Navigation by ground lights? (non-empty this time!)
Dr. Erdelen
Hello all,
[sorry for my previous empty post - tried to use a *decent* editor :-( ]
When travelling (by bus :-( ) from Hannover to the Ruhr area a couple of
nights ago, I noticed in the hilly region around Bielefeld lots of power-
ful lights, always in groups of two or three, and mounted on stationary
towers (power line style). From the ground I could not make out the overall
arrangement (along hill ridges?), but these things were distributed over
several kilometers. The lights seemed to be pointed upwards (as well they
ought to, not to blind all road traffic...)
Could this be a kind of system for (military?) air navigation, perhaps
used as guidance to the bases?
I remember that I once saw something similar from an airliner approaching
Germany fromthe south west (via the Eifel hill range), but the pattern
then didn't make sense to me, either.
I wonder if this idea of a navigation system by visual cues isn't rather
far-fetched, in these times of radio navigation.
Any info appreciated.
Regards,
Martin
Kerry Kurasaki
>
>Hello all,
>[sorry for my previous empty post - tried to use a *decent* editor :-( ]
>
>When travelling (by bus :-( ) from Hannover to the Ruhr area a couple of
>nights ago, I noticed in the hilly region around Bielefeld lots of power-
>ful lights, always in groups of two or three, and mounted on stationary
>towers (power line style). From the ground I could not make out the overall
>arrangement (along hill ridges?), but these things were distributed over
>several kilometers. The lights seemed to be pointed upwards (as well they
>ought to, not to blind all road traffic...)
>Could this be a kind of system for (military?) air navigation, perhaps
>used as guidance to the bases?
>I wonder if this idea of a navigation system by visual cues isn't rather
>far-fetched, in these times of radio navigation.
I don't know specifically about those lights, but I doubt if they are
used by the military.
In general, I believe the navigating by ground lights is, in general,
a bad idea. One of the problems is that lights of one town look very
much like light of another town. Worse, unlighted areas can be
deceiving. For example, in the SF Bay Area, lack of lights are an
indicator of 1) water, or 2) hills (or mountains for right coasters).
I can admit to having mis-navigated more than once in the past few
years when I used the 'lights on the ground' method. A specific, lighted
object (the Mormon Temple in the East SF Bay) can be an excellent
reference point, or a [football/baseball] stadium when it is the only
one of a particular shape for 50 miles works too.
Electronic navigation is not the only method at night. I still find that
heading and time are still very good ways of navigating. IFR (I Follow
Road) for some of the major highways isn't too bad. You can pick out
the headlights pretty well.
'nuff said?
Stefano Pagiola
> When travelling (by bus :-( ) from Hannover to the Ruhr area
> a couple of nights ago, I noticed in the hilly region around
> three, and mounted on stationary towers (power line style).
> From the ground I could not make out the overall arrangement
> (along hill ridges?), but these things were distributed over
> several kilometers. The lights seemed to be pointed upwards
> (as well they ought to, not to blind all road traffic...)
> Could this be a kind of system for (military?) air navigation,
> perhaps used as guidance to the bases?
If these were actually power line towers, the purpose of the light is
more likely to help low-flying aircraft avoid flying into the power
lines.
--
-
Stefano Pagiola
Food Research Institute, Stanford University
spag...@frinext.stanford.edu (NeXTMail encouraged)
spag...@FRI-nxt-Pagiola.stanford.edu (NeXTMail encouraged)
Lars-Henrik Eriksson
I wonder if this idea of a navigation system by visual cues isn't rather
far-fetched, in these times of radio navigation.
Any info appreciated.
I don't know what you saw, but the idea of visual cues navigation
itself is not so far-fetched, at least not in some circumstances. Many
Norwegian airports use an extensive circling light system.
Often, the airport is located deep in a fiord, so there is only one
approach direction - over the fiord. Should the wind blow the wrong
way, circling to the other runway can be really hairy at night or in
poor visibility conditions. To facilitate, there is a system of
circling lights that defines the proper flight path.
The most amazing example I've seen is the localiser approach to Mo i
Rana. The localiser leads to a place about 2.5 nautical miles from the
airport - the missed approach point is 2 miles further away, and a 120
degree turn is required to line up with the nearest runway. Six
circling lights are used to define the route from the MAP to the
threshold. Should a landing in the opposite direction be required,
four additional circling lights defines a teardrop-like manouver from
the airport to threshold of the opposite runway.
--
Lars-Henrik Eriksson Internet: l...@sics.se
Swedish Institute of Computer Science Phone (intn'l): +46 8 752 15 09
Box 1263 Telefon (nat'l): 08 - 752 15 09
S-164 28 KISTA, SWEDEN Fax: +46 8 751 72 30