COMBINATION OF ANTENNA PHASE CENTER OFFSETS AND VARIATIONS ---------------------------------------------------------- Antenna calibration set: IGS_01 Date: 30-JUN-96 prepared by Markus Rothacher Gerry Mader Astronomical Institute US Department of Commerce, NOAA University of Berne Geosciences Laboratory, N/OES13 Sidlerstrasse 5 1305 East-West Highway, Sta.8110 CH-3012 Berne Silver Spring, Maryland 20910 Switzerland USA rothacher@aiub.unibe.ch gerry@mozart.grdl.noaa.gov 1. Introduction ------------ This set of antenna phase center offsets and elevation-dependent phase center corrections, named IGS_01, has been obtained by combining phase center variations estimated from GPS calibration campaigns and chamber measurements. This set is a test set to be sanctioned by the IGS and to be used by the global IGS Analysis Centers as well as by the RNAAC (Regional Network Associated Analysis Centers) after successful tests. The designation IGS_01 should be given in the SINEX file (in the SITE/GPS_PHASE_CENTER block) for solutions produced using this set of antenna phase center calibration values. The combination of the individual phase center offsets and patterns was performed in two steps: 1) First the phase center OFFSETS were combined. 2) The resulting mean phase center offsets were then used as reference offsets for the combination of the ELEVATION-DEPENDENT PATTERNS. To obtain the best possible results when processing GPS data of a mixture of different antennas the phase center offsets AND the elevation-dependent variations should be applied. If you do not have any possibility to correct for elevation-dependent variations you should at least use the mean offsets given. They were computed using an elevation cut-off angle of 15 degrees and are therefore best suited for this cut-off angle. The user should be aware of the fact, however, that large errors (up to 10 cm) in height may result for some antenna combinations if troposphere zenith delay parameters are estimated and only the mean offsets are applied (neglecting the elevation-dependent corrections) ! To correct for the offsets you have to ADD the offset value to the antenna height and the horizontal offsets. To apply the elevation-dependent calibration values you have to interpolate within the 5-degree elevation table to obtain the correction for the elevation angle of the satellite. The correction has to be ADDED to the computed distance between satellite and receiver antenna or SUBTRACTED from the observations. The correction for a linear combination of the original L1/L2 observations is computed as the linear combination of the phase center corrections for L1 and L2. The following files with antenna phase center information will soon be available at the IGS Central Bureau Information System (IGSCB@IGSCB.JPL.NASA.GOV): IGS_01.TXT This file IGS_01.PCV Phase center offsets and elevation-dependent corrections IGS_01.RAW Raw individual sets of elevation-dependent corrections used in the combination IGS_01_S.PS Summary plots of the combined phase center variations and the individual sets included in the combination (5 pages) IGS_01_I.PS Individual plots of the phase center variations for each antenna and frequency (36 pages) RCVR_ANT.TAB Table of the IGS receiver and antenna name conventions ANTENNA.GRA Dimensions of the antennas (drawings) Pictures of most antenna types may be found at NGS on the following WWW page: http://www.grdl.noaa.gov/GPS/PROJECTS/ANTCAL/antcal.html . There are still some remaining issues to straighten out. Especially the naming and identification of the Ashtech antenna types is not yet completely solved (e.g. ASHTECH 700228 with NOTCHES, RINGS, ...) and some antenna dimension and drawings are still missing. Note that the antenna named ASHTECH 700936 RADOM, that was calibrated by NGS and AIUB (see IGS_01.PCV), is probably identical with the antenna DORNE MARGOLIN ASH (see ANTENNA.GRA), but has a radom on it. We think that the set now available is an important step forward despite of the shortcomings mentioned above and we encourage everybody to start testing and using this set. Please contact us if you have any problems or questions or if you dispose of additional information that should be included in the combination procedure or in the various data files. 