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13th International Laser Ranging
Workshop
"Toward Millimeter Accuracy"
Submitted
Abstracts
Improved or Upgraded Systems - Poster Session (F. Pierron and Y. Fumin)
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| SLR2000: Current Test Results and Recent Developments | Jan McGarry | ||||||||||||||||||
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Jan McGarry Anthony Mallama Randall Ricklefs Anthony Mann Presented by: John Cheek Much of the SLR2000 software has been tested by using software simulators, prior to having the full SLR2000 system hardware available. This has allowed us to check the predictions, test the decision making processes, verify the inter-computer communications, make use of the remote terminal, and ensure that the entire data path works properly. Especially important to test by simulation are the decision-making processes of the Pseudo-Operator (POP). Results of this testing will be presented along with details of recent additions to the SLR2000 software capabilities and a status of the software development effort. Poster presentation; received August 16, 2002 |
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McDonald Ranging: 30 Years and Still Going |
Peter Shelus | ||||||||||||||||||
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University of Texas at Austin, Center for Space Research J. G. Ries, J. R. Wiant, R. L. Ricklefs The McDonald Laser Ranging Station (MLRS), a part of the NASA SLR network, ranges to artificial satellites and to the Moon. It is located on Mt. Fowlkes at McDonald Observatory, near Fort Davis, Texas and was built to replace the original 2.7-m lunar-only system that operated from the late 1960’s through the mid-1980's. It is built around a computer controlled 0.76-m x-y mounted Cassegrain/Coudé reflecting telescope and a short pulse, frequency doubled, 532-nm, neodymium-YAG laser with appropriate computer, electronic, meteorological, and timing interfaces. An aircraft radar allows it to operate safely with a single operator. The MLRS's epoch timing system makes all targets equivalent and crew members routinely range to many different targets, from the closest of artificial satellites to the Moon, during a single shift. Over the years it has undergone a vast number of modifications and up-grades, some minor and some major. This poster introduces MLRS personnel and describes the station as it exists now, summarizing some of the more recent changes. Poster presentation; received August 16, 2002 |
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Replacement of the LURE Telescope Controller Using COTS Components Using Commercial Off-The-Shelf Components |
Daniel O'Gara | ||||||||||||||||||
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University of Hawaii IfA W. Lindsey, M. Waterson, J. Kamibayashi The original 1972 vintage telescope controller at LURE (HOLLAS) had been replaced in March 2000 with a system designed and constructed by a sub-contractor. This system did not meet specifications, and before it could be fixed, the sub-contractor when out of business. A few weeks of research convinced us that a replacement could be designed and constructed using only commercial off-the-shelf components, and could be completed in less time and for less money by using University technicians and engineers rather than going out for bid and engaging another sub-contractor. The performance of the University designed system met or exceeded the original technical specifications. The final product could be used as designed by any telescope system that uses Inductosyn transducers, or position sensors that output A quad B signals, and is driven by DC torque motors. This paper will identify the commercial products used, the basic design of the controller, and the performance attained. Poster presentation; received August 19, 2002 |
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| System Stability Improvement of Changchun SLR System | You Zhao | ||||||||||||||||||
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Changchun Observatory of CAS Cunbo Fan, Chengzhi Liu, Xinwei Han, Jianyong Shi, Xinhua Zhang,
Haitao Zhang The paper presents some work done in Changchun station to keep and improve the SLR system stability since the system upgrade in 1997, such as the laser improvement, new encoder and servo system, and control system. These work brings and keeps Changchun SLR system to an high level in data quantity and quality during the past several years, and makes the station to be one of the standard and important stations in ILRS. Poster presentation; received August 22, 2002 |
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| Improving SALRO Accuracy | Abdallah Azzeer | ||||||||||||||||||
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Space Research Institute John Guilfoyle With the evident improved system reliability, attention is being given to the elimination of ranging system biases, to be addressed via these broad categories:
A series of site surveys will be undertaken soon to confirm invariant point coordinates in the local datum and relative positions of ground targets, while a test is being designed to better characterize the asymmetry in the receive paths. A new monument is to be established and a GPS antennae distribution facility added to allow calibration of GPS field-positioning instruments at the same time as performing time-transfer roles. Poster presentation; received August 22, 2002 |
