[time-nuts] Trimble Resolution [T, SMT, SMT GG] - spontaneous GPS loss of signal events, multiple locations

[Mike Cook]

> Le 14 sept. 2015 à 13:28, Wojciech Owczarek <wojciech at owczarek.co.uk> a écrit :
> 
> Hello Time Nuts,
> 
> I was wondering if other people have seen this. 20+ receivers and they all
> use different variants of the Resolution boards - majority are the old
> Resolution T.We have observed sudden GPS loss of signal occurring.
> Seemingly nothing unusual, these things happen, that's what holdover is
> for, etc... however:
> 
> - All devices are connected via decent distribution amps,
> - All installations use roof-mounted antennas with unobstructed 180 degree
> sky view
> - All devices see about 11 birds most of the time
> - None of these events coincided with known GPS SV outages
> 
> And here's the fun part:
> 
> - This is happening in multiple locations in the US, AND in the UK
> - The log timestamps (UTC) for the alarms, are *exactly the same* across
> all sites, down to the second. This happens twenty to ten seconds before
> midnight, and usually recovers within two or three minutes.
> 
> The last event was on 5th September, at 23:59:37 UTC. We have seen this
> happening anywhere between once every month to once every two months. Time
> may differ by a few seconds, but it's the same across all devices.
> 
> I'm trying to establish whether the issue is with Trimble or with the
> vendor who embedded Trimble. Because of what I refer to as "vendor
> anal-digital decoupling delay", I have to investigate in parallel.
> 
> Has anyone seen this with Resolution? Unfortunately I have no visibility
> into firmware versions in the Resolution boards.


Hi,
  I have both -T and SMT and have not seen this on the 5th or afik any other day. If you have other dates, I can check those in more detail.

 I would suggest that if you have spare capacity, that you remove one of the receivers from its platform and monitor with it hooked up independently. If it is shows no issue then you can go back to the vendor with the evidence.


> Any pointers welcome.
> 
> Many thanks,
> Wojciech
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