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This project combines GNSS-R technology and UAVs in the context of the aerial remote sensing field, from the design of the assembly of the UAVs and GNSS-R to the execution of the different tests, as well as the data collection and analysis. As it will be seen in the document, this analysis has allowed to improve the original design of the system. The remote sensing technology based on GNSS reflected signals is simply called GNSS-R, and the greatest advantage of UAV as a mounting platform is the low cost, high system availability, and fast installation. Thus the main task of this project is to experimentally verify the possibility of CTTC's own developed GNSS-R working with UAVs. In this report, first I explain some basic principles of GNSS and GNSS-R, as they are important technical backgrounds for the whole project. Secondly, I describe the application of the RTKPOST software, which is an important processing and analyzing tool in the entire project, mainly describing the positioning methods used in the different processing modes in RTKPOST, also the parameter needed for analysis. Then, the design of the UAV-GNSS-R assembly is discussed, with different options based on the characteristics of the UAV, such as weight, payload space, and so on. The whole experimental process is also explained, and all the test data are analyzed and processed by using the Static mode or Kinematic mode in RTKPOST, and the data results are analyzed and compared in terms of satellite visibility, signal-to-noise ratio, elevation angle, Standard Deviation and Root Mean Square. The experimental process is roughly divided into three parts. The initial verification test is used to collect signal data as a basis, through which it is found that drone interferes with GNSS-R to a greater extent, and that the reflector antenna cannot receive the signal if the drone is placed too close to the ground. The second part of the experiment is a stationary test, where the UAV is placed on a tripod, and it', Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles

Significant Wave Height (SWH) is a key parameter to characterize waves, which is typically used in sea state monitoring such as wave forecast to ensure ocean navigation safety. Satellite radar altimeter is probably the primary tool to obtain SWH information. However, it cannot be used for large-scale sea state monitoring unless many of theses satellites are deployed. In this article, we aim to study the potential of Global Navigation Satellite System (GNSS)-Reflectometry (GNSS-R) in SWH measurement based on spaceborne Delay-Doppler Maps (DDMs) data. First, 3 observables (i.e., Delay-Doppler Map Average (DDMA), leading edge slope (LES) of normalized integrated delay waveform (NIDW) (LES-NIDW), and trailing edge slope (TES) of NIDW (TES-NIDW) derived from the DDMs are introduced for SWH estimation. Then, an empirical SWH retrieval model is proposed based on three observables. Subsequently, ERA5 SWH is used as reference data to verify the performance of the proposed model. The experimental results show that the Root Mean Square Error (RMSE) and Correlation Coefficient (CC) estimated by SWH of the three observables are better than 0.54 m and 0.88 m, respectively. Among them, the estimation performance based on DDMA observable is the best, with RMSE and CC of 0.49 m and 0.89 m. This study shows the potential of spaceborne GNSS-R in SWH retrieval. © 2022 IEEE., This work was supported by the Grant RYC-2016-20918 financed by MCIN/AEI /10.13039 /501100011033 and by ESF Investing in your future., Peer Reviewed, Postprint (published version)

The lens-less technique of microwave holography is expected to provide information of three-dimensional structures of plasma with a wide field of view. From the complex amplitudes of waves, which are observed on a single planar array of antennas, we will be able to obtain an imaging of the three-dimensional object. With a geometry of back-scattering observation, the feasibility is examined with a numerical tool of electromagnetic analysis on dielectric objects. With respect to the variety of the dielectric constant and shape of object, it is shown that useful information can be acquired in regarding the complex amplitude distribution at planar detector., source:https://doi.org/10.1585/pfr.16.1402063, identifier:0000-0002-5008-7285

Global Navigation Satellite System (GNSS)-Reflectometry (GNSS-R) technology has opened a new window for ocean remote sensing because of its unique advantages, including short revisit period, low observation cost, and high spatial-temporal resolution. In this article, we investigated the potential of estimating swell height from delay-Doppler maps (DDMs) data generated by spaceborne GNSS-R. Three observables extracted from the DDM are introduced for swell height estimation, including delay-Doppler map average (DDMA), the leading edge slope (LES) of the integrated delay waveform (IDW), and trailing edge slope (TES) of the IDW. We propose one modeling scheme for each observable. To improve the swell height estimation performance of a single observable-based method, we present a data fusion approach based on particle swarm optimization (PSO). Furthermore, a simulated annealing aided PSO (SA-PSO) algorithm is proposed to handle the problem of local optimal solution for the PSO algorithm. Extensive testing has been performed and the results show that the swell height estimated by the proposed methods is highly consistent with reference data, i.e., the ERA5 swell height. The correlation coefficient (CC) is 0.86 and the root mean square error (RMSE) is 0.56 m. Particularly, the SA-PSO method achieved the best performance, with RMSE, CC, and mean absolute percentage error (MAPE) being 0.39 m, 0.92, and 18.98%, respectively. Compared with the DDMA, LES, TES, and PSO methods, the RMSE of the SA-PSO method is improved by 23.53%, 26.42%, 30.36%, and 7.14%, respectively., This work was supported in part by the National Natural Science Foundation of China under Grant 42174022, in part by the Future Scientists Program of China University of Mining and Technology under Grant 2020WLKXJ049, in part by the Postgraduate Research & Practice Innovation Program of Jiangsu Province under Grant KYCX20_2003, in part by the Programme of Introducing Talents of Discipline to Universities, Plan 111, Grant No. B20046, and in part by the China Scholarship Council (CSC) through a State Scholarship Fund (No. 202106420009)., Peer Reviewed, Postprint (published version)

