Riga
SLR System Configuration Definition
Pad id#: 1884
Address: Astronomical observatory of the
Latvian University,
Boulevard Rainis 19
LV-1586, Riga, Latvia.
Contact: Dr. K. Lapushka.
Phone: (7) 0132 611984
Fax: 371 88 20180
E-Mail: LAPUSHKA@ASTR2.LU.LV
SLRS1884@ASTR2.LU.LV
Section 1.3 Sysytem Ranging Targets
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Target/feature Current Ranging Capability
Day Night
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Internal calibration no no
External calibration yes yes
Lageos 1. 2. no yes
ERS-1 no yes
TOPEX no yes
Starlette no yes
Stella no yes
Ajisai no yes
Etalon 1. 2. no yes
Glonass 3. 5. no tested. no orbital elements.
GPS-35 answers not received.
Geosynchron.sat. no tests.
Moon no no
Two color capability no no
Tracking automated under visual control.
Section 2.0 - HARDWARE CONFIGURATION / CAPABILITY
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Section 2.1 Laser Configuration
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LASER / Specification /Date
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Type of laser medium / NeYAG /7-7-94
Energy/Pulse (mJ) / 120 /7-7-94
Pulsewidth (ps) / 360 /7-7-94
Beam size / 8 mm /7-7-94
Beam divergence / 150 microrad no controlled. /7-7-94
Amplitude stability / 7 % /7-7-94
Timing stability / 1500 ns /7-7-94
Transverse mode structure/ TEM oo /7-7-94
Ranging Wavelength / 532.0 nm /7-7-94
Repetition rate / 5 Hz /7-7-94
>It is foreseen at June 1994 go for testing laser transmitter with
>100 ps pulse width, 40 mJ energy, NeYAG, 532 nm. No more information
>at the moment.
Section 2.2 MOUNT CONFIGURATION CATAGORY
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SECTION 2.2.1 Telescope/Mount
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Telescope/Mount /Specification / Date
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Telescope type / Cassegrain - Coude, three axial. / 7-7-94
Mount type / Alt - Azim. / 7-7-94
Field of view / 3 arcmin. for main opt.system / 7-7-94
/ 30 arcmin. for guiding opt.system / 7-7-94
Focal length / 11.6 m for M.O.S. / 7-7-94
1.2 m primary mirror fl for M.O.S
/ 4.44 m for G.O.S. / 7-7-94
Pointing accuracy / 10 arcsec. / 7-7-94
Common T/R OP for sat. / 3912 mm / 7-7-94
Separate T/R OP for sat. / T=1595 mm, R=1300 mm / 7-7-94
Common T/R OP for cal. / no / 7-7-94
Separate T/R OP for cal. / T=820 mm, R=605 mm / 7-7-94
Orthogonality of axes / 5 arcsec / 7-7-94
ELEVATION
Range / 0 - 90 degrees / 7-7-94
Encoder / no / 7-7-94
Maximum EL velocity / 2 degrees per sec. / 7-7-94
Maximum EL acceler. / 600 arcsec per sec. / 7-7-94
AZIMUTH
Range / 0 - 360 degrees / 7-7-94
Encoder / no / 7-7-94
Maximum AZ velocity / 2 degrees per sec. / 7-7-94
Maximum AZ acceler. / 600 arcsec per sec. / 7-7-94
PRIMARY MIRROR
Type / spherical / 7-7-94
Clear aperture / 1000 mm / 7-7-94
Focal length / 4000 mm / 7-7-94
Optical coating / Aluminium / 7-7-94
SECONDARY MIRROR
Type / outside aluminium coated divergent lens.
Clear aperture / 250 mm / 7-7-94
COUDE MIRRORS
Type / flat / 7-7-94
Number / 5 , three fixed, two rotating-10rps. / 7-7-94
Optical coating / Alumin. coated. / 7-7-94
Section 2.3 Optical Configuration Catagory
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TRANSMIT/RECEIVE OPTICS / SPECIFICATION /Date
============================================================================
T/R coupling scheme: / three-in-one, transmit, / 7-7-94
receiving and guiding thru
main optic.system with
switching by rotating and
fixed mirrors.
Spatial filter:
-Fielf of View / diaphragmas, / 7-7-94
3,7,15,30,60,90,180 arcsec.
Band-pass Filter:
-Type / holographyc retroflecting / 7-7-94
-Bandwidth / 1.5 Angstr. 532 nm. / 7-7-94
-Retroreflecting efficiency / 96 % / 7-7-94
Receive signal amplitude / not controled. / 7-7-94
Section 2.4 TRANSMIT/ RECIEVE (T/R) ELECTRONIC CONFIGURATION
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T/R ELECTRONICS /SPECIFICATION / DATE
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Transmit detector / avalanche laser photodiode / 7-7-94
-Rise time / 2 ns / 7-7-94
Receive detector / ordinary 10 dinodes PMT / 7-7-94
-QE / 7 % / 7-7-94
-Rise time / 3 ns / 7-7-94
Amplifier / self made, two transistor / 7-7-94
-Bandwidth / 1.5 Ghz / 7-7-94
Target imaging capability/ 3 stages image amplifier / 7-7-94
/ TV camera LI-703 / 7-7-94
Signal processing technique/ / 7-7-94
-Type of device / CFD ORTEC model 934. / 7-7-94
-Length of EDC / 130 cm / 7-7-94
-Bandwidth / 100 Mhz / 7-7-94
-Dynamic range / 0 - 10 Volts / 7-7-94
-Jitter / 10 ps. / 7-7-94
EVENT TIME MEASUREMENT / A911E, self made computerized / 7-7-94
timing system on PC basis.
