A Small Satellite-based System for Active and Passive Sounding of the Ionosphere, Direct Current (DC) through High Frequency (HF)

ABSTRACT: The design of a new instrument for a small satellite is described that incorporates the specifications for an RF Topside Ionospheric Sounder (TIS) with Double Probe (DP) electric field sensors. Six 7.5-m booms, configured into three orthogonal 15-m tip-to-tip dipoles and 3 orthogonal double probes (DP), are assumed. The proposed"DPTIS"instrument can be flown within or above the ionosphere. The TIS design scans frequencies from 0.1 - 30 MHz and specifies the wave polarization (O/X) in the ionograms and the echo angle-of-arrival for ionospheric skymaps. The TIS design uses LDI/UML heritage from the IMAGER/RPI instrument and ground-based Digisondes and provides high programming flexibility to accommodate diverse S/C orbits. Ionogram/radio-skymap cadences of 10 s will provide high spatial resolution. Heritage autoscaling software can derive real-time electron density profiles from the S/C altitude to the F2-layer peak. The double probe measurements use isolated spheres mounted at the end of the 6 antenna booms. The DP will measure the field components from ~DC to 1 KHz. Outside the ionogram/skymap time windows the DP voltages are continuously sampled at nominally 4 kS/s. The DP design and processing is based on heritage instrumentation that UNH developed and delivered for the MMS and other missions. BENEFIT: The DPTIS design is sufficiently flexible to fly on research missions in the F layer, both above or below the F2 peak for detailed studies of equatorial spread F and scintillations, or on a fleet of topside surveying missions for the mapping of the global ionosphere. Accurate near real-time topside electron density profiles can be ingested into the GAIM model and will constrain the model in terms of foF2, hmF2, and accurate topside profiles to ~1,000 km altitude in all regions including those currently inaccessible with ground-based observations.