In the HYFLEX (Hypersonic Flight Experiment), a consecutive hypersonic flight duration of some five minutes is secured. Therefore, it is expected to get the hypersonic aerodynamic/aerothermodynamic performance data good enough in both qualitative and quantitative sense for the region in which M is greater than ten, where best performance is crucial for the reusable space vehicles. Selection of the measurement items for the onboard measurement system was made among both aerodynamics and aerothermodynamics including the real gas effects, thermo-structural evaluation data, basic data for evaluation of lifting body technology (guidance, navigation and control) etc. consisting of some 250 channels in total. Decision to select measurement items, the analyses and tests for design and confirmation, specifications of each items are outlined and discussed in this paper. But mostly measurement mission items are discussed in this paper. Major objective of HYFLEX onboard measurement is to contribute to establishing reliable prediction/design methods for the winged space vehicles. To do this, the comparison between the flight data and the predictions made in advance based on ground test and analyses is indispensable. For the meaningful comparison, the atmospheric condition along flight path must be known accurately enough. In HYFLEX, the utilization of the remotely sensed atmospheric data by NOAA meteorological satellite was planned to raise the inference accuracy. Data analysis program is briefly presented., 極超音速飛行実験においては、5分間程度の持続的な極超音速飛行時間が確保されるため、往還機に重要なM＞10領域の空力、空力加熱特性データが質量とも充実したレベルで得られることが期待された。機上計測項目の選定においては、これら極超音速領域の実在気体効果を含む空力、空力加熱特性データ、熱構造の特性評価用データ、および主目的のひとつである揚力飛行体の基本技術評価に関わるデータ(姿勢・軌道制御に関するデータなど)などを抽出し、バス系の計測項目をあわせて約250チャンネルの計測計画をたてた。各計測項目を選定した基準、設計のための事前解析・試験、各項目の計測系仕様について述べる。具体的議論は主に実験計測系に限った。また、計測の目的は宇宙往還機設計などへ利用できる予測ツール・手法の確立に資することである。そのため、地上での試験やCFD(数値流体力学)による予測とフライトデータとを比較するが、その際に飛行時の大気状態を可能な限り正確に把握する必要がある。今回は大気状態量の特定のため、NOAA衛星のリモートセンシングデータを使用し推定精度を上げることを試みた。これを含むデータ解析計画の概略を述べた。

In the HYFLEX (Hypersonic Flight Experiment), a consecutive hypersonic flight duration of some five minutes is secured. Therefore, it is expected to get the hypersonic aerodynamic/aerothermodynamic performance data good enough in both qualitative and quantitative sense for the region of M greater than 10, where best performance is crucial for the reusable space vehicles. Selection of the measurement items for the onboard measurement system was made among both aerodynamics and aerothermodynamics to get the real gas effects, thermostructural evaluation data, basic data for evaluation of lifting body technology (guidance, navigation and control) etc., consisting of some 250 channels in total. Grounds to select measurement items, the analysis and tests for design and confirmation, and specifications of each items are outlined and discussed in this paper. But mostly measurement mission items are discussed in this paper. Major objective of HYFLEX onboard measurement is to contribute to establishing reliable prediction/design methods for the winged space vehicles. To do this, the comparison between the flight data and the predictions made in advance based on ground tests and analyses is indispensable. For the meaningful comparison, the atmospheric condition along flight path must be known accurately enough. In HYFLEX, the utilization of the remotely sensed atmospheric data by NOAA meteorological satellite was planned to raise the inference accuracy. Data analysis program is briefly presented., 極超音速飛行実験においては、5分間程度の持続的な極超音速飛行時間が確保されるため、再使用型往還機に重要なM＞10領域の極超音速空力、空力加熱特性データが質的および量的ともに充実したレベルで得られることが期待された。機上搭載計測系のための計測項目の選定において、極超音速領域の実在気体効果を得るための空力、空力加熱特性データ、熱構造特性評価用データ、および揚力飛行物体の基本データ(誘導、航法および軌道制御に関するデータ)などを抽出し、約250チャンネルの計測項目計画をたてた。ここでは各計測項目を選定した基準、設計とその確認のための解析・試験、各項目の仕様について概観し、特に具体的議論は主にデータ計測系に限った。HYFLEX機上搭載計測の主目的は有翼宇宙往還機に対する信頼度の高い予測手法や設計手法の確立に資することである。そのためには、地上での事前試験や解析に基づいた予測をフライトデータと比較することが不可欠となる。有意義な比較のためには、飛行経路に沿った大気状態を充分正確に把握する必要がある。NOAA気象衛星のリモートセンシング大気データを使用し、推定精度を上げることを試みている。データ解析計画の概略も述べてある。

