From: Mike Bevan <mike@vrnews.demon.co.uk>
Subject: Re: TECH: GPS in helmet tracking?
Date: Fri, 5 Apr 1996 09:42:31 +0000
Message-ID: <828693767.19993.0@vrnews.demon.co.uk>


From: Mike Bevan <mike@vrnews.demon.co.uk>

>> My understanding is that the military have
>> much higher resolution systems, but we (the general public) cannot
>> access them.

>I believe the military systems are called *differential* GPS. 

For enlightenment on the above, I can thoroughly recommend a 76-page
booklet called "GPS: A Guide to the Next Utility", published by
Trimble Navigation (Sunnyvale, CA: 408/481-2900, fax 408/730-2997;
price $8.95 (about four years ago); Trimble Part No. 18239).

The booklet provides simple and concise explanations, with diagrams,
of GPS operation, accuracy assessment, error sources, differential
GPS, DoD-controlled 'Selective Availability' operation (intended to
make life difficult for the enemy), and lots more, plus an excellent
glossary.

Mike Bevan
Editor - VR NEWS