MINIATURE ATOMIC CLOCK MAY REVOLUTIONIZE PRECISE NAVIGATION
Sam Wormley
MINIATURE ATOMIC CLOCK MAY REVOLUTIONIZE PRECISE NAVIGATION
A new atomic clock about 100 times smaller than any other previously
developed atomic clocks was experimentally proven feasible by
researchers of the Commerce Department's National Institute of
Standards and Technology (NIST) headquartered at Gaithersburg, MD.
More information is available at:
http://www.nist.gov/public_affairs/releases/miniclock.htm
http://www.spacedaily.com/news/energy-tech-04zzf.html
Hans-Georg Michna
Sam,
great! To us this may mean quicker satellite acquisition, higher
precision, 3D navigation with 3 satellites in sight, rather than
4, possibly 2D navigation with just 2 sats.
Hans-Georg
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Stan Gosnell
> MINIATURE ATOMIC CLOCK MAY REVOLUTIONIZE PRECISE NAVIGATION
Sam, you're slipping. Someone beat you to it. ;-)
--
Regards,
Stan
Alan Browne
>>A new atomic clock about 100 times smaller than any other previously
>>developed atomic clocks was experimentally proven feasible by
>>researchers of the Commerce Department's National Institute of
>>Standards and Technology (NIST) headquartered at Gaithersburg, MD.
>>
>>More information is available at:
>>
>> http://www.nist.gov/public_affairs/releases/miniclock.htm
>>
>> http://www.spacedaily.com/news/energy-tech-04zzf.html
>
>
> Sam,
>
> great! To us this may mean quicker satellite acquisition, higher
> precision, 3D navigation with 3 satellites in sight, rather than
> 4, possibly 2D navigation with just 2 sats.
Not sure that is so as the local clock is not slaved to the GPS
clocks until an accurate PVT is known and the local clock is far
less accurate than the times derived from the sat signals. The
time ambiguity of the orbiting clocks is still undetermined by
this clock. Further, this clock is not in the same grav field as
the orbiting clocks, may be an issues as well. I may be wrong
about all this, but that's how I see it. Discuss.
IAC it cannot be used as a pseudo range source (eg: like an
altimeter) as it is not at an independant known position (an
altimeter gives distance to the ctr of the earth for the purpose
of computing position as if it were a P-R source).
The advantage of a very accurate local clock in operations would
be ... what? the receiver is already slaved to very accurate in
orbit clocks, 1000X more accurate than this new tiny clock. It
could help marginally with coasting, the time when a nav solution
is not possible or is compromised. But for ongoing tracking, the
benefit of the accuracy would be lost in the noise (I believe).
The benefits of this clock are really in reducing the uncertainty
of the time at startup (and can be arranged to eliminate
unintentional user errors in entering the time in the system. I
don't believe they will help very much with acquisition time, as
the correlators initially have to be driven loose to account for
velocity and position unknowns (some receivers allow these to be
controlled, but most consumer grade Rx do not allow a velocity
vector to be entered, only time and position).
It is just a lab device at this point, and there is no telling
how well it will perform in a real environment (-40C to +40C at
least and -55 to +71 for more severe environments). Before they
perfect, package and qualify this device for the market it will
take some time.
As stated in the ref'd article, the major benefit of this chip
would really accrue to communications systems, with a minor
contribution to GPS operations, IMO.
Cheers,
Alan
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Jon Parmet
> Sam Wormley <swor...@mchsi.com> wrote in news:41335829...@mchsi.com:
>
> > MINIATURE ATOMIC CLOCK MAY REVOLUTIONIZE PRECISE NAVIGATION
>
> Sam, you're slipping. Someone beat you to it. ;-)
Time to take the TTFF module in for a tune-up? ;)