[time-nuts] GPS timing recievers and INTERFERENCE

Glenn glenn at net127.com
Wed May 3 10:00:42 EDT 2006

Normand Martel wrote:

> Just as Tom Van Baak said, a timing receiver is
> designed to be used in a FIXED position, such as a
> cell site or a metrology lab. I never tried to use a
> timing receiver in a vehicle, but (what i think) it
> will probably lose sync with the satellites once in
> motion. On te other side, a positioning receiver will
> keep synchronized, whatever it's in motion or kept
> immobilized. but it's 1PPS signal (it it has one...)
> will be somewhat less accurate.

My Oncore UT+ "timing receiver" claims 25m (w/o SA) position accuracy. 
"Position Hold" (for timing applications) is an _optional_ mode. I 
haven't tried it in my truck (yet), but it should work fine.

BTW, "Jamming Immunity" of the Oncore UT+ (Desgined in ~1996, built in 
2000, discontinued in 2003(?)) is claimed as:

"Immune to the following CW jamming signal levels measured at the input 
to the Oncore Active Antenna when the receiver is in position-hold mode. 
Values are typical:

-50 dBm @ 1570 MHz
-79 dBm @ 1575.42 MHz
-56 dBm @ 1580 MHz"

This is from page 3.10 of the  "Oncore User's Guide; June 1998; Motorola 
TRM0003 Rev 3.2" which I think I got from the synergy-gps.com web site. 
(Thanks for putting these online!)


BTW, Timing accuracy of the UT+ is listed as "In position hold mode, 
<50ns (1 sigma) with SA on." Does anyone have claimed or measured values 
for timing accuracry WITHOUT SA?

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