30 research outputs found
A WIRELESS SENSOR NETWORK BOARD FOR ENVIRONMENTAL MONITORING USING GNSS AND ANALOG TRIAXIAL ACCELEROMETER
No full textWireless Sensor Networks (WSNs) have attracted an increasing attention in recent years because of the large number of potential applications. They are used for collecting, storing and sharing data, for monitoring applications, surveillance purposes and much more. On the other hand GNSSs are used in various systems devoted to monitor different atmospheric parameters and to trace displacements of landslides and glaciers in severe environmental conditions and in all weather situations. A first example of low cost DGPS wireless sensor network was installed in 2009 on a serac located at 4100 m above a populated area in the Aosta Valley, Italy, and it is still operative. This work presents an evolution of the WSN node used in that systems with improved functionalities and flexibility. The electronic board developed as a multipurpose board to be used in different WSNs, has been completely redesigned as an open system in order to reduce its sizes and to be configured by only varying the firmware on the microcontroller. It allows different interfaces and is equipped with a recovery system, guaranteed by a watchdog chip which continuously monitor the onboard microcontroller. The board is equipped with both a GNSS module and an analog triaxial accelerometer in order to merge GNSS raw data and accelerometer data to keep track of both fast events and slow events. A free open source operative system has been ported on the microcontroller in order to perform multiple operations and to manage the communications between the network nodes with improved efficiency. The board firmware can be modified in real time using a custom bootloader to avoid difficult maintenance operation
Cirrus clouds monitoring using a V-band radar for HAPS: a feasibility analysis
No full textAccording to a report of the Intergovernmental Panel on Climate Change (IPCC, 2007) one of the largest uncertainties in predicting climate change is the coupling between clouds and the Earth's climate system. Cirrus clouds (or ice crystal clouds) are one of the specific type of clouds that are the main responsible of such uncertainty in predicting climate change. At any time in the midlatitudes, cirrus can cover about 30% of the Earth's surface, and in the Tropics this coverage can increase to about 60-70%. With such a spatial and temporal coverage it is not hardly surprising that cirrus is an important component of the Earth-atmosphere radiation balance and hydrological cycle. Our knowledge on radar meteorology and on 77 GHz automotive radars, used also for rain monitoring, will allow us to electromagnetically characterize the cirrus and develop a preliminary study to use a 75 GHz radar (IEEE V-band) for clouds monitoring. The idea of the work is to formulate the scattering mechanism occurring at 75 GHz in the cirrus (potentially using and extend already existent ice-crystal model) in order to accomplish the following feasibility analysis of a small radar operating at such frequency. This radar could be carried on-board on a HAPS, in order to extend the HAPS and satellite Earth observation activities and available technologies. Therefore, the presented activity is divided into 2 sections: 1) The cirrus scattering model at 75 GHz. The scientific literature present different scattering models for lower frequency bands, with respect to IEEE V-band, and for the 94 GHz Cloud Sat vertical cloud-profiling radar. The study will fill the gap and present the advantages of using this frequency band, potentially also in cooperations with the others. 2) The feasibility analysis of a radar operating at such frequency for cirrus clouds monitoring
On the Use of a 77 GHz Automotive Radar as a Microwave Rain Gauge
No full textThe European Telecommunications Standards Institute (ETSI) defines the frequency band of 77 GHz (W-band) as the one dedicated to automatic cruise control long-range radars. A car can be thought as a moving integrated weather sensor since it can provide meteorological information exploiting the sensors installed on board. This work presents the preliminary analysis of how a 77 GHz mini radar can be used as a short range microwave rain gauge. After the discussion of the Mie scattering formulation applied to a microwave rain gauge working in the W-band, the proposal of a new Z-R equation to be used for correct rain estimation is given. Atmospheric attenuation and absorption are estimated taking into account the ITU-T recommendations. Functional requirements in adapting automatic cruise control long-range radar to a microwave rain gauge are analyzed. The technical specifications are determined in order to meet the functional requirements
A LoRaWAN based network for monitoring operation of environmental pollution and meteorological parameters using public transport
No full textThe LoRa (Long Range Low Power) technology and in particular the LoRaWAN (LoRa Wireless Area Network) is a Low Power Wide Area Network (LPWAN) is used to connect different sensors in a regional, national or global network and making sensed data available on the Internet of Things (IoT). LoRaWAN provides secure bi-directional data transfer and communication. Equipment using such technology can work over for years without a battery change.
LoRaWAN specification provides seamless interoperability among IoT without the need of complex local installations and gives back the freedom to the user. At the same time, the number of fields of application of LoRa
sensors is continuously increasing. Among them, LoRa technology can be used in meteorology. LoRa uses adaptive data rate, which allows receiving messages from a high number of devices. Considering that a node can send unlimited messages per day, a set of meteorological sensors (e. g. rain gauges, disdrometers, hygrometers, thermometers, etc.) can be thought as nodes of a star topology network in order to capillary monitor a portion of territory, improving also weather forecasting, services and operations.
The present work aims to realize a control network for pollutant emissions including sound emissions) and meteorological purpose by exploiting the vehicular traffic of public transport. A specific detection system is placed on a fleet of public transport vehicles to measure both the level of emissions and meteorological parameters along the tracks of the vehicles, thus defining hourly and daily trends. Concerning pollution, it is possible to identify where levels are higher than what required by the law.
