SBIR-STTR Award

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.

Keywords:
Topside Ionospheric Sounder, Double Probe E-Field Measurements, Electron Density Profiles, Spread F And Scintillation, Ionosphere, Small Satellite

It is proposed to build the breadboard functional proof unit of a new space borne instrument ?DPTIS? (Double-Probe & Topside Ionosphere Sounder) that simultaneously measures in situ electric fields and the vertical electron density profiles from the spacecraft altitude to the F2 layer peak. The instrument is designed for a small satellite and integrates an RF Topside-Ionosphere-Sounder (TIS) with Double-Probe (DP) electric field sensors. Availability of six booms, configured into three orthogonal dipoles and 3 isolated double probes, is assumed. The TIS scans from 0.1 - 30MHz and specifies the wave polarization (O/X) and the echo angles-of-arrival for ionospheric skymap construction. Heritage from IMAGER/RPI and Digisondes is used, providing high programming flexibility that can adapt to diverse spacecraft orbits. Ionogram cadences of 10s provide high spatial resolution. Heritage autoscaling software derives real-time electron density profiles from the spacecraft altitude to the F2 peak. For the double-probe measurements, isolated spheres are mounted at the end of six antenna booms. The DPs will measure the 3 electric field components from DC to 1 KHz. DP voltages are continuously sampled at 2.5kS/s. DP design and processing is based on heritage instrumentation that UNH developed and delivered for the MMS and other missions.

Benefit:
Unambiguous measurement of the topside electron density profiles will provide unique data for the specification of the topside electron density distribution, which is otherwise only provided by incoherent scatter radars at a few points and at limited times. Assimilation of these data into an ionospheric model like IRI RTAM or GAIM will for the first time provide an accurate real-time assimilative model for the ionospheric electron density specification up to the spacecraft altitude (~1000 km). A fleet of topside satellites with DPTIS can provide near real-time high resolution maps of foF2 and hmF2 over the oceans and land, complementing the ground-based ionosonde measurements, as well as global near real time specifications of the topside electron density profiles which are affecting all transionospheric radio signals, including GPS. Ionospheric research missions in the F layer, both above or below the F2 peak, for detailed studies of equatorial spread F and scintillations, or auroral and polar cap irregularity structures can easily be carried out with DPITS because of its flexible programmability.

Keywords:
Topside Ionosphere Sounder, Double Probe E-Field Measurements, Topside Electron Density Profiles, Spread F And Scintillation, Ionosphere, Iri Real-Time Assimilative Model