ANTINFO: Antenna Information Format, Version 003 Giovanni Sella, Steve Hilla National Geodetic Survey (NGS) original: 08 June 2011 revised: 17 October 2022 CONTENTS 1.0 INTRODUCTION 2.0 FILE EXTENSION 3.0 ANTINFO VERSION 003 FORMAT DEFINITIONS 3.1 FORMAT FOR THE FIRST LINE 3.2 FORMAT FOR THE STANDARD 11-LINE HEADER 3.3 FORMAT OF INDIVIDUAL ANTENNA CALIBRATIONS 4.0 EXAMPLES 4.1 EXAMPLE RELATIVE ANT_INFO.003 FILE 4.2 EXAMPLE ABSOLUTE NGSXX.003 FILE 4.3 EXAMPLE OLDER RELATIVE ANT_INFO.003 FILE 1.0 INTRODUCTION This document summarizes the format definitions for the ant_info.003 file, which has been used by NGS and others since the latter part of 1999. The ant_info.003 file has had additional antennas added to it over many years. The ant_info.003 file originally contained relative antenna patterns derived using a reference antenna (the AOAD/M_T antenna). There are also antenna files, such as those in the ANTEX format (see https://files.igs.org/pub/data/format/antex14.txt), that can contain absolute calibrations. These absolute calibrations are more accurate for longer GNSS baselines where the elevation angles to a satellite at each end of the baseline are significantly different (e.g., at ~ 111 km the elevation angle difference is about 1 degree). It is possible to convert an ANTEX file to the ant_info.003 format. Such a file can then be used in older GNSS processing software, to reap the main benefit of using the absolute calibrations. This has been done with the ngsXX.003 file, where "XX" indicates the reference frame of the calibrations. It is still preferable to use the full ANTEX file, however, since it contains: phase center variations that are also a function of azimuth, phase center variations and offsets for the GPS and GLONASS satellites, and phase center variations that are specific to GLONASS observations. Although an additional label was added in columns 16 through 61 of the first line (to designate whether the file type is relative or absolute), it was decided to keep the format version at 003. 2.0 FILE EXTENSION It is recommended that the file extension be .003 for all ANT INFO files. The older, relative files were always called ant_info.003, but the newer, absolute file will be called ngsXX.003. 3.0 ANTINFO VERSION 003 FORMAT DEFINITIONS 3.1 FORMAT FOR THE FIRST LINE The format version label is defined in columns 1 through 14 as shown in the example below. The description label in columns 16 through 61 can be a maximum of 46 characters long. Both of these labels should always begin with '<' and end with '>'. The file type is specified in columns 21 through 23 as either 'ABS' or 'REL'. The source files are listed in columns 29 through 60 with the filenames separated by commas. The fields in columns 63 through 80 are of fixed width; the '<' is always in col 63 and the '>' is always in col 80. +--------------------+------------------------------------------+------------+ | HEADER LABEL | DESCRIPTION | FORMAT | | Columns (1-80) | | | +--------------------+------------------------------------------+------------+ | FORMAT VERSION | - Format version | A14,1X | | | always '' | | | | | | | DESCRIPTION LABEL | - Description of the type of file and | | | File Type: | its source files. The max 