i've been thinking about coordinating a local RINEX ftp site.
shorten our baseline lengths and have more vectors to use. seems a little bit of work for a good set of benefits.
below is an email i have sent to a couple of prospective contributors:
"""Good morning gents,
As a follow up to a meeting with Howard County Engineering a couple years back, Rafael (Ralph) Mercado suggested we exchange RINEX data files for mutual use. More vectors and shorter baselines will support our networks and give us better results.
Currently, our I.T. agent is going to earmark a network drive for our use. Should be available soon.
We have some other things to think about and work towards, (please submit your thoughts and input):
For those with the use of RTK, you will have to record your data, of course. It is my belief we should base our data on static observations (at least to begin)
Common epochs. I think 5 seconds should be standard.
Observation time minimum of 15 minutes and maximum of 5 hours.
A common datasheet format. Something quick and easy for recovery, if necessary. Enclosed is an NGS write-able pdf datasheet. http://www.ngs.noaa.gov/CORS-Proxy/project_tracking/surveyproposal AND http://www.ngs.noaa.gov/PROJECTS/NGSforms/obslog.pdf AND http://www.ngs.noaa.gov/PROJECTS/NGSforms/obslog-OPUS.pdf AND http://www.ngs.noaa.gov/PROJECTS/GPSmanual/data.htm#recovery
Maybe we don’t necessarily have to complete the entire forms, but they are a starting point.
NGS based stability of marker specification. a b c d
A bedrock setting or drilled deep marker
B large foundation
C lighter structures
D shallow rod, pavement, nail, etc.
Not sure if we want to use this or not; but computed standard deviation, stochastics and reliability of processed and adjusted coordinates. Could just be an option.
Some sort of Outlook type calendar for data entry marking.
Who else can we/should we bring in on this? I am thinking SHA and some other local companies.
""""
does anyone else do this?
what are your thoughts?
What do you mean rinex ftp site? Do you mean basically running your our CORS site? Like each company will keep a receiver running outside their office at all times with the data available for download?
> What do you mean rinex ftp site? Do you mean basically running your our CORS site? Like each company will keep a receiver running outside their office at all times with the data available for download?
not at all. RINEX files from any field work done on any given day by any of the parties/companies that want to be involved. input your RINEX in the ftp. if some other group has RINEX in there as well, on that day and somewhat nearby, you upload their RINEX to your project.
additional data=additional vectors. usually=shorter and better vectors to support your network. i think it will be a useful endeavor. i would be a bit surprised if this has not already been done.
anyone has any other input/opinions?
Oh. In that case, I believe what you are purposing is a complete waste of time and adds nothing to a network GPS campaign. The amount of coordination needed to make sure observation times are lined up would convince most surveyors to not bother with it. Why do my jobs and my schedule rely on some other guy who has no vested interest? The random chance that I was doing a GPS survey and some other surveyor just happened to be nearby occupying a point that I found useful (most passive NGS marks aren't useful for anything but a check around here) at the very same time I was doing a GPS survey, and captured enough data to coincide with mine to bother post processing it, seems like one in a thousand to me. Not worth my time with the bother, nor the worrying about the field procedures of some other surveyor's crew, or worrying about whether his rinex file is properly formatted, or if he even knows the correct NGS definition for his antenna, etc., etc., etc. If you are designing a proper GPS campaign, data like this is pretty useless. I'd only expect it to introduce more doubt and uncertainty, far outweighing any theoretical improvement from shorter baselines. It all goes back to, you can't rely on anyone but yourself if you expect to be successful in business.
> '''Oh. In that case, I believe what you are purposing is a complete waste of time and adds nothing to a network GPS campaign. The amount of coordination needed to make sure observation times are lined up would convince most surveyors to not bother with it.'''
if i get enough different parties interested, then the density and odds of concurrent data increase.
'''Why do my jobs and my schedule rely on some other guy who has no vested interest?'''
all parties would have a vested interest, as it is a give and take of data. this ftp site can be a download or upload.
'''The random chance that I was doing a GPS survey and some other surveyor just happened to be nearby occupying a point that I found useful (most passive NGS marks aren't useful for anything but a check around here) at the very same time I was doing a GPS survey, and captured enough data to coincide with mine to bother post processing it, seems like one in a thousand to me.'''
i never said it was a passive ngs mark. could be a nearby mark that was just set, and just collected data upon.
'''Not worth my time with the bother, nor the worrying about the field procedures of some other surveyor's crew, or worrying about whether his rinex file is properly formatted, or if he even knows the correct NGS definition for his antenna, etc., etc., etc. If you are designing a proper GPS campaign, data like this is pretty useless. I'd only expect it to introduce more doubt and uncertainty, far outweighing any theoretical improvement from shorter baselines. It all goes back to, you can't rely on anyone but yourself if you expect to be successful in business.'''
sir, i am successful in my business. what i am proposing is a different method of using existing data. yes, there could be a risk of someone else using the wrong antenna definition, etc. simply process the data; if it seems like an outlier, do not use the vector. there would be an element of trust to the quality of data and metadata. if i am not mistaken, a receiver writes its own make and model, as well as the make and model of the antenna into the header of the RINEX file. having mentioned that, a larger part of the risk/trust element would be ARP height and centering.
this message has got me pretty well unnerved. i am going to try it. there is a possibility it will not work very well, but it also seems no one else has tried it. i will be sure to keep the group updated with my results.
thanks, Joe. i will work on this.