Forgive me for what appears to be a dumb beginner question. We have acquired some used (and free) 5800's for the sole purpose of getting moderately precise elevations and positions of features within the Smoky Mountains. ftp://ftp.trimble.com/pub/tmsupport/Survey%20controller/CD/Trimble%20Survey%20Controlle... illustrates the methods of measuring the correct height of the 5800 antenna. My question pertains to configuring the 5800 start-up config with antenna height. Should I be entering the antenna height (assuming a 2 m range pole) in the Antenna Height box in the Antenna tab in Trimble Configurator? If I do enter a height there, do I set height when I upload to OPUS to 0? Or, do I set height in the Configurator and OPUS to 2 m. Or...(whew)....do I set it to 0 in the configurator and 2 m at OPUS? I seem to recall that OPUS ignored antenna heights in RINEX.
My next question pertains to logging interval, am I correct in assuming that the configurator defaults (5 sec logging, 15 min position) are suitable for OPUS? Any advantage of increasing logging/position interval on a 4-6 hour occupation with only factory memory installed?
Thanks!
In my opinion....
If you are doing this for OPUS only....
And you are configuring a Power Up file for the 5800....
Leave the antenna height at 0 in GPS configurator.
Set it at 2 meters or whatever in OPUS...
15 or 30 seconds is the rate you want for OPUS....
IF you are going to send 4-6 hour sessions to OPUS...DO NOT set the limit to 15 minutes in GPS Configurator...you will be sad when you are sending them 15 minute files...
Not to sound suspicious, but since you appear to be new to posting, why are you asking? How will you use the information? If this is your first attempt at using OPUS, now is NOT the time to use the info for anything other than learning the limitations and proper application of survey grade GPS equipment. I would strongly recommend that you contact someone locally with previous experience (even if they use different brand of equipment) to help you. Advice you receive here is generally VERY, VERY good, but may miss some important factor(s) that you could only get at the project location.
If I were you - and you are a licensed surveyor or working for a licensed surveyor, I would occupy a point some place safe and nearby my home. The point should have a known published elevation and no canopy of trees overhead to do some trial and error submissions. It will take a couple of submissions to get a feel for the results, but for ballpark values, OPUS can be amazing.
Tom Bryant, thanks for your quick reply. regarding the logging interval/position inverval, should those 2 both be set to 15 - 30 seconds? Thanks.
OPUS ignores whatever height you have entered into your data collector and is stored in whatever data you record, and only uses the height you enter into the webpage.
You can set the interval however you wish. If you set at 5 or 10 or 15 seconds you can use that data when you post process. However, if you send that data to OPUS they will throw out everything except the 30 second interval. So if you are only using OPUS for processing set the interval to 30 seconds and keep your file size small.
To expand a little on Mighty Moe and Joe's points above.
OPUS will “accept” files (RINEX et.al.) with intervals of 1,2,3,5,10,15,or 30 seconds. REGARDLESS of the interval sent, OPUS decimates the file to 30 seconds using TEQC. So IF the ONLY thing you plan on doing with the observation, is submitting to OPUS, then 30 seconds is the best way to go (both units).
IF on the other hand, you want to set one unit up as a “base”, and run the other around doing “fast static” (less than 2 hours) and then process the local “inter-station” vectors from the “base” using commercial software, then you might want to drop down to 10 or 15 seconds (BOTH units need to be collecting at the SAME rate though).
If you plan on setting both 5800s up simultaneously, on different points, and then post process the inter-station (base-base) vector using your post processing software, then 30 seconds will probably work okay, because your observation time should be about 2 hours (assuming that you set them up at roughly the same time).
Two L1/L2 units, when used in conjunction with OPUS does however open up some intriguing possibilities though. By “leap-frogging” the two units around your project, occupying various sites for >2hours, you can control quite an area in just one day (limited by easy access between stations of course).
If you develop a good “plan,” and end up with 6-8 observations in a given day, you can submit all of the observations to OPUS, AND post process your inter-station vectors too. Drop all of the vector data into an LSA program, and you are really walking in tall cotton. Even just using the “two-station” scenario data in an LSA can tighten things up quite a bit.
Just remember, MORE observation DURATION, is always better than less. There is a point of diminishing returns, but few of us have that kind of time.
Loyal
OPUS will decimate to 30s (OPUS-S). The logging interval must be an integer divisor (is that the right term?) of 30. i.e. 1,2,3,5,6,10,15. 20 would not work, for example, although it might use every third epoch, not sure how OPUS is setup in that regard. Trimble default is 15s. Anything more (less?) than that for static is, in my opinion, a waste.
The position setting does not matter. That is how often the receiver writes a position record (i.e. computed from pseudorange data, maybe corrected by WAAS if you have that enabled) to the dat file. I believe Trimle default is 5 minutes. In any case, it doesn't matter, except you do want at least one position in the file so that OPUS can figure out what CORS are nearest. It doesn't help anything to have a position every epoch.
Back-in-the-USA. At ORD. Hope to get to the house in time to watch Steelers-Ravens. Should be a GOOD game. If I can stay awake. If not, I will get it on DVR.