[FOSS-GPS] Accurate timestamp in rtkpost

[David Kelley]

Musa:
Maybe I gave an answer here for the wrong problem.
If all you want to do is get more digits in the precision of the time in 
the output file, then in Options -> Tab  Output, set the value for the 
"# of Decimals" from 3 (the default) to be larger, try ten.
Here is a scrap of output with 10 digits showing how the time estimate 
is iterating about the current second.

% 
(lat/lon/height=WGS84/ellipsoidal,Q=1:fix,2:float,3:sbas,4:dgps,5:single,6:ppp,ns=# 
of satellites)
%  GPST                         latitude(deg) longitude(deg)  
height(m)   Q  ns   sdn(m)   sde(m)   sdu(m) sdne(m)  sdeu(m)  sdun(m) 
age(s)  ratio
2015/12/01 03:43:48.0000000029   34.127739348 -117.825401491   
271.0814   2   6   0.0075   0.0115   0.0411 -0.0015   0.0160  -0.0052   
0.00    1.8
2015/12/01 03:43:49.0000000011   34.127739329 -117.825401496   
271.0846   2   6   0.0053   0.0081   0.0291 -0.0011   0.0113  -0.0037   
0.00    1.8
2015/12/01 03:43:50.0000000052   34.127739344 -117.825401482   
271.0871   2   6   0.0044   0.0066   0.0237 -0.0009   0.0092  -0.0030   
0.00    1.8
2015/12/01 03:43:51.0000000047   34.127739347 -117.825401465   
271.0879   2   6   0.0038   0.0057   0.0205 -0.0008   0.0080  -0.0026   
0.00    1.9
2015/12/01 03:43:52.0000000007   34.127739338 -117.825401443   
271.0907   2   6   0.0034   0.0051   0.0184 -0.0007   0.0072  -0.0023   
0.00    1.9
2015/12/01 03:43:52.9999999982   34.127739330 -117.825401417   
271.0913   2   6   0.0031   0.0047   0.0168 -0.0006   0.0065  -0.0021   
0.00    1.8
2015/12/01 03:43:53.9999999994   34.127739321 -117.825401393   
271.0937   2   6   0.0029   0.0043   0.0155 -0.0006   0.0060  -0.0020   
0.00    1.8
2015/12/01 03:43:55.0000000039   34.127739312 -117.825401380   
271.0916   2   6   0.0027   0.0041   0.0145 -0.0005   0.0057  -0.0019   
0.00    1.8


On 12/4/2015 8:45 PM, David Kelley wrote:
>
> Musa:  What is your end goal here? Convert your data to RINEX with 
> RTKLIB's convert tool and look at when your measurement epochs 
> actually occurred.  Chances are that they are aligned to the second, 
> and that is what is driving you time alignment.  Can you have the 
> Topcon output at a rate greater then 1Hz, and then look at that?  As 
> general rule, the actual observation time stamp is precise to units 
> steps of 100ns (presuming that the nav filter will then resolve this 
> further, to pSec in the case of good RTK) , but the vast majority of 
> devices will not "wake up" with some random offset point and then 
> provide 1Hz measurements from that point, rather they will align to 
> the current second and give you the summed average of the range and 
> range rate of the past 1000 CA code intervals. Net result; you get 1Hz 
> data aligned to the second unless you work real hard.
> Regards, David Kelley
>
> On 12/4/2015 7:11 PM, ABM Musa wrote:
>> Hi,
>>
>> I’m using a Topcon GR3 as a rover to collect some data and then post 
>> processing it with rtkpost along with data from a nearby CORS 
>> station. I’m using rover navigation and observation files, 
>> base-station observation file, and precise orbital file (sp3). 
>> However, the timestamp in the solution file is only with accuracy of 
>> whole seconds. Can you please let me know how I can get the timestamp 
>> accuracy in milliseconds?
>>
>> -Musa
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>