46-characters| '' characters. | | | REL=Relative | This label may be less than 46 chars. | | | Source File(s): | Source files are separated by commas. | 1X,'SRC:', | | (comma delimited) | When ant_info.003 files are used as a | A32,'>' | | | source, they are listed with their | | | | creation date: ant_info.YY/MM/DD . | | | | | | | FILE CREATOR, | - File creator initials (or agency) | 1X,'<',A3 | | CREATION DATE, | - Date created | | | # OF ANTENNAS | YY/MM/DD | | | | YY - 2 digit year | '-',I2 | | | MM - 2 digit month | '/',I2 | | | DD - 2 digit day-of-month | '/',I2 | | | - Total number of calibrations in file | '=',I3,'>' | +--------------------+------------------------------------------+------------+ 3.2 FORMAT FOR THE STANDARD 11-LINE HEADER The 11-lines of the standard header always include two blank lines. The header example below can be used when building an ant_info file. Lines 2 through 11 can be used verbatim since they contain only format comments. The 11-line header is that portion between the dashed lines shown below. The numbers above and below the dashed lines are column numbers. 11111111112222222222333333333344444444445555555555666666666677777777778 12345678901234567890123456789012345678901234567890123456789012345678901234567890 -------------------------------------------------------------------------------- ANTENNA ID + RADOME DESCRIPTION DATA SOURCE (# OF TESTS) YR/MO/DY |AVE = # in average [north] [ east] [ up ] | L1 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L1 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) [north] [ east] [ up ] | L2 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L2 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) -------------------------------------------------------------------------------- 11111111112222222222333333333344444444445555555555666666666677777777778 12345678901234567890123456789012345678901234567890123456789012345678901234567890 3.3 FORMAT OF INDIVIDUAL ANTENNA CALIBRATIONS There are seven lines used for each individual antenna block. The example shown below is taken from a relative ant_info.003 file. TRM22020.00+GP NONE Geodetic L1/L2 compact +groundplane NGS ( 4) 97/10/27 -.1 -.6 74.2 .0 4.6 8.9 12.6 15.8 18.3 20.0 20.9 21.1 20.6 19.5 18.1 16.3 14.5 13.0 12.0 11.8 .0 .0 -.5 2.8 70.5 .0 .3 1.0 1.9 2.8 3.6 4.3 4.8 5.1 5.0 4.7 4.1 3.3 2.4 1.4 .5 -.1 .0 .0 +--------------------+------------------------------------------+------------+ | INFORMATION TYPES | DESCRIPTION | FORMAT | | Columns (1-80) | | | +--------------------+------------------------------------------+------------+ |Antenna | - Antenna type | A15,1X | |Information | - radome type | A4 | | | - Description of the Antenna type | 1X,A40 | | | - Data Source e.g. Agency Abbreviation | 1X,A3,1X | | | - # of individual antennas calibrated | '(',I3,')' | | | - Date created | | | | YY/MM/DD | | | | YY - 2 digit year | 1X,I2 | | | MM - 2 digit month | '/',I2 | | | DD - 2 digit day-of-month | '/',I2 | +--------------------+------------------------------------------+------------+ |NORTH EAST UP | L1 Eccentricities of the mean antenna | 3F10.1 | | | phase center relative to the antenna | | | | reference point (ARP). North, East, and | | | | Up component (in