2. The Calibration Sets Contributing to the Combination ---------------------------------------------------- The sets contributing to the combination described below were obtained from the following sources: a) The latest set from NGS (Gerry Mader) dated June 11, 1996, available on the WWW, obtained from GPS calibration campaigns. b) The chamber measurements performed by UNAVCO, called Ball chamber results. c) Sets obtained from a few antenna calibration campaigns processed at the AIUB: - THUN94: Thun, Switzerland, organized by the Federal Office of Topography, Berne (Adrian Wiget) - GRAZ94: Data collected in Graz, Austria, by the Institute for Space Research (Peter Pesec) - HEER94: Data collected in Heerbrugg, Switzerland, by Leica - WETT95: Wettzell, Germany, organized by the Institute for Applied Geodesy (Wolfgang Schlueter) - WINT95: Wettzell, Germany, organized by the Institute for Applied Geodesy (Wolfgang Schlueter) - WIEN96: Data collected in Vienna, Austria, by Institute for Theoretical Geodesy (Robert Weber) - EBRE96: Data collected in Ebre, Spain, by the Institut Cartografic de Catalunya (Carme Parareda) We would like to thank all the contributors for making these data and results available for the combination. 3. Combination of the Mean Phase Center Offsets -------------------------------------------- With the exception of the Ball chamber values all the sets of mean offsets included in the combination were computed with an elevation cut-off angle of 15 degrees. Most of the GPS-derived offset estimates refer to the Dorne Margolin T antenna, which was assumed to have mean horizontal offsets equal to zero and mean vertical offsets of 0.110 and 0.128 meters for L1 and L2, respectively. The "WEIGHTED MEAN" values for each of the antennas and each frequency given below were obtained by a weighted mean of the individual sets. The weight of each set was given by the number of antennas of the same type calibrated in the experiment or campaign. Values with an asterisk "*" were not used in the computation of the mean and the corresponding RMS error. Because the height offsets from the Ball chamber tests do not refer to an elevation cut-off of 15 degrees they were not included in the combination. Assuming that the azimuth-dependence is negligible the Ball chamber values were used in the determination of the mean horizontal offsets, however. The "mean" vertical offsets resulting from this combination were used as reference values in the combination of the elevation-dependent corrections (see next section). For the DORNE MARGOLIN R and the DORNE MARGOLIN ASH antennas no calibration values are available at present. The offsets of the DORNE MARGOLIN R have been set to the values of the DORNE MARGOLIN B antenna, those of the DORNE MARGOLIN ASH to the values of the DORNE MARGOLIN T. We hope that with time we will be able to add more and more individual sets from various sources to the lists given below. VENDOR: ALLEN OSBORNE OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** DORNE MARGOLIN T 1 0.2 -0.2 110.0* BERNE WETT95 15-JUN-96 3 a) DORNE MARGOLIN T 1 0.5 -0.4 110.0* BERNE WINT95 15-JUN-96 2 a) DORNE MARGOLIN T 1 -0.5* 0.0* 113.0* BERNE WINT95 15-JUN-96 1 b) DORNE MARGOLIN T 1 0.0* 0.0* 110.0* BERNE THUN94 15-JUN-96 1 DORNE MARGOLIN T 1 0.0* 0.0* 110.0* BERNE GRAZ94 15-JUN-96 1 DORNE MARGOLIN T 1 0.0* 0.0* 110.0* NGS (MADER) 11-JUN-96 3 DORNE MARGOLIN T 1 0.9 -0.4 100.1* BALL CHAMBER 18-OCT-95 1 ----------------------------------------------------------------------------- DORNE MARGOLIN T 1 0.4 -0.3 110.0 WEIGHTED MEAN 30-JUN-96 6/ 0 0.3 0.1 RMS ============================================================================= DORNE MARGOLIN T 1 0.0 0.0 110.0 IGS RECOMM. 