We estimate spatial gradients in the ionosphere using the Global Positioning System (GPS) and GLONASS (Russian global navigation system) observations, utilising data from multiple GPS stations in the vicinity of Murchison Radio-astronomy Observatory (MRO). In previous work the ionosphere was characterised using a single-station to model the ionosphere as a single layer of fixed height and this ...

Triggered by several severe ionosphere storms that have occurred in recent years, research has been done to studying those anomalies, the physics behind them, and their potential impact on augmented GNSS users. In previous work [1-5], it was found that such ionosphere anomalies can threaten LAAS users under extreme conditions. To determine this, a spatial-gradient “threat model” was established...

The long-term goal of this project is to study waves, irregularities, and propagation in the earth's ionosphere, particularly with respect to GPS. The project has two foci: first, to understand how the ionosphere affects GPS signals and second, how GPS can be used for remote sensing of the ionosphere. In association with these goals, we additionally conduct in situ experiments on satellites and...

The Earth’s magnetic field creates a cavity in interplanetary space, called the magnetosphere. Physical processes in this region of space determine how mass and energy from the solar wind reach the ionosphere, the partially ionized upper atmosphere. Magnetosphere and ionosphere are strongly coupled. Together, they modulate the impacts of solar activity on man and technology. This paper presents...

Model calculations indicate that the lower ionosphere of Saturn is controlled by photochemical processes, with basic features similar to the Jovian ionosphere. The scale height of the upper ionosphere is large (•3350 km). A peak electron density of •10•cm -s 2250 km above a 10•9cm -a reference level is expected assuming an eddy coefficient at the homopause of 1.3 x 10øcmas -• and a relatively h...

Venus has no internal magnetic dynamo and thus its ionosphere and hot oxygen exosphere dominate the interaction with the solar wind. The solar wind at 0.72AU has a dynamic pressure that ranges from 4.5 nPa (at solar max) to 6.6 nPa (at solar min), and its flow past the planet produces a shock of typical magnetosonic Mach number 5 at the subsolar point. At solar maximum the pressure in the ionos...

As reported in [2,4,5], previous Stanford research has identified the potential for severe ionosphere spatial gradients to affect Local Area Augmentation System (LAAS) integrity. In previous work [1], real-time position-domain geometry screening was used to maximize LAAS availability in the presence of ionosphere anomalies by broadcasting an inflated value of σ vig so that the maximum-ionospher...

An L band geosynchronous synthetic aperture radar (GEO SAR) differential interferometry system (D-InSAR) will be obviously impacted by the background ionosphere, which will give rise to relative image shifts and decorrelations of the SAR interferometry (InSAR) pair, and induce the interferometric phase screen errors in interferograms. However, the background ionosphere varies within the long in...

in this study, absorption of high frequency radio waves in the ionospheric plasma have beeninvestigated. the wave equation was obtained in terms of ionospheric parameters. the numerical values ofthe absorption have been calculated for 4 mhz, 4.5 mhz and 5 mhz waves. the necessary parameters forcalculation have been obtained using an international reference ionosphere (iri) model. the altitudina...

This paper describes the impact that extreme ionospheric spatial gradients occurring during severe ionosphere storms have on GNSS Ground Based Augmentation Systems (GBAS) and how the U.S. Local Area Augmentation System (LAAS) mitigates the integrity risk due to these events. Gradients in slant ionosphere delay of as large as 425 mm/km over baselines of 40 – 100 km have been observed in CONUS du...