Gaussian-beam weak scintillation on ground-to-space paths: compact descriptions and Rytov-method applicability

Abstract

Recent papers comparing weak-scintillation data from waveoptics simulations with predictions derived from the Rytov perturbation method for ground-to-space Gaussian beams have revealed a region of inaccuracy in the Rytov-based predictions. The discrepancy region is defined by beam diameter and focus settings that place the target in the beam far field and the turbulence in the transmitter near field. Under such conditions turbulence-induced beam wander dominates the scintillation at the target. We develop a solution to the turbulent propagation physics that is applicable in the discrepancy region, and demonstrate agreement in scintillation behavior with our own wave-optics simulation data and with predictions from a rigorous extended Huygens-Fresnel analysis. A combination of our solution and Rytov-based scintillation theory can be used to yield accurate scintillation predictions throughout the weak-scintillation regime for ground-to-space beams. Separately, we show that Rytov-based scintillation theory best describes the physics of a wander-tracking transmitter ͑where beam wander has been removed from the propagation physics͒ at the mean transmitter aim point on the target plane, as opposed to the physics of a stationary transmitter. © 2005 Society of Photo-Optical Instrumentation Engineers.

Optical communications in turbulence: a tutorial

“…24 as a function of beam radius W 0 along with computer simulation data. 42 The tracked results are tip/ tilt-corrected based on Eq. ( 121), whereas the untracked results come from Eq.…”

“…Fig.24On-axis scintillation index for both tracked (tilt-corrected) and untracked collimated beams to LEO as a function of beam radius (simulation results courtesy of G. J. Baker42 ).…”

Statistical and temporal irradiance fluctuations modeling for a ground-to-geostationary satellite optical link

“…These studies usually rely on the Rytov perturbation method (RPM) [6]. However, discrepancies appear for ground-to-space paths which are usually attributed to beam wander [7,8]. Moreover, the temporal aspects of the irradiance fluctuations are usually described by the number of fades per second and the mean fade time.…”

Analysis of beam wander effects for a horizontal-path propagating Gaussian-beam wave: focused beam case

“…1,12,[15][16][17] Estimates of the induced scintillation from beam wander were given in Baker and Benson, 17 and a similar study by Andrews et al 12 led to a different analytic expression for the wander-induced scintillation associated with an uplink path to space. The derivation of the scintillation expressions given in this section have been published elsewhere, 7,12 so we will simply summarize the theoretical models rather than derive them again.…”