Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Performance Processing Scheme from Level 0 to Level 3 GOCE Mature Processing Methods and Algorithms The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 59 Performance Simulation Input GOCE mission characteristics measurement duration orbit 12 months almost circular altitude 250 km 96.5 un-synchroneous) position errors in monitoring the SST high-low (GPS/GLONASS) x (along track) y (cross-track) z (radial) 2 cm / Hz 1 cm / Hz 3 cm / Hz gravity gradiometer error spectrum frequency f < 10-3 Hz frequency 510-3 < f < 10-1 Hz full diagonal instrument (Vxx,Vyy,Vzz) and Vxz 1/f coloured noise white noise < 510-3 E / Hz measurement sampling time 1 second The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 60 Performance End-to-End Simulation Scheme The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 61 Performance Four Error Classes GOCE instrument errors satellite errors instrument/satellite coupling errors post processing errors The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 62 Performance The 4 Error Classes: Simulated Results Instrument Error Coupling Error Satellite Error Post-Flight Error GOCE this total error is used in the geoid and gravity field retrievals Total Error The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 63 Performance Spherical Harmonic Error Spectrum The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 64 Performance Spectral Error Results GOCE 1 cm geoid and 1 mgal gravity field accuracies are well recovered at wavelength of 100 km (degree and order 200) The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 65 Performance Spatial Error Results GOCE 1 cm geoid and 1 mgal gravity field accuracies are well recovered at wavelength of 100 km (degree and order 200) for all latitudes except near the poles. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 66 Performance Science Requirements: Summary GOCE science requirements AP PLICATION ACCURACY Gravity (mGal) 1-2 SP AT IAL RESOL UT ION half wavelength - D (km) 100 sedimentary basins rifts tectonic motions seismic hazards 1-2 1-2 1-2 1 50-100 20-100 100-500 100 ocean lithosphere / asthenosphere 0.5 100-200 G eoid (cm) lithosphere / upper mantle density continental lithosphere SO LID EARTH short scale OCEANOG RAP HY ICE SHEETS GE ODESY basin s cale rock basement ice vertical movements lev elling by GPS unified height systems INS orbits 1-2 0.2 ~ 0.1 2 1 1 SEA LEVE L CHANG E are 100 200 1000 1-5 50-100 100-1000 100-1000 100-20000 ~ 1-5 100-1000 ~ 1-3 100-1000 Many of the above applications, with their specific requirements, relevant to studies of sea level change The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 67 Performance Simulation Results GOCE simulated GOC E perform ance spatia l resolution D (half wavelength ) m aximum deg ree L (corresponds to D ) ge oid heig ht [mm ] gravity anoma ly [m Gal] 1000 km 20 0.4 0.0006 400 km 50 0.5 0.001 200 km 100 0.6 0.03 100 km 200 2.5 65 km 300 ~ 45 10 0.08 1 ~2 the simulated results suggest excellent performance versus scientific requirements The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 68 Performance Solid Earth Physics The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 69 Performance Oceanography The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 70 Performance Geodesy The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT GOCE S 71 Conclusions Uniqueness and Complementarity GOCE • GOCE will be the first gravity gradiometer in space • an ambient temperature, capacitive gradiometer instrument is selected in combination with GPS high-low tracking • GOCE will map the Earth’s gravity field in three dimensions providing a: - geoid error < 1 cm at 100 km spatial resolution - gravity field error << 1 mgal at 100 km spatial resolution • The GOCE data will complement data from altimetric missions, Oersted, CHAMP, GRACE, ICESAT and Cryosat The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 72 Conclusions Advancement of European E.O. capabilities GOCE • the gradiometer accelerometers and GPS receiver are based on European technology • the drag free system technology offers new opportunities in a wide range of applications including E.O. from low orbit altitude • a multi-disciplinary user community within fields of Solid Earth Physics, Geodesy and Oceanography is well prepared to utilize the new and accurate gravity field and geoid data at high spatial resolution The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 73 Conclusions Feasibility and Level of Maturity GOCE • all technologies have been demonstrated (except micro-thrusters) and the development schedule is acceptable • an end-to-end and closed loop simulator provides realistic and comprehensive insight into system performance from the sensor level to the retrievals of the gravity field and geoid signals • the processing schemes (from Level 0 to Level 3) and algorithm maturity are meeting the requirements • impact studies show very promising results for applications in the disciplines of solid Earth physics, absolute ocean circulation and geodesy The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 74 Conclusions Timeliness and Programmatics GOCE • the GOCE Mission is very timely in the context of the user needs and their associated readiness • no implementation constraints exist • the proposed launch in 2004 is in the low activity region of the solar cycle) • the expected launch in late 2006 still OK. The Four Candidate Earth Explorer Core Missions Consultative Workshop 12-14 October 1999, Granada, Spain, Revised 2006-01-05 by CCT S 75