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#1
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
NGA GPS Ephemeris/Station/Antenna Offset Documentation
Ref: http://earth-info.nga.mil/GandG/sath...c2004_04a.html Effective date April 05, 2004 NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY GPS PRECISE EPHEMERIDES, SATELLITE CLOCK PARAMETERS AND SMOOTHED OBSERVATIONS PRECISE EPHEMERIS Earth-centered Earth-fixed trajectory Coordinate system: WGS84 (G1150) Position -- x,y,z (km) Velocity -- dx/dt,dy/dt,dz/dt (dm/s) GPS time -- year, day, hour, minute Trajectory interval: 15 min. Standard Trajectory referenced to satellite center of mass Optional Trajectory referenced to satellite antenna phase center SATELLITE CLOCK PARAMETERS Clock parameters for each satellite: Time offset (microseconds) Frequency offset (10E-4 microsec/s = parts in 10E10) Time interval for parameters: 15 min. Satellite clock events: All events processed as reinitializations SMOOTHED OBSERVATIONS Smoothed range and range difference observations (km) with corrections applied (see below) GPS time of observation (year, day, seconds from beginning of day) Standard deviation of observation (km) Coordinate system: WGS84 (G1150) Station coordinates: Position -- x,y,z (m), Epoch 2001.0 Velocity -- dx/dt,dy/dt,dz/dt (m/year) Temperature (degrees Celsius) Pressure (millibars) Humidity (percent) Data interval: 15 min. Smoothing uses carrier phase to smooth range and range difference measurements collected at a 1.5 second rate for NIMA and Air Force monitor stations and at a 30 second rate for IGS monitor stations Minimum elevation angle for observation: 10 degrees National Imagery and Mapping Agency and Air Force monitor station data collected and smoothed using similar procedures References: Computer Program Development Spec., Master Control Station, Ephemeris/Clock Computer Program, NAVSTAR GPS Operational Control System Segment, CP-MCSEC-302C, Part 1, Appendix A, 7 May1993. Description of the Smoothing Algorithm in the NIMA Monitor Station Network, (MSN29), Applied Research Laboratories, The University of Texas at Austin, GR-SGG-97-1, 3 April 1997. PHYSICAL CONSTANTS GM(Earth) = 398600.4418 km**3/s**2 GM(Sun) = 132712400000 km**3/s**2 GM(Moon) = 4902.799186 km**3/s**2 Moon radius = 1738 km Sun radius = 696000 km Earth semi-major axis (a) = 6378.137 km Inverse flattening (1/f) = 298.257223563 Earth angular velocity = 0.72921158553 X 10**-4 Rad/s Speed of light = 299792.458 km/s Love's constant = 0.290 Solar constant = 4.560 X 10**-6 N/m**2 Astronomical Unit = 149597870.691 km STATION COORDINATES (GEODETIC) WGS84 (G1150) Epoch 2001.0 STATION COORDINATES (CARTESIAN) WGS84 (G1150) Epoch 2001.0 Due to security concerns surrounding the current threat situations, the coordinates for the NGA/Air Force/IGS stations have been removed. Any such information needed about the NGA stations should be requested, until further notice, at: (314) 263-4120 or DSN 693-4120 CORRECTIONS APPLIED TO MEASUREMENTS Ionospheric delay: 2-frequency, 1st order correction Tropospheric refraction: Saastamoinen hydrostatic and wet zenith delay models and Niell hydrostatic and wet mapping functions Periodic relativistic effects Satellite antenna offset (satellite body centered coordinates, meters) Block II PRN's - Delta x= 0.2794, Delta y= 0.0000, Delta z= 0.9519 Block IIA PRN's - Delta x= 0.2794, Delta y= 0.0000, Delta z= 0.9519 Block IIR PRN 11 - Delta x= 0.0019, Delta y= 0.0011, Delta z= 1.5141 Block IIR PRN 13 - Delta x= 0.0024, Delta y= 0.0025, Delta z= 1.6140 Block IIR PRN 14 - Delta x= 0.0018, Delta y= 0.0002, Delta z= 1.6137 Block IIR PRN 16 - Delta x= -0.0098, Delta y= 0.0060, Delta z= 1.6630 Block IIR PRN 18 - Delta x= -0.0098, Delta y= 0.0060, Delta z= 1.5923 Block IIR PRN 19 - Delta x= -0.0100, Delta y= 0.0064, Delta z= 1.5620 Block IIR PRN 20 - Delta x= 0.0022, Delta y= 0.0014, Delta z= 1.6140 Block IIR PRN 21 - Delta x= 0.0023, Delta y= -0.0006, Delta z= 1.5840 Block IIR