This week I'm working in Alberta Canada. I'm sending some Static data to Canadian Spatial Reference System for and OPUS like check. When submitting RINEX files at http://www.geod.nrcan.gc.ca/products-produits/ppp_e.php There is no field to enter the antenna type or height like OPUS. I assume CSRS only reads this info from the RINEX file. I just submitted the files, so still waiting for an email on the results.
I think I try sending the same data to OPUS, see what happens.
LeeGreen
Lee you are correct that the antenna height is read directly from the RINEX data. When comparing to OPUS note that the vertical reference datum will be different.
The other difference is that PPP is a single point solution. The satellite clock drift and other error sources are modelled. There will be no direction/distance vectors to other stations.
Yup. I was right. They read it from the RINEX data.
Wow the Canadians got it all over NGS. They provide a formatted easy to read 7 page PDF file with coordinates, sky plots, error plots, carrier phase residuals, and a host of other detailed color graphs and charts for each GPS point submitted.
LeeGreen
Lee: yes, I wish NGS would read the antenna type and HI from the RINEX file. Not sure why they don't. I agree the NRCAN output is "prettier". That would be a nice option on OPUS. But, it is useful to have a plain text file that can be parsed by other programs to extract data. I have several programs that can read an OPUS email and get what I need out of it for reports, or also to be able to adjust the computed vectors along with my own data.
Hello,
Quick side question:
With 0 obstruction/clear skies, from experience, what would be the recommended recording time when using a dual-frequency receiver (GPS5800) for successful processing by PPP?
Thanks,
Georges
Howdy,
The RINEX files I get frequently have wrong HI's. Requiring manual entry of the value is required by AUSPOS as well as OPUS.
Also, remember that the CSRS-PPP provides CSRS version of NAD83.
When using precise point positioning tools remember that they do not do differencing and therefore waiting for final orbits and other after-the-fact products is more critical. Of course the real time products have gotten pretty good.
HTH,
DMM
What is so wonderful about using RINEX is that they are ASCII, and can be edited to put the correct information in them. I can think of no good excuse why a RINEX file would be submitted with the incorrect information. What could be done is that it could be read from the header, then a box pops up to verify the information. You would either accept the info or correct it.
:good:
I think about the best you are going to see for PPP from a relative long occupation of a few hours is maybe 20 cm relative to the satellite coordinate system, how well that gets transformed to a NAD83 position of the correct flavor on the ground is subject to a few other things.
I suppose with a few days occupation the 20 cm might be improved upon?
SHG
Hello Shelby,
I did a bit of research today on CSRS-PPP service provided by NRCAN.
The service does provide tighter results than 20 cm's. From the government website "Collect several hours (12 or 24 hours if you strive for centimetric accuracy)"
Here's a link to CSRS-PPP accuracy page:
http://www.geod.nrcan.gc.ca/products-produits/ppp_acc_e.php
Regards,
Georges
Good stuff! I based my ealier comments on the PPp software I use, obviously with longer observations some outstanding PPP results can be obtained.
SHG