30-JUN-96 c) ============================================================================= DORNE MARGOLIN T 2 0.5 -0.6 128.0* BERNE WETT95 15-JUN-96 3 a) DORNE MARGOLIN T 2 0.3 0.2 128.0* BERNE WINT95 15-JUN-96 2 a) DORNE MARGOLIN T 2 0.2* 0.4* 131.2* BERNE WINT95 15-JUN-96 1 b) DORNE MARGOLIN T 2 0.0* 0.0* 128.0* BERNE THUN94 15-JUN-96 1 DORNE MARGOLIN T 2 0.0* 0.0* 128.0* BERNE GRAZ94 15-JUN-96 1 DORNE MARGOLIN T 2 0.0* 0.0* 128.0* NGS (MADER) 11-JUN-96 3 DORNE MARGOLIN T 2 -0.4 0.6 125.7* BALL CHAMBER 18-OCT-95 1 ----------------------------------------------------------------------------- DORNE MARGOLIN T 2 0.3 -0.1 128.0 WEIGHTED MEAN 30-JUN-96 6/ 0 0.3 0.5 RMS ============================================================================= DORNE MARGOLIN T 2 0.0 0.0 128.0 IGS RECOMM. 30-JUN-96 c) ============================================================================= a) Because the antennas were rotated during the experiment horizontal offsets could be estimated from GPS data for the Dorne Margolin T antenna, normally used as reference. b) The Dorne Margolin T antenna was used with an Ashtech Z-12 receiver. c) These values are set to the manufacturer values and were in most cases used as reference values for the determination of the phase center offsets from GPS data. VENDOR: ALLEN OSBORNE OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** DORNE MARGOLIN B 1 -2.2* 1.1* 76.0 BERNE WETT95 15-JUN-96 1 a) DORNE MARGOLIN B 1 -3.3* 2.4* 75.9 BERNE WINT95 15-JUN-96 1 a) DORNE MARGOLIN B 1 0.0 0.9 73.3 BERNE GRAZ94 15-JUN-96 1 ----------------------------------------------------------------------------- DORNE MARGOLIN B 1 0.0 0.9 75.1 WEIGHTED MEAN 30-JUN-96 1/ 3 1.5 RMS ============================================================================= DORNE MARGOLIN B 1 0.0 0.0 78.0 IGS RECOMM. 30-JUN-96 b) ============================================================================= DORNE MARGOLIN B 2 -3.0* -0.5* 93.4 BERNE WETT95 15-JUN-96 1 a) DORNE MARGOLIN B 2 -3.5* 0.6* 92.8 BERNE WINT95 15-JUN-96 1 a) DORNE MARGOLIN B 2 -1.3 0.0 96.1 BERNE GRAZ94 15-JUN-96 1 ----------------------------------------------------------------------------- DORNE MARGOLIN B 2 -1.3 0.0 94.1 WEIGHTED MEAN 30-JUN-96 1/ 3 1.8 RMS ============================================================================= DORNE MARGOLIN B 2 0.0 0.0 96.0 IGS RECOMM. 30-JUN-96 b) ============================================================================= a) The two sets are not independent: the same ground truth was used in both cases. The antenna was not rotated and the horizontal ground truth is only known to within about 3 mm in this case. The horizontal offsets are therefore not used. The height estimates are ok. b) The recommended offsets have been set to the offset values already in use by the IGS to minimize changes in the global IGS solutions and because they are within the uncertainty limits of the estimated values. VENDOR: TRIMBLE OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** 4000ST L1/L2 GEOD 1 -0.3 -3.7 76.2 BERNE WETT95 15-JUN-96 2 4000ST L1/L2 GEOD 1 -0.7 -3.7 75.1 BERNE WINT95 15-JUN-96 2 4000ST L1/L2 GEOD 1 0.5 -2.8 79.7 BERNE THUN94 15-JUN-96 2 4000ST L1/L2 GEOD 1 1.4 -2.4 73.1 BERNE GRAZ94 15-JUN-96 1 4000ST L1/L2 GEOD 1 0.3 -2.3 83.5 NGS (MADER) 11-JUN-96 2 4000ST L1/L2 GEOD 1 -0.9 -2.8 58.9* BALL CHAMBER 18-OCT-95 1 a) ----------------------------------------------------------------------------- 4000ST L1/L2 GEOD 1 0.0 -3.0 78.0 WEIGHTED MEAN 30-JUN-96 10/ 9 0.7 0.6 3.8 RMS ============================================================================= 4000ST L1/L2 GEOD 1 0.0 -3.0 78.0 IGS RECOMM. 