PRN 22 - Delta x= 0.0018, Delta y= -0.0009, Delta z= 0.0598 Block IIR PRN 28 - Delta x= 0.0018, Delta y= 0.0007, Delta z= 1.5131 Station displacement due to tides Yaw Bias: JPL yaw bias model for Block II and IIA satellites in eclipse, except PRN's 2, and 23 FORCE MODELING Gravitational: EGM96 Earth gravity model truncated at degree 12 and order 12 Solar and Lunar gravity using the DE403 ephemeredes, J2000 epoch, and IAU Resolutions on Astronomical Constants, Time Scales, and the Fundamental Reference Frame (1976-1980) Solid Earth tides Non-gravitational: Radiation Pressure ROCKWELL ROCK42 model for Block II and IIA satellites Lockheed Martin table look up model for Block IIR satellites Thrusts Momentum dumps Kinematic: Luni-solar and planetary precession (IAU Resolutions, as above) Nutation (IAU Resolutions, as above) Earth rotation (IAU Resolutions, as above) Polar Motion (using NIMA initial values generated the week before the orbit fit) + diurnal and semi-diurnal effects UT1-UTC (using NIMA initial values generated the week before the orbit fit) + Zonal tide effects + diurnal and semi-diurnal effects Integration step size: 300 seconds, reduced to 10 seconds during eclipse boundary crossings ORBIT ESTIMATION METHOD Kalman Filter/RTS Smoother (Square Root Information implementation) Initial conditions: From previous fit Solution parameters: Satellite state vector in element form at trajectory epoch -- semi-major axis eccentricity * sin(argument of perigee) eccentricity * cos(argument of perigee) inclination mean anomaly + argument of perigee right ascension of the ascending node Satellite clock parameters -- Time offset, Frequency offset Monitor station clock parameters (excluding master station) -- Time offset, Frequency offset Polar motion parameters -- Pole and pole rate components along Greenwich meridian, Pole and pole rate components along meridian 90 deg west of Greenwich, Rate of change and acceleration of UT1-UTC Satellite radiation pressure parameters -- Radiation pressure scale, and Y-axis acceleration Tropospheric refraction -- One stochastic zenith delay parameter per station Minimum range observation uncertainty(1-sigma):100 cm (IGS Stations) 100 cm (Station 85128) 80 cm (Station 85130) 40 cm (other stations) Minimum range difference observation uncertainty (1-sigma): 1.5 cm Process noise in Kalman Filter: Radiation pressure (each satellite)-- Decorrelation time 14,400 s Steady state sigmas -- SCALE 0.05 Y-AXIS 0.5 X 10**-12 km/s**2 Tropospheric refraction variance rate: 2.89 cm**2/hr Station clock white noise spectral density: (each station) -- Time offset 0.1111 X 10**-2 (microseconds)**2/s Frequency offset 0.1111 X 10**-8 (ppm)**2/s Satellite clock white noise spectral density: (each satellite) Time offset 0.1111 X 10**-2 (microseconds)**2/s Frequency offset 0.1111 X 10**-8 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s SATELLITE CLOCK ESTIMATION METHOD Kalman Filter/RTS Smoother (Square Root Information implementation) Orbit solutions from above method are held fixed for satellite clock estimation Solution parameters: Satellite clock parameters -- Time offset, Frequency offset Monitor station clock parameters (excluding master station) -- Time offset, Frequency offset Tropospheric refraction -- One stochastic zenith delay parameter per station. Minimum range observation uncertainty(1-sigma):100 cm (IGS Stations) 100 cm (Station 85128) 80 cm (Station 85130) 40 cm (other stations) Minimum range difference observation uncertainty (1-sigma): 15.0 cm Process noise in Kalman Filter: Tropospheric refraction variance rate: 2.89 cm**2/hr Station clock white noise spectral densities: NGA stations and Air Force Colorado Springs station: Time offset 0.1944 X 10**-8 (microseconds)**2/s Frequency offset 0.4440 X 10**-19 (ppm)**2/s Air Force stations (except Colorado Springs) and IGS stations: Time offset 0.3456 X 10**-8 (microseconds)**2/s Frequency offset 0.4440 X 10**-19 (ppm)**2/s Satellite clock white