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The importance of earth observation (EO) from space is felt today more than ever in many different fields of human activity. Governments, international organizations, military bodies, private industry, and even individuals benefit every day of the products of spaceborne remote sensing technology.

While about 60 governments or intergovernment ventures worldwide operate EO systems and provide (most of) the relevant datasets for free to the interested institutional and commercial parties, the recent trend is for private operators to sell the EO imagery as a service. The added values of such new ventures, all of them based on small satellite constellations in low earth orbit (LEO), lie essentially in enhanced ground sampling distance (GSD) and/or shorter revisit time with respect to traditional systems. Planet Labs, one of the major players in the “New Space” scenario, operates a network of more than 170 micro/nanosatellites, about half of them weighing 5 kg each, with GSD of 3 m and 72 cm. The present resolution target of 25–30 cm for commercial missions is in line with the requirement of military users, opening the way to unprecedented dual-use opportunities [1].

An overview of some of the main trends in the EO scenario, focusing on the emergence of a new paradigm for EO space systems, is presented; namely: the ongoing, disruptive shift from large satellites to constellations of small spacecraft, fueled by the recent introduction of several key technologies, such as for instance electric propulsion. The outline of a tool specifically conceived to assist the system architect in the early design phase of an EO constellation of microsatellites equipped with electric thrusters is outlined. A case study for the application of a multisegmented constellation, with visual, thermal infrared, and radar components to remotely monitor a national railway network, is discussed, by showing that, in spite of the complexity of modern small satellite constellations, preliminary design can be successfully performed in a simplified and effective way [2]. Some observations on how sensor miniaturization is working in favor of small satellite design are given.

1. G. Denis et al., « Towards disruptions in Earth observation? New Earth observation systems and markets evolution: Possible scenarios and impacts », Acta Astronaut., vol. 137, pp. 415-433, 2017.

2. S. Marcuccio, S. Ullo, M. Carminati, O. Kanoun, « Smaller Satellites, Larger Constellations: Trends and Design Issues for Earth Observation Systems”, IEEE Aerospace and Electronic Systems Magazine, Volume 34, No. 10, pages 50-59, 1 October 2019.

Prof. Danilo Orlando (Universita degli Studi Niccolo’ Cusano, Roma, Italy)

Abstract: Nowadays, radar systems are bound to operate in spectrally Nowadays, radar systems are bound to operate in spectrally crowded environments where multiple electromagnetic intentional and/or unintentional sources might interfere with the signal of interest. Many approaches can be pursued to overcome this drawback as, for instance, the real-time adaptation of the transmitted wave forms to the specific scenario after having sensed it or the design of suitable detection architectures that incorporate signal-processing-related Electronic Counter-Counter Measures against interfering signals. In this talk, we focus on the latter solution and present some recent advances in this context. Specifically, we start with the design of suitable estimation procedures for the interference covariance matrix capable of accounting for the presence of noise-like jammers in addition to clutter and thermal noise. Then, we consider the problem of contrasting structured interference (deceptive jammers) and describe effective solutions based upon compressive sensing techniques which allow for signal classification. Finally, we exploit such techniques to come up with selective detection architectures, whose probability of detection rapidly decreases when the target signature moves away from the nominal pointing direction. Thus, they can work in target rich environments at the price of a performance degradation for perfectly matched signals where multiple electromagnetic intentional and/or unintentional sources might interfere with the signal of interest. Many approaches can be pursued to overcome this drawback as, for instance, the real-time adaptation of the transmitted wave forms to the specific scenario after having sensed it or the design of suitable detection architectures that incorporate signal-processing-related Electronic Counter-Counter Measures against interfering signals. In this talk, we focus on the latter solution and present some recent advances in this context. Specifically, we start with the design of suitable estimation procedures for the interference covariance matrix capable of accounting for the presence of noise-like jammers in addition to clutter and thermal noise. Then, we consider the problem of contrasting structured interference (deceptive jammers) and describe effective solutions based upon compressive sensing techniques which allow for signal classification. Finally, we exploit such techniques to come up with selective detection architectures, whose probability of detection rapidly decreases when the target signature moves away from the nominal pointing direction. Thus, they can work in target rich environments at the price of a performance degradation for perfectly matched signals.

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