PM2 Question on epoch
Posted By tripod harry on 12/14/2002 at 7:53 AM

I use a 1 second epoch for base and rover, except when doing static work for a tie to a CORS station. In that case I match the CORS output. In my area they are all 5 seconds. Available memory on the PM2 has not been a problem.

Is there an advantage to using the 1 second epoch for stop-n-go work or am I over collecting?

I find the results of a 1 second epoch only a tad better than a 2 second epoch for stop-n-go work using a a 30 second time on site recording interval. Accuracy does not improve much but I get a lot fewer partial solutions when post processing.

Are 30 epochs that much better than 15 epochs?

A one second epoch matches my CORS sites every 5th epoch if I need a check but the 2 second won't match until the 10th CORS epoch.

Is my logic reasonable or faulted?

TH


I like your reasoning....
Posted By Mike Margolis_ on 12/14/2002 at 11:36 AM

as long as you don't run out of memory.

The spec's say "up to 14 hours of 10 satellite data at a 2 second data rate."

Regarding the 30 epochs vs 15 epochs, you can trim time off a 30 epoch observation and see how well you do.


Re: PM2 Question on epoch
Posted By Phil Stevenson on 12/16/2002 at 4:34 PM

I would probably still go with the 2 second rate or a five second rate with at least one minute occupations.

Accuracy is not so much about the number of epochs as it is about the change in geometry.

If you use the 2 second rate it will use every other epoch from that CORS.

That is probably fine if you are talking about just processing your base station against it since it will have the ten second data in common. If you are processing the rover data against the CORS I would suggest using the five second rate to match the CORS and extending the occupation time a little more.



Re: PM2 Question on epoch
Posted By ROSSER BAXTER on 12/17/2002 at 9:07 AM

I HAD A SIMILAR QUESTION AND RECEIVED MY ANSWER. THANKS TO ALL WHO HAVE ANSWERED QUESTIONS ON THIS BOARD. I FEEL MORE COMFORTABLE USING THE PM2 TO DO WORK.


Re: PM2 Question on epoch
Posted By Dan Barry on 12/18/2002 at 7:15 AM

Guess I wasn't paying attention before; had thought that the PM2 collected data in the static mode at a ten second rate.
Dan


Re: PM2 Question on epoch
Posted By J.D. Billings on 12/19/2002 at 12:08 AM

Dan

The original static only ProMark2 units were restricted to 10 second recording intervals. The kinematic capable units are modified so as to handle down to 1 second epochs, for stop and go, continuous kinematic, and static.