On Sat, Mar 30, 2019 at 9:01 AM jimlux <jim...@earthlink.net> wrote: > > On 3/27/19 11:49 AM, coderman via time-nuts wrote: > > Compiled the software, but... > > > he user specifies the GPS satellite constellation through a GPS broadcast > > ephemeris file. The daily GPS broadcast ephemeris file (brdc) is a merge of > > the individual site navigation files into one. The archive for the daily > > file is: > > > > ftp://cddis.gsfc.nasa.gov/gnss/data/daily/ > > There's a ton of files under that.. broken down by year/day of year/ and > then some subdirectories with dozens of files, that appear to be RINEX > (the names are things like > > ftp://cddis.gsfc.nasa.gov/gnss/data/daily/2019/088/19f/USN700USA_R_20190880000_01D_CN.rnx.gz > > A casual browse did not find the brdc. >
Yes the CDDIS holdings are not easy to find things in... The organization from the data/daily/ is 4 digit year (e.g. '2019'), 3 digit day of the year. Then it's 2 digit truncated year, followed by 'n' (for 'n'avigation) e.g. '19n'. The brdc file is in there, and as you say, is in RINEX format. The individual observations made by the GNSS receiving sites live in the '19o' directories with a 4 letter site code name. For more precise work (probably not relevant for a GPS simulator), if enough time has passed for the processing, you may want to the use the post-processed products in ftp://cddis.nasa.gov/gnss/products/ which are organized by GPS week number (for...reasons...) and documented at https://cddis.nasa.gov/Data_and_Derived_Products/GNSS/orbit_products.html. The precise orbits are in igsWWWWD.sp3.Z where 'WWWW' is the GPS week number and 'D' the day in the week. Hope this helps, Tim > > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.