In order to connect the individual sensors to the central data collection and processing server, a LoRaWAN is implemented. The network is made up of individual slave nodes, corresponding to the sensors mounted on each vehicle. Each slave node is connected with a cluster node (placed at a maximum distance of 10 km) installed on the poles present at public transport stops. All the cluster nodes receives and re-transmits the information until reaching the final cluster represented by a centralized server.
The presented project is intended to be sustainable from both environmental and economic point of view and allows to acquire information with high spatial and temporal resolution
High resolution KE-maps with X-band mini weather radar
No full textThe erosion of the terrain starts with the process of soil detachment by raindrop impact. The Kinetic Energy (KE)of a single raindrop can represent the basic and most commonly used unit of raindrop erosivity. KE is functions of the drop size, drop shape and its terminal velocity. It can be expressed as the rain kinetic energy per unit area and per unit time (KEtime, time-specific kinetic energy) or, alternatively, as the amount of rain kinetic energy per unit volume of rain (KEmm volume-specific kinetic energy).
The total KE of rainfall is evaluated by summing up the individual kinetic energies of all the raindrops. Therefore, KE can be calculated directly for any rainfall event by knowing its intensity (I) and by using one of the so-called KE–I relationships, which are present in large number in the scientific landscape, relations that in turn derive from an assumed Drop Size Distribution (DSD). Alternatively, it would be more pertinent to relate KE with
data obtained by a disdrometer: however, such instruments are costly, complex (and therefore critics to use) and,
consequently not generally available.
Short-range X band weather radars are a good alternative solution to estimate KE. They can provide measure of radar reflectivity factor (Z) taking into account that indeed Z is related to the drops kinetic energy than the rain intensity itself. By using the weather radar, it is possible to measure KE exploiting the KE-Z relationships.
In this work, we consider a pulsed X-band radar, non-coherent, non-Doppler, with vertical polarization, acquiring reflectivity maps each minute with radial resolution of 60 meters, up to a maximum range of 30 km. By using the high temporal and spatial resolution radar maps it is possible to realize high-resolution KE maps exploiting one of the KE-Z relations available in the literature, in particular the one by Yu et. al. in 2012. Starting from the maps acquired by the radar in the form of digital number, the radar reflectivity maps are obtained exploiting signal processing algorithms and the consequent KE maps are evaluated. A significant correlation between a strong rain event and some landslides in the nearby hills is presented.
The high-resolution KE maps can put in evidence the spatial and temporal variability of the kinetic energy of rainfall. Used in conjunction with GIS layers concerning topography, soil properties and land use, such KE maps have a strong potential for geosciences applications
77 GHz radar for meteorological purposes: preliminary results
No full textThe European Telecommunications Standards Institute defines the frequency band around 77 GHz as dedicated to automatic cruise control long-range radars, but recent works demonstrated that, under specific assumption and with the right theoretical background, it is also possible to use a W-band radar as a short range microwave rain gauge.
Working at 77 GHz, raindrop size are comparable to the used wavelength and therefore it is necessary to use the general Mie scattering theory. In order to avoid underestimation of rain (up to -20 dB), the proper relation between the radar reflectivity factor Z and the rainfall rate R (the so-called Z-R equation) should be used, specifically determined for such frequency with the Mie scattering theory. A possible Z-R equation for 77 GHz radar has been presented by Bertoldo et. al. in 2017, during the EGU General Assembly.
An overview of functional requirements to adapt an automatic cruise control long-range radar (of particular interests for its low cost) to a short-range microwave rain gauge is given qualified for achieving rainfall measurements. Using a commercial prototype of W-band radar some preliminary measurements were made and will be presented. It is shown that it is possible to use W-band radar for monitoring weather events. A good Quantitative Precipitation Estimation (QPE) can be achieved with an acceptable approximation
Car as a moving meteorological integrated sensor
No full textNowadays, common cars are equipped with set of sensors, systems and technologies commonly used to improve car and passengers' safety and comfort. These cars are often referred to with the innovative conception of "car as a sensor". A car can be also thought as a moving integrated weather sensor since it can provide meteorological information along specific tracks, exploiting all the information acquired by the installed sensors processed by specific ad-hoc software and technologies. The paper will present an analysis of the sensor installed on car with a panoramic of the software and technologies that can be used to use the car as integrated moving sensor for meteorological purposes, including also some communications techniques. The descriptions of some activities are presented, some technical points are addressed and some examples of applications are reported
77 GHz automotive anti-collision radar used for meteorological purposes
No full textAn always-growing number of cars are equipped with radars, mainly used for drivers and passengers’ safety. In particular, according to European Telecommunications Standards Institute (ETSI) one specific frequency band is dedicated to automatic cruise control long-range radar operating around 77 GHz (W-band). After the discussion of the Mie scattering formulation applied to a weather radar working in the W-band, the proposal of a new Z-R equation to be used for correct rain estimation is given. Functional requirements to adapt an automatic cruise control long-range radar to a mini-weather radar are analyzed and the technical specifications are evaluated. Results provide the basis for the use of a 77 GHz automotive anti-collision radar for meteorological purposes
Localization of RFID tags for environmental monitoring using UAV
No full textThe 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
