How bad is the BMW nav system --- or do I have a flawed copy of the software

<ahall · 2012-09-04T21:12:04+00:00

My 2011 335xi's navigation system is really pathetic.It frequently tries to take me to a correct address butleaves me a mile or more from the actual location.Twice it has changed the town I entered (via bluetooth).I found the correct addresses in my address book, selectedthem, the BMW screen showed the correct towns, but when Iselected "Start Guidance" the car changed the town --- onceto the next town, once to a town 15 miles from where I was going.Is this typical, or should I ask them to reinstall the software?Thanks,

Sep 04, 2012 22 Replies

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fred 14 years ago

That article also has the sentence, "...Many receivers can use as many as twelve channels simultaneously, allowing quicker fixes....".

So the question becomes, can the almanac be downloaded in pieces from multiple satellites simultaneously, thus allowing the entire almanac to be downloaded in less time than it takes to download it from start to end from one satellite?

There is nothing that says a data file (i.e., the almanac) cannot be broken up and downloaded in pieces from various locations simultaneously. Indeed, that is how bit torrent works.

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R. Mark Clayton 13 years ago

Well indeed. I had assumed the aGPS was using the [known] position of the mast to get approximate position of the reciver, however the article tells you it just downloads the almanac if it can (

Indeed it can, but remember these birds are doing five miles per second, so even a tiny error will put you hundreds of metres out.

As described in the article anything that helps (accurate time, approx position or knowing you are stationary) helps speed up a fix.

Anyway early 747's had a hole in the cockpit roof through which a specially designed sextant was used to get a celestial fix. On KAL 007 they got the fix OK, but then navigated on a magnetic bearing instead of a true one...

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