Modeling the Effects of Topography on Delay-Doppler Maps

Abstract

A method for simulating delay-Doppler maps (DDMs) of global navigation satellite system signals reflected from land surfaces with heterogeneous terrain is developed from first principles. The method follows previous work for ocean DDMs in the geometric optics limit of the Kirchhoff approximation. Unlike the ocean method, however, where surface heights are assumed to be random with homogeneous statistics, this method decomposes the surface heights into a deterministic part obtained from a digital elevation map (DEM) and a random part representing the residual between the surface and the DEM. The method accounts for the displacement of reflected power into bins of lower delay due to raised surface terrain. The method also provides for the modulation of the normalized bistatic radar cross section by DEM-derived surface slopes over the glistening zone of the DDM. A technique to register Cyclone Global Navigation Satellite System (CYGNSS) DDM bins in delay-Doppler space for land applications is also proposed. The DEM-based method is applied to a CYGNSS track over the Soil Moisture Sensing Controller And oPtimal Estimator (SoilSCAPE) site at Tonzi Ranch, CA, USA. The DEM-based method has potential application for spaceborne monitoring of a variety of environmental parameters.

Analytical Kirchhoff Solutions (Aks) and Numerical Kirchhoff Approach (Nka) for First-Principle Calculations of Coherent Waves and Incoherent Waves at P Band and L Band in Signals of Opportunity (Soop)

“…Results show that the f 2 profiles of fine scale topography have significant effects. The results of three Kirchhoff approaches fall in-between the results of the two versions of Geometric Optics (GO) approximations to the Kirchhoff integral [1,2]. The two GO versions are with and without attenuation due to microwave roughness.…”

“…It was first used in GNSS-R for ocean reflection [13] by truncating the ocean spectrum to eliminate the small roughness so as to derive the pdf of slopes. For GNSS-R land applications, it was also used by [1] and [2]. However, a second version of geometric optics in ocean problem was proposed [14] in which the attenuation factor exp(−4k 2 h 2 1 cos 2 θ i ) is attached to account for the effects of microwave small roughness.…”

An Improved Method for Pan-Tropical Above-Ground Biomass and Canopy Height Retrieval Using CYGNSS

“…To further develop the potential of GNSS-R in the forest biomass, this paper investigates the effects of the soil moisture on AGB/CH retrievals. In addition, the effects of topography on spaceborne GNSS-R signals have been modeled and verified in previous works [44,45]. However, the purpose of this paper was to consider and remove the effects of soil moisture on AGB/CH retrievals.…”

Peer Review #2 of "Emerging IoT domains, current standings and open research challenges: a review (v0.1)"

“…This service delivery model emphasizes the need for low-cost micro-satellites to deliver high bandwidth, high data rate services to connect with ground systems. The research in this domain primarily focuses on deploying these micro- Manuscript to be reviewed Computer Science Reference(s) Application Campbell et al (2020) Terrain and topography monitoring using Global Navigation Satellite System Reflectometry (GNSS-R) Huang et al (2019) Landslide monitoring for early detection and disaster recovery applications Anghel et al (2019) Monitoring large built structures using satellite interferometry Chen et al (2020b) Urban densification analysis using satellite imagery Mendez-Espinosa et al (2020) Analysis of air quality during pandemics and periods of extended lockdowns Ouaadi et al (2020) Monitoring wheat crops using satellite interferometry Castaño et al (2020) Disaster prevention scheme to monitor thermal anomalies and volcanic eruptions using infrared satellite imagery Chen et al (2020a)…”