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From: | Gerry Creager - NOAA Affiliate |
Subject: | Re: [gpsd-dev] [PATCH 5/9] Define TTFF |
Date: | Fri, 17 Apr 2015 21:02:15 -0500 |
“It was to wait” below should be “It has to wait”.
> On Apr 17, 2015, at 10:54 AM, Sanjeev Gupta <address@hidden> wrote:
>
> ---
> www/gps-hacking.html | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/www/gps-hacking.html b/www/gps-hacking.html
> index 3bdacc9..bee0274 100644
> --- a/www/gps-hacking.html
> +++ b/www/gps-hacking.html
> @@ -383,12 +383,13 @@ feel for what your GPS has to say, and how often it says it.</p>
>
> <h1>Locking and Loading</h1>
>
> -<p>The time required for a GPS to get a fix can vary from under 15
> -seconds up to just under 30 minutes (actually, 29 plus calculation
> -time). The main factors affecting this latency are (a) whether it has
> -an almanac available, (b) whether it has satellite ephemerides
> -available, and (c) whether it has recent fix available. Of course the
> -quality of signal at your location matters as well.</p>
> +<p>The time required for a GPS to get a fix (Time To First Fix (TTFF))
> +can vary from under 15 seconds up to just under 30 minutes (actually,
> +29 plus calculation time). The main factors affecting this latency are
> +(a) whether it has an almanac available,
> +(b) whether it has satellite ephemerides available, and
> +(c) whether it has recent fix available.
> +Of course the quality of signal at your location matters as well.</p>
>
> <p>If a GPS has not been on for several months, then it has no current
> almanac available. It was to wait to download one before it can
> --
> 2.1.4
>
>
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