NASDA Special Publication, 宇宙開発事業団特別報告

It is known to become a plasma state by electrolyzing the gas around the vehicle under hypersonic speed flight. Therefore, the radio wave is reflected by the plasma layer, and the blackout phenomena occurs. In the other, it is also reported that temperature, pressure and density around the vehicle deviates from the prediction which do not assume electrolyzing of the gas. Although it is difficult to obtain the such kind of data in the ground test, present HYFLEX (Hypersonic Flight Experiment) plan is the precious opportunity which can acquire the data of plasma state around the vehicle. In HYFLEX, it was planned that the ionizing phenomena of the gas around the airframe was measured by the reflectometer from the onboard, and the data acquisition was done. Acquired data is the change of reflection intensity and phase of the radio wave. In the meantime, the plasma density field was calculated using the real gas CFD (Computational Fluid Dynamics) code and the radio wave reflection analysis was carried out in order to compare with the flight test. Flight test result and numerical calculation result agreed well, and the real gas CFD code was verified at an error of about two times by the conversion to the plasma electron density. Although the verification accuracy has to be raised more by examination of the radio wave reflection analysis technique, etc., this flight test data was very useful as basic data of plasma electron density field around hypersonic flight vehicle, and as verification data of real gas CFD code and the radio wave reflection analysis technique., 極超音速での飛行中には機体まわりの気体が電解離してプラズマ状態になることが知られている。このため、プラズマ層によって電波が反射されブラックアウト現象が生じ、また、温度や圧力が気体の電解離を仮定しない場合の予測からはずれる。ところが、この種のデータは地上試験で得ることが困難であり、今回のHYFLEX(極超音速飛行実験)機飛行試験はこの種のデータを取得できる貴重な機会である。HYFLEXでは、機体まわりで生じる気体の電離現象を、リフレクトメータによって機上から測定した。取得したデータは、電波の反射強度および位相の変化である。一方、飛行試験結果と比較するため、実在気体CFD(数値流体力学)コードを用いた数値解析によってプラズマ密度場を計算し、この結果を用いて電波反射解析を行った。飛行試験結果と数値計算結果はよく一致し、実在気体CFDコードの結果を、プラズマ電子密度に換算して2倍程度の誤差で検証することができた。今後、電波反射解析手法の検討などにより、さらに検証精度を上げる必要があるが、本飛行試験データは、機体まわりのプラズマ電子密度場の基礎データとして、また、CFDおよび電波反射解析手法の検証データとして非常に有用であった。

The RF (Radio Frequency) link by using flight data of Hypersonic Flight Experiment (HYFLEX), and the reflectometer of HYFLEX were analyzed and evaluated, and the results were reported. In the analysis and evaluation of the RF link, antenna radiation pattern data and real flight path data of HYFLEX and TF (Test Flight)-1 of J-1 rocket were used. Actual reception data of four ground stations (AGC (Automatic Gain Control) data and radar data) were superimposed on the results of the RF link analysis, and the effects of each event of the flight and of the rocket plume were evaluated. The design values were verified based on the analysis. Next, the reflectometer data were analyzed. For this purpose, the radio wave reflection coefficient and the phase up to the reflection point were calculated using telemetry data. The received telemetry data was found to be consistent, indicating a normal reflectometer performance. The design values were thus confirmed valid., 極超音速飛行実験機(HYFLEX)の飛行時のデータを用いたRF(無線周波)リンクに関する解析評価、およびリフレクトメータに関する解析評価について、その成果を報告した。RFリンクに関する解析評価については、アンテナ放射パターンデータと、HYFLEXおよびJ-1ロケットのTF(試験飛行)-1の実飛行経路データを用いてRFリンク解析を行った。4つの地上局の実測受信データ(AGC(自動利得制御)データおよびレーダデータ)とRFリンク解析結果の受信データを重ね合わせた。この結果に基づいて、各イベントの影響および噴煙の影響についてRFリンクの評価を行い、設計結果が妥当であることを確認した。次に、リフレクトメータの解析評価については、リフレクトメータのテレメトリデータから電波反射係数および反射点までの位相を算出した。この結果、受信したテレメトリデータが良好であることが分かった。リフレクトメータは正常に作動しており、設計結果が妥当であることを確認した。

