X-band mini weather radar network and other wireless sensor networks for environmental monitoring

The main section of the present Ph. D. thesis is related to X-band radars. Since 2005 the Remote Sensing Group of Department of Electronics and Telecommunications of Politecnico di Torino developed an X-band mini weather radar as a standalone sensor to measure rain. Some early results have been presented until 2011 showing the proper functioning and it has been decided to realize an experimental and operative integrated network of X-band radar devoted to rain measurement. The network structure deployed during the Ph. D. period is presented, together with the analysis, the study and the realizations of some operative services, calibration procedures (including Quantitative Precipitation Estimation, QPE) and software and applications developed for the institutions which support the network realizations. The design of an innovative and low cost method to check the radar stability and proper functioning is presented: by simply acquiring a large number of ground clutter echoes during clear sky days and computing some analysis, it is shown it is possible to identify some statistical indicators that allow users and radar operators to know if the radar equipments suffered some degradations of failure. The second part of the thesis is dedicated to Wireless Sensor Networks (WSNs). After a study on WSN technologies for environmental monitoring, a first developed prototypal DGPS network is presented. Using the same multipurpose node designed for such network (or its updated releases with very small differences) and varying only their firmware, other two prototypal and fully operative WSNs are described. The designed choices are described for what concern both hardware and software

Hail Sensing Probes: Feasibility Analysis for Probes to Monitor and Study Hail

This work presents the feasibility study regarding the realization of hail sensing probes for remote sensing and study of hail. The probes are designed as artificial hailstones in order to study both the physical properties of the portion of atmosphere where the formation of hail occurs and the modification of atmospheric conditions while the hailstones are falling to the ground. The basic idea is to realize sensors with a similar fluid-dynamic behavior with respect to hailstones; the density, the weight and the size of the probes are determined. Consequently, the specification of the electronic boards, sensors, and material to realize the probes are studied and presented. The hail sensing probes can be dropped by a plane, or potentially a UAV (Unmanned Aircraft Vehicle), which fly above and through the clouds where the hail formation occurs. During their falling to the ground, the sensors installed on the probe measure directly different parameters such as humidity, temperature, pressure, acceleration. All data are sent to a receiver located on the ground. The study of the sampling frequency of each sensor is presented, together with the analysis of the propagation channel, in order to assure a robust communication link between probes and the ground receiver. The energy balance is also computed. The work demonstrates that a set of this kind of disposable sensors can be realized. They can be used for efficient monitoring operations and studies of hail formation dynamics and conditions, thus increasing the set of instruments for the monitoring and remote sensing of hail

A Wireless Sensor Network Ad-Hoc Designed as Anti-Theft Alarm System for Photovoltaic Panels

Photovoltaic (PV) systems have attracted increasing attention in last years as well as Wireless Sensor Networks (WSNs), which have been used in many application fields. In PV plants, especially in ground installations, a lot of thefts and damages occur due to the still high cost of the modules. A new experimental WSN ad-hoc has been designed to be an anti-theft alarm system. Each node of the network is directly installed under each PV string and it is equipped with an accelerometer sensor capable to detect a minimum displacement of the panel from its steady position. The WSN presents a star topology: a master node cyclically interrogates the slave nodes through RF link. It collects all the nodes responses and communicates though a RS-232 interface with a control PC checking the network status. When a slave node detects an alarm, continuous messages are sent to the control PC which turns on all the alarm signaling systems. The control PC is equipped with an open source operative system and software and provides for SMS, e-mail and sound-light signaling in case of alarm. It also communicates with a remote server where all the WSN information is stored. A first low cost experimental WSN has been already installed and it is working properl

Developing a low cost multipurpose X-band FMICW radar

FMCW radar, X-band, multipurpose radar, low cost, atmospheric monitoring, target detection, radar altimete

