5 Series E39 530d (M57) SAL
VS-22/Klötzer
Baugruppe/Group: 65
65 10 99 (467)
weltweit
all countries
08/1999
GPS receiver week counter overflow
E38, E39 with option 609
Situation:
On 22nd August, 1999 there will be an overflow in all GPS receivers employed in BMW
navigation systems to the so-called "week counter".
The week counter states the number of weeks which have elapsed since
the GPS system was initialised by NASA. It will count continuously up to
week 1023, after which it will start at 0 again. The GPS system was initialised in early 1980,
making the end of week 1023 the 21st/22nd August, 1999. Along with other signals, the
week counter is used for the computation of the orbits of satellites. This makes it easier to
search the skies for satellites.
The week counter overflow means that on GPS receivers, up to and including software
status "5.04", the satellite orbit data will briefly be inaccurately entered. This leads to a
longer time needed to locate an orbiting satellite and to download the correct data
(depending on the uninterrupted receivability from a satellite approx. 13 minutes).
The upshot is that the navigation system will, once only, need a longer period of time
before the location computer is supported by GPS.
This will have no effect on the route guidance of the navigation system, provided that the
correct location was stored before the vehicle was parked. In some cases, when this is not
the case (e.g. parking in non-digitalised parts of the road network, such as multi-storey car
parks, garages etc.), incorrect locations may be computed for approximately 20 minutes
after starting a journey. This will automatically be corrected.
GPS receivers up to software status "5.04" were installed in BMW vehicles with navigation
system Mk1 until the end of August 1997.
GPS receivers from September 1997 (introduction of navigation system Mk2) do not display
these irregularities as the counter overflow is already programmed into the software.
This counter overflow should not be confused with the so-called "Year 2000 Problem"
which is seen in conjunction with 2-digit data record for the year in computers and
computer-supported systems after 1st January, 2000.
Affected
vehicles:
E38, E39 with navigation system (option 609)
Manufacturing period: from start of series production until 31st August, 1997
Procedure:
In case of complaint or questions from the customer, the situation should be explained.
Due to the "self-rectification effect", no action is necessary on the vehicle.
In isolated cases, the battery may be disconnected for approx. 10 minutes the first time the
vehicle is operated after 22nd August, 1999. Following this, the "incorrect" almanac in the
GPS receiver will have been cleared (the almanac contains the calculated satellite orbit
data). The subsequent software procedure will ensure that the satellites are located more
quickly. In this case, the initiation will be approx. 13 minutes shorter.
However, please bear in mind that the overall time required for such "fault prevention" is no
shorter than the "self-rectification time" of the GPS receiver.
SI GPS receiver week counter overflow E38 E39 with option 609
BMW AG - TIS
20.02.2013 10:21
Issue status (12/2007) Valid only until next DVD is issued
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