noise spectral densities: Satellite Block IIR Rubidium clocks Time offset 0.8640 X 10**-9 (microseconds)**2/s Frequency offset 0.1110 X 10**-18 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite Block II/IIA Rubidium clocks Time offset 0.1944 X 10**-8 (microseconds)**2/s Frequency offset 0.1110 X 10**-18 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite Cesium clocks Time offset 0.13824 X 10**-7 (microseconds)**2/s Frequency offset 0.1000 X 10**-17 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite 'Noisy' Cesium clocks Time offset 0.2000 X 10**-7 (microseconds)**2/s Frequency offset 0.1110 X 10**-16 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Reference: Swift, E., Mathematical Description of the GPS Multi-Satellite Filter/Smoother, NSWCDD Report (Oct. 2001). 
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#2
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
"Sam Wormley" wrote in message ... NGA GPS Ephemeris/Station/Antenna Offset Documentation Ref: http://earth-info.nga.mil/GandG/sath...c2004_04a.html Effective date April 05, 2004 NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY GPS PRECISE EPHEMERIDES, SATELLITE CLOCK PARAMETERS AND SMOOTHED OBSERVATIONS PRECISE EPHEMERIS Earth-centered Earth-fixed trajectory Coordinate system: WGS84 (G1150) Position -- x,y,z (km) Velocity -- dx/dt,dy/dt,dz/dt (dm/s) GPS time -- year, day, hour, minute Trajectory interval: 15 min. Standard Trajectory referenced to satellite center of mass Optional Trajectory referenced to satellite antenna phase center SATELLITE CLOCK PARAMETERS Clock parameters for each satellite: Time offset (microseconds) Frequency offset (10E-4 microsec/s = parts in 10E10) Time interval for parameters: 15 min. Satellite clock events: All events processed as reinitializations SMOOTHED OBSERVATIONS Smoothed range and range difference observations (km) with corrections applied (see below) GPS time of observation (year, day, seconds from beginning of day) Standard deviation of observation (km) Coordinate system: WGS84 (G1150) Station coordinates: Position -- x,y,z (m), Epoch 2001.0 Velocity -- dx/dt,dy/dt,dz/dt (m/year) Temperature (degrees Celsius) Pressure (millibars) Humidity (percent) Data interval: 15 min. Smoothing uses carrier phase to smooth range and range difference measurements collected at a 1.5 second rate for NIMA and Air Force monitor stations and at a 30 second rate for IGS monitor stations Minimum elevation angle for observation: 10 degrees National Imagery and Mapping Agency and Air Force monitor station data collected and smoothed using similar procedures References: Computer Program Development Spec., Master Control Station, Ephemeris/Clock Computer Program, NAVSTAR GPS Operational Control System Segment, CP-MCSEC-302C, Part 1, Appendix A, 7 May1993. Description of the Smoothing Algorithm in the NIMA Monitor Station Network, (MSN29), Applied Research Laboratories, The University of Texas at Austin, GR-SGG-97-1, 3 April 1997. PHYSICAL CONSTANTS GM(Earth) = 398600.4418 km**3/s**2 GM(Sun) = 132712400000 km**3/s**2 GM(Moon) = 4902.799186 km**3/s**2 Moon radius = 1738 km Sun radius = 696000 km Earth semi-major axis (a) = 6378.137 km Inverse flattening (1/f) = 298.257223563 Earth angular velocity = 0.72921158553 X 10**-4 Rad/s Speed of light = 299792.458 km/s Love's constant = 0.290 Solar constant = 4.560 X 10**-6 N/m**2 Astronomical Unit = 149597870.691 km STATION COORDINATES (GEODETIC) WGS84 (G1150) Epoch 2001.0 STATION COORDINATES (CARTESIAN) WGS84 (G1150) Epoch 2001.0 Due to security concerns surrounding the current threat situations, the coordinates for the NGA/Air Force/IGS stations have been removed. Any such information needed about the NGA stations should be requested, until further notice, at: (314) 263-4120 or DSN 693-4120 CORRECTIONS APPLIED TO MEASUREMENTS Ionospheric delay: 2-frequency, 1st order correction Tropospheric refraction: Saastamoinen hydrostatic and wet zenith delay models and Niell hydrostatic