corrections derived from GPS measurements INNAME Input UV file name (name) INCLASS Input UV file name (class) INSEQ 0.0 9999.0 Input UV file name (seq. #) INDISK 0.0 9.0 Input UV file disk unit # ANTENNAS Antennas to correct SUBARRAY 0.0 9999.0 Subarray to correct 0 -> all OPCODE Corrections to apply 'IFR ' - Faraday rotation only 'DISP' - dispersive delay and Faraday rotn default: IFR only INVERS Version number of GP table containing GPS data GAINVER Input CL table version GAINUSE Output CL table version PRTLEV Print level 0 -> none 1 -> solutions 2 -> more detail

APGPS Task: Uses GPS delay data stored in a GP table to calculate phase corrections due to the excess path length of the ionosphere and to calculate the ionospheric Faraday rotation. Moving sources are supported if there is a PO table. Adverbs INNAME.....Input UV file name (name). Standard defaults. INCLASS....Input UV file name (class). Standard defaults. INSEQ......Input UV file name (seq. #). 0 => highest. INDISK.....Disk drive # of input UV file. 0 => any. ANTENNAS...List of antenna numbers to correct. If all of the entries are zero then ionospheric corrections will be generated for all antennas. If any of the entries are not blank then corrections will only be generated for those antennas with numbers listed in this array unless at least one entry is negative when corrections will be generated for all antennas except those whose numbers correspond to the absolute values of the non-zero entries. SUBARRAY...Subarray to correct. Corrections will only be generated for the subarray with this number unless this number is zero, in which case all antennas matching the ANTENNAS selection will be corrected in all subarrays. OPCODE.....Type of corrections to generate. If this is 'DISP' then both dispersive delay and ionospheric Faraday rotation corrections will be generated otherwise only ionospheric Faraday corrections will be generated. INVERS.....Version number of GP table. 0 => highest GAINVER....Version number of CL table to use. 0 => highest (used to define times at which corrections are calculated) GAINUSE....Version number of output CL table. 0 => new PRTLEV.....Print level 0 => no printout (default) 1 => model TEC, gradients in latitude and longitude and residual sum of squares

APGPS: Calculate ionospheric Faraday rotation and delay from GPS data Documentor: Chris Flatters Related Programs: LDGPS APGPS fits a simple model of the total electron content of the ionosphere to GPS delay data and uses this model to calculate corrections for the ionospheric Faraday rotation and delay. The model is parameterized by the total electron content at the zenith above the GPS receiver and linear gradiants in latitude and longitude. This isa reasonable model only for reasonably compact arrays situated close to a GPS receiver. If you use APGPS for arrays more than a few kilometers in size, you should use ANTENNAS to make sure that corrections are only applied to antennas close to the receiver. If you have data from more than one receiver then you can run APGPS for each receiver, selecting a different set of antennas for each run. This program is primarily intended to correct VLA data using data from GPS receivers at the VLA site. PRINTOUT If PRTLEV is set to 1 or a greater value then APGPS will print out - the model TEC at the zenith, - the TEC gradients in latitude and longitude, - the residual sum of the squares, and - the fractional error bound every time it recalculates the ionospheric model. If the true ionospheric model is characterized by a vector x (with x(1) = TEC, x(2) = gradient in longitude, x(3) = gradient in latitude) and the model calculated by APGPS is x' then the fractional error that is printed is an upper bound on || x - x' || / || x || where || x || denotes the L2 norm (or the sum of the squares) of x. The residual sum of the squares and the error bound may help in finding poor solutions. If PRTLEV is set to 2 or more then APGPS will also print out the model zenith TEC for each satellite that provided data in the solution interval (identified by PRN) and the mean and standard deviations of the measured zenith TECs.