[ntp:questions] how do you like the Trimble Resolution T
unruh at invalid.ca
Wed Feb 29 23:47:48 UTC 2012
On 2012-02-29, Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
> On 2/29/2012 12:45 AM, Ron Frazier (NTP) wrote:
>> Hi all,
>> Is anyone using the Trimble Resolution T GPS for timing? I was looking
>> at an ad for one on ebay. For my purposes, any accuracy under 1 ms is
>> great. I don't have to have 15 ns. Of course, smaller numbers are always
>> better. Is this device hard to setup and program for PPS and use with
>> NTPD? What accessories are needed?
>> This is what the ad says is included:
>> quote on ->
>> The Resolution T Starter Kit provides everything you need to start
>> integrating the module into your application. The kit includes an
>> active, external 5-VDC Bullet-style antenna
>> 50 feet of RG-59 cable, and an AC/DC power adapter. The starter kit
>> enclosure includes a mother board that provides serial output, and a
>> serial interface cable. A reference manual and monitor programs are
>> provided on CD-ROM.
>> <- quote off
>> I notice the unit only tracks 12 satellites and has 141 dbm sensitivity,
>> which seems to be less than some units. Is that a problem?
> ISTR that only three satellites are required to determine the location
> of your antenna. Once this position is accurately known, you can live
> with a single satellite.
IF you gps chipset remembers the location. It can also use 4 satellites
to determine location and time at each instant of time (if the receiver
measures velocity, it has t odo this since the location changes). Some
have the ability to tell it that the receiver is stationary, and to
remember the position.
> The last time I heard there were something like 27 GPS satellites in
> service. There are usually something like 8 satellites above the
> horizon. Enough for most purposes!
I have records from about 38 satellites all of which were tracked at one
time or another by my system.
>> Finally, what is sawtooth correction?
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