>From my understanding, it was originally thought that GPS superseded
LORAN C, and the LORAN was slated for termination. However later many
folks protested, and in addition it was realized that there were
scenarios that would result in total GPS failure (Due to hostile
attacks) but that LORAN was more viable due to its distributed nature.
I.e., if you attack a single LORAN station, all the others keep
operating. To take out the whole thing, you would have to destroy many
stations, all over the world. So they decided to keep it going, and
have recently finished upgrading all the US LORAN stations.

Apparently, due to the low power of the GPS signal, it would be
relatively easy to jam. Whereas the LORAN signal has very high power,
and would therefore be more difficult to jam.

I think you can buy new receiverfs that incorporate both LORAN and
GPS, so you can get a fix in situations where no satellites are
visible.

If this is a student exercise, I think doing it with LORAN is far more
feasible than with GPS, even though the resulting accuracy may be
different. I personally would never attempt to design a GPS receiver,
but I think I could easily succeed at designing a LORAN C receiver.

Neil

On 1/21/06, John Nall <jwnall@gmail.com> wrote:
> Wouter van Ooijen wrote:
> > > And from what I
> > read Loran C can be better than 50-60 meters in repeatability (!=
> > accuracy), which is what matters for a roaming robot.
> >
> >
> Well, I can confirm it from experience for you.  I use Loran C all the
> time, in fishing, and once you find a spot and have the Loran C
> coordinates for  that spot, you can go back to it with great accuracy.
> What you cannot do is go to a spot for the very first time (using just a
> chart with Loran C coordinates superimposed upon it) with accuracy.
>
> So far as the government stopping support, they have been threatening to
> do that for a long time now here in the U.S. but have not yet done so.
> There is a fairly well-organized coalition of fishermen (both commercial
> and recreational) who lobby for continuation of the service.  And it
> doesn't cost that much to maintain the stations.  The real problem is
> that it is almost impossible to buy new Loran C receivers any more, so
> people are trying their best to get all those Loran C fishing spots
> converted to GPS fishing spots.  Once that is far enough along, then I
> would guess that it will gradually be phased out.
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