In this paper, a method to obtain crack initiation, location and width in concrete structures subjected to bending and instrumented with an optical backscattered reflectometer (OBR) system is proposed. Continuous strain data with high spatial resolution and accuracy are the main advantages of the OBR system. These characteristics make this structural health monitoring technique a useful tool in early damage detection in important structural problems. In the specific case of reinforced concrete structures, which exhibit cracks even in-service loading, the possibility to obtain strain data with high spatial resolution is a main issue. In this way, this information is of paramount importance concerning the durability and long performance and management of concrete structures. The proposed method is based on the results of a test up to failure carried out on a reinforced concrete slab. Using test data and different crack modeling criteria in concrete structures, simple nonlinear finite element models were elaborated to validate its use in the localization and appraisal of the crack width in the testing slab., Peer Reviewed, Postprint (author’s final draft)

This Thesis covers the development of a six-port and slotted waveguide based measurement system for the determination of the variation of moisture content (mc) of stacked lumber. A Six-port reflectometer was developed and used throughout the trials incorporating an automatic calibration system. This was implemented using switched coaxial standards, producing improvement in the long term stability of the six-port. In addition the measurement of the dielectric properties of the typical lumber types of Heartwood, Sapwood and internal Branches is examined. Measurements were made using the waveguide cell technique covering the frequency range of 2.3 to 6.5GHz. Additional work was undertaken to establish a method to correct these measurements for variations in basic density and Earlywood \Latewood banding, giving rise to a potential moisture content estimation error of 0.63%. Both an explicit first order model and multivariate regression analysis of the sensor was proposed and experimental results presented for lumber mc spanning the range of 10 to 180% by dry basis. From these trials a mc measurement error of 3% for the explicit model and 2% for regression of individual boards covering the sensor was determined without incorporating density effects.

In this work, a waveguide impedance generator based on the use of three motor-controlled metallic stubs, a monomode cavity loaded with water and PTFE cylinders is used to calibrate a waveguide ten-port reflectometer. Radial basis function neural networks are used to learn the relationship between the actual reflection coefficient and the power detectors’ output. Results indicate that this impedance generator can be successfully used to calibrate the ten-port reflectometer.

In this study, a novel ten-port waveguide microwave sensor is designed, implemented, calibrated and tested in order to obtain the reflection coefficient magnitude and phase. This reflectometer is based on the well known six-port structure but the number of detectors has been increased to eight in order to improve the sampling procedure of the standing wave present within the waveguide. In addition, a learning method based on neural networks’ usage has been implemented for autonomous calibration from the data collected by a vector network analyzer. An automated procedure consisting of a moving sample within a multimode cavity has enabled different reflection coefficients to be obtained. Neural networks have been employed in order to learn the relationship between the actual reflection parameter and the acquired signals from eight power detectors. This novel device has been calibrated with a neural architecture based on radial basis functions and the error of device measurements has been analyzed. This new design and the incorporated neural network calibration allow one to avoid problems caused by fault or nonlinearity of the detectors, and to get robustness, flexibility and adaptability characteristics for the presented device.

This work presents the design, manufacturing process, calibration and validation of a new microwave ten-port waveguide reflectometer based on the use of neural networks. This low-cost novel device solves some of the previous reflectometer shortcomings such as non-linear behavior of power sensors, noise presence and the complexity of the calibration procedure, which is often based on complex mathematical equations. These problems, which imply the reduction of the reflection coefficient measurement accuracy, have been overcome by using a higher number of probes than usual six-port configurations and by means of the use of Radial Basis Function (RBF) neural networks in order to reduce the influence of noise and non-linear processes over the measurements. Additionally, this sensor can be reconfigured whenever some of the eight coaxial power detectors fail, still providing accurate values in real time. The ten-port performance has been compared against a highcost measurement instrument such as a vector network analyzer and applied to the measurement and optimization of energy efficiency of microwave ovens, with good results.

Sea surface salinity can be remotely measured by means of L-band microwave radiometry. However, the brightness temperature also depends on the sea surface temperature and on the sea state, which is probably today one of the driving factors in the salinity retrieval error budgets of the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission and the NASA-Comision Nacional de Actividades Espaciales Aquarius/SAC-D mission. This paper describes the Passive Advanced Unit (PAU) for ocean monitoring. PAU combines in a single instrument three different sensors: an L-band radiometer with digital beamforming (DBF) (PAU-RAD) to measure the brightness temperature of the sea at different incidence angles simultaneously, a global positioning system (GPS) reflectometer [PAU-reflectometer of Global Navigation Satellite Signals (GNSS-R)] also with DBF to measure the sea state from the delay-Doppler maps, and two infrared radiometers to provide sea surface temperature estimates. The key characteristic of this instrument is that both PAU-RAD and the PAU-GNSS/R share completely the RF/IF front-end, and analog-to-digital converters. Since in order to track the GPS-reflected signal, it is not possible to chop the antenna signal as in a Dicke radiometer, a new radiometer topology has been devised which makes uses of two receiving chains and a correlator, which has the additional advantage that both PAU-RAD and PAU-GNSS/R can be operated continuously and simultaneously to perform the sea-state corrections of the brightness temperature. This paper presents the main characteristics of the different PAU subsystems, and analyzes in detail the PAU-radiometer concept., Peer Reviewed

A new, seven-state switched perturbation two-port (PTP) for vector reflection measurement based on scalar measurement only was designed and realized in microstrip structure using PIN diodes. The structure was experimentally tested by means of vector measurements of different impedances in frequency band with relative bandwidth of 2.5 octaves. Good agreement with data obtained using a precise vector network analyzer was achieved. The new calibration method for the PTP was designed and tested on real measured data.

