Propagation Experiment at <italic>Ka</italic>-Band in French Guiana: First Year of Measurements

Abstract

ONERA, the French Aerospace Lab, and CNES, the French Space Agency, are currently running a Ka-band propagation experiment at the Guiana Space Centre (CSG) in Kourou (French Guiana). A rain gauge and a beacon receiver able to record the 20.2 GHz beacon signal of the Amazonas 3 satellite have been deployed. The equipment is operational since January 1, 2017 and the duration of the experiment has been set to 3 years. This letter addresses some results of the first year of measurements (from January 2017 to December 2017). The annual and monthly Complementary Cumulative Distribution Functions of rainfall rate and rain attenuation are presented as well as a comparison with the rain attenuation prediction method recommended in ITU-R P.618-13.

Rainfall Estimation from Tropospheric Attenuation Affecting Satellite Links

“…Rain-induced attenuation A R is extracted starting from the received beacon power levels that were collected by the NASA Ka-band receiver located in Milan. The typical, well-established approach to derive A R from the received beacon power P R is to first low-pass filter P R with a typical cut-off frequency of 0.03 Hz, to remove scintillations [14]. Afterwards, rain events are identified, usually both by taking advantage of the local rain sensors (if present) and by inspecting the trend of P R : indeed, the impact of rain on the link might be longer than what is recorded by the disdrometer, especially at the beginning and/or the end of the event.…”

“…Afterwards, rain events are identified, usually both by taking advantage of the local rain sensors (if present) and by inspecting the trend of P R : indeed, the impact of rain on the link might be longer than what is recorded by the disdrometer, especially at the beginning and/or the end of the event. Afterwards, rain attenuation is calculated by subtracting from P R the power level that is the linear interpolation of P R just before the beginning and after the end of each event [14]. Lastly, the attenuation data are averaged to obtain a sampling period equal to the one of the disdrometer (1-min per sample).…”

“…An example of such a well-established procedure, which, for instance, is also employed in [14], is depicted in Figures 2-4, where the sequence of operations (low-pass filtering, rain event detection, and estimation of the reference power level during the rain event through linear interpolation) are applied to the received power on 7th September 2017.…”

“…Recently, increasing attention has been paid to the exploitation of satellite downlink signals for the estimation of rainfall, as most of the commercial satellite communication systems currently operate in the Ku band (12)(13)(14)(15)(16)(17)(18) and the K band (18)(19)(20)(21)(22)(23)(24)(25)(26): in fact, in such a frequency range, rain significantly impairs the propagation of electromagnetic waves [5,6]. Some approaches have been developed for estimating the intensity of precipitation on a large scale from space-borne signals, with a spatiotemporal resolution between that of rain gauges and of weather radars.…”

Rain Statistics Investigation and Rain Attenuation Modeling for Millimeter Wave Short-Range Fixed Links

“…Both time diversity and orbital diversity were studied. In [7], rain attenuation was measured at 20.2 GHz based on Amazonas 3 satellite and compared with ITU-R P.618-13 model. In [8], rain attenuation was measured at 20.2 GHz and 30.5 GHz based on a GSAT-14 satellite in a tropical region.…”