Download or read book Radio Frequency Interference in Microwave Radiometry Statistical Analysis and Study of Techniques for Detection and Mitigation written by José Miguel Tarongí Bauzá and published by . This book was released on 2013 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microwave radiometry field has been increasing its performance with higher accuracy measurements, leading to a more presence in the remote sensing field. Several space-borne, air-borne and ground-based radiometers have been developed to perform measurement campaigns; however, the actual sensitivity of a radiometer is often limited by man-made radio emissions such as radars, broadcasting emissions, wireless communications and many other communication systems based on electromagnetic waves, limiting the improvement in the radiometers¿ performance. Consequently, in order to maintain the accuracy in the radiometric measurements, it has been researched in the Radio Frequency Interference (RFI) detection and mitigation systems and algorithms for the microwave radiometry field. The scope of this doctoral thesis is the development and testing of RFI detection and mitigation algorithms in order to enhance radiometric measurements performed by the Multifequency Experimental Radiometer with Interference Tracking for Experiments over Land and Littoral (MERITXELL). The MERITXELL has been developed during this thesis with the idea studying the RFI present in several radiometric bands and the way to mitigate it, as well as to obtain data from diverse frequency bands and devices in only one measurement campaign.

Download or read book Radio Frequency Interference Characterization and Detection in L band Microwave Radiometry written by Mustafa Aksoy and published by . This book was released on 2015 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio Frequency Interference (RFI) is a major issue in microwave radiometry and prevents correct estimation of geophysical parameters via remote sensing. This problem is reported even in the protected portion of the L-band (1400-1427MHz) which is allocated for only remote sensing of Earth from space. RFI contamination in radiometric measurements and the methods to mitigate it have previously been discussed in the literature. On the other hand, a comprehensive characterization of the RFI environment and an optimal RFI detection procedure which combines multiple RFI detection algorithms to effectively operate in that environment have yet to be presented. This dissertation aims to fill this gap for L-band microwave remote sensing research efforts. First, the RFI problem in microwave radiometry and previously developed RFI detection algorithms and their applications in current microwave radiometers are reported. Then, the L-band RFI environment is characterized in terms of its temporal, spectral, spatial, and statistical properties using space-borne and air-borne measurements from European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) missions as well as local air-borne campaigns. It is demonstrated that RFI is a global problem, and its temporal, spectral and statistical properties may change significantly. Thus, classical RFI detection algorithms based on certain assumptions on these properties are insufficient to resolve the RFI problem and a more sophisticated approach is needed. This dissertation introduces NASA's Soil Moisture and Active Passive (SMAP) radiometer which was launched on January 31, 2015 as one of the first radiometers which implements such a multifaceted RFI detection technique. SMAP's comprehensive multi-domain RFI detection approach is summarized and analyzed in terms of its performance under different RFI exposure scenarios using pre-launch and post-launch RFI studies. Finally, several improvements to the SMAP baseline algorithm, and future investigations to obtain a more efficient RFI mitigation are discussed.

Download or read book Studies of Radio Frequency Interference Detection Methods in Microwave Radiometry written by Barış Güner and published by . This book was released on 2009 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel method for RFI detection that uses the Shapiro-Wilk test of normality is also elucidated. Comparisons are made with another method based on the normality of thermal noise, the kurtosis detection technique, for the pulsed sinusoidal RFI case. Results prove that the Shapiro-Wilk technique is a viable alternative for RFI mitigation in actual systems. The thesis is concluded with a theoretical performance comparison against pulsed sinusoidal RFI using the three most commonly used RFI detection methods: Pulse detection, cross-frequency detection, and kurtosis detection. Particular emphasis is given to the cross-frequency detection method. It is shown that cross-frequency detection method provides good detection performance regardless of duty cycle for this important type of RFI.

Download or read book Introduction to Satellite Remote Sensing written by William Emery and published by Elsevier. This book was released on 2017-08-30 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to Satellite Remote Sensing: Atmosphere, Ocean and Land Applications is the first reference book to cover ocean applications, atmospheric applications, and land applications of remote sensing. Applications of remote sensing data are finding increasing application in fields as diverse as wildlife ecology and coastal recreation management. The technology engages electromagnetic sensors to measure and monitor changes in the earth’s surface and atmosphere. The book opens with an introduction to the history of remote sensing, starting from when the phrase was first coined. It goes on to discuss the basic concepts of the various systems, including atmospheric and ocean, then closes with a detailed section on land applications. Due to the cross disciplinary nature of the authors’ experience and the content covered, this is a must have reference book for all practitioners and students requiring an introduction to the field of remote sensing. Provides study questions at the end of each chapter to aid learning Covers all satellite remote sensing technologies, allowing readers to use the text as instructional material Includes the most recent technologies and their applications, allowing the reader to stay up-to-date Delves into laser sensing (LIDAR) and commercial satellites (DigitalGlobe) Presents examples of specific satellite missions, including those in which new technology has been introduced

