Historic archive of defunct list thumbgps-devel@lists.bufferbloat.net
 help / color / mirror / Atom feed
From: Hal Murray <hmurray@megapathdsl.net>
To: esr@thyrsus.com
Cc: thumbgps-devel@lists.bufferbloat.net, hmurray@megapathdsl.net,
	gpsd-dev@nongnu.org
Subject: Re: [Thumbgps-devel] [gpsd-dev] PPS over USB
Date: Wed, 02 May 2012 00:58:08 -0700	[thread overview]
Message-ID: <20120502075808.6CC7880003B@ip-64-139-1-69.sjc.megapath.net> (raw)
In-Reply-To: Message from "Eric S. Raymond" <esr@thyrsus.com> of "Tue, 01 May 2012 23:33:45 EDT." <20120502033345.GA11913@thyrsus.com>


esr@thyrsus.com said:
> Clock time should be OK even with a single sat - multiple birds are needed
> for the spherical trig to compute position, but atomic time you get directly
> from each sat sample. 

I think it's more complicated than that.

You can get time with only 1 sat if know where you are located.  It takes 
special software, usually called "timing".

The usual approach for finding the location is to do a "survey".  That 
requires more special software which is usually included in the timing 
package.  It collects a 1000 (or whatever) good samples and averages the 
position.  The "good" qualifier means they don't use low-quality samples 
which might be way off.

It's worth asking Navisys if they have the timing mode software.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.




  reply	other threads:[~2012-05-02  7:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20120501151435.4a6a5373.gem@rellim.com>
2012-05-01 22:16 ` [Thumbgps-devel] Fwd: " Dave Taht
2012-05-02  1:40 ` [Thumbgps-devel] " Dave Taht
2012-05-02  3:07   ` Jim Thompson
2012-05-02  3:33   ` Eric S. Raymond
2012-05-02  7:58     ` Hal Murray [this message]
2012-05-06 21:28       ` Eric S. Raymond
2012-05-02 11:09     ` tz
     [not found]       ` <20120502131310.7dd7f799.gem@rellim.com>
2012-05-02 20:33         ` tz
2012-05-02 21:19         ` Hal Murray
2012-05-02 21:43           ` tz
2012-05-02 13:40     ` Ron Frazier (NTP)
     [not found]       ` <20120502124227.28ef9fa6.gem@rellim.com>
2012-05-03  4:07         ` Ron Frazier (NTP)
2012-05-06 22:09       ` Eric S. Raymond
     [not found] ` <4FA43068.2080606@wildgooses.com>
     [not found]   ` <20120504160455.4514ac26.gem@rellim.com>
     [not found]     ` <20120506214138.GB14699@thyrsus.com>
     [not found]       ` <4FA6F396.70307@tmsw.no>
     [not found]         ` <4FA7BDF1.7030708@wildgooses.com>
     [not found]           ` <4FA7CFB2.9080807@tmsw.no>
     [not found]             ` <4FA7E197.9010902@wildgooses.com>
     [not found]               ` <20120507205843.GA21259@thyrsus.com>
2012-05-07 21:14                 ` Dave Taht
2012-05-07 21:52                   ` Eric S. Raymond

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20120502075808.6CC7880003B@ip-64-139-1-69.sjc.megapath.net \
    --to=hmurray@megapathdsl.net \
    --cc=esr@thyrsus.com \
    --cc=gpsd-dev@nongnu.org \
    --cc=thumbgps-devel@lists.bufferbloat.net \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox