[gps-talkusers] Re: version 3?
- From: Michael May <MikeMay@xxxxxxxxxxxxxxxx>
- To: gps-talkusers@xxxxxxxxxxxxx
- Date: Thu, 20 May 2004 11:08:40 -0700
Casey,
Version 1 came out in May 2002.
Version 2 shipped in September 2003.
GPS Version 3 is next. We aren't close enough to being finished to have a
release date or to announce details yet.
We'll try to keep the upgrades coming at least once a year.
Mike
At 10:25 AM 5/20/2004, you wrote:
>wow, I just got version 2... How often do new versions come out?
>Are we allowed to know what's new in 3 yet?
>
>
>Casey
>
>----- Original Message -----
>From: "Michael May" <MikeMay@xxxxxxxxxxxxxxxx>
>To: <gps-talkusers@xxxxxxxxxxxxx>
>Sent: Thursday, May 20, 2004 1:12 PM
>Subject: [gps-talkusers] Re: GPS mathematics
>
>
>John,
>
>You are absolutely correct that longer distances are tricky to calculate.
>We have made improvements in this in version 3.
>
>Mike
>
>
>At 09:41 AM 5/20/2004, you wrote:
> >Greetings,
> >
> > Interesting you should ask this question. I did some distance
> >traveling with the BN GPS last week and found some interesting things,
> >some of which may very well be related to the mathematics of GPS.
> >
> > First I should say that I don't have an answer to your question..
> >What I do know is that you can't find the distance in an X y coordinate
> >system for a latitude and longitude. This is because the earth is not
> >flat. Hence, if you are at the equator you'll find that longitude lines
> >are a particular distance apart (I don't know the specific distance, but
> >if you know the circumference of the earth and you divide accordingly,
> >you'll figure it out. Anyway, as you travel north from the equator the
> >longitude lines will get closer and closer together. Eventually, they
> >all meet at the north pole.
> >
> > So, in order to compute the distance between two points you need
> >to account for the curve of the earth. For short distances,
> >particularly in computations near the equator, any error introduced by
> >not doing this may be fairly minor. For longer distances, particularly
> >as your distance from the equator increases, these errors will be
> >dramatic.
> >
> > So, as to the interesting thing I saw last week.
> >
> > I was in a car. We traveled from Arlington Massachusetts to
> >Stamford Connecticut. On the trip down, the BN GPS measured the
> >distance at about 200 miles. I felt this was not accurate. I'd always
> >believed the distance to be more like 180 miles. On the return trip,
> >taking the same roads, the car clocked the distance at 177 miles. My BN
> >GPS crashed about three times on that trip so I couldn't clock the trip
> >again.
> >
> > At one point though, we were driving east on I-90 (the Mass
> >pike) when the driver saw a sign saying 26 miles to I-95. From that
> >sign, to the I-95 ramp, the BN GPS clocked nearly 36 miles. This is a
> >pretty substantial error. Clearly such a substantial error cannot have
> >existed throughout the entire 177 mile trip otherwise BN GPS would have
> >reported a distance that was 68 miles in error. So I'm wondering if BN
> >GPS is more inaccurate when traveling east/west then north/south because
> >the earth's curviture is not accurately being accounted for.
> >
> > Since the Mass Pike is a bit north of Longitude 42N it is nearly
> >half way to the pole. Is it possible that BN GPS isn't accurately
> >dealing with this fact?
> >
> >John
> >
> >-----Original Message-----
> >From: gps-talkusers-bounce@xxxxxxxxxxxxx
> >[mailto:gps-talkusers-bounce@xxxxxxxxxxxxx] On Behalf Of Matthias
> >Weingart
> >Sent: Thursday, May 20, 2004 10:47 AM
> >To: gps-talkusers@xxxxxxxxxxxxx
> >Subject: [gps-talkusers] GPS mathematics
> >
> >
> >Hi,
> >
> >maybe I am asking in the wrong group (this is a group for GPS users, and
> >not developers?), but I would like to know something of the GPS basics.
> >In fact I would like to calculate the distance and angle between 2 GPS
> >coordinates (or position in a x-y diagram, where one coordinate is
> >(0,0)). (starting from the NMEA-string, result should be meters).
> >
> >I would be very happy, if somebody here could point me to some good
> >ressources.
> >
> > Matthias
>
>
>Michael G. May
>
>CEO Sendero Group
>
>Developers and distributors of BrailleNote GPS
>Now distributing BrailleNote, VoiceNote, Miniguide, The Tissot Silen-T
>tactile watch and the ID Mate, bar code reader
>
>MikeMay@xxxxxxxxxxxxxxxx
>http://www.SenderoGroup.com
>
>(530) 757-6800, Fax (530) 757-6830, Mobile (530) 304-0007
>Sendero Group, LLC
>1118 Maple Lane, Davis, CA 95616-1723, USA
>
>Latitude, 38 33 9.239 North
>Longitude, 121 45 40.145 West
Michael G. May
CEO Sendero Group
Developers and distributors of BrailleNote GPS
Now distributing BrailleNote, VoiceNote, Miniguide, The Tissot Silen-T
tactile watch and the ID Mate, bar code reader
MikeMay@xxxxxxxxxxxxxxxx
http://www.SenderoGroup.com
(530) 757-6800, Fax (530) 757-6830, Mobile (530) 304-0007
Sendero Group, LLC
1118 Maple Lane, Davis, CA 95616-1723, USA
Latitude, 38 33 9.239 North
Longitude, 121 45 40.145 West
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