Download or read book Radio Frequency Interference Detection and Mitigation Techniques for Navigation and Earth Observation written by Jorge Querol Borràs and published by . This book was released on 2018 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio-Frequency Interference (RFI) signals are undesired signals that degrade or disrupt the performance of a wireless receiver. RFI signals can be troublesome for any receiver, but they are especially threatening for applications that use very low power signals. This is the case of applications that rely on the Global Navigation Satellite Systems (GNSS), or passive microwave remote sensing applications such as Microwave Radiometry (MWR) and GNSS-Reflectometry (GNSS-R). In order to solve the problem of RFI, RFI-countermeasures are under development. This PhD thesis is devoted to the design, implementation and test of innovative RFI-countermeasures in the fields of MWR and GNSS. In the part devoted to RFI-countermeasures for MWR applications, first, this PhD thesis completes the development of the MERITXELL instrument. The MERITXELL is a multi-frequency total-power radiometer conceived to be an outstanding platform to perform detection, characterization, and localization of RFI signals at the most common MWR imaging bands up to 92 GHz. Moreover, a novel RFI mitigation technique is proposed for MWR: the Multiresolution Fourier Transform (MFT). An assessment of the performance of the MFT has been carried out by comparison with other time-frequency mitigation techniques. According to the results, the MFT technique is a good trade-off solution among all other techniques since it can mitigate efficiently all kinds of RFI signals under evaluation. In the part devoted to RFI-countermeasures for GNSS and GNSS-R applications, first, a system for RFI detection and localization at GNSS bands is proposed. This system is able to detect RFI signals at the L1 band with a sensitivity of -108 dBm at full-band, and of -135 dBm for continuous wave and chirp-like signals when using the averaged spectrum technique. Besides, the Generalized Spectral Separation Coefficient (GSSC) is proposed as a figure of merit to evaluate the Signal-to-Noise Ratio (SNR) degradation in the Delay-Doppler Maps (01Ms) due to the external RFI effect. Furthermore, the FENIX system has been conceived as an innovative system for RFI detection and mitigation and anti-jamming for GNSS and GNSS-R applications. FENIX uses the MFT blanking as a pre-correlation excision tool to perform the mitigation. In addition, FENIX has been designed to be cross-GNSS compatible and RFI-independent. The principles of operation of the MFT blanking algorithm are assessed and compared with other techniques for GNSS signals. Its performance as a mitigation tool is proven using GNSS-R data samples from a real airborne campaign. After that, the main building blocks of the patented architecture of FENIX have been described. The FENIX architecture has been implemented in three real-time prototypes. Moreover, a simulator named FENIX-Sim allows for testing its performance under different jamming scenarios. The real-time performance of FENIX prototype has been tested using different setups. First, a customized VNA has been built in order to measure the transfer function of FENIX in the presence of several representative RFI/jamming signals. The results show how the power transfer function adapts itself to mitigate the RFI/jamming signal. Moreover, several real-time tests with GNSS receivers have been performed using GPS L1 C/A, GPS L2C, and Galileo E1OS. The results show that FENIX provides an extra resilience against RFI and jamming signals up to 30 dB. Furthermore, FENIX is tested using a real GNSS timing setup. Under nominal conditions, when no RFI/jamming signal is present, a small additional jitter on the order of 2-4 ns is introduced in the system. Besides, a maximum bias of 45 ns has been measured under strong jamming conditions (-30 dBm), which is acceptable for current timing systems requiring accuracy levels of 100 ns. Finally, the design of a backup system for GNSS in tracking applications that require high reliability against RFI and jamming attacks is proposed.

Download or read book Demystifying Radio Frequency Interference written by Donald J. Arndt and published by Trafford on Demand Pub. This book was released on 2009 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: With more and more wireless devices comes more interference, this book shows engineers how to locate, reduce and eliminate the source!