A new, seven-state switched perturbation two-port (PTP) for vector reflection measurement based on scalar measurement only was designed and realized in microstrip structure using PIN diodes. The structure was experimentally tested by means of vector measurements of different impedances in frequency band with relative bandwidth of 2.5 octaves. Good agreement with data obtained using a precise vector network analyzer was achieved. The new calibration method for the PTP was designed and tested on real measured data.

A new, seven-state switched perturbation two-port (PTP) for vector reflection measurement based on scalar measurement only was designed and realized in microstrip structure using PIN diodes. The structure was experimentally tested by means of vector measurements of different impedances in frequency band with relative bandwidth of 2.5 octaves. Good agreement with data obtained using a precise vector network analyzer was achieved. The new calibration method for the PTP was designed and tested on real measured data.

A new, seven-state switched perturbation two-port (PTP) for vector reflection measurement based on scalar measurement only was designed and realized in microstrip structure using PIN diodes. The structure was experimentally tested by means of vector measurements of different impedances in frequency band with relative bandwidth of 2.5 octaves. Good agreement with data obtained using a precise vector network analyzer was achieved. The new calibration method for the PTP was designed and tested on real measured data.

A new, seven-state switched perturbation two-port (PTP) for vector reflection measurement based on scalar measurement only was designed and realized in microstrip structure using PIN diodes. The structure was experimentally tested by means of vector measurements of different impedances in frequency band with relative bandwidth of 2.5 octaves. Good agreement with data obtained using a precise vector network analyzer was achieved. The new calibration method for the PTP was designed and tested on real measured data.

A new, seven-state switched perturbation two-port (PTP) for vector reflection measurement based on scalar measurement only was designed and realized in microstrip structure using PIN diodes. The structure was experimentally tested by means of vector measurements of different impedances in frequency band with relative bandwidth of 2.5 octaves. Good agreement with data obtained using a precise vector network analyzer was achieved. The new calibration method for the PTP was designed and tested on real measured data.

En télédétection aérienne, on peut obtenir des images du sol avec différents types de capteurs, justifiés par l'usage que l'on souhaite faire des images. Le système utilisé par le laboratoire de télédétection aérienne de l'UQAC est la vidéographie aérienne multispectrale (VAM). Ce système de caméra peut capter indépendamment jusqu'à 6 bandes spectrales, réparties du violet au proche infrarouge. Un système comme celui-ci peut donc nous permettre d'obtenir de l'information au sol dans des plages de longueurs d'onde bien définies, ce qui simplifie l'étude de certains aspects du sol. L'usage d'un capteur sensible au proche infrarouge est particulièrement intéressant pour étudier les stades phénologiques des végétaux. Ceux-ci peuvent se discriminer en observant la variation temporelle de l'albédo dans cette bande, caractéristique de la chlorophylle qui est produite par les végétaux. La télédétection aérienne avec la bande proche infrarouge est donc souvent employée pour faire le suivi dans le temps d'un secteur particulier. Prenons par exemple des zones dévastées par des feux de forêt ou encore des zones agricoles. H faut alors faire plusieurs survols espacés temporellement d'un même endroit pour constater s'il y a eu ou non évolution de l'albédo des végétaux observés. Malheureusement, il était impossible avec le système original de constater une évolution de l'albédo car il n'y avait pas d'appareils pouvant nous assurer que les observations avaient été faites dans les mêmes conditions de lumière incidente. La variation dans l'intensité de signal alors reçu au capteur dépendait beaucoup plus de la lumière incidente que de la variation de l'albédo. La comparaison directe d'imagerie aérienne ne devrait alors être faite que lorsque l'on sait que la lumière ambiante disponible était la même au moment de la prise d'information. Malheureusement, ce n'est à proprement parler jamais le cas car l'intensité et le contenu spectral de la lumière incidente dépendent beaucoup de facte

Parametric design models were created to optimize cable sensitivities in a structural health-monitoring system. Experiments were also conducted to determine the sensitivity of a working system. The system consists of time domain reflectometry (TDR) signal processing equipment and specially designed sensing cables. The TDR equipment sends a high-frequency electric pulse (in the gigahertz range) along the sensing cable. Any change in electric impedance along the cable reflects some portion of the electric pulse back to the TDR equipment. The time delay, amplitude, and shape of the reflected pulse provides the means to respectively locate, determine the magnitude, and indicate the nature of the change in impedance. The change in the sensing cable impedance may be caused by cable elongation (change in resistance), shear deformation (change in capacitance), corrosion of the cable or the materials around the cable (change in inductance), etc. The sensing cables are an essential part of the health-monitoring system because the cable design parameters determine the cable impedance sensitivity to structural changes. By using parametric design models, the optimum cable parameters can be determined for specific cases and used to select or design an appropriate cable. Proof-of-concept and resolution experiments were also conducted to provide, respectively, verification and sensitivity of the system.

