Are there any specific calibration requirements for any Spark Fun GNSS receivers beyond what the factory may have done before use ? For example, after a year of use?
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I was simply going to visit a known government marker and take a measure.
What your probably wanting is a site calibration. To be able to come back and repeat results. Tie 3 to 5 known high order benchmarks, (make sure you’re in the same datum) and do a site calibration which is available in most survey software. Another option is to burn a very long observation as static and process with opus and use that point as your base control.
We have done the site calibration option at the municipality I work for and are able to revisit and visit other benchmarks and get within about 0.02 or better horizontally.
With a site calibration you want to surround the site in a polygonal or triangular fashion and not linear.
What are you trying to accomplish?
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Aorpls, thanks for the very informative answer. I think your answering a question I should have asked. But the question was really about the hardware it’s self. Other then firmware updates do Spark Fun GNSS receivers require any “bench calibration”. Or is the method you describe the only calibration you can do?
I mean the antennas are NGS certified. other than that I’m not sure how firmware updates would aid in a datum since that’s the purpose of datums.
I could be wrong here but I don’t think the receiver needs any calibration on it’s own. It just stits there and does math on the signals it receives and spits out answers. Any errors in the reception would affect all received signals and could be corrected for in math.
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OK, .
NGS ? Stands for ?
And really the antenna for its arp is what is calibrated, the firmware just deciphers the GNSS signals and does the math.
Aorpls, thanks again. I have some home work to do !
First, let’s clarify what “calibration” even stands for. Generally speaking, it’s not a process of doing something to your measurement device to retain its measurement capabilities (as seemingly implied in your original question).
It’s a process of comparing the measurement taken by your device with the reference measurement.
It’s generally done for two specific purposes.
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First, to ensure that you are still getting accurate results. For the GNSS measurements, it’s mostly related not to your receiver, but to your setup and settings for the measurements you take. Such as accurate antenna description data, coordinate reference settings, etc. This is what you might need in two cases:
when you somehow change your setup to ensure it’s still valid;
when your workflow allows you to “tie” your measurement of unknown points to the measurements you take at known points in current conditions (which unlikely applies to you). -
Second, and that doesn’t apply to you directly, there’s an antenna calibration process that was already mentioned. It’s done once by NGS for a specific antenna model to find out the parameters that every user of such antenna can plug into their settings and get accurate measurements.
Bushman_K, thanks for further input on this topic.
For myself, I will be using a receiver as a “rover” connected to my own base or will make use of a correction service here in southern Ontario, Canada.
Just making ground control points for aerial mapping.
I think I’m just going to do measurements at a few known “markers” before heading out on a job. These “markers” or “stations” are maintained by Ministry of Natural Resources here in Canada, and their web site shows the lat, long, elevation, datum and other info and date measurement was taken.
And , of course, do everything the same way each time, including which correction service.