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| Ultra mobile station FTLRS: Software Control | Monique Pierron | ||||||||||||||||||
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Observatoire de la Cote d'Azur/CERGA Francis Pierron, Jocelyn Paris French Transportable Laser Ranging Station (FTLRS) is now in a new version, specially designed for the actual mission (Calibration campaign in Corsica for the oceanic satellite JASON-1); the actual software structure and its capabilities will be presented there. Embedded real-time software control is managed by a remote LINUX station through a TCP/IP link. During tracking, a lot of commands are now available (laser power, telescope tracking, fast swapping between two "near" satellites like Jason/Topex, etc). Automatic detection of valid echoes is achieved and many hardware survey and test have been added during tracking phase. It is now possible to operate on FTLRS from our Grasse facilities, for software maintenance, improvement test and eventually for tracking (after on site station setup by an operator). Poster presentation; received August 23,, 2002 |
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| The New MLRS Encoder System: Progress Report | Jerry Wiant | ||||||||||||||||||
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University of Texas, McDonald Observatory/MLRS J. G. Ries, R. L. Ricklefs, P. J. Shelus The McDonald Laser Ranging Station (MLRS), a part of the NASA SLR network, ranges to numerous artificial satellites and the Moon. Successful lunar data acquisition requires very accurate telescope pointing and tracking. At present, absolute encoders combined with physical mount modeling provides 1 arcsecond precision lunar tracking over several minutes and reproducible pointing at the few arcseconds level. However, since the manufacturer of the yoke axis encoder no longer provides bulbs for our model, we need to be prepared to replace the system. The cost of buying a new absolute encoder with the same 0.62 arcsecond precision and the required interface upgrades makes this approach unrealistic. Our solution is to mount a linear encoder tape on the "belly" of the yoke axis, with a stationary read head mounted on the telescope frame. This incremental encoder would send pulses indicating 0.1 arcsecond steps to the existing up-down counter, maintaining resolution for the servo system while improving resolution for the telescope pointing. Although the new encoder requires zeroing after each time the system is powered down, the computer-assisted procedure would require about a minute of work by the observer. This is a reasonable trade off for the factor of 10 reduction in cost. Progress on this work will be presented at the meeting. Poster paper; received August 23, 2002 |
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| Improvements of the French Transportable Laser Ranging Station to high accuracy level | Francis Pierron | ||||||||||||||||||
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Observatoire de la Côte d'Azur/CERGA E. Samain, J. Nicolas, J.-L. Hatat, M. Pierron, J.-F. Mangin,
H. Viot, M. Laplanche, J. Paris, E. Cuot The very small (300 kg) French Transportable Laser Ranging Station (FTLRS) has been greatly improved the past two years and we’ll summarize herein main improvements and different tests performed on the station. The aim was to reach both high accuracy and stability necessary for JASON1 orbit validation and altimeter calibration experiment. These characteristics are also essential for station positioning adjustment, precise orbit determination, and terrestrial reference frame computation. To reach this performance, many major improvements have been carried out on the FTLRS, they mainly concern:
The success of all these upgrades has been confirmed at the level of few millimeters by the analysis of a collocation experiment performed at the Grasse observatory between the three laser instruments (autumn 2001) and the evaluation of the eight months set of data from the Corsica campaign still in progress. Poster paper; received August 23, 2002 |
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| Upgrading of the Simeiz-1873 SLR Station | Sergiy Filikov | ||||||||||||||||||
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Crimean Astrophysical Observatory A. Dmitrotsa, O. Minin, D. Neyachenko, L. Shtirberg S. Tatevian In 1999-2000 the performance of the SIMEIZ-1873 satellite laser station has been greatly improved due to valuable assistance of Michael Pearlman and Daniel Nugent and with the financial support of the CRDF grant UG1-332. A description of the system configuration is shown in Table 1. Now the station is still operating in semiautonomuos ranging mode with night tracking , but an upgrading of the SLR software and an installation of the new laser generator are planned in the nearest future. In 2001 more than 550 satellite passes have been tracked with the improved precision. The SLR station is collocated with the permanent GPS receiver and the Crimean VLBI station is 1.3 km away. Table 1, SIMEIZ-1873 SLR System Configuration.