Ultra-light disposable radio probes for atmospheric monitoring

Representation of clouds remains a latent ambiguity for weather forecasting and climate models since their characteristics depends on multidisciplinary processes in a wide range of natural scales, from the collision of micron-sized droplets and particles to the thousand-of-meters scale of airflow dynamics. Within the Horizon 2020 Innovative Training Network Cloud-MicroPhysics-Turbulence-Telemetry (ITN-COMPLETE), the development of ultra-small light disposable radio probes for fluctuation-inside-cloudsmonitoring is promoted and financed. Being light-weighted (less than 20 grams), the probes will have a fluid-dynamic behavior to allow them to “float” inside warm clouds after been released by an aircraft or an Unmanned Aerial Vehicle (UAV). Each disposable probe is equipped with compact size microprocessors (presently the first prototype uses Arduino© Nano), controllers and a set of sensors for the measurement of atmospheric parameters such as velocity, acceleration, pressure, temperature and humidity variations. All probes are part of the Internet-of-Things (IoT) world. In fact, while floating, they collect, store and then send the coded information to a base station located at the ground through a dedicated radio transmission link. It is to be noted that long-range communication link (10 km) should be assured with low power consumption technology: a network based on the Long Range Wide Area Network (LoRaWAN© protocol) to connect and exchange data within the end-modules and the base station is the potential adopted solution. As far as possible biocompatible elements within the mini ultra-light radio probes will be used to avoid any environmental pollution

Localization of RFID tags for environmental monitoring using UAV

The paper presents the experimental implementation of a method to localize RFID tags in an outdoor environment using UAV. During the installation phase, it is possible to measure the coordinates of the installation point using a topographic GNSS receiver. The tags positions can evolve with time and after a specific desired period of time (e. g. 1 month or 1 year) it is necessary to relocate them. This can be done estimating the distance between the tags and a UAV, exploiting the measurements of the Received Signal Strength Indicator (RSSI). The tags are placed over an outdoor test area and a large amount of RSSI measurements are made in different position, well distributed in space, using a UAV equipped with a specific tag reader. On such data, a multilateration-based localization algorithm is applied achieving good results. The description of RFID tags is reported together with the localization algorithm, the test description and the preliminary results

Determining Real Permittivity from Fresnel Coefficients in GNSS-R

Global Navigation Satellite System Reflectometry (GNSS-R) can be used to derive information about the composition or the properties of ground surfaces, by analyzing signals emitted by GNSS satellites and reflected from the ground. If the received power is measured with linearly polarized antennas, under the condition of smooth surface, the reflected signal is proportional to the modulus of the perpendicular and parallel polarization Fresnel coefficients, which depend on the incidence angle θ, and on the dielectric constant ε of the soil. In general, ε is a complex number; for non-dispersive soils, the imaginary part of ε can be neglected, and a real value of ε is sought. We solve the real valued problem explicitly giving formulas that can be used to determine the dielectric constant ε and we compare the analytical solution with experimental data in the case of sand soil

ON THE REALIZATION OF A COMMUNICATION SYSTEM FOR ATMOSPHERIC PROBES BASED ON LORA TECHNOLOGIES: PRELIMINARY MEASUREMENTS AND RESULTS

Characterization of atmospheric properties remains a latent ambiguity for weather forecasting and climate models since their characteristics depends on multidisciplinary processes in a wide range of natural scales. The development of ultra-small light disposable radio probes is important to understand this properties Being light-weighted, the probes will have a fluiddifferent atmospheric layers after been released, thus simulating the behaviour of small particles (e.g. drops). Each disposable probe is equipped with compact size microprocessors (presently the first prototype uses velocity, acceleration, pressure, temperature). The probes collect, store and then send the coded information to a base station located at the ground through a dedicated radio transmission link. It is to be noted that longrange communication link (10 km) should be assured with low power consumption technology: a network -modules and the base station is the potential adopted solution. In order to realize the communication system for the atmospheric probes, some prototypal links and networks have bene realized using the Adafruit Feather 32u4 LoRa Radio RFM95 modules. It is an embedded module, which contains a LoRa transceiver RFM95 and an ATmega32u4 microcontroller. The radio module can be powered using 3.3 volts either by using a micro USB or an external battery and it can transmit from +5 dBm to +20 dBm, which are theoretically enough for the purpose of this study. The present work presents the preliminary measurements made both in indoor and outdoor environment considering differ find the best set of parameters to work in the harsh environment to acquire information about warm clouds and send them to the ground receiver. Particularly detailed measurements have been made in harsh environmental found inside a warm cloud. The measurements techniques and results are presented together with the realization of a first operational prototype of both probes and ground receiver