GPS Orbits
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Transcript of GPS Orbits
GPS Orbits
Jim Rohde, Bob Dulaney, Bill Kass, Steve Hilla
National Geodetic Survey 2005 ConvocationOctober 24-28, 2005Silver Spring, MarylandHoliday Inn8777 Georgia Avenue
Improvements to Orbit Processing in 2004/2005
• Stars Procedure – Added redundant baselines by processing sub-networks and combining their normal equations
• Integer phase ambiguity fixing
• Moved production from HP to SUN x86 platform
• Orbit adjustment done more rigorously (ADJEPH)
• Fixed pole tide sign error
• Improved sub-daily EOP model
• Absolute Antenna Phase Center Offsets and PCVs
• Monuments as Reference Points (future)
• Updated Ocean Tide Loading Model (future)
Multiyear CORS
• Motivation– To provide long-term consistent solution of all data– Results used for CORS coordinates and velocities –
realization of NSRS– Implement recent improvements in GPS Data
Processing
• Time Span – 1994 through 2005
• Reference Frame IGb00 – IGS realization of ITRF00
Multiyear CORS (cont.)
• Procedure
– Streamline processing to fit with routine operations and avoid repeated reprocessing
– Step 1: Daily Global Solution – orbits, EOPs, IGS and some CORS site positions; solutions stacked weekly for the IGS
– Step 2: Daily CORS Solution – CORS and some North American IGS site positions; solutions stacked weekly for NAREF
– Step 3: Daily Multiyear Solution – combination of all normal equations for orbits, EOPs, and all IGS and CORS site positions
Multiyear CORS (cont.)
– Step 4: Weekly Multiyear Solution – Stack 7 daily multiyear solutions and archive results
– Step 5: Full Multiyear solution – Stack all weeks together to solve for site velocities
• Schedule – Begin processing January 2006, complete in 3-6 months