millimeters). | | +--------------------+------------------------------------------+------------+ |L1 Elevation | L1 Phase pattern values in millimeters | 10F6.1 | |dependent pattern | from 90 to 45 degrees elevation angle | | | | with an increment of -5 degrees. | | | | L1 Phase pattern in millimeters from | 9F6.1 | | | 40 to 0 degrees elevation angle with an | | | | increment of -5 degrees. | | +--------------------+------------------------------------------+------------+ |NORTH EAST UP | L2 Eccentricities of the mean antenna | 3F10.1 | | | phase center relative to the antenna | | | | reference point (ARP). North, East, and | | | | Up component (in millimeters). | | +--------------------+------------------------------------------+------------+ |L2 Elevation | L2 Phase pattern values in millimeters | 10F6.1 | |dependent pattern | from 90 to 45 degrees elevation angle | | | | with an increment of -5 degrees. | | | | L2 Phase pattern in millimeters from | 9F6.1 | | | 40 to 0 degrees elevation angle with an | | | | increment of -5 degrees. | | +--------------------+------------------------------------------+------------+ 4.0 EXAMPLES The examples below show three very abbreviated ant_info files, each with five antennas rather than the full set of over 300. Note that although the ant_info.003 format was introduced in 1999, the files themselves use antenna calibration data going back to 1997; such calibration data was also used in earlier antenna file formats. 4.1 EXAMPLE RELATIVE ANT_INFO.003 FILE ANTENNA ID DESCRIPTION DATA SOURCE (# OF TESTS) YR/MO/DY |AVE = # in average [north] [ east] [ up ] | L1 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L1 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) [north] [ east] [ up ] | L2 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L2 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) NONE NONE NGS ( 0) 99/10/04 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 AERAT2775_43 NONE Choke Ring Geodetic L1/L2 NGS ( 3) 01/05/09 2.3 -.6 88.3 .0 .1 .6 1.3 2.0 2.7 3.4 3.8 4.1 4.2 4.0 3.7 3.2 2.6 2.1 1.6 1.3 .0 .0 -.2 .2 94.1 .0 -.7 -1.0 -1.2 -1.3 -1.3 -1.3 -1.4 -1.4 -1.6 -1.7 -1.7 -1.7 -1.4 -.8 .3 1.8 .0 .0 ASH700829.3 SNOW Geodetic III 'Whopper' (USCG) +radome NGS ( 7) 97/10/27 -1.2 -.8 87.7 .0 1.6 3.5 5.5 7.5 9.3 10.7 11.7 12.2 12.1 11.6 10.6 9.2 7.5 5.6 3.7 2.0 .0 .0 .9 -1.6 59.8 .0 -2.3 -3.9 -5.0 -5.7 -6.2 -6.5 -6.6 -6.7 -6.7 -6.6 -6.3 -5.8 -5.0 -3.7 -1.7 1.0 .0 .0 AOAD/M_T NONE Dorne Margolin T, chokerings TurboRogue NGS ( 0) 97/10/27 0.0 0.0 110.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 128.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 TRM22020.00+GP NONE Geodetic L1/L2 compact +groundplane NGS ( 4) 97/10/27 -.1 -.6 74.2 .0 4.6 8.9 12.6 15.8 18.3 20.0 20.9 21.1 20.6 19.5 18.1 16.3 14.5 13.0 12.0 11.8 .0 .0 -.5 2.8 70.5 .0 .3 1.0 1.9 2.8 3.6 4.3 4.8 5.1 5.0 4.7 4.1 3.3 2.4 1.4 .5 -.1 .0 .0 4.2 EXAMPLE ABSOLUTE NGS14.003 FILE ANTENNA ID + RADOME DESCRIPTION DATA SOURCE (# OF TESTS) YR/MO/DY |AVE = # in average [north] [ east] [ up ] | L1 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L1 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) [north] [ east] [ up ] | L2 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L2 