Optical Quantum Properties of GPS Signal Propagation Medium—D Layer

Abstract

Uncontrollable sporadic distortions of global positioning system (GPS) satellite signals, caused by phase and group delays in the propagation of electromagnetic radiation through a medium, take place during periods of high solar activity and formation of geomagnetic disturbances in the Earth's ionosphere. Determining ways of ensuring sustainability of GPS systems is a fundamental scientific and technical challenge. Above-background incoherent ultra-high frequency (UHF) radiation is formed at altitudes of the E and D layers of the Earth's ionosphere. Wavelengths of this radiation correspond to a range from 1 dm to 1 mm. This emission is caused by transitions between Rydberg states of atoms and molecules, which are excited by electrons in plasma and are surrounded by a neutral particle environment. Reliable information about UHF radiation flux power in this wavelength range is not currently available. The answer to this question depends entirely on the knowledge of impact and radiation quenching of Rydberg state dynamics and the kinetics of their location in a lower ionosphere, i.e., on the quantum optical properties of a perturbed environment. Analysis of existing experimental data has shown that UHF radiation is formed in the atmospheric layer located at altitudes of 60-110 km. A physical mechanism of satellite signal delay is caused by cascade resonance re-emissions of electromagnetic waves in the decimeter range while passing through this layer over a set of Rydberg states. The most promising approach to studies of medium optical quantum properties can be a simultaneous analysis of background additional noise and GPS signal propagation time delay, which determines a positioning error. Using standard methods of noise measurement, one cannot detect physical and