.\"
.\" ----------------------------------------------------------------------------
.\" "THE BEER-WARE LICENSE" (Revision 42):
.\" <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
.\" can do whatever you want with this stuff. If we meet some day, and you think
.\" this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
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.\" $Id: intro.ms,v 1.4 2008/11/02 19:47:55 phk Exp $
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.2C
.ds RH Introduction
.NH
Introduction
.PP
LORAN-C signals, like GPS signals, offer wireless access to very
stable and calibrated, and thus expensive, frequency sources and
can therefore be used to steer cheaper oscillators to correct
frequency.
.LP
Despite stern warnings to the contrary, the world today is more
or less entirely frequency locked to the GPS satellites because
that is the most convenient and cheap technology available.
.LP
This little project attempts to show that an equally cheap
solution can be made based on the Loran-C signals, which are
broadcast over most of the northeren hemishere.
.LP
Compared to GPS, Loran-C signals are just about as different
as can be, where GPS satellits transmit their signals with only
50W using 1.2 GHz microwaves from 20,000 km above the Earth,
Loran-C transmits are 200 meter tall steel towers which transmit
several hundred kW at a frequency of 100 kHz.
.LP
This makes Loran-C the perfect backup for GPS, since there are
almost no overlap between threads to the two systems.
.LP
This paper documents what is clearly a "work in progress", and
as time and energy permits, I will update both this paper and
the source-code that goes with it.
.LP
\fIPoul-Henning Kamp\fP