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) NONE NONE NGS ( 0) 99/10/04 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 AERAT2775_43 NONE Aeroantenna L1/L2 GPS Survey Antenna NGS ( 3) 11/03/25 2.88 -0.97 70.15 0.00 -0.13 -0.30 -0.63 -1.22 -1.92 -2.56 -3.29 -3.77 -4.01 -4.06 -3.69 -3.03 -1.95 -0.18 2.29 5.77 0.0 0.0 -0.28 -0.39 86.45 0.00 -0.83 -1.51 -2.28 -3.09 -3.88 -4.69 -5.57 -6.21 -6.81 -6.95 -6.56 -5.73 -4.23 -2.13 0.79 4.55 0.0 0.0 ASH700829.3 SNOW Geodetic III "Whopper" Model 700829.3 NGS ( 7) 11/03/25 -0.62 -1.17 69.55 0.00 1.37 2.60 3.57 4.28 4.68 4.74 4.61 4.33 3.89 3.54 3.21 2.97 2.95 3.32 4.39 6.47 0.0 0.0 0.82 -2.19 52.15 0.00 -2.43 -4.41 -6.08 -7.49 -8.78 -9.89-10.77-11.51-11.91 -11.85-11.16 -9.83 -7.83 -5.03 -1.21 3.75 0.0 0.0 AOAD/M_T NONE Dorne Margolin with chokerings IGS ( 2) 11/03/25 0.58 -0.37 91.85 0.00 -0.23 -0.90 -1.93 -3.22 -4.62 -5.96 -7.09 -7.87 -8.21 -8.06 -7.39 -6.23 -4.55 -2.28 0.69 4.47 9.08 14.23 -0.08 -0.59 120.35 0.00 -0.13 -0.51 -1.08 -1.79 -2.58 -3.39 -4.17 -4.81 -5.21 -5.25 -4.86 -4.03 -2.83 -1.33 0.49 2.75 5.68 9.44 TRM22020.00+GP NONE Geod. L1/L2 compact, with groundplane IGS ( 27) 11/03/25 1.25 -1.44 70.58 0.00 0.64 2.34 4.51 6.42 7.47 7.38 6.24 4.44 2.45 0.65 -0.82 -1.99 -2.90 -3.45 -3.26 -1.75 1.50 6.44 -1.49 1.43 62.97 0.00 0.06 0.20 0.32 0.29 0.02 -0.49 -1.15 -1.79 -2.26 -2.47 -2.43 -2.24 -1.98 -1.62 -0.94 0.50 3.16 7.26 4.3 EXAMPLE OLDER RELATIVE ANT_INFO.003 FILE There are older ant_info.003 files, made prior to May 2011, which will have no description label in columns 16 through 61 on the first line. When this is the case, the missing label should be interpreted as: where the YY/MM/DD is the creation date in columns 68 through 75. Also, in older ant_info.003 files the radome codes are often blank. Whenever the 4-char radome code is " ", this should be interpreted as "NONE". ANTENNA ID DESCRIPTION DATA SOURCE (# OF TESTS) YR/MO/DY |AVE = # in average [north] [ east] [ up ] | L1 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L1 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) [north] [ east] [ up ] | L2 Offset (mm) [90] [85] [80] [75] [70] [65] [60] [55] [50] [45] | L2 Phase at [40] [35] [30] [25] [20] [15] [10] [ 5] [ 0] | Elevation (mm) NONE NONE NGS ( 0) 99/10/04 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 AERAT2775_43 Choke Ring Geodetic L1/L2 NGS ( 3) 01/05/09 2.3 -.6 88.3 .0 .1 .6 1.3 2.0 2.7 3.4 3.8 4.1 4.2 4.0 3.7 3.2 2.6 2.1 1.6 1.3 .0 .0 -.2 .2 94.1 .0 -.7 -1.0 -1.2 -1.3 -1.3 -1.3 -1.4 -1.4 -1.6 -1.7 -1.7 -1.7 -1.4 -.8 .3 1.8 .0 .0 ASH700829.3 SNOW Geodetic III 'Whopper' (USCG) +radome NGS ( 7) 97/10/27 -1.2 -.8 87.7 .0 1.6 3.5 5.5 7.5 9.3 10.7 11.7 12.2 12.1 11.6 10.6 9.2 7.5 5.6 3.7 2.0 .0 .0 .9 -1.6 59.8 .0 -2.3 -3.9 -5.0 -5.7 -6.2 -6.5 -6.6 -6.7 -6.7 -6.6 -6.3 -5.8 -5.0 -3.7 -1.7 1.0 .0 .0 AOAD/M_T Dorne Margolin T, chokerings TurboRogue NGS ( 0) 97/10/27 0.0 0.0 110.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 128.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 TRM22020.00+GP Geodetic L1/L2 compact +groundplane NGS ( 4) 97/10/27 -.1 -.6 74.2 .0 4.6 8.9 12.6 15.8 18.3 20.0 20.9 21.1 20.6 19.5 18.1 16.3 14.5 13.0 12.0 11.8 .0 .0 -.5 2.8 70.5 .0 .3 1.0 1.9 2.8 3.6 4.3 4.8 5.1 5.0 4.7 4.1 3.3 2.4 1.4 .5 -.1 .0 .0