30-JUN-96 ============================================================================= 4000ST L1/L2 GEOD 2 -3.0 -1.1 74.1 BERNE WETT95 15-JUN-96 2 4000ST L1/L2 GEOD 2 -3.2 -1.6 72.6 BERNE WINT95 15-JUN-96 2 4000ST L1/L2 GEOD 2 -3.5 -2.1 74.1 BERNE THUN94 15-JUN-96 2 4000ST L1/L2 GEOD 2 -2.7 -1.6 74.4 BERNE GRAZ94 15-JUN-96 1 4000ST L1/L2 GEOD 2 -2.1 -0.1 77.0 NGS (MADER) 11-JUN-96 2 4000ST L1/L2 GEOD 2 -4.2 -1.1 67.2* BALL CHAMBER 18-OCT-95 1 a) ----------------------------------------------------------------------------- 4000ST L1/L2 GEOD 2 -3.1 -1.3 74.4 WEIGHTED MEAN 30-JUN-96 10/ 9 0.6 0.7 1.6 RMS ============================================================================= 4000ST L1/L2 GEOD 2 -3.1 -1.3 74.4 IGS RECOMM. 30-JUN-96 ============================================================================= a) Ball chamber values are not referring to a 15 degrees elevation cut-off. VENDOR: TRIMBLE OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** TR GEOD L1/L2 GP 1 1.5 -1.1 71.7 BERNE WETT95 15-JUN-96 2 TR GEOD L1/L2 GP 1 1.3 -1.7 72.7 BERNE WINT95 15-JUN-96 2 TR GEOD L1/L2 GP 1 1.8 -1.7 101.2* BERNE WINT95 15-JUN-96 2 a) TR GEOD L1/L2 GP 1 0.8* -1.4* 72.2* BERNE WIEN96 15-JUN-96 1 b) TR GEOD L1/L2 GP 1 3.1* 2.6* 73.2 BERNE THUN94 15-JUN-96 2 c) TR GEOD L1/L2 GP 1 1.6 -0.7 78.9 NGS (MADER) 11-JUN-96 4 TR GEOD L1/L2 GP 1 0.8 -1.5 53.7* BALL CHAMBER 18-OCT-95 1 d) ----------------------------------------------------------------------------- TR GEOD L1/L2 GP 1 1.5 -1.2 75.1 WEIGHTED MEAN 30-JUN-96 11/10 0.3 0.5 3.3 RMS ============================================================================= TR GEOD L1/L2 GP 1 1.5 -1.2 75.1 IGS RECOMM. 30-JUN-96 ============================================================================= TR GEOD L1/L2 GP 2 -1.7 1.6 68.2 BERNE WETT95 15-JUN-96 2 TR GEOD L1/L2 GP 2 -1.7 1.2 68.3 BERNE WINT95 15-JUN-96 2 TR GEOD L1/L2 GP 2 -1.6 0.6 97.8* BERNE WINT95 15-JUN-96 2 a) TR GEOD L1/L2 GP 2 -1.5* 1.4* 68.2* BERNE WIEN96 15-JUN-96 1 b) TR GEOD L1/L2 GP 2 0.8* -2.5* 65.8 BERNE THUN94 15-JUN-96 2 c) TR GEOD L1/L2 GP 2 0.0 2.4 71.8 NGS (MADER) 11-JUN-96 4 TR GEOD L1/L2 GP 2 -2.1 1.8 61.3* BALL CHAMBER 18-OCT-95 1 d) ----------------------------------------------------------------------------- TR GEOD L1/L2 GP 2 -1.1 1.7 69.2 WEIGHTED MEAN 30-JUN-96 11/10 0.9 0.7 2.4 RMS ============================================================================= TR GEOD L1/L2 GP 2 -1.1 1.7 69.2 IGS RECOMM. 30-JUN-96 ============================================================================= a) Still a problem with the height to be solved. b) The offsets of this set were not adjusted, but used as reference for the WIEN96 Campaign. These offset values were not used in the combination. c) The two antennas used in the THUN94 campaign are very consistent but seem to have a different orientation of the ground plane (?) compared to Gerry's results. They are not used in the combination. d) Ball chamber values are not referring to a 15 degrees elevation cut-off. VENDOR: TRIMBLE OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** TR GEOD L1/L2 W/O GP 1 3.3 2.0 87.6 BERNE THUN94 15-JUN-96 2 TR GEOD L1/L2 W/O GP 1 2.9 -0.3 85.5 NGS (MADER) 11-JUN-96 2 ----------------------------------------------------------------------------- TR GEOD L1/L2 W/O GP 1 3.1 0.9 86.6 WEIGHTED MEAN 30-JUN-96 4/ 4 0.2 1.3 1.2 RMS ============================================================================= TR GEOD L1/L2 W/O GP 1 3.1 0.9 86.6 IGS RECOMM. 30-JUN-96 ============================================================================= TR GEOD L1/L2 W/O GP 2 1.9 -2.4 80.0 BERNE THUN94 15-JUN-96 2 TR GEOD L1/L2 W/O GP 2 0.4 2.2 83.3 NGS (MADER) 11-JUN-96 2 ----------------------------------------------------------------------------- TR GEOD L1/L2 W/O GP 2 1.2 -0.1 81.7 WEIGHTED MEAN 30-JUN-96 4/ 4 0.9 2.7 1.9 RMS ============================================================================= TR GEOD L1/L2 W/O GP 2 1.2 -0.1 81.7 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700228 1 -1.8 -1.4 80.6 BERNE WETT95 15-JUN-96 2 ASHTECH 700228 1 5.0 3.6 78.5 BERNE THUN94 15-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700228 1 0.5 0.3 79.9 WEIGHTED MEAN 30-JUN-96 3/ 3 3.9 2.9 1.2 RMS ============================================================================= ASHTECH 700228 1 0.5 0.3 79.9 IGS RECOMM. 