Engineering topics

Paolo De Matthaeis

Publications and source records attributed to Paolo De Matthaeis.

5 records

NASA NTRS2022

The Fourth Stokes Parameter for Geolocation in Passive Microwave Remote Sensing from Space

Polarimetric microwave radiometers such as SMAP are capable of measuring the fourth Stokes parameter in brightness temperature over the Earth surface. The value of this parameter is normally small but exhibits sharp spikes when the scene includes large differences in emission from the surface, such occur at land/water boundaries. In this manuscript, it is shown that these spikes can be used to accurately locate coastlines with potential application to geolocation in passive microwave remote sensing from space. Examples are presented using the L-band radiometer on SMAP, first with theory using calculations with the SMAP antenna pattern and orbit and then with SMAP measurements of the fourth Stokes parameter over Madagascar. Using the SMAP data, the coastline is located with a standard deviation less than 2 km. The results are consistent with the conventional approach used for geolocation of the SMAP radiometer footprint.

Passive Microwave Remote Sensing↗

NASA NTRS2021

Study of a Strong RFI Source at L-Band Using SMAP Radiometer Data

This paper presents an analysis of Radio Frequency Interference (RFI) in the 1.400-1.427 GHz frequency band. The study considers the sudden and strong increase of interference from a particular emitter in China that has been observed in July 2020 by radiometers from both ESA's SMOS (Soil Moisture Ocean Salinity) and NASA's SMAP (Soil Moisture Active Passive) missions. It provides an example of the characterization of a source of RFI and illustrates the capabilities of the SMAP radiometer receiver and RFI processing incorporated in it to identify and understand interference.

Radio Frequency Interface↗

NASA NTRS2021

Study of a Strong L-Band RFI Source

CN006 is the name given by the European Space Agency (ESA) in their reports on radio frequency interference (RFI) to an instance of RFI in the L-band spectral window at 1.413 GHz protected for passive use only. The source of the interference is located east of the Chinese city of Hangzhou in an area with radar installations. Its effect was initially indistinguishable from that of many such RFI sources observed by the ESA's SMOS and NASA's Soil Moisture Active Passive (SMAP) radiometers over China. However, in July 2020, the level of radiation increased dramatically reaching levels exceeding 1700000 K as reported by Soil Moisture and Ocean Salinity (SMOS) becoming the strongest source observed by SMOS. This article describes an analysis of this very strong source (a radar). It provides information to provide insight into an example of a well-defined source of RFI and illustrates the powerful capability of the SMAP radiometer receiver and RFI processing incorporated in it for identifying and understanding interference.

Radio Frequency Interface↗

NASA NTRS2020

Agenda Items of the World Radiocommunication Conference 2023 Relevant to Remote Sensing

The important task of deciding and revising frequency allocations at international level falls under the responsibility of the World Radiocommunication Conference (WRC) which is organized by a specialized agency of the United Nations, the Radiocommunications Sector of the International Telecommunications Union (ITU-R). A WRC is held every approximately four years for the purpose of updating the international Radio Regulations (RR). The most recent of these conferences, WRC-19, held at the end of 2019, also defined the Agenda Items for the next WRC that is scheduled to occur in 2023. Here, we review and discuss the WRC-23 Agenda Items that are likely to have the most impact on future remote sensing operations.

Spectrum Management↗

NASA NTRS2020

Retrieval of RFI Characteristics Using L-Band Satellite Data

Radio-frequency interference (RFI) has had a detrimental effect on L-band passive observatories such as SMOS, Aquarius and SMAP. A better knowledge of the characteristics of RFI signals might help mitigate this issue by leading to additional and better focused RFI detection algorithms and it might help identify RFI emitters on the ground. In this study we present approaches to retrieve some of the features of the RFI signals using SMAP data and we present some statistical considerations about the temporal and spectral characteristics of RFI sources.

Yan Soldo↗