Poster paper; received August 22, 2002 |
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| First Laser Ranging Results of the new Potsdam SLR System | Ludwig Grunwaldt | ||||||||||||||||||
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GeoForschungsZentrum Potsdam, Division 1 Reinhart Neubert, Harald Fischer Kalvis Salminsh Jorge del Pino After completing the hardware installation and alignment of main optical components, successful laser ranging has been carried out since summer 2001 using the new Potsdam SLR system. The optical system consists of separated transmit and receive telescopes featuring direct drives for the telescope axes and separately driven, servo-controlled telescope housings. For target calibration, a direct optical link between transmit and receive telescope is established. Special emphasis was put on the efficient PC-based remote control of important system components thus allowing for a strict single-observer operation of the system. Data filtering and management software is build as a client-server database application running under MS-Windows. Data conversion into dedicated formats and data publishing is strongly supported by the internal use of the flexible XML format. Collocation using both the new and the presently operated SLR system (7836) is under way using different satellites. First results using both a Hamamatsu Hybrid PMT and a Silicon Sensor SPAD as a receiver are reported. Poster paper; received September 04, 2002 |
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| System Upgrades of the NASA SLR Network | David Carter | ||||||||||||||||||
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NASA Goddard Space Flight Center The NASA SLR Network has been fully operational in the field for over twenty years. During this time the Network has seen many modifications and upgrades to maintain system operations and more importantly, to increase data quantity and quality. Through a declining budget, NASA continues to ensure system operations and performance are maintained at the highest level. During the last two years, the MOBLAS, TLRS, MLRS, and HOLLAS have received both hardware and software changes to maintain and enhance system operations. This poster paper will detail the upgrades to the timing subsystem, the receiver subsystem, the laser subsystem, the communications subsystem, the mount subsystem, and the processing software of the NASA SLR Network. Poster paper; received September 13, 2002 |
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| Upgrades of Shanghai Satellite Laser Ranging Station | Yang Fumin | ||||||||||||||||||
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Shanghai Observatory, Chen Wanzhen, Zhang Zhongping, Chen Juping, Hu Jingfu, Li XinShanghai
Observatory,
Poster paper; received September 16, 2002 |
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| NASA SLR Network MCP PMT Upgrade | Howard Donovan | ||||||||||||||||||
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Honeywell Technology Solutions, Inc. Loyal Stewart, Jack Stevens, Mark LevyHoneywell Technology Solutions,
Inc. Currently, the NASA SLR Network uses the International Telephone and Telegraph (ITT) F4129F Microchannel Plate (MCP) Photomultiplier Tube (PMT). Originally purchased between1985 and 1989, the ITT MCP PMTs were installed throughout the NASA SLR network beginning in 1986. Replacing the Amperex XP2233B PMT, the ITT MCP PMT, coupled with the Tennelec 454 Constant Fraction Discriminator (CFD), greatly enhanced the resolution and accuracy of the NASA SLR Network. After 15 years, the original ITT MCP PMTs have long since lived their useful life. As the original PMTs failed, they were replaced with the spares. Now, these supplementary units are beginning to fail. Efforts to find a suitable replacement for the ITT MCP PMT were begun three years ago, with the first unit being delivered in June of 2002. While the initial purchase of the new MCP PMTs was in progress, investigative efforts continued in an effort to find other manufactures that would meet the needs of the SLR Network. This poster paper will cover the laboratory verification, testing and calibration of the new MCP PMTs for the SLR Network as well as cover the field testing of a developmental MCP PMT from a separate manufacturer. Poster paper; received September 17, 2002 |
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| GUTS – A New SLR System for Japan | Thomas Oldham | ||||||||||||||||||
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Honeywell Technology Solutions Inc. David McClure and HTSI GUTS TeamHoneywell Technology Solutions
Inc. Honeywell Technology Solutions Inc (HTSI) is currently integrating the Global High Accuracy Trajectory System SLR system for NASDA in the STALAS facility at the Goddard Geophysical and Astronomical Observatory. This system will ultimately be installed at the NASDA facility on Tanegashima Island in Japan. HTSI is manufacturing the SLR control system, electronics, optics, and aircraft warning radar system; producing and implementing the control, scheduling, and data processing software; integrating the NEC-manufactured laser and the Brashear-manufactured 1-meter telescope with our items; and preparing for collocation with the HTSI-operated NASA MOBLAS-7. The GUTS SLR system will have the capability to range to satellites in orbits ranging from low Earth to geosynchronous. In addition, special modifications to the HTSI control software will allow the system to be operated remotely from the NASDA facility in Tsukuba via a low bandwidth data link as well as by a local operator at Tanegashima. Initial integration testing of the system has produced outstanding results. Ranging to the calibration cube located on the system’s optical table produces ranges with an RMS of ~2 mm. This is expected to be degraded to no worse than 2.5 mm when ranging is performed to the external calibration pier following the installation of the telescope. HTSI would like to acknowledge the cooperation and support that we have received from NASDA (especially from Mr. Takashi Uchimura) and NEC (from the team led by Mr. Kaoru Asaba) in the implementation of this system. Poster paper; received September 30, 2002 |
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| Integration of 1.5m Telescope and ranging system in CRL | Hiroo Kunimori | ||||||||||||||||||
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Communications Research Laboratory Futaba Katuso John Guilfoyle Takuma Satoh The Keystone stations (Miura and Tateyama) were dismantled and the 75cm telescopes were transferred to other institute in Japan. Laser and electronics were moved and integrated to Koganei (CRLLAS) 1.5m telescope as basis of conventional SLR system but without routine operation. We switch lasers between 50mJ/50ps 20Hz (high precision) and 200mJ/3ns/ 10Hz (high power) for requirement of various targets acquisition such as LRE or ADEOS-II. Multiple tracking cameras are used in different FOV (0.5arcdeg/2arcmin/50arcsec)and sensitivity (Mag.9-13). In addition to the conventional SLR system, we plan a next generation of laser ranging collaborated with optical communication by integrating CW laser with Pseudo-noise modulation and wideband correlator. Poster paper; received October 04, 2002 |
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