30-JUN-96 ============================================================================= ASHTECH 700228 2 -3.7 2.2 79.8 BERNE WETT95 15-JUN-96 2 ASHTECH 700228 2 3.7 -2.0 78.0 BERNE THUN94 15-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700228 2 -1.2 0.8 79.2 WEIGHTED MEAN 30-JUN-96 3/ 3 4.3 2.4 1.0 RMS ============================================================================= ASHTECH 700228 2 -1.2 0.8 79.2 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700228 NOTCH 1 -0.2 -1.0 80.8 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700228 NOTCH 1 -0.2 -1.0 80.8 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= ASHTECH 700228 NOTCH 1 -0.2 -1.0 80.8 IGS RECOMM. 30-JUN-96 ============================================================================= ASHTECH 700228 NOTCH 2 -1.9 3.8 77.8 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700228 NOTCH 2 -1.9 3.8 77.8 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= ASHTECH 700228 NOTCH 2 -1.9 3.8 77.8 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700228 RINGS 1 -2.2 0.0 86.0 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700228 RINGS 1 -2.2 0.0 86.0 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= ASHTECH 700228 RINGS 1 -2.2 0.0 86.0 IGS RECOMM. 30-JUN-96 ============================================================================= ASHTECH 700228 RINGS 2 -3.7 3.2 78.2 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700228 RINGS 2 -3.7 3.2 78.2 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= ASHTECH 700228 RINGS 2 -3.7 3.2 78.2 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700578 1 -1.2 -1.0 79.5 BERNE THUN94 15-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700578 1 -1.2 -1.0 79.5 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= ASHTECH 700578 1 -1.2 -1.0 79.5 IGS RECOMM. 30-JUN-96 ============================================================================= ASHTECH 700578 2 -4.6 1.6 78.3 BERNE THUN94 15-JUN-96 1 ----------------------------------------------------------------------------- ASHTECH 700578 2 -4.6 1.6 78.3 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= ASHTECH 700578 2 -4.6 1.6 78.3 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700718 1 3.4 1.0 87.3 NGS (MADER) 11-JUN-96 3 ----------------------------------------------------------------------------- ASHTECH 700718 1 3.4 1.0 87.3 WEIGHTED MEAN 30-JUN-96 3/ 3 RMS ============================================================================= ASHTECH 700718 1 3.4 1.0 87.3 IGS RECOMM. 30-JUN-96 ============================================================================= ASHTECH 700718 2 3.1 -1.3 63.4 NGS (MADER) 11-JUN-96 3 ----------------------------------------------------------------------------- ASHTECH 700718 2 3.1 -1.3 63.4 WEIGHTED MEAN 30-JUN-96 3/ 3 RMS ============================================================================= ASHTECH 700718 2 3.1 -1.3 63.4 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700829 1 -0.7 0.4 92.0 NGS (MADER) 11-JUN-96 5 ----------------------------------------------------------------------------- ASHTECH 700829 1 -0.7 0.4 92.0 WEIGHTED MEAN 11-JUN-96 5/ 5 RMS ============================================================================= ASHTECH 700829 1 -0.7 0.4 92.0 IGS RECOMM. 11-JUN-96 ============================================================================= ASHTECH 700829 2 -0.1 -0.8 60.1 NGS (MADER) 11-JUN-96 5 ----------------------------------------------------------------------------- ASHTECH 700829 2 -0.1 -0.8 60.1 WEIGHTED MEAN 11-JUN-96 5/ 5 RMS ============================================================================= ASHTECH 700829 2 -0.1 -0.8 60.1 IGS RECOMM. 