The effects of time-dependent electron density fluctuations on a synthesized time domain reflectometry response of a one-dimensional cold plasma sheath are considered. Numerical solutions of the Helmholtz wave equation, which describes the electric field of a normally incident plane wave in a specified static electron density profile, are used. Included in this work is a study of the effects of Doppler shifts resulting from moving density fluctuations in the electron density profile of the sheath.

The effects of time-dependent electron density fluctuations on a synthesized time domain reflectometry response of a one-dimensional cold plasma sheath are considered. Numerical solutions of the Helmholtz wave equation, which describes the electric field of a normally incident plane wave in a specified static electron density profile, are used. Included in this work is a study of the effects of Doppler shifts resulting from moving density fluctuations in the electron density profile of the sheath.

This work presents a design process for developing a dedicated hybrid thick-film time domain reflectometer. The design process allows for variation of the pulse generator characteristics as well as the output impedance of the unit. The unit is fabricated using standard thick-film hybrid techniques while giving consideration to problems encountered at microwave frequencies. This thesis also presents an overview of time domain reflectometry and its applications. Special emphasis is given to the problem of characterizing material dielectric constants using delay measurements.

Tato bakalářská práce pojednává o fyzikální metodě s názvem reflektometrie a její aplikaci k detekci poruch na vedeních a následnou klasifikaci. Práce popisuje možnost aplikovat metodu jak na koaxiální tak i na optické vedení. Teoretická část je rozdělena na blok týkající se koaxiální reflektometrie a blok optické reflektometrie. Nastíněny jsou základní principy fungování obou metod, přístroje jsou popsány jak blokovými schématy tak i rozborem reálných reflektometrů různých výrobců. Díky těmto moderním přístrojům jsem schopni během velmi krátké doby zjistit stav vedení, popřípadě určit jaká je jeho délka. Pro tuto schopnost jsou reflektometry velmi ceněné přístroje a jejich vývoj jde kupředu velmi rychle. Závěr práce je vyhrazen pro realizaci laboratorní úlohy, jež má za úkol přiblížit metodu reflektometrie dalším studentům., This bachelor thesis is focused on physical method called reflectometry and it deals with problem of detection faults in cables and its formatting. This thesis describe the posibility of aplication of this method to a coaxial or an optical cable. Theoretical part of this project is devided in two parts. First part is about a coaxial reflektometry and second part is about an optical reflectometry. Both methods are desribed by block diagrams and even by analysis of real machines. Due to modern devices, we are able to find out in very short time the cable lenght or if the cable is damaged. Because of this ability the reflectometer is very valuable and powerful tool and the research in this technical sector is intesive. Final part of this bachelor thesis inscribe the proposal of laboratorial work, which should introduce the reflectometry to other students.

Tato bakalářská práce pojednává o fyzikální metodě s názvem reflektometrie a její aplikaci k detekci poruch na vedeních a následnou klasifikaci. Práce popisuje možnost aplikovat metodu jak na koaxiální tak i na optické vedení. Teoretická část je rozdělena na blok týkající se koaxiální reflektometrie a blok optické reflektometrie. Nastíněny jsou základní principy fungování obou metod, přístroje jsou popsány jak blokovými schématy tak i rozborem reálných reflektometrů různých výrobců. Díky těmto moderním přístrojům jsem schopni během velmi krátké doby zjistit stav vedení, popřípadě určit jaká je jeho délka. Pro tuto schopnost jsou reflektometry velmi ceněné přístroje a jejich vývoj jde kupředu velmi rychle. Závěr práce je vyhrazen pro realizaci laboratorní úlohy, jež má za úkol přiblížit metodu reflektometrie dalším studentům., This bachelor thesis is focused on physical method called reflectometry and it deals with problem of detection faults in cables and its formatting. This thesis describe the posibility of aplication of this method to a coaxial or an optical cable. Theoretical part of this project is devided in two parts. First part is about a coaxial reflektometry and second part is about an optical reflectometry. Both methods are desribed by block diagrams and even by analysis of real machines. Due to modern devices, we are able to find out in very short time the cable lenght or if the cable is damaged. Because of this ability the reflectometer is very valuable and powerful tool and the research in this technical sector is intesive. Final part of this bachelor thesis inscribe the proposal of laboratorial work, which should introduce the reflectometry to other students.

