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13th International Laser Ranging
Workshop
"Toward Millimeter Accuracy"
Submitted
Abstracts
System Calibration (I. Prochazka and U. Schreiber)
| Title | Primary Author |
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| Portable Calibration Standard Capabilities | Ivan Prochazka |
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Czech Technical University Karel Hamal The Portable Calibration Standard (PCS) has been operated at nine different satellite laser ranging sites within the last five years. The first generation Standard based on the Stanford Research SR620 time interval counter did verify the concept of the Standard, the Portable-Pico Event Timer (P-PET) based version did demonstrate the capability to identify numerous range and time bias sources on the millimeter level. The results from the calibration missions will be presented. Oral paper; received August 22, 2002 |
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| Use of free surface of liquids in interferometric methods: application to split corner cubes | Jean-Louis Oneto |
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OCA/CERGA Jean Gaignebet A method to adjust and control split corner cubes down to a sub arc-second accuracy is presented, based on an interferometric setup involving use of free-surface of liquids. Such a split corner cube can then be used as a convenient method to adjust parallelism of emission/reception optical axis in laser ranging stations. Oral paper; received August 22, 2002 |
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| Portable Calibration Standard Mission Review | Karel Hamal |
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Czech Technical University Ivan Prochazka To examine the millimeter SLR capability the Portable Calibration Standard (PCS) based on P-PET, HP Time and Frequency GPS Receiver, meteo sensor and ground calibration targets was installed at different sites (Graz ’97 and ‘99, WLRS ‘98, Zimmerwald ‘98, Herstmonceux ‘98, TIGO ‘99, Shanghai ‘01). The ranging jitter (ground and satellite targets) ranges between 1-20 mm. Oral paper; received August 22, 2002 |
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| High accuracy short range laser rangefinder for system calibration and installation | Peter Sperber |
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Deggendorf University of Applied Sciences T. Stautmeister, J. Kölbl, H. Tauscher, J. Kellner Modern Satellite Laser Ranging Systems are actually able to deliver data with an inherent accuracy of 1 mm and better. Therefore, the position of these systems relative to geodetic markers and the calibration value to the intersection of axis has to be monitored continuously with better than 100 micrometer accuracy. The Deggendorf University of Applied Sciences in cooperation with Micro-Optronic GmbH has developed a rugged handheld rangefinder with a calibrated single measurement accuracy of better than 50 micrometer in high accuracy mode. The system guarantees this accuracy up to 5 m distance to any surface and up to 100 m distance to reflectors. Due to the new patent pending operating scheme the instrument delivers up to 100 measurements per second with 30 micrometer single shot stability. With intelligent internal calibration procedures this stability transfers into a extremely high absolute accuracy. In this paper we will present the operational scheme an first ranging results. The instrument will be available to the public in spring 2003. Oral paper; received August 23, 2002 |
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| An experimental common detector, coaxial Cassegrain laser telescope and its calibration | Matti Paunonen |
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Finnish Geodetic Institute Metsahovi SLR (7806) has used a common detector (PMT) and axially shifted laser beam in a 1-m Cassegrain laser telescope since 1998. As an additional test of the calibration constant the laser beam was positioned in the blind area of the telescope. The beam was transmitted through the secondary mirror axially, using an added 62-mm diameter collimating lens. The return signal from the calibration target, a prism at a distance of 320 m, followed the same path, and continued through the laser insertion mirror to the receiving channel. The start pulse was derived from the laser oscillator, before amplifiers. The delay difference from the regular measurement could be calculated precisely from the telescope geometry. The measurement showed a rms precision of 75 ps, and the calculated calibration constants agreed well within 50 ps. This scheme would be good also for a close target, because no parallactic effects are encountered. Oral paper; received August 23, 2002 |
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| Local Surveys at Goddard | Jim Long |
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Honeywell Technology Solutions, Inc. Nagendra Paudel This poster will provide a summary of the on-going local survey projects and recent results at the Goddard Geophysical and Astronomic Observatory (GGAO). The GGAO fills an important role for the realization of the International Terrestrial Reference Frame (ITRF) because of the four collocated geodetic space techniques, SLR, VLBI, GPS, and DORIS. Precise local survey ties, which determine the relative positions of the collocated space techniques, are critical to the combination of the different techniques in the ITRF solutions. Also the local survey projects at GGAO provide the accurate relative positions of the SLR ground calibration targets necessary to establish the operational calibration ranges used by the SLR system, MOBLAS 7. The poster will include a description of the GGAO survey control network, a description of the survey equipment and methods utilized, and a description of the survey data results and analysis. Poster paper; received September 09, 2002 |
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| Local Survey Relationships to System Calibration and Bias Identification | Paul Stevens |
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Honeywell Technology Solutions, Inc. Jim Long, Nagendra Paudel For SLR systems that perform system calibrations to external ground targets, it is important to have multiple targets that vary in range and azimuth to help in the identification of system bias, target or station movement. The periodic ranging to multiple terrestrial targets, and the subsequent analysis, can serve as an initial diagnostic tool in detecting potential ground target movement. Local surveys and system ties are also necessary to help monitor the local site stability between system and terrestrial targets. Inaccuracies or movements in survey values to primary calibration targets above tolerances will contaminate calibration data leading to biased satellite data. Movements in ground targets have occurred as a result of apparent subsurface events affecting the geological stability and characteristics on which these piers are supported. Movements of have been isolated within short periods of time; thus rendering regular monitoring of ground target stability essential to operational activities. This poster will describe the importance of multiple terrestrial ground targets; the value of regular ground testing to multiple ground targets, and the monitoring of calibration data in the detection of potential target movements. It will also present evidence supporting the importance of performing regular survey to maintain accuracy of system ties. To help describe the potential problems associated with this issue, this poster will provide a summary of recent events at the Goddard Geophysical and Astronomical Observatory (GGAO) and present recommendations for ensuring accurate ground calibration ranges and preventing the loss of satellite range data due to calibration bias. Poster paper; received September 17, 2002 |
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Last Updated:
September 17, 2002