11-JUN-96 ============================================================================= VENDOR: ASHTECH OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** ASHTECH 700936 RADOM 1 -0.1 -0.2 111.4 BERNE WINT95 15-JUN-96 1 ASHTECH 700936 RADOM 1 0.3 0.1 108.0 NGS (MADER) 11-JUN-96 2 ASHTECH 700936 RADOM 1 0.3 0.1 99.5* BALL CHAMBER 18-OCT-95 1 a) ----------------------------------------------------------------------------- ASHTECH 700936 RADOM 1 0.2 0.0 109.1 WEIGHTED MEAN 30-JUN-96 4/ 3 0.2 0.2 2.0 RMS ============================================================================= ASHTECH 700936 RADOM 1 0.0 0.0 110.0 IGS RECOMM. 30-JUN-96 b) ============================================================================= ASHTECH 700936 RADOM 2 0.5 0.3 128.6 BERNE WINT95 15-JUN-96 1 ASHTECH 700936 RADOM 2 0.6 1.7 128.2 NGS (MADER) 11-JUN-96 2 ASHTECH 700936 RADOM 2 0.0 0.2 120.3* BALL CHAMBER 18-OCT-95 1 a) ----------------------------------------------------------------------------- ASHTECH 700936 RADOM 2 0.4 1.0 128.3 WEIGHTED MEAN 30-JUN-96 4/ 3 0.3 0.8 0.2 RMS ============================================================================= ASHTECH 700936 RADOM 2 0.0 0.0 128.0 IGS RECOMM. 30-JUN-96 b) ============================================================================= a) Ball chamber values are not referring to a 15 degrees elevation cut-off. b) Recommended offsets are set to the values of the DORNE MARGOLIN T antenna, which has exactly the same antenna design (with the exception of the radom). VENDOR: LEICA OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** INTERNAL 1 2.1 -0.3 116.6 BERNE WETT95 15-JUN-96 2 a) INTERNAL 1 4.3 -0.8 109.6 BERNE WIEN96 15-JUN-96 1 a) INTERNAL 1 4.0 0.7 109.5 BERNE WIEN96 15-JUN-96 1 b) ----------------------------------------------------------------------------- INTERNAL 1 3.1 -0.2 113.1 WEIGHTED MEAN 30-JUN-96 4/ 4 1.2 0.6 4.1 RMS ============================================================================= INTERNAL 1 3.1 -0.2 113.1 IGS RECOMM. 30-JUN-96 ============================================================================= INTERNAL 2 0.5 -3.5 118.2 BERNE WETT95 15-JUN-96 2 a) INTERNAL 2 2.7 -4.4 116.3 BERNE WIEN96 15-JUN-96 1 a) INTERNAL 2 1.3 -2.7 116.1 BERNE WIEN96 15-JUN-96 1 b) ----------------------------------------------------------------------------- INTERNAL 2 1.3 -3.5 117.2 WEIGHTED MEAN 30-JUN-96 4/ 4 1.0 0.7 1.2 RMS ============================================================================= INTERNAL 2 1.3 -3.5 117.2 IGS RECOMM. 30-JUN-96 ============================================================================= a) An SR299 receiver was used. b) An SR399 receiver was used. VENDOR: LEICA OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** EXTERNAL WITHOUT GP 1 2.3 -0.2 69.4 BERNE THUN94 15-JUN-96 1 a) EXTERNAL WITHOUT GP 1 -1.6 -1.0 69.2 BERNE HEER94 15-JUN-96 1 a) EXTERNAL WITHOUT GP 1 -0.2 0.1 66.9 BERNE WIEN96 15-JUN-96 1 b) EXTERNAL WITHOUT GP 1 1.5 1.4 82.3* BALL CHAMBER 18-OCT-95 1 c) ----------------------------------------------------------------------------- EXTERNAL WITHOUT GP 1 0.5 0.1 68.5 WEIGHTED MEAN 30-JUN-96 4/ 3 1.7 1.0 1.4 RMS ============================================================================= EXTERNAL WITHOUT GP 1 0.5 0.1 68.5 IGS RECOMM. 30-JUN-96 ============================================================================= EXTERNAL WITHOUT GP 2 0.4 -2.5 53.7 BERNE THUN94 15-JUN-96 1 a) EXTERNAL WITHOUT GP 2 -1.7 -1.5 49.8 BERNE HEER94 15-JUN-96 1 a) EXTERNAL WITHOUT GP 2 -1.0 -0.9 52.8 BERNE WIEN96 15-JUN-96 1 b) EXTERNAL WITHOUT GP 2 3.4 -2.7 73.4* BALL CHAMBER 18-OCT-95 1 c) ----------------------------------------------------------------------------- EXTERNAL WITHOUT GP 2 0.3 -1.9 52.1 WEIGHTED MEAN 30-JUN-96 4/ 3 2.3 0.8 2.0 RMS ============================================================================= EXTERNAL WITHOUT GP 2 0.3 -1.9 52.1 IGS RECOMM. 30-JUN-96 ============================================================================= a) An SR299 receiver was used. b) An SR399 receiver was used. c) Ball chamber values are not referring to a 15 degrees elevation cut-off. VENDOR: LEICA OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** EXTERNAL WITH GP 1 4.8 1.9 49.2 BERNE THUN94 15-JUN-96 1 ----------------------------------------------------------------------------- EXTERNAL WITH GP 1 4.8 1.9 49.2 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= EXTERNAL WITH GP 1 4.8 1.9 49.2 IGS RECOMM. 30-JUN-96 ============================================================================= EXTERNAL WITH GP 2 3.4 -5.2 41.8 BERNE THUN94 15-JUN-96 1 ----------------------------------------------------------------------------- EXTERNAL WITH GP 2 3.4 -5.2 41.8 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= EXTERNAL WITH GP 2 3.4 -5.2 41.8 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: MACROMETER OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** MACROMETER X-DIPOLE 1 2.2 -8.2 163.1 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- MACROMETER X-DIPOLE 1 2.2 -8.2 163.1 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= MACROMETER X-DIPOLE 1 2.2 -8.2 163.1 IGS RECOMM. 30-JUN-96 ============================================================================= MACROMETER X-DIPOLE 2 4.3 2.0 91.3 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- MACROMETER X-DIPOLE 2 4.3 2.0 91.3 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= MACROMETER X-DIPOLE 2 4.3 2.0 91.3 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: TOPCON OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** TOPCON 72110 1 -3.9 7.3 147.1 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- TOPCON 72110 1 -3.9 7.3 147.1 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= TOPCON 72110 1 -3.9 7.3 147.1 IGS RECOMM. 30-JUN-96 ============================================================================= TOPCON 72110 2 -4.4 6.5 127.8 NGS (MADER) 11-JUN-96 1 ----------------------------------------------------------------------------- TOPCON 72110 2 -4.4 6.5 127.8 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= TOPCON 72110 2 -4.4 6.5 127.8 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: GEOTRACER OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** GEOTRACER 2200 1 0.8 -1.7 95.4 BERNE WIEN96 15-JUN-96 1 ----------------------------------------------------------------------------- GEOTRACER 2200 1 0.8 -1.7 95.4 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= GEOTRACER 2200 1 0.8 -1.7 95.4 IGS RECOMM. 30-JUN-96 ============================================================================= GEOTRACER 2200 2 0.4 0.1 73.9 BERNE WIEN96 15-JUN-96 1 ----------------------------------------------------------------------------- GEOTRACER 2200 2 0.4 0.1 73.9 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= GEOTRACER 2200 2 0.4 0.1 73.9 IGS RECOMM. 30-JUN-96 ============================================================================= VENDOR: OFFSETS (M) ANTENNA TYPE FRQ N E U SOURCE DATE #ANT ******************** *** **.* **.* ***.* ************ ********* ***** M-PULSE L1/L2 SURVEY 1 0.0 0.0 79.6 BERNE EBRE96 15-JUN-96 1 a) ----------------------------------------------------------------------------- M-PULSE L1/L2 SURVEY 1 0.0 0.0 79.6 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= M-PULSE L1/L2 SURVEY 1 0.0 0.0 79.6 IGS RECOMM. 30-JUN-96 ============================================================================= M-PULSE L1/L2 SURVEY 2 0.0 0.0 93.2 BERNE EBRE96 15-JUN-96 1 a) ----------------------------------------------------------------------------- M-PULSE L1/L2 SURVEY 2 0.0 0.0 93.2 WEIGHTED MEAN 30-JUN-96 1/ 1 RMS ============================================================================= M-PULSE L1/L2 SURVEY 2 0.0 0.0 93.2 IGS RECOMM. 