Electron number density profiles derived from radio occultation on the CASSIOPE spacecraft

Shume, E. B.; Vergados, Panagiotis; Komjáthy, A.; Langley, Richard B.; Durgonics, Tibor

doi:10.1002/2017rs006321

Cited by 5 publications

(3 citation statements)

References 24 publications

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“…The GPS Attitude and Profiling Experiment (GAP) on Swarm-E consists of five GPS receivers. Electron number density profiles have been derived from radio measurements using GPS to Swarm-E satellite radio links (Shume et al 2017) and these were shown to be in good agreement with those estimated from ionosondes. Differences in the characteristics of the electron number density profiles retrieved from radio occultation over landmasses and oceans exhibited different characteristics and these differences were attributed to wave coupling mechanisms operating over oceans and landmasses.…”

Section: The High-latitude Ionospherementioning

confidence: 80%

Variability of Ionospheric Plasma: Results from the ESA Swarm Mission

et al. 2022

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Swarm is the first European Space Agency (ESA) constellation mission for Earth Observation. Three identical Swarm satellites were launched into near-polar orbits on 22 November 2013. Each satellite hosts a range of instruments, including a Langmuir probe, GPS receivers, and magnetometers, from which the ionospheric plasma can be sampled and current systems inferred. In March 2018, the CASSIOPE/e-POP mission was formally integrated into the Swarm mission through ESA’s Earthnet Third Party Mission Programme. Collectively the instruments on the Swarm satellites enable detailed studies of ionospheric plasma, together with the variability of this plasma in space and in time. This allows the driving processes to be determined and understood. The purpose of this paper is to review ionospheric results from the first seven years of the Swarm mission and to discuss scientific challenges for future work in this field.

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Section: The High-latitude Ionospherementioning

confidence: 80%

Variability of Ionospheric Plasma: Results from the ESA Swarm Mission

et al. 2022

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“…GAP was conceived and developed by the University of New Brunswick in partnership with the University of Calgary and Bristol (now Magellan) Aerospace. RO processing and data analysis have been undertaken by colleagues at various institutes (Shume et al 2015(Shume et al , 2017Watson et al 2018;Perry et al 2019).…”

Section: Introductionmentioning

confidence: 99%

CASSIOPE orbit and attitude determination using commercial off-the-shelf GPS receivers

et al. 2019

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As part of the "GPS Attitude, Positioning, and Profiling experiment (GAP)" of the Canadian CASSIOPE science and technology mission, a set of four geodetic GPS receivers connected to independent antennas on the top-panel of the spacecraft can be operated concurrently to collect dual-frequency code and phase measurements on both the L1 and L2 frequencies. The qualification of the commercial off-the-shelf (COTS) GPS receivers is discussed, and flight results of precise orbit and attitude determination are presented. Pseudorange and carrier phase errors amount to roughly 65 cm and 8 mm for the ionospherefree dual-frequency combination, which compares favorably with other missions using fully qualified space GPS receivers and is mainly limited by choice of simple patch antennas without choke rings. Precise orbit determination of CASSIOPE using GPS observations can achieve decimeter-level accuracy during continued operations but suffers from onboard and mission restrictions that limit the typical data availability to less than 50% of each day and induce regular long-duration gaps of 4-10 h. Based on overlap analyses, daily peak orbit determination errors can, however, be confined to 1 m 3D on 84% of all days, which fulfills the mission needs for science data processing of other instruments. The attitude of CASSIOPE can be determined with a representative precision of about 0.2° in the individual axes using three GAP receivers and antennas. Availability of dual-frequency measurements is particularly beneficial and enables single-epoch ambiguity fixing in about 97% of all epochs. Overall, the GAP experiment demonstrates the feasibility of using COTS-based global navigation satellite system receivers in space and the benefits they can bring for small-scale science missions.

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“…In addition, high‐latitude GAP‐O peak F region density ( N m F 2 ) and height ( h m F 2 ) parameters were compared with ground‐based ionosonde and digisonde measurements. Shume et al () compared low‐latitude to midlatitude GAP‐O electron density profiles with electron densities of FORMOSAT‐3/COSMIC, ground ionosondes, and the International Reference Ionosphere (IRI).…”

Section: Introductionmentioning

confidence: 99%

Enhanced Polar Outflow Probe Ionospheric Radio Occultation Measurements at High Latitudes: Receiver Bias Estimation and Comparison With Ground‐Based Observations

et al. 2018

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This paper presents validation of ionospheric Global Positioning System (GPS) radio occultation measurements of the GPS Attitude, Positioning, and Profiling Experiment occultation receiver (GAP‐O). GAP is one of eight instruments comprising the Enhanced Polar Outflow Probe (e‐POP) instrument suite on board the Cascade Smallsat and Ionospheric Polar Explorer (CASSIOPE) satellite. One of the main error sources for certain GAP‐O data products is the receiver differential code bias (rDCB). A minimization of standard deviations (MSD) technique has shown the most promise for rDCB estimation, with estimates ranging primarily from −40 to −28 total electron content units (TECU = 1016 el m−2; 21.6 to 15.1 ns), including a long‐term decrease in rDCB magnitude and variability over the first 3 years of instrument operation. In application of the MSD method, the sensitivity of bias estimates to ionospheric shell height are as large as 4.5 TECU per 100 km. MSD calculations also agree well with the “assumption of zero topside TEC” method for rDCB estimate at satellite apogee. Bias‐corrected topside TEC of GAP‐O was validated by statistical comparison with topside TEC obtained from ground‐based GPS TEC and ionosonde measurements. Although GAP‐O and ground‐based topside TEC had similar variability, GAP‐O consistently underestimated the ground‐derived topside TEC by up to 7 TECU. Ionospheric electron density profiles obtained from Abel inversion of GAP‐O occultation TEC showed good agreement with F region densities of ground‐based incoherent scatter radar measurements. Comparison of GAP‐O and ionosonde measurements revealed correlation coefficients of 0.78 and 0.79, for peak F region density and altitude, respectively.

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Electron number density profiles derived from radio occultation on the CASSIOPE spacecraft

Cited by 5 publications

References 24 publications

Variability of Ionospheric Plasma: Results from the ESA Swarm Mission

Variability of Ionospheric Plasma: Results from the ESA Swarm Mission

CASSIOPE orbit and attitude determination using commercial off-the-shelf GPS receivers

Enhanced Polar Outflow Probe Ionospheric Radio Occultation Measurements at High Latitudes: Receiver Bias Estimation and Comparison With Ground‐Based Observations

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