and wet mapping functions Periodic relativistic effects Satellite antenna offset (satellite body centered coordinates, meters) Block II PRN's - Delta x= 0.2794, Delta y= 0.0000, Delta z= 0.9519 Block IIA PRN's - Delta x= 0.2794, Delta y= 0.0000, Delta z= 0.9519 Block IIR PRN 11 - Delta x= 0.0019, Delta y= 0.0011, Delta z= 1.5141 Block IIR PRN 13 - Delta x= 0.0024, Delta y= 0.0025, Delta z= 1.6140 Block IIR PRN 14 - Delta x= 0.0018, Delta y= 0.0002, Delta z= 1.6137 Block IIR PRN 16 - Delta x= -0.0098, Delta y= 0.0060, Delta z= 1.6630 Block IIR PRN 18 - Delta x= -0.0098, Delta y= 0.0060, Delta z= 1.5923 Block IIR PRN 19 - Delta x= -0.0100, Delta y= 0.0064, Delta z= 1.5620 Block IIR PRN 20 - Delta x= 0.0022, Delta y= 0.0014, Delta z= 1.6140 Block IIR PRN 21 - Delta x= 0.0023, Delta y= -0.0006, Delta z= 1.5840 Block IIR PRN 22 - Delta x= 0.0018, Delta y= -0.0009, Delta z= 0.0598 Block IIR PRN 28 - Delta x= 0.0018, Delta y= 0.0007, Delta z= 1.5131 Station displacement due to tides Yaw Bias: JPL yaw bias model for Block II and IIA satellites in eclipse, except PRN's 2, and 23 FORCE MODELING Gravitational: EGM96 Earth gravity model truncated at degree 12 and order 12 Solar and Lunar gravity using the DE403 ephemeredes, J2000 epoch, and IAU Resolutions on Astronomical Constants, Time Scales, and the Fundamental Reference Frame (1976-1980) Solid Earth tides Non-gravitational: Radiation Pressure ROCKWELL ROCK42 model for Block II and IIA satellites Lockheed Martin table look up model for Block IIR satellites Thrusts Momentum dumps Kinematic: Luni-solar and planetary precession (IAU Resolutions, as above) Nutation (IAU Resolutions, as above) Earth rotation (IAU Resolutions, as above) Polar Motion (using NIMA initial values generated the week before the orbit fit) + diurnal and semi-diurnal effects UT1-UTC (using NIMA initial values generated the week before the orbit fit) + Zonal tide effects + diurnal and semi-diurnal effects Integration step size: 300 seconds, reduced to 10 seconds during eclipse boundary crossings ORBIT ESTIMATION METHOD Kalman Filter/RTS Smoother (Square Root Information implementation) Initial conditions: From previous fit Solution parameters: Satellite state vector in element form at trajectory epoch -- semi-major axis eccentricity * sin(argument of perigee) eccentricity * cos(argument of perigee) inclination mean anomaly + argument of perigee right ascension of the ascending node Satellite clock parameters -- Time offset, Frequency offset Monitor station clock parameters (excluding master station) -- Time offset, Frequency offset Polar motion parameters -- Pole and pole rate components along Greenwich meridian, Pole and pole rate components along meridian 90 deg west of Greenwich, Rate of change and acceleration of UT1-UTC Satellite radiation pressure parameters -- Radiation pressure scale, and Y-axis acceleration Tropospheric refraction -- One stochastic zenith delay parameter per station Minimum range observation uncertainty(1-sigma):100 cm (IGS Stations) 100 cm (Station 85128) 80 cm (Station 85130) 40 cm (other stations) Minimum range difference observation uncertainty (1-sigma): 1.5 cm Process noise in Kalman Filter: Radiation pressure (each satellite)-- Decorrelation time 14,400 s Steady state sigmas -- SCALE 0.05 Y-AXIS 0.5 X 10**-12 km/s**2 Tropospheric refraction variance rate: 2.89 cm**2/hr Station clock white noise spectral density: (each station) -- Time offset 0.1111 X 10**-2 (microseconds)**2/s Frequency offset 0.1111 X 10**-8 (ppm)**2/s Satellite clock white noise spectral density: (each satellite) Time offset 0.1111 X 10**-2 (microseconds)**2/s Frequency offset 0.1111 X 10**-8 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s SATELLITE CLOCK ESTIMATION METHOD Kalman Filter/RTS Smoother (Square Root Information implementation) Orbit solutions from above method are held fixed for satellite clock estimation Solution parameters: Satellite clock parameters -- Time offset, Frequency offset