On May 2018 the world’s first dual-frequency Global Navigation Satellite System (GNSS) smartphone produced by Xiaomi equipped with a Broadcom BCM47755 chip was launched. It is able to receive L1/E1/ and L5/E5 signals from GPS, Galileo, Beidou, and GLONASS (GLObal NAvigation Satellite System) satellites. The main aim of this work is to achieve the phone’s position by using multi-constellation, dual frequency pseudorange and carrier phase raw data collected from the smartphone. Furthermore, the availability of dual frequency raw data allows to assess the multipath performance of the device. The smartphone’s performance is compared with that of a geodetic receiver. The experiments were conducted in two different scenarios to test the smartphone under different multipath conditions. Smartphone measurements showed a lower C/N0 and higher multipath compared with those of the geodetic receiver. This produced negative effects on single-point positioning as showed by high root mean square error (RMS). The best positioning accuracy for single point was obtained with the E5 measurements with a DRMS (horizontal root mean square error) of 4.57 m. For E1/L1 frequency, the 2DRMS was 5.36 m. However, the Xiaomi Mi 8, thanks to the absence of the duty cycle, provided carrier phase measurements used for a static single frequency relative positioning with an achieved 2DRMS of 1.02 and 1.95 m in low and high multipath sites, respectively.

Google Earth (GE) has recently become the focus of increasing interest and popularity\ud among available online virtual globes used in scientific research projects, due to the\ud free and easily accessed satellite imagery provided with global coverage. Nevertheless,\ud the uses of this service raises several research questions on the quality and uncertainty\ud of spatial data (e.g. positional accuracy, precision, consistency), with implications for\ud potential uses like data collection and validation. This paper aims to analyze the\ud horizontal accuracy of very high resolution (VHR) GE images in the city of Rome\ud (Italy) for the years 2007, 2011, and 2013. The evaluation was conducted by using\ud both Global Positioning System ground truth data and cadastral photogrammetric\ud vertex as independent check points. The validation process includes the comparison of\ud histograms, graph plots, tests of normality, azimuthal direction errors, and the\ud calculation of standard statistical parameters. The results show that GE VHR imageries\ud of Rome have an overall positional accuracy close to 1 m, sufficient for deriving\ud ground truth samples, measurements, and large-scale planimetric maps

Homegrown fruits and vegetables are gaining popularity in many metropolitan areas with several facets connected to the wider urban agriculture phenomenon. At the same time, the relationship between urban food production and irrigation water is pivotal in terms of resource management. In this paper, we investigated water savings through the collection and use of harvestable rainwater from buildings' rooftops to irrigate 2631 fruits and vegetables gardens in the urban area of Rome (Italy). The methodology makes use of existing geospatial data and data derived from satellite image classification to estimate food gardens' irrigation requirements and harvestable rainwater from nearby buildings' rooftops. The comparison of the annual harvestable rainwater with irrigation needs allowed for computing the proportion of water self-sufficient gardens as well as the amount of gardens whose water needs might be partially fulfilled with rainwater. Statistics were produced by land use type (horticulture, mixed crops, olive groves, orchards, and vineyards) and under the hypothesis that irrigation systems with low and high field application efficiency might be employed. We found that 19% and 33% of the gardens could be water self-sufficient for the low and high irrigation efficiency scenario, respectively. The remaining gardens, by using the available rainwater, could satisfy 22% (low efficiency) and 44% (high efficiency) of the water needs resulting in a reduction in the use of conventional water sources.

Site selection for waste disposal is a complex task that should meet the requirements of communities and stakeholders. In this article, three decision support methods (Boolean logic, index overlay and fuzzy gamma) are used to perform land suitability analysis for landfill siting. The study was carried out in one of the biggest metropolitan regions of Italy, with the objective of locating suitable areas for waste disposal. Physical and socio-economic information criteria for site selection were decided by a multidisciplinary group of experts, according to state-of-the-art guidelines, national legislation and local normative on waste management. The geographic information systems (GIS) based models used in this study are easy to apply but require adequate selection of criteria and weights and a careful evaluation of the results. The methodology is arranged in three steps, reflecting the criteria defined by national legislation on waste management: definition of factors that exclude location of landfills or waste treatment plants; classification of the remaining areas in terms of suitability for landfilling; and evaluation of suitable sites in relation to preferential siting factors (such as the presence of quarries or dismissed plants). The results showed that more than 80% of the provincial territory falls within constraint areas and the remaining territory is suitable for waste disposal for 0.72% or 1.93%, according to the model. The larger and most suitable sites are located in peripheral areas of the metropolitan system. The proposed approach represents a low-cost and expeditious alternative to support the spatial decision-making process.

ABSTRACT:On April 6, 2009, an earthquake of 6.3 magnitude struck central Italy with its epicentre near L'Aquila, at 42.3502° N, