engleski

Low-cost space weather sensor for identification and estimation of GNSS perfomance space weather effects

Space weather and ionospheric effects have already been identified as a major sources of GNSS positioning errors. Attempts to mitigate the problem of GNSS ionospheric delay on the global scale provide modest to good results, mainly due to inability to model properly fast-developing ionospheric disturbances, both locally and globally. In due course, continuous monitoring of the space weather and ionospheric dynamics becomes a fundamental task in understanding and modelling space weather effects on GNSS performance. A number of international networks of GNSS reference stations has been established recently, with the aim to provide geospatially distributed sets of GNSS and ionospheric (derived from dual-frequency receivers) data observables. Despite the efforts, the international networks of GNSS reference stations either still do not cover equally the land areas, or the observables collected are not available to scientists and researchers. At the same time, the alternative means of low-cost sensing the ionospheric disturbances can be put in operation fairly easily and with wider geospatial coverage, providing less accurate but more well geospatially dispersed observables. In addition, the deployment of the alternative means of ionospheric disturbance monitoring provide an excellent opportunity to students, young researchers and general public to get involved in research activities for the benefits for society. Here the experience in combined utilisation of the VLF SID (Sudden Ionospheric Disturbance) monitor and a single-frequency maritime GPS receiver for identification and estimation of space weather effects on GPS performance is presented. The VLF radio SID monitor is developed by the Stanford University team in order to encourage wider perception and understanding of the ionospheric disturbances. The experimental network of four reference stations has been established in northern Croatia. The VLF signal strength observables have been combined with space weather and ionospheric indices with the aim to contribute to understanding of the patterns of local ionospheric dynamics. At the same time, the correlation between the VLF signal strength and GPS positioning errors has been observed, aiming to develop a model for identification and estimation of the ionospheric effects on GPS performance. Paper concludes with identified relations between local ionospheric dynamics and GPS positioning errors, and outlines plans for further research in mitigation of space weather effects on GPS perfomance

cost sensors ; ionospheric disturbance ; satellite navigation

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