Re: garmin rebate



miso@xxxxxxxxx wrote:
Dale DePriest wrote:
miso@xxxxxxxxx wrote:

Here is my issue. When you hike steep or rugged terrain, i.e. a path
where you can't make decent forward progress, a virtual compass is
pretty worthless since the differential readings (perhaps sequential
is a better word) are not far enough apart. I'd like the compass not
to be fussy. It really wouldn't have to be all the accurate for hiking,
but I've seen the Garmin compass in action on older models and it just
won't do.
while your concerned is well founded it is not based on how the GPS
actually computes direction. It is not done with sequential readings but
is computed from the Doppler shift from the satellite data. Only one
reading is needed but there has to be a velocity component that is not
zero or nearly zero.

Dale

Get general GPS information at:
http://www.gpsinformation.net/

Your website doesn't seem to agree with you:

http://www.gpsinformation.net/main/gpsbearing.htm
"The GPS computes it's bearing to the next waypoint based on knowing
the coordinates of the target AND the GPS receiver's current location.
(Assuming the target is a km or more away, the bearing will normally
be very accurate indeed. This is true if or not the GPS is in motion or
at rest.) HOWEVER, the GPS computes it's DIRECTION OF TRAVEL (as
opposed to bearing to the next waypoint) by computing its position at
approximately 1 second intervals and calculating DIRECTION OF
MOVEMENT."

Guess I'll have to have a talk with Joe :-)

Dale

--
_ _ Dale DePriest
/`) _ // http://users.cwnet.com/dalede
o/_/ (_(_X_(` For GPS and GPS/PDAs
.

Relevant Pages

  • Re: garmin rebate
    ... Dale DePriest wrote: ... pretty worthless since the differential readings (perhaps sequential ... I'd like the compass not ... "The GPS computes it's bearing to the next waypoint based on knowing ...
    (sci.geo.satellite-nav)
  • Re: GPS Vs COMPASS
    ... In lowland rambles I have had to use the compass to point me across a pasture or ploughed field to find the crossing point at the far boundary. ... if you know where the crossing point is then you can ask the GPS to take you there. ... If you know a bearing, make a waypoint where you are and project it beyond the field on the bearing angle and follow a bearing to it may be easier than entering a waypoint by hand at a grid reference. ... It will tell you where you are and where the next waypoint is, subject to your skill at programming it from the map. ...
    (uk.rec.walking)
  • Re: My theory on why the GPS argument will never be settled
    ... after taking a bearing off the ... to line up my compass with something in the distance (FSVO ... following a GPS GOTO is that you *don't* have to walk in a straight line ...
    (uk.rec.walking)
  • Re: GPS Vs COMPASS
    ... >using my compass to orient my map and to take bearings when it is not ... A GPS ... Normally, with a map, if you are walking up a hill etc it is usual to ... GPS note the indicated bearing to destination and then transfer this ...
    (uk.rec.walking)
  • Re: compass or gps?
    ... can't make full use of your GPS without it. ... It's what I do (using the GPS for a grid reference then using a compass) if I use the GPS at all. ... I reckon 90% of my navigation is with a map, 9.99% with a compass and 0.01% with a GPS. ... But I would say that the bit I use the gps for is incredibly useful, because a compass bearing isn't much good when you don't know where you are. ...
    (uk.rec.walking)