The U.S. commercial space launch industry has changed considerably since the enactment of the Commercial Space Launch Amendments Act of 2004. FAA is required to license or permit commercial space launches, but to allow the space tourism industry to develop, the act prohibited FAA from regulating crew and spaceflight participant safety before 2012—a moratorium that was later extended but will now expire on September 30, 2015. Since October 2014, there have been three mishaps involving FAA licensed or permitted launches.

美聯邦航空廳(Federal Aviation Administration)의 航空機 製作檢査 制度의 現況

Satellite communications (SatComs) have recently entered a period of renewed interest motivated by technological advances and nurtured through private investment and ventures. The present survey aims at capturing the state of the art in SatComs, while highlighting the most promising open research topics. Firstly, the main innovation drivers are motivated, such as new constellation types, on-board processing capabilities, non-terrestrial networks and space-based data collection/processing. Secondly, the most promising applications are described, i.e., 5G integration, space communications, Earth observation, aeronautical and maritime tracking and communication. Subsequently, an in-depth literature review is provided across five axes: i) system aspects, ii) air interface, iii) medium access, iv) networking, v) testbeds & prototyping. Finally, a number of future challenges and the respective open research topics are described.

/pdf/satellite-communications-in-the-new-space-era-a-survey-and-13ge69opzh.pdf

Satellite Communications in the New Space Era: A Survey and Future Challenges

Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

Wireless mediums, such as RF, optical, or acoustical, provide finite resources for the purposes of remote sensing (such as radar) and data communications. Often, these two functions are at odds with one another and compete for these resources. Applications for wireless technology are growing rapidly, and RF convergence is already presenting itself as a requirement for both users as consumer and military system requirements evolve. The broad solution space to this complex problem encompasses cooperation or codesigning of systems with both sensing and communications functions. By jointly considering the systems during the design phase, rather than perpetuating a notion of mutual interference, both system’s performance can be improved. We provide a point of departure for future researchers that will be required to solve this problem by presenting the applications, topologies, levels of system integration, the current state of the art, and outlines of future information-centric systems.

Survey of RF Communications and Sensing Convergence Research

Communication systems: An introduction to signals and noise in electrical communication

Atomic decomposition (AD) extracting the time–frequency characteristics of signals has been investigated in the frame of complex radar signal detection and classification. AD uses the chirplet dictionary to obtain high-resolution time–frequency representations. Significant improvements on previous AD algorithms have been introduced to increase the detection performance (dictionary extension) and to overcome the resolution problems of AD (greediness detector). An interception receiver based on AD has been analysed and characterised. It is composed of a two-stage scheme: detection of signal components through an AD-based detector, and modulation classifier using AD as a feature extractor.

Atomic decomposition-based radar complex signal interception

A facet model of targets is proposed to simulate inverse synthetic aperture radar (ISAR) images and radar back-scattering of moving targets with rigid and nonrigid motions. Targets are composed of solid objects which are modeled by triangular facets. It is shown that a facet can be treated as an equivalent point-scatterer whose radar cross section (RCS) and position depend on the shape of the triangle, the frequency, and the angle of incidence. A shadowing algorithm is also developed to detect the facets which actually have influence on the signal received by the radar. Besides, a facet division algorithm is implemented to improve the result of the shadowing algorithm and to have at least one facet per resolution cell. Finally, we apply our simulator to obtain the ISAR images of a ship and a helicopter and to calculate the micro-Doppler signature of a human.

Facet Model of Moving Targets for ISAR Imaging and Radar Back-Scattering Simulation

An automatic modulation classifier (AMC) based on low-complexity signal features and a hierarchical decision tree is presented for pulsed radar applications. This AMC is implemented on a field-programmable gate array (FPGA) platform. The algorithm has been designed to minimize the computational burden to achieve real-time operation. The novelty of the paper consists of the development of a low-computational-complexity radar AMC suitable for real-time FPGA implementation.

Real-time low-complexity automatic modulation classifier for pulsed radar signals

This paper presents a W -band high-resolution radar sensor for short-range applications. Low-cost technologies have been properly selected in order to implement a versatile and easily scalable radar system. A large operational bandwidth of 9 GHz, required for obtaining high-range resolution, is attained by means of a frequency multiplication-based architecture. The system characterization to identify the performance-limiting stages and the subsequent design optimization are presented. The assessment of system performance for several representative applications has been carried out.

/pdf/low-cost-cw-lfm-radar-sensor-at-100-ghz-4x8sl11nwh.pdf

Low-Cost CW-LFM Radar Sensor at 100 GHz

In this paper, we explore the promising capabilities of atomic decomposition (AD) for radar-related applications from a practical point of view Some enhancements and new approaches are proposed herein, and their implementations are fully detailed We apply the AD algorithms in two different environments, for signal detection where high sensitivity is the main requirement, and for inverse synthetic aperture radar (ISAR) imaging where focused images, target feature extraction, and computational burden are the fundamental concerns

Omar A. Yeste-Ojeda

Papers

Atomic decomposition-based radar complex signal interception

Facet Model of Moving Targets for ISAR Imaging and Radar Back-Scattering Simulation

Real-time low-complexity automatic modulation classifier for pulsed radar signals

Low-Cost CW-LFM Radar Sensor at 100 GHz

Atomic decomposition for radar applications