It works that way in the air as well Moose, and lighthouses are very
useful.
My first automated navigation system was in the Jaguar; it was based
on an inertial navigation system and a very small computer. But it
had moving map display so that you knew where it thought you were and
which way it thought you were going. It was truly excellent, but
nothing like looking out of the cockpit and recognising places.
Flying the F-16, without any moving map (I have a feeling that no US
fighter yet has a moving map), but with a mapping radar was similar.
It was all very well being told where you were, but seeing was always
believing ...
The Tornado GR4 now has an integrated GPS, so nothing can possibly go
wrong ... go wrong ... go wrong ;-)
Lighthouses are extremely useful for 3 reasons: you can identify them
from a distance on the radar; you can see them visually, also from a
reasonable distance (day or night) to confirm that you have
identified the right radar return; and they are next to the sea, so
you can use radar altimeter ranging to update the aircraft's height
channel, an essential part of weapon aiming.
Chris
~~ >-)-
C M I Barker
Cambridgeshire, Great Britain.
+44 (0)7092 251126
www.threeshoes.co.uk
homepage.mac.com/zuiko
On 21 Dec 2005, at 00:40, Moose wrote:
> Johan Malmstrom wrote:
>
>> Lighthouses only purpose seems to be be photogenic. No need for
>> the light as
>> GPS has become ubiquitous.
>>
>>
> It would appear that you have never spent any time navigating at sea,
> particularly in coastal waters in poor weather.
>
> The key to safety is redundancy. A GPS unit can fail to operate, or
> worse, give wrong results. Sure, it it the major tool, but any time
> one
> is in costal waters with hidden obstacles, poor weather, etc., visual
> fix location and radar ranging location are essential for safety.
> Also,
> in harbors and harbor approaches, esp. at night, things can become
> quite
> visually confusing. Lights and markers set up sight lines to keep
> one on
> the correct heading directly, without reference to chart, GPS, etc.
> this
> can be very important in busy, complex areas and in dark places.
>
> Just knowing that keeping two lights ligned up as I steer will keep me
> in the channel and that there are another pair at the turning makes
> safe
> navigation easier.
>
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