-Clock frequency / 40 Mhz / 7-7-94
-Number of channels / 2 / 7-7-94
-Number of verniers / 2 / 7-7-94
-Minimum dead time / 20 milisec / 7-7-94
Ranging measurement RMS / 20 psec / 7-7-94
Amplitude measurement / foreseen in future. / 7-7-94
System delay calibration / by external target. / 7-7-94
Range of target / 41866 mm / 7-7-94
External calibration capability/ 1. classic pre-post calibration / 7-7-94
2. continous calibration synchronous
to satellite ranging during
pass time.
3. delay compensation method-
measuring between retroflected
pulses from target and satellite.
* Since 1.january 1994 delay compensation method is used.
SECTION 2.6 TIMING CONFIGURATION
================================
TIMING / SPECIFICATION / DATE
====================================================================
Frequency standards used / rubidium FS. / 7-7-94
Short term stability / 2E-11 sec. / 7-7-94
Long term stability / 3E-12 24 hours / 7-7-94
Epoch time measurement
-Type of Device / GPS receiver ( if possible) / 7-7-94
sec.pulse from Moscow thru TV / 7-7-94
-Resolution / no calibrated. / 7-7-94
-Timing closure / UTC(GPS) / 7-7-94
Section 2.7 METEOROLOGICAL SENSORS CONFIGURATION
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METEOROLOGICAL SENSORS / SPECIFICATIONS / DATE
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Thermometer / mercury, 0.1 degrees Celsium, / 7-7-94
from -35 to +40.
Barometric pressure system / "PAULIN" 0.1 mm Hg, 690-790 mmHg. /7-7-94
Relative humidity system / hair hygrometer accur. 10 % / 7-7-94
/ psychrometer accur. 10%. / 7-7-94
Wind measurement system / no / 7-7-94
SECTION 4.0 SURVEY MEASUREMENTS CONFIGURATION/ CAPABILITY
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SECTION 4.1 SURVEY MEASUREMENTS
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SECTION 4.2 SURVEY ANALYSIS
===========================
SURVEY ANALYSIS TECHNIQUE
=========================
SECTION 4.3 SURVEY CALIBRATION TARGET
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TARGET / TYPE / RANGE / AZ / EL / RANGE / RANGE / SHORT / LONG
/ / ACCURACY/ / / PRECISION / / TERM / TERM
/ / / / / / / STABILITY / STABILITY
===============================================================================
1 / / / / / / / /
2 / / / / / / / /
3 / / / / / / / /
4 / / / / / / / /
SECTION 4.4 ECCENTRICITY DETERMINATION
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/ NORTH / EAST / UP
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Mean Value / / /
Accuracy / / /
Precision / / /
Short Term Stability / / /
Long Term Stability / / /
SECTION 5.0 CALIBRATION TECHNIQUE / CAPABILITY
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SECTION 5.1 CALIBRATION DEVICES AND FREQUENCY
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===============================================================================
// FREQUENCY
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DEVICE/ FEATURE / SATELLITE / PASS / DAY / MONTH / YEAR
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Event Timer / / / / /
Time of Flight Devices / / / / /
Discriminator / / / / /
Pressure Sensor / / / / /
Temperature Sensor / / / / /
Timing System / / / / /
System Delay / / / / /
SECTION 6.0 SYSTEM TIMING CLOSURE CONFIGURATION
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SECTION 6.1 TIMING CLOSURE
===========================
Reference Time:
Accuracy of Timing:
Modeling of Time Drift:
SECTION 7.0 SYSTEM DATA ANALYSIS CONFIGURATION / CAPABILITY
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SECTION 7.1 DATA ANALYSIS
=========================
DATA CORRECTIONS ( YES : NO ) / ADDITIONAL INFORMATION
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7.1.1 Transmit Signal Amplitudes: /
7.1.2 Receive Signal Amplitudes: /
7.1.3 Timing /
7.1.4 Instrument Non-Linearities /
7.1.5 Geometric Corrections /
7.1.6 Atmosphere /
* DATA CORRECTION: electronic system delay
SECTION 7.2 System Delay Computation:
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SYSTEM DELAY COMPUTATION FREQUENCY / ( YES : NO ) /ADDITIONAL INFORMATION
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7.2.1 Shot by Shot: / /
7.2.2 Burst or Short Time Aggregate: / /
7.2.3 Aggregate: / /
SECTION 7.3 DATA ANALYSIS TECHNIQUES / CAPABILITIES
===================================================
7.3.1 Normal Point Computation / Herstmonceux 1984
7.3.2 Fitting Routine (Algorithms) / Polynomial fitting
7.3.3 Noise Filtering and Editing Procedures / 2 sigma criteria
7.3.4 Data Quality Control Procedures / RMS, skewness and curtosis
7.3.5 System Computational Capability / 7600 data points
*data corrections: electronic system delay. epoch time
SECTION 8.0 SYSTEM ATMOSPHERIC TECHNIQUES
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SECTION 8.1 ATMOSPHERIC MODEL
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8.1 Atmospheric Model Used:
* ( PLEASE DESCRIBE THE MODEL IN AS MUCH DETAIL AS POSSIBLE )
SECTION 9.0 SYSTEM PERFORMANCE CHARACTERISTICS
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SECTION 9.1 RANGING SYSTEM ERRORS
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RANGING SYSTEM ERRORS / ACCURACY / 1 SIGMA / PEAK - PEAK / DATE /
================================================================================
Temporal Stability / / / / /
Wavefront Distortion / / / / /
Signal Strength Dependence / / / / /
Calibration Path / / / / /
Mount Eccentricities / / / / /
Meteorological Measurement / / / / /
Event Timer / / / / /
Time of Flight Measurement / / / / /
Epoch Time Measurement / / / / /
Data Analysis / / / / /
Normal Point Computation / / / / /
System Delay Computation / / / / /
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