[time-nuts] over-determined clock solution

[Joseph Gwinn]

On Sat, 25 Jun 2016 22:00:25 -0400, time-nuts-request at febo.com wrote:
> 
> Message: 3
> Date: Sat, 25 Jun 2016 10:07:30 -0400
> From: Steve <steve65 at suddenlink.net>
> To: Discussion of precise time and frequency measurement
> 	<time-nuts at febo.com>
> Subject: [time-nuts] over-determined clock solution
> Message-ID: <9d1c7e89-c192-36bc-8f93-7ebac3d293d9 at suddenlink.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> The phrase "over-determined clock solution" is used in the Trimble 
> Thunderbolt user manual in describing operation of the Thunderbolt GPS 
> receiver. The manual does not discuss the phrase in any detail, 
> appearing to assume the reader understands its meaning. An internet 
> search on "over-determined clock solution" did not turn up any 
> substantive hits.
> 
> What does "over-determined clock solution" mean?
> 
> Thanks.
> 
> Steve, K8JQ
> 
> End of time-nuts Digest, Vol 143, Issue 41
> ******************************************

As others have said, it means that there are more satellites than the 
minimum required to compute a fix.  The minimum for a full fix is four, 
to cover x, y, z, and t.

The term "over determined" comes from Linear Algebra, and this is the 
best place to look.  

I am partial to Intro to Linear Algebra, 5th edition, by Gilbert 
Strang:  
<http://www.wellesleycambridge.com/images/linearalgebra5_Front.jpg>.  
Strang is a MIT Math Prof, and his lectures are all available gratis on 
the MIT website.

The classic application leading to an over determined linear system is 
least-squared fitting.

Joe Gwinn