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NEW ARTICLE: Navigation in Winter

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 UKC Articles 16 Mar 2015
Taking a bearing in harsh conditions, 4 kbNavigation is not the only factor in getting in and out of the mountains in one piece, but it's a pretty fundamental one, and very, very important. You don't have to be a wizard, just be able to find what you're after and then get home, or at a minimum get off the mountain, so here is a run down of techniques and strategies for winter navigation.

Rich Parker MIC gives us his tips for navigating in Winter.



Read more at http://www.ukclimbing.com/articles/page.php?id=7183
In reply to UKC Articles:

Good article.

A bit of pedantry and a warning:

Magnetic declination is the difference between magnetic and true norths, not grid north. For map & compass navigators, Grid Magnetic Angle is what is needed. GMA depends on the local magnetic declination, and the local grid convergence (the difference between grid and true norths caused by the map projection).

http://www.ordnancesurvey.co.uk/resources/maps-and-geographic-resources/fin...

In mountainous regions, a GNSS receiver can be fooled by strong reflections from nearby cliff faces. These can pull the computed position by hundreds of metres, and the errors cannot be corrected by WAAS/EGNOS. GNSS/GPS should be treated as another navigation aid, but you need, like all navigation aids, to check that what it is saying is sane. Never trust any navigation device completely.
 King prawn 17 Mar 2015
In reply to UKC Articles:

If you're new to this, practice in poor conditions in a known area (inside a ring-road or large, fenced area). My internal compass always pulls me east even if following a compass bearing; it takes discipline for me to trust the compass. I concentrate on this and have very few problems in featureless areas.
 Rich W Parker 22 Mar 2015
In reply to captain paranoia:

"strong reflections from nearby cliff faces"....I assume if you're positioned under or adjacent rather than above?
In reply to Murko Fuzz:
That would depend on the beam profile of the antenna. Ideally (but unlikely in practice), the antenna will have zero response below its horizon, but then you have the issues of receiver attitude and the orientation of the antenna horizontal plane within the receiver (which is rarely documented). For these reasons, it's hard to be sure that a reflection from below you will not be picked up by the receiver, assuming there's a line of sight between the receiver and the reflecting surface.

If there's an obvious strong reflector, you may be able to shield the receiver from it by putting your body in the way; we're mostly water, and water is pretty good at stopping L-band signals... The downside of that is that your body and head are common shadowing objects for the receiver, especially if you hold it at your waist, and peer down at the thing...

PS reflections are also a problem in high-rise urban areas, causing the same drift of computed position, compounded by the 'urban canyon' which restricts sky visibility, blocking out the satellite constellation. That's why your smart phones fuses GNSS position with WiFi signal strength maps, etc, to come up with a composite solution to try to reduce the effect of reflections.
Post edited at 10:59

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