Monitor station clock parameters (excluding master station) -- Time offset, Frequency offset Tropospheric refraction -- One stochastic zenith delay parameter per station. Minimum range observation uncertainty(1-sigma):100 cm (IGS Stations) 100 cm (Station 85128) 80 cm (Station 85130) 40 cm (other stations) Minimum range difference observation uncertainty (1-sigma): 15.0 cm Process noise in Kalman Filter: Tropospheric refraction variance rate: 2.89 cm**2/hr Station clock white noise spectral densities: NGA stations and Air Force Colorado Springs station: Time offset 0.1944 X 10**-8 (microseconds)**2/s Frequency offset 0.4440 X 10**-19 (ppm)**2/s Air Force stations (except Colorado Springs) and IGS stations: Time offset 0.3456 X 10**-8 (microseconds)**2/s Frequency offset 0.4440 X 10**-19 (ppm)**2/s Satellite clock white noise spectral densities: Satellite Block IIR Rubidium clocks Time offset 0.8640 X 10**-9 (microseconds)**2/s Frequency offset 0.1110 X 10**-18 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite Block II/IIA Rubidium clocks Time offset 0.1944 X 10**-8 (microseconds)**2/s Frequency offset 0.1110 X 10**-18 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite Cesium clocks Time offset 0.13824 X 10**-7 (microseconds)**2/s Frequency offset 0.1000 X 10**-17 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite 'Noisy' Cesium clocks Time offset 0.2000 X 10**-7 (microseconds)**2/s Frequency offset 0.1110 X 10**-16 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Reference: Swift, E., Mathematical Description of the GPS Multi-Satellite Filter/Smoother, NSWCDD Report (Oct. 2001). Of course the operative phrase in this post is "Periodic relativistic effects". I challenge "Sam Wormley" to post one or more examples of these "Periodic relativistic effects" adjustments, and show how it proves that GR was essential to the design and operation of the GPS system, and if he is able, to show how the "Periodic relativistic effects" adjustment, proved GR to the exclusion of other factors. I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. -- Tom Potter http://tompotter.us
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#3
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
"Sam Wormley" wrote in message ... NGA GPS Ephemeris/Station/Antenna Offset Documentation Ref: http://earth-info.nga.mil/GandG/sath...c2004_04a.html Effective date April 05, 2004 NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY GPS PRECISE EPHEMERIDES, SATELLITE CLOCK PARAMETERS AND SMOOTHED OBSERVATIONS PRECISE EPHEMERIS Earth-centered Earth-fixed trajectory Coordinate system: WGS84 (G1150) Position -- x,y,z (km) Velocity -- dx/dt,dy/dt,dz/dt (dm/s) GPS time -- year, day, hour, minute Trajectory interval: 15 min. Standard Trajectory referenced to satellite center of mass Optional Trajectory referenced to satellite antenna phase center SATELLITE CLOCK PARAMETERS Clock parameters for each satellite: Time offset (microseconds) Frequency offset (10E-4 microsec/s = parts in 10E10) Time interval for parameters: 15 min. Satellite clock events: All events processed as reinitializations SMOOTHED OBSERVATIONS Smoothed range and range difference observations (km) with corrections applied (see below) GPS time of observation (year, day, seconds from beginning of day) Standard deviation of observation (km) Coordinate system: WGS84 (G1150) Station coordinates: Position -- x,y,z (m), Epoch 2001.0 Velocity -- dx/dt,dy/dt,dz/dt (m/year) Temperature (degrees Celsius) Pressure (millibars) Humidity (percent) Data interval: 15 min. Smoothing uses carrier phase to smooth range and range difference measurements collected at a 1.5 second rate for NIMA and Air Force monitor stations and at a 30 second rate for IGS monitor stations Minimum elevation angle for observation: 10 degrees National Imagery and Mapping Agency and Air Force monitor station data collected and smoothed using similar procedures References: Computer Program Development Spec., Master