Download or read book Implementation of Radio Frequency Interference Detection and Mitigation Algorithms for Communications and Navigation written by Jorge Querol Borràs and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: [ANGLÈS] Radio Frequency Interference (RFI) is an increasing problem that degrades or, even, disrupts the performance of electronic devices. A specific case of great concern is the electromagnetic emissions in the L1 band (1.5742 GHz) that affect GNSS receivers and prevent them from retrieving position, and timing information. Although several RFI detection and mitigation techniques have been developed, none of them exhibit enough rejection against different kinds of interference signals. The aim of this work is to implement an anti-jamming hardware specific for GPS receivers by optimally combining some of the known techniques to take advantage of the best properties of each of them. These techniques include time-frequency analysis based on the Short-Time Fourier Transform and statistical filtering using the Kurtosis normality test and robust standard deviation estimation. The hardware that has been implemented has been tested with a real commercial GPS jammer signal exhibiting a rejection ratio of up to 50 dB. This result is a first step forward in the fight against RFI. Future improvements will include RF bandwidth increase, larger filter bank and additional normality tests.

Download or read book Survey of Potential Radio Frequency Interference Sources written by C. David Crandall and published by . This book was released on 1980 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is a survey of the potential Radio Frequency Interference (RFI) sources that are currently affecting the analysis of data from the SEASAT Scanning Multichannel Microwave Radiometer (SMMR) and those sources that could affect the design of the Large Antenna Multichannel Microwave Radiometer (LAMMR) for the National Oceanic Satellite System (NOSS). The SEASAT SMMR survey is limited to the 6.5 to 6.7 GHz channel and to emitters on the West Coast of the United States and Canada where RFI has been encountered. The NOSS LAMMR survey covers all of the potential frequencies of interest; 3.0 to 7.6 GHz, 10.5 to 11.0 GHz, 13.4 to 14.0 GHz, 14.5 to 14.7 GHz, 17.0 to 18.8 GHz, 20.8 to 22.4 GHz, 34.0 to 35.5 GHz, 36.0 to 37.0 Ghz, 76.0 to 77.0 GHz, and 88.0 to 94.0 GHz. Also included are excerpts from the current international frequency allocation tables and excerpts from the U.S. position which was presented at the 1979 World Administration Radio Conference (WARC). (Author).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book On Detection of Radio Frequency Interference in Spaceborne Microwave Radiometers Using Negentropy Approximations and Complex Signal Kurtosis as Test Statistics written by Damon C. Bradley and published by . This book was released on 2014 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microwave radiometers are passive, sensitive radio receivers used as spacecraft instruments for Earth remote sensing. Microwave radiometers work by measuring average power of naturally occurring thermal emission from Earth. Radiometer data are used by researchers to monitor Earth's hydrosphere and a number of important geophysical processes critical to our understanding of and survival on the planet.

Download or read book Artificial Intelligence for Communications and Networks written by Xianbin Wang and published by Springer Nature. This book was released on 2021-11-02 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: This two-volume set LNICST 396 and 397 constitutes the post-conference proceedings of the Third EAI International Conference on Artificial Intelligence for Communications and Networks, AICON 2021, held in September 2021. Due to COVID-19 pandemic the conference was held virtually. The 79 full papers were carefully reviewed and selected from 159 submissions. The papers are organized in topical sections on Artificial Intelligence in Wireless Communications and Satellite Communications; Artificial Intelligence in Electromagnetic Signal Processing; Artificial Intelligence Application in Wireless Caching and Computing; Artificial Intelligence Application in Computer Network.

Download or read book Simple Pulse Blanking Technique and Implementation in Digital Radiometer written by Noppasin Niamsuwan and published by . This book was released on 2005 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Radio Frequency Interference (RFI) can adversely impact microwave passive remote sensing measurements, and prohibits passive observations outside protected portions of the radio frequency spectrum. A microwave radiometer including a digital back-end with a simple real-time RFI mitigation technique for reducing pulsed RFI has been developed to address this issue; the process is termed "asynchronous pulse blanking" (APB). The idea of this technique is to remove incoming data whose power exceeds the mean power by a specified number of standard deviations. Although successful performance of this algorithm has been qualitatively demonstrated through local experiments with the digital radiometer, a detailed quantitative assessment of its performance in a variety of RFI environments has not been reported. To address this issue, a simulation study of the APB algorithm was initiated using data obtained from the L-Band Interference Surveyor/Analyzer (LISA), an airborne instrument developed for observing the RFI in the region 1200-1700 MHz. LISA was deployed on NASA's P3-B aircraft to observe RFI in flights in the US and Japan. This data set is very useful for assessing the APB algorithm, since many RFI environments were observed that include multiple sources of interference. Several aspects of algorithm use and performance have been studied, including means for choosing the algorithm's parameters and the robustness of the method in a realistic RFI environment. Effects of the blanking process on the final output are also examined. In order to further quantitatively demonstrate the performance of the system, a series of L-band sky observations was performed. These experiments were based on the predictable brightness of the cold sky background, so that long-term measurements of instrument performance are possible. The results reported in this thesis confirm stability of the system for six hours of observation. In addition, post-processing techniques proposed for removing other types of RFI have been tested. While the algorithm is conceptually simple, developing a process that is both automatic and robust requires careful consideration of the implementation details. Issues regarding implementation in field-programmable gate array (FPGA) devices are also discussed in this thesis.

Download or read book WindSat Radio Frequency Interference Signature and Its Identification Over Land and Ocean written by and published by . This book was released on 2006 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio-frequency interference (RFI) in the spaceborne multichannel radiometer data of WindSat and the Advanced Microwave Scanning Radiometer EOS is currently being detected using a spectral difference technique. Such a technique does not explicitly utilize multichannel correlations of radiometer data, which are key information in separating RFI from natural radiations. Furthermore, it is not optimal for radiometer data observed over ocean regions due to the inherent large natural variability of spectral difference over ocean. In this paper, we first analyzed multivariate WindSat and Scanning Multichannel Microwave Radiometer (SMMR) data in terms of channel correlation, information content, and principal components of WindSat and SMMR data. Then two methods based on channel correlation were developed for RFI detection over land and ocean. Over land, we extended the spectral difference technique using principal component analysis (PCA) of RFI indices, which integrates statistics of target emission/scattering characteristics (through RFI indices) and multivariate correlation of radiometer data into a single statistical framework of PCA. Over ocean, channel regression of X-band can account for nearly all of the natural variations in the WindSat data. Therefore, we use a channel regression-based model difference technique to directly predict RFI-free brightness temperature, and therefore RFI intensity. Although model difference technique is most desirable, it is more difficult to apply over land due to heterogeneity of land surfaces. Both methods improve our knowledge of RFI signatures in terms of channel correlations and explore potential RFI mitigation, and thus provide risk reductions for future satellite passive microwave missions such as the NPOESS Conical Scanning Microwave Imager/Sounder. The new RFI algorithms are effective in detecting RFI in the C- and X-band Windsat radiometer channels over land and ocean.

Download or read book Radio Frequency Interference in Communications Systems written by Bruce Elbert and published by Artech House. This book was released on 2016-02-01 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This authoritative resource describes how to assess and mitigate RF interference in radio systems and presents effective methods to identify and resolve RFI before, during and after its appearance. Authored by a leading authority in the field, this book provides engineers and managers with the knowledge they need in the control of Radio Frequency Interference. Readers find practical guidance in an array of critical areas, including engineering of radiocommunication and wireless systems in light of RFI, identifying RFI modes, electromagnetic compatibility and spectrum sharing. Key concepts in evaluating radio frequency interference, propagation on obstructed paths, interference protection radio and RFI resolution and mitigation techniques such as filtering, spectral capture, radiolocation, cancellation and cognitive radio are covered in this book. This book concludes with prospective for RFI resolution in future radiocommunication systems.

Download or read book Artificial Intelligence for Cyber Physical Systems Hardening written by Issa Traore and published by Springer Nature. This book was released on 2022-11-23 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents advances in security assurance for cyber-physical systems (CPS) and report on new machine learning (ML) and artificial intelligence (AI) approaches and technologies developed by the research community and the industry to address the challenges faced by this emerging field. Cyber-physical systems bridge the divide between cyber and physical-mechanical systems by combining seamlessly software systems, sensors, and actuators connected over computer networks. Through these sensors, data about the physical world can be captured and used for smart autonomous decision-making. This book introduces fundamental AI/ML principles and concepts applied in developing secure and trustworthy CPS, disseminates recent research and development efforts in this fascinating area, and presents relevant case studies, examples, and datasets. We believe that it is a valuable reference for students, instructors, researchers, industry practitioners, and related government agencies staff.

Download or read book Experimental Investigation of the Correction of Electrical Range Errors by Passive Microwave Radiometry written by Fred O. Guiraud and published by . This book was released on 1971 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Qualitative Study of Radio frequency Interference in Radiac telemetry Systems written by H. A. Zagorites and published by . This book was released on 1962 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: A qualitative evaluation was made of the effects of radio frequency interference (RFI) and bandwidh limitation on the accuracy and reliability of transmitted data from a typical nuclear radiation instrument coupled to a standard telemetry system. Significant errors resulted from RFI. These errors demonstrated the need for RF isolation in high impedance elements of nuclear radiation instruments coupled to telemetry equipment or operating in RF environments. Bandwidth limitation did not significantly affect the accuracy or reliability of the pulsed output system used; however, noise reduced data reliability at very low pulse repetition rates. (Author).