DGPS is useful, which is 
- (more or less) a fixed antenna and GPS system which knows where it is, and 
- subtracts where it "seems" to be by GPS every second, and broadcasts the 
- resulting error data on some terrestrial system to receivers locally.  The 
- result is errors down to the 1-meter level and even lower.  That system 
- compensates for both natural errors and S/A, so the whole purpose of having 
- S/A is negated.  Eventually S/A will probably be turned off permanently, but 
- even then we'll want to continue to use DGPS systems.

    Close, but not quite:
S/A is an ADJUSTABLE variable, not on/off. it can reduce accuracy to 
10 meters or 100 meters or whatever. It's a DoD term, not NWO term.
    The "this is where you really are" percision location (forgot 
the designation off hand) is ENCRYPTED (yes, there is crypto 
revelance here...) in the data stream from the satellites. The 
difference S/A makes is on the order of magnitude, therefore not 
"useless." It should be pointed out that different regions of the 
earth can have different degrees of accuracy based on the S/A system.
    I doubt S/A will ever be turned off, but this is my opinion. I 
know Jim's opinion. Discussion of this point is pointless.
    DGPS transmission are made from a multiple single points, which 
(to the best of my knowledge) are not networked.
    glenn