Control Station, Ephemeris/Clock Computer Program, NAVSTAR GPS Operational Control System Segment, CP-MCSEC-302C, Part 1, Appendix A, 7 May1993. Description of the Smoothing Algorithm in the NIMA Monitor Station Network, (MSN29), Applied Research Laboratories, The University of Texas at Austin, GR-SGG-97-1, 3 April 1997. PHYSICAL CONSTANTS GM(Earth) = 398600.4418 km**3/s**2 GM(Sun) = 132712400000 km**3/s**2 GM(Moon) = 4902.799186 km**3/s**2 Moon radius = 1738 km Sun radius = 696000 km Earth semi-major axis (a) = 6378.137 km Inverse flattening (1/f) = 298.257223563 Earth angular velocity = 0.72921158553 X 10**-4 Rad/s Speed of light = 299792.458 km/s Love's constant = 0.290 Solar constant = 4.560 X 10**-6 N/m**2 Astronomical Unit = 149597870.691 km STATION COORDINATES (GEODETIC) WGS84 (G1150) Epoch 2001.0 STATION COORDINATES (CARTESIAN) WGS84 (G1150) Epoch 2001.0 Due to security concerns surrounding the current threat situations, the coordinates for the NGA/Air Force/IGS stations have been removed. Any such information needed about the NGA stations should be requested, until further notice, at: (314) 263-4120 or DSN 693-4120 CORRECTIONS APPLIED TO MEASUREMENTS Ionospheric delay: 2-frequency, 1st order correction Tropospheric refraction: Saastamoinen hydrostatic and wet zenith delay models and Niell hydrostatic and wet mapping functions Periodic relativistic effects Satellite antenna offset (satellite body centered coordinates, meters) Block II PRN's - Delta x= 0.2794, Delta y= 0.0000, Delta z= 0.9519 Block IIA PRN's - Delta x= 0.2794, Delta y= 0.0000, Delta z= 0.9519 Block IIR PRN 11 - Delta x= 0.0019, Delta y= 0.0011, Delta z= 1.5141 Block IIR PRN 13 - Delta x= 0.0024, Delta y= 0.0025, Delta z= 1.6140 Block IIR PRN 14 - Delta x= 0.0018, Delta y= 0.0002, Delta z= 1.6137 Block IIR PRN 16 - Delta x= -0.0098, Delta y= 0.0060, Delta z= 1.6630 Block IIR PRN 18 - Delta x= -0.0098, Delta y= 0.0060, Delta z= 1.5923 Block IIR PRN 19 - Delta x= -0.0100, Delta y= 0.0064, Delta z= 1.5620 Block IIR PRN 20 - Delta x= 0.0022, Delta y= 0.0014, Delta z= 1.6140 Block IIR PRN 21 - Delta x= 0.0023, Delta y= -0.0006, Delta z= 1.5840 Block IIR PRN 22 - Delta x= 0.0018, Delta y= -0.0009, Delta z= 0.0598 Block IIR PRN 28 - Delta x= 0.0018, Delta y= 0.0007, Delta z= 1.5131 Station displacement due to tides Yaw Bias: JPL yaw bias model for Block II and IIA satellites in eclipse, except PRN's 2, and 23 FORCE MODELING Gravitational: EGM96 Earth gravity model truncated at degree 12 and order 12 Solar and Lunar gravity using the DE403 ephemeredes, J2000 epoch, and IAU Resolutions on Astronomical Constants, Time Scales, and the Fundamental Reference Frame (1976-1980) Solid Earth tides Non-gravitational: Radiation Pressure ROCKWELL ROCK42 model for Block II and IIA satellites Lockheed Martin table look up model for Block IIR satellites Thrusts Momentum dumps Kinematic: Luni-solar and planetary precession (IAU Resolutions, as above) Nutation (IAU Resolutions, as above) Earth rotation (IAU Resolutions, as above) Polar Motion (using NIMA initial values generated the week before the orbit fit) + diurnal and semi-diurnal effects UT1-UTC (using NIMA initial values generated the week before the orbit fit) + Zonal tide effects + diurnal and semi-diurnal effects Integration step size: 300 seconds, reduced to 10 seconds during eclipse boundary crossings ORBIT ESTIMATION METHOD Kalman Filter/RTS Smoother (Square Root Information implementation) Initial conditions: From previous fit Solution parameters: Satellite state vector in element form at trajectory epoch -- semi-major axis eccentricity * sin(argument of perigee) eccentricity * cos(argument of perigee) inclination mean anomaly + argument of perigee right ascension of the ascending node Satellite clock parameters -- Time offset, Frequency offset Monitor station clock parameters (excluding master station) -- Time offset, Frequency offset Polar motion parameters -- Pole and pole rate components along Greenwich