[ntp:questions] how do you like the Trimble Resolution T

unruh 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
>> <http://www.ioffer.com/info/redirect_notice?url=http%3A//item.taobao.com/auction/item_detail.jhtml%3Fitem_id%3D9a519ec253fb6de5012d1e206938da00%26x_id%3D0db1%23>,
>> 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?
>>
>> Sincerely,
>>
>> Ron
>>
>>
>



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