190 likes | 295 Views
Swarm End-to-End Mission Performance Simulator. Recovery of the Lithospheric Magnetic Field Stefan Maus et al. GeoForschungsZentrum Potsdam Final Presentation, 18 June 2004 ESTEC, Noordwijk, NL. 300. 667. aeromagnetic and marine surveys. 133. 60. Goal:
E N D
Swarm End-to-End Mission Performance Simulator Recovery of the Lithospheric Magnetic Field Stefan Maus et al.GeoForschungsZentrum Potsdam Final Presentation, 18 June 2004ESTEC, Noordwijk, NL
300 667 aeromagnetic and marine surveys 133 60 Goal: Bridge the gap in resolution between present satellite and aeromagnetic surveys Requirement: lithospheric field model to less than 300 km scales
Internal & External sources Expected signal spectrum at satellite altitude (400 km)
Constellation # 1(Proposal): • 2 Satellites at 550 km altitude,separated by 180° in orbit phase • 2 Satellites at 400 km altitude,separated by 500 to 1000 km along the orbit
Input Data Set for Constellation # 1 • Complete magnetic field of synthetic data • Removal of core field up to degree 13 • Considered spacecraft: SW1, SW2, SW3, SW5 • Noise-free data at 5s sampling
Constellation Constraints • Longitude separation at equator <25° • Time separation of equator crossings <1h
Spectral Degree Correlation derived from Constellation # 1
Constellation # 2: • 2 Satellites at 550 km altitude,separated by 180° in orbit phase • 2 Satellites at 400 km altitude,flying side-by-side separated by 1.5° in longitude
Inversion Approach for Constellation # 2 • Nightside data, 22 to 05 LT • Determination of external field on track-by-track basis • Utilization of field gradient, if two low satellites are considered • Inversion of complete mission (5 years) in one run
Degree Correlation for Constellation # 2 Separations: SW4/5 = 1.5°, SW4/6 = 12° in longitude
Sensitivity Matrixrelative errors forConstellation # 2, SW4/5
Azimuthal Separation Sensitivity of gradient method versus resolution in spherical harmonics for three different spacecraft separations in longitude
Evolution of Spacecraft Separation, Constellation # 2 Orbit maintenance by along-track manoeuvres Close orbit control of the pair
Degree Correlation high-resolution lithosphere model using SW4/7
Crustal signal • Summary • The Swarm constellation of satellites offers a large improvement in model resolution • The goal to resolve the lithospheric field to degree and order 130 could be reached • Employing the magnetic field gradients in the inversion enhances the resolution of small scales significantly • Selecting an optimal orbit constellation is an important issue for this objective
Proposed Next Steps • Refine the gradient method in the inversion technique using realistic orbit configurations • Study the feasibility of optimal orbit constellations • Assess the impact of mid-latitude ionospheric irregularities and F-region currents on the gradient method