meridian, Pole and pole rate components along meridian 90 deg west of Greenwich, Rate of change and acceleration of UT1-UTC Satellite radiation pressure parameters -- Radiation pressure scale, and Y-axis acceleration Tropospheric refraction -- One stochastic zenith delay parameter per station Minimum range observation uncertainty(1-sigma):100 cm (IGS Stations) 100 cm (Station 85128) 80 cm (Station 85130) 40 cm (other stations) Minimum range difference observation uncertainty (1-sigma): 1.5 cm Process noise in Kalman Filter: Radiation pressure (each satellite)-- Decorrelation time 14,400 s Steady state sigmas -- SCALE 0.05 Y-AXIS 0.5 X 10**-12 km/s**2 Tropospheric refraction variance rate: 2.89 cm**2/hr Station clock white noise spectral density: (each station) -- Time offset 0.1111 X 10**-2 (microseconds)**2/s Frequency offset 0.1111 X 10**-8 (ppm)**2/s Satellite clock white noise spectral density: (each satellite) Time offset 0.1111 X 10**-2 (microseconds)**2/s Frequency offset 0.1111 X 10**-8 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s SATELLITE CLOCK ESTIMATION METHOD Kalman Filter/RTS Smoother (Square Root Information implementation) Orbit solutions from above method are held fixed for satellite clock estimation Solution parameters: Satellite clock parameters -- Time offset, Frequency offset Monitor station clock parameters (excluding master station) -- Time offset, Frequency offset Tropospheric refraction -- One stochastic zenith delay parameter per station. Minimum range observation uncertainty(1-sigma):100 cm (IGS Stations) 100 cm (Station 85128) 80 cm (Station 85130) 40 cm (other stations) Minimum range difference observation uncertainty (1-sigma): 15.0 cm Process noise in Kalman Filter: Tropospheric refraction variance rate: 2.89 cm**2/hr Station clock white noise spectral densities: NGA stations and Air Force Colorado Springs station: Time offset 0.1944 X 10**-8 (microseconds)**2/s Frequency offset 0.4440 X 10**-19 (ppm)**2/s Air Force stations (except Colorado Springs) and IGS stations: Time offset 0.3456 X 10**-8 (microseconds)**2/s Frequency offset 0.4440 X 10**-19 (ppm)**2/s Satellite clock white noise spectral densities: Satellite Block IIR Rubidium clocks Time offset 0.8640 X 10**-9 (microseconds)**2/s Frequency offset 0.1110 X 10**-18 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite Block II/IIA Rubidium clocks Time offset 0.1944 X 10**-8 (microseconds)**2/s Frequency offset 0.1110 X 10**-18 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite Cesium clocks Time offset 0.13824 X 10**-7 (microseconds)**2/s Frequency offset 0.1000 X 10**-17 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Satellite 'Noisy' Cesium clocks Time offset 0.2000 X 10**-7 (microseconds)**2/s Frequency offset 0.1110 X 10**-16 (ppm)**2/s Frequency drift 0. (ppm/s)**2/s Reference: Swift, E., Mathematical Description of the GPS Multi-Satellite Filter/Smoother, NSWCDD Report (Oct. 2001). Of course the operative phrase in this post is "Periodic relativistic effects". I challenge "Sam Wormley" to post one or more examples of these "Periodic relativistic effects" adjustments, and show how it proves that GR was essential to the design and operation of the GPS system, and if he is able, to show how the "Periodic relativistic effects" adjustment, proved GR to the exclusion of other factors. I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. -- Tom Potter http://tompotter.us
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#4
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
Tom Potter wrote:
Of course the operative phrase in this post is "Periodic relativistic effects". I challenge "Sam Wormley" to post one or more examples of these "Periodic relativistic effects" adjustments, and show how it proves that GR was essential to the design and operation of the GPS system, and if he is able, to show how the "Periodic relativistic effects" adjustment, proved GR to the exclusion of other factors. I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. Potter, don't you ever get tired of making a fool of yourself?