30-JUN-96 ============================================================================= a) Horizontal offsets not known. 4. Combination of Elevation-Dependent Phase Center Variations ---------------------------------------------------------- At the AIUB a special program was written to combine the elevation- dependent antenna phase center corrections from various sources into one consistent set of values. Input to the program are N sets of elevation- dependent corrections at 5-degree intervals together with the corresponding height offsets and the number of antennas contributing to this set. The table of all the sets at our disposal for the combination is given in the file IGS_01.RAW. The program estimates a) the 5-degree values of the combined phase center correction, b) an arbitrary, constant phase offset (constant over all elevations) for each set and, c) optionally, height offsets may be determined for individual sets showing a height problem. The combination was performed by first converting all the individual sets to the mean vertical offsets obtained from the combination outlined above in section 3. In a first attempt all the available sets of elevation-dependent corrections were then included in the combination. Sets that showed large deviations were identified and a height offset was set up for these sets. If the estimation of a height offset did not help, the set was totally excluded from the combination. Plots of all the combination results are available in the files IGS_01_S.PS (summary) or IGS_01_I.PS (full) (see section 1 above). These plots contain the following information: a) The resulting elevation-dependent corrections of the combination (solid line). b) The individual sets contributing to the combination (dashed lines). c) Sets for which a height offset had to be estimated or which were not used at all (dotted lines). The source (e.g. MADER or WETT95) is in these cases preceded by one or two asterisks, respectively. d) The value of the height offset (if estimated) is given in brackets after the source name. e) The rms of the combination, the number of sets (campaigns, sources) and antennas considered in the combination are listed at the bottom of the plot. f) All the values are relative to the Dorne Margolin T antenna pattern, which was set to zero for all elevations. The combination results are promising. The Ball chamber measurements could only be included in a few cases, however. Especially the L2 sets could not be used, maybe due to a problem in the L2 Dorne Margolin T calibration which was used as a reference. The antennas for which only one contribution is available should be used with care. The elevation-dependent corrections of the combined set (compiled in the file IGS_01.PCV) were set to zero for the antennas DORNE MARGOLIN B, DORNE MARGOLIN R, DORNE MARGOLIN ASH, and ASHTECH 700936 RADOM in order to be as consistent as possible with the values used so far within the IGS and because the estimated elevation-dependent corrections are very small for these antennas. For the sake of completeness the values that were actually obtained for the DORNE MARGOLIN B and the ASHTECH 700936 RADOM are listed here: 12345678911234567892123456789312345678941234567895123456789612345678971234567898 0 0 0 0 0 0 0 0 VENDOR MODEL # DESCRIPTION (AVE) 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) ROGUE DORNE MARGOLIN B ( 3) 96/06/30 0.0 0.0 75.1 0.0 -0.2 -0.7 -1.1 -1.1 -0.8 -0.6 -0.6 -0.6 -0.4 -0.4 -0.7 -1.0 -0.9 -0.5 -0.7 -2.2 0.0 0.0 0.0 0.0 94.1 0.0 0.2 0.7 1.1 1.1 0.8 0.5 0.5 0.7 0.8 0.7 0.5 0.5 0.7 1.0 1.7 3.2 0.0 0.0 ASHTECH 700936 RADOM Mod.700936 with radom ( 4) 96/06/30 0.2 0.0 109.1 0.0 0.2 0.5 0.8 0.4 0.3 0.1 -0.1 -0.2 -0.2 -0.5 -0.4 0.1 0.5 1.0 1.4 2.1 0.0 0.0 0.4 1.0 128.3 0.0 0.3 0.6 0.8 0.9 1.2 1.2 1.2 1.1 1.0 1.1 0.8 0.5 0.5 1.0 1.4 1.0 0.0 0.0 ---------------------------------