The GPS radio occulation technique

By E. Kursinski, George Hajj, Stephen S. Leroy, B. Herman. 2000

225 citations recorded by the source corpus.

Radio occultation observations represent a planetary-scale optics experiment in which the atmosphere acts as a lens and alters the propagation velocity and paths of microwave signals passing through it. In this paper we review the process of inverting the radio occultation observations acquired using the Global Positioning System (GPS) in order to derive atmospheric quantities of interest including temperature, geopotential and water vapor. Beginning with geometric optics, we derive the Abel integral used to transform the observations into profiles of refractivity. In the process, we characterize why the Abel transform works so well as a first approximation for deriving atmospheric profiles. We discuss the resolution of the observations and the improvements that can be achieved via the backpropagation concept where the receiver’s position is effectively moved closer to the limb of the Earth in post-processing. We discuss several factors that complicate the observations in the Earth’s troposphere including critical refraction and atmospheric multipath. Critical refraction refers to the situation where the bending becomes so great that the occulted signal disappears whereas atmospheric multipath refers to the situation where multiple signal paths connect the transmitter and receiver. We describe the derivation of temperature, pressure and water vapor from the observations including the optimal combining of the occultation observations with weather and climate analyses. We describe some key issues in deriving profiles from real data including the correction of clock errors and ionospheric effects, and the estimation of the resolution and atmospheric Doppler in a self-consistent manner. We conclude by summarizing the expected and achieved accuracy and resolution.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/7253be494ec35945261c2d8980cd5f78e5686305

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Aerospace Engineering

In Astronomy and Astrophysics

In Atomic and Molecular Physics, and Optics

Richard Anthes

Citations in the corpus

A technical description of atmospheric sounding by GPS occultation (2002, background): “…et al., 1994; Mel- 17 bourne et al., 1994; Kursinski et al., 1995; Hoeg et al., 1995; Gorbunov, 1996; Gorbunov et al., 1996a,b; Kursin- 19 ski et al., 1997; Karayel and Hinson, 1997; Mortensen and Hoeg, 1998; Ahmad and Tyler, 1998; Ahmad and Tyler, 21 1999; Kursinski et al., 2000; Healy, 2001).”
Exploring earth's atmosphere with radio occultation: contributions to weather, climate and space weather (2011, unknown): “The RO method for obtaining atmospheric soundings is described by Kursinski et al. (1997, 2000), Lee et al. (2000), Steiner et al. (2001), Hajj et al. (2002), and Kuo et al. (2004).”
Applications of COSMIC to Meteorology and Climate (2000, methodology): “The radio occultation method for obtaining atmospheric soundings is described elsewhere in this issue (Kursinski et al., 2000).”
Effect of superrefraction on inversions of radio occultation signals in the lower troposphere (2003, background): “…(such as the Global Positioning System (GPS) and low Earth orbiting (LEO) satellites) [Melbourne et al., 1994; Hocke, 1997; Kursinski et al., 1997; Rocken et al., 1997; Steiner et al., 1999; Feng and Herman, 1999; Syndergaard, 1999; Kursinski et al., 2000; Wickert et al., 2001; Hajj et al., 2002].”
Planetary boundary layer heights from GPS radio occultation refractivity and humidity profiles (2012, background): “While the assumed 8 temperature error will affect the accuracy of the water vapor retrieval, its impact on the derived PBL height is expected to be small in the tropics and sub-tropics [Kursinski et al., 2000] (see also Sec.”
Full Spectrum Inversion of radio occultation signals (2003, background): “[2] In general terms, the radio occultation technique is based on the bending of radio waves caused by refractive index gradients in a planetary atmosphere [e.g., Kursinski et al., 1997, 2000].”
ARTS, the Atmospheric Radiative Transfer Simulator – version 2.2, the planetary toolbox edition (2017, methodology): “For satellite-to-satellite links, the user can instead select to make use of some standard analytical approximations (e.g., given in Kursinski et al., 2000, Sect.”