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#5
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
Tom Potter wrote:
Of course the operative phrase in this post is "Periodic relativistic effects". I challenge "Sam Wormley" to post one or more examples of these "Periodic relativistic effects" adjustments, and show how it proves that GR was essential to the design and operation of the GPS system, and if he is able, to show how the "Periodic relativistic effects" adjustment, proved GR to the exclusion of other factors. I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. Potter, don't you ever get tired of making a fool of yourself?
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#6
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
TossPotter wrote:
I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. And luckily for the rest of us, they ignored them all.
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#7
April 4th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
TossPotter wrote:
I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. And luckily for the rest of us, they ignored them all.
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#8
April 6th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
"Tom Potter" wrote:
"Sam Wormley" wrote in message ... NGA GPS Ephemeris/Station/Antenna Offset Documentation Ref: http://earth-info.nga.mil/GandG/sath...c2004_04a.html Effective date April 05, 2004 snip I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data.  Thanks Tom. I needed that! Jim
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#9
April 6th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
"Tom Potter" wrote:
"Sam Wormley" wrote in message ... NGA GPS Ephemeris/Station/Antenna Offset Documentation Ref: http://earth-info.nga.mil/GandG/sath...c2004_04a.html Effective date April 05, 2004 snip I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. Thanks Tom. I needed that! Jim
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#10
April 6th 04
posted to sci.physics
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NGA GPS Ephemeris/Station/Antenna Offset Documentation
"Jim" wrote in message ... "Tom Potter" wrote: "Sam Wormley" wrote in message ... NGA GPS Ephemeris/Station/Antenna Offset Documentation Ref: http://earth-info.nga.mil/GandG/sath...c2004_04a.html Effective date April 05, 2004 snip I must mention, that I used to call on the old "Aeronautical Chart and Information Center" in St Louis, and I gave them a lot of good ideas, on how to gather, analyze and store data. Thanks Tom. I needed that! Although I suspect this post is sarcasm, I dare say that the poster was unaware of how the state of the art was progressing in the 60's and 70's. Many of the more bureaucratic companies and organizations were using comptometers, keypunches, COBOL, and all kinds of old technologies, long after the state of the art passed them by. As a matter of fact, government educators were still training millions of people to program in COBOL ( And ADA), and to keypunch when almost no one was using these technologies. You should have seen some of the stepper switch, vacuum tube flip flops, and switch panels, used in digital applications in the 60's and 70's, and the labor intensive and error prone ways that aerial photos were analyzed, in those days. Of course, some places, like the University of Michigan Radiation Labs, used advanced methods that few people even know about today, such as optical computers to recognize RADAR signatures, to analyze RADAR signals that had been stored on the first, low cost, two inch tape, Ampex, video recorders. They used the best coherent sources available, even before LASERs came on the scene, and managed to spot the missile construction in Cuba using this technology. -- Tom Potter http://tompotter.us
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