[time-nuts] GPS from a window seat

[Robert Atkinson]

Hi Bjorn,
The car was Thrust-SSC, Design phase was late 1995, running 1996/7. We were limited on funds too. One unit we looked at was the Rockwell Jupiter, I just looked at the spec and can't see a speed limitation, but it was a problem at the time. Dispite the stories that it was a well funded effort, the whole project was hand to mouth with equipment being selected on availability as much as suitability. A lot of stuff was begged borrowed or removed from a skip (dumpster) ;-). I was responsible for the cockpit instrumentation, engine electrics, various other system bits and was part of the start/turnaround team that ran the car in Jordan and Blackrock Nevada.
 
Robert G8RPI.

--- On Fri, 2/10/09, bg at lysator.liu.se <bg at lysator.liu.se> wrote:


From: bg at lysator.liu.se <bg at lysator.liu.se>
Subject: Re: [time-nuts] GPS from a window seat
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Friday, 2 October, 2009, 1:00 PM


Hi Robert,

The limit is 515 m/s, 1000 knots or 1854 km/h. I presume your car did 1227
km/h, right?  This is within CoCom limits. Then both altitude AND speed
must be over the limit to break the rules. Where your car also driving
over 18000m altitude?

http://trl.trimble.com/docushare/dsweb/Get/Document-183796/13441+Resolution+FA2.pdf

As for 1Hz... 20Hz and for some years even 50Hz and 100Hz GPS measurements
has been available. Look at L1 OEM-boards from Novatel, Ashtech, Topcon,
Javad etc.

uBlox-5 receivers are often specified at 4Hz, <50km alt, <500m/s, <4g.

--

    Björn

> Well Jim brought up cars, 
> I did look at using a GPS as a speed sensor for a car some time ago. The
> 1000kPH limit (and 1s update rate) stopped that idea. The car
> finally hit over 1227kph average. We used wheel speed and pitot pressure
> in the end (plus external time & distance).
>  
> Robert G8RPI



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