topic Re: GPS time format in Counter/Timer

GPS time format

sandy — Wed, 17 Aug 2005 08:02:56 GMT

Hi..
I am using NAVILI>CK GPS for our work related to Laser radar data aquisition. Through the simple code attached, I can read the time stamp in the way 12:23:45 (say UTC, hh:mm:ss). But I want to have the time stamp as 12:23:45.7653 (see change in the ss stamp). How to generate this?
Pls post your reply
Regards
Sandy

Re: GPS time format

sandy — Wed, 17 Aug 2005 10:14:28 GMT

Hi..
Here is the attached file
Sandy

Re: GPS time format

Ingo_Schumacher — Thu, 18 Aug 2005 07:35:27 GMT

Hello Sandy,

as I can see in your programming, you retrieve the timestamp information from your GPS device via the serial port. Can you configure the device to send the millisecond information you need?
Otherwise you would have to generate your own timestamp in LabVIEW. Maybe you can use the VI "Tick count (ms).vi" out of the time&dialog palette to get the ms information. This VI is reading out an internal timer and displaying the result in milliseconds. You could calculate an offset from a starting point of the measurement and add the information to the timestamp you get from your device. Generating a timestamp beyond the millisecond resolution is tricky on windows systems, because 1ms is the smallest unit in software timing. You would need a counter signal or some other kind of hardware you could use to time your loop.

Re: GPS time format

sandy — Thu, 18 Aug 2005 08:44:17 GMT

Hi..Ingo Schumacher
Thanks a lot. If I could understand you properly, then I have to calculate the start time in milli-second and then calcuate the offset by subtracting it from milli-second timer.Well, I want only a precision of second like 31.33, 31.66 and 31.99 second like this.. Can you pls correct me.
Regards
Sandy
P.S: Earlier we used the time stamp from the processor and now we want to use the GPS time at every data file. Unfortunately the GPS device does not create the ss.sss precision.

Re: GPS time format

Ingo_Schumacher — Thu, 18 Aug 2005 09:21:08 GMT

Hello Sandy,

yes, this is what I meant. What you also can do, instead of calculating the difference, is to use the quotient and remainer function to divide the timervalue by 1000. The remainder output will then give you a value between 0 and 1000, corresponding to the ms in a second. You would only have to add this value to your timestring.

Re: GPS time format

sandy — Thu, 18 Aug 2005 10:16:03 GMT

Hi..
I modfied the vi (attached) according to your idea. Did you mean to divide the timervalue by 1000, that time value is in Second? If second , then my vi may be correct to get the milli-second. But it still gives me the data as the time stamp 12:23:34.345,12:23:34.345,12:23:34.345 (as hh:mm:ss.sss) and then the sss changes. Do you think, is there again any problem in my modified vi? Or something wrong with the Serial Communication?
Pls do reply
Sandy

Re: GPS time format

sandy — Thu, 18 Aug 2005 10:16:43 GMT

Sorry..again forget to attach
Sandy

Re: GPS time format

Ingo_Schumacher — Thu, 18 Aug 2005 11:07:25 GMT

Hi,

have a look at the attatched VI. I had to remove the Serial VIs and added string controls so I could test it.
But it should explain more clearly what I meant.

Re: GPS time format

sandy — Thu, 18 Aug 2005 12:21:13 GMT

Hi..
Thanks a lot..It works out the HH:mm:ss.sss
Regards
Sandy

Re: GPS time format

henry Henry — Mon, 05 Dec 2011 15:34:29 GMT

Hi Sandy,

Sorry to disturb you. Just now i have the same question as you. i want to use the serial port to read the GPS time in HH:mm:ss.sss. i saw you have figured it out, so I just wonder how did you achieve that? Thanks very much for your help!

Best regards,

Henry