V této práci je proveden rozbor metod průchozích měřících systému pro měření poměru stojatých vln a vysokofrekvenčního výkonu. Reflektometr, zařízení měřící poměr stojatých vln pracuje v rozsahu frekvencí VKV (145 MHz, 443 MHz), pro tuto šířku pracovních frekvencí je použita konstrukce reflektometru se směrovým vedením. Měřič vf. výkonu pracuje do rozsahu 1 kW. Dále je v práci probrána problematika komunikačních sběrnic pro přenos údajů z jednotky monitoru PSV a vf. výkonu do vyhodnocovacího modulu. Vzhledem k vysokofrekvenčnímu rušení je vybrána sériová komunikace RS-485 , která je odolnější vůči rušení. Dále je navržena vyhodnocovací jednotka MASTER, jednotka SLAVE a moduly pro detekci výkonu a PSV. Na závěr je sestaven firmware pro jednotky, This work deals with analysis methods continuous measuring systems for measurement standing wave ratio and high frequency power. Reflectometr, provision measuring standing wawe ratio, works in range frequence VHF (145 MHz, 443 MHz), for this width working frequence is used construction reflectometer with directive lead. Measurer HF power works into range 1kW. Further is in work go through problems communications bus for transmission data from unit monitor SWR a HF power into score modulus. With regard to high frequency interference is choice serial communication RS-485 , which is immune against disturbance. Further is designed evaluation unit MASTER, unit SLAVE and modules for measurement power and SWR. In finish is build up the firmware for units.

Tato práce se zabývá metodami měření impedancí anténních systémů v rozsahu kmitočtů v pásmu dlouhých až velmi krátkých vln. Jsou diskutovány různé metody měření impedancí a každá z nich je kriticky zhodnocena. V rámci projektu jsou také srovnávány profesionální anténní analyzátory. Na základě tohoto srovnání je stanovena koncepce návrhu vlastního přístroje. V práci je podrobně popsán návrh dílčích částí přístroje včetně softwarového vybavení. Navržený přístroj byl zkonstruován a proběhlo základní testovací měření., This project is dealing with methods of measuring impedances of the antenna systems in the frequency range from the low frequencies to the very high frequencies. There is a discussion about different methods of measuring impedance and each technique is critically evaluated. In terms of this project is compared few types of the professional antenna analyzers. According to this comparison there was made the concept of my own antenna analyzer. There is a detailed description of the design of this device’s important parts including software equipment. Designed instrument has been built and tested.

Tato práce se zabývá metodami měření impedancí anténních systémů v rozsahu kmitočtů v pásmu dlouhých až velmi krátkých vln. Jsou diskutovány různé metody měření impedancí a každá z nich je kriticky zhodnocena. V rámci projektu jsou také srovnávány profesionální anténní analyzátory. Na základě tohoto srovnání je stanovena koncepce návrhu vlastního přístroje. V práci je podrobně popsán návrh dílčích částí přístroje včetně softwarového vybavení. Navržený přístroj byl zkonstruován a proběhlo základní testovací měření., This project is dealing with methods of measuring impedances of the antenna systems in the frequency range from the low frequencies to the very high frequencies. There is a discussion about different methods of measuring impedance and each technique is critically evaluated. In terms of this project is compared few types of the professional antenna analyzers. According to this comparison there was made the concept of my own antenna analyzer. There is a detailed description of the design of this device’s important parts including software equipment. Designed instrument has been built and tested.

V této práci je proveden rozbor metod průchozích měřících systému pro měření poměru stojatých vln a vysokofrekvenčního výkonu. Reflektometr, zařízení měřící poměr stojatých vln pracuje v rozsahu frekvencí VKV (145 MHz, 443 MHz), pro tuto šířku pracovních frekvencí je použita konstrukce reflektometru se směrovým vedením. Měřič vf. výkonu pracuje do rozsahu 1 kW. Dále je v práci probrána problematika komunikačních sběrnic pro přenos údajů z jednotky monitoru PSV a vf. výkonu do vyhodnocovacího modulu. Vzhledem k vysokofrekvenčnímu rušení je vybrána sériová komunikace RS-485 , která je odolnější vůči rušení. Dále je navržena vyhodnocovací jednotka MASTER, jednotka SLAVE a moduly pro detekci výkonu a PSV. Na závěr je sestaven firmware pro jednotky, This work deals with analysis methods continuous measuring systems for measurement standing wave ratio and high frequency power. Reflectometr, provision measuring standing wawe ratio, works in range frequence VHF (145 MHz, 443 MHz), for this width working frequence is used construction reflectometer with directive lead. Measurer HF power works into range 1kW. Further is in work go through problems communications bus for transmission data from unit monitor SWR a HF power into score modulus. With regard to high frequency interference is choice serial communication RS-485 , which is immune against disturbance. Further is designed evaluation unit MASTER, unit SLAVE and modules for measurement power and SWR. In finish is build up the firmware for units.

Sea surface salinity can be remotely measured by means of L-band microwave radiometry. However, the brightness temperature also depends on the sea surface temperature and on the sea state, which is probably today one of the driving factors in the salinity retrieval error budgets of the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) mission and the NASA-Comision Nacional de Actividades Espaciales Aquarius/SAC-D mission. This paper describes the Passive Advanced Unit (PAU) for ocean monitoring. PAU combines in a single instrument three different sensors: an L-band radiometer with digital beamforming (DBF) (PAU-RAD) to measure the brightness temperature of the sea at different incidence angles simultaneously, a global positioning system (GPS) reflectometer [PAU-reflectometer of Global Navigation Satellite Signals (GNSS-R)] also with DBF to measure the sea state from the delay-Doppler maps, and two infrared radiometers to provide sea surface temperature estimates. The key characteristic of this instrument is that both PAU-RAD and the PAU-GNSS/R share completely the RF/IF front-end, and analog-to-digital converters. Since in order to track the GPS-reflected signal, it is not possible to chop the antenna signal as in a Dicke radiometer, a new radiometer topology has been devised which makes uses of two receiving chains and a correlator, which has the additional advantage that both PAU-RAD and PAU-GNSS/R can be operated continuously and simultaneously to perform the sea-state corrections of the brightness temperature. This paper presents the main characteristics of the different PAU subsystems, and analyzes in detail the PAU-radiometer concept., Peer Reviewed

© (2014) Trans Tech Publications, Switzerland. The article describes the diagnostics system of the power transmission lines of 6/10 kVolts on the basis of smart electric modems. It shows the description of the smart electric modem and the creation principle of the diagnostics system. The main feature here is the use of power transformers as coupling devices with a high-voltage power line.

© (2014) Trans Tech Publications, Switzerland. The article describes the diagnostics system of the power transmission lines of 6/10 kVolts on the basis of smart electric modems. It shows the description of the smart electric modem and the creation principle of the diagnostics system. The main feature here is the use of power transformers as coupling devices with a high-voltage power line.

V této práci je proveden rozbor metod průchozích měřících systému pro měření poměru stojatých vln a vysokofrekvenčního výkonu. Reflektometr, zařízení měřící poměr stojatých vln pracuje v rozsahu frekvencí VKV (145 MHz, 443 MHz), pro tuto šířku pracovních frekvencí je použita konstrukce reflektometru se směrovým vedením. Měřič vf. výkonu pracuje do rozsahu 1 kW. Dále je v práci probrána problematika komunikačních sběrnic pro přenos údajů z jednotky monitoru PSV a vf. výkonu do vyhodnocovacího modulu. Vzhledem k vysokofrekvenčnímu rušení je vybrána sériová komunikace RS-485 , která je odolnější vůči rušení. Dále je navržena vyhodnocovací jednotka MASTER, jednotka SLAVE a moduly pro detekci výkonu a PSV. Na závěr je sestaven firmware pro jednotky, This work deals with analysis methods continuous measuring systems for measurement standing wave ratio and high frequency power. Reflectometr, provision measuring standing wawe ratio, works in range frequence VHF (145 MHz, 443 MHz), for this width working frequence is used construction reflectometer with directive lead. Measurer HF power works into range 1kW. Further is in work go through problems communications bus for transmission data from unit monitor SWR a HF power into score modulus. With regard to high frequency interference is choice serial communication RS-485 , which is immune against disturbance. Further is designed evaluation unit MASTER, unit SLAVE and modules for measurement power and SWR. In finish is build up the firmware for units.

Tato bakalářská práce pojednává o fyzikální metodě s názvem reflektometrie a její aplikaci k detekci poruch na vedeních a následnou klasifikaci. Práce popisuje možnost aplikovat metodu jak na koaxiální tak i na optické vedení. Teoretická část je rozdělena na blok týkající se koaxiální reflektometrie a blok optické reflektometrie. Nastíněny jsou základní principy fungování obou metod, přístroje jsou popsány jak blokovými schématy tak i rozborem reálných reflektometrů různých výrobců. Díky těmto moderním přístrojům jsem schopni během velmi krátké doby zjistit stav vedení, popřípadě určit jaká je jeho délka. Pro tuto schopnost jsou reflektometry velmi ceněné přístroje a jejich vývoj jde kupředu velmi rychle. Závěr práce je vyhrazen pro realizaci laboratorní úlohy, jež má za úkol přiblížit metodu reflektometrie dalším studentům., This bachelor thesis is focused on physical method called reflectometry and it deals with problem of detection faults in cables and its formatting. This thesis describe the posibility of aplication of this method to a coaxial or an optical cable. Theoretical part of this project is devided in two parts. First part is about a coaxial reflektometry and second part is about an optical reflectometry. Both methods are desribed by block diagrams and even by analysis of real machines. Due to modern devices, we are able to find out in very short time the cable lenght or if the cable is damaged. Because of this ability the reflectometer is very valuable and powerful tool and the research in this technical sector is intesive. Final part of this bachelor thesis inscribe the proposal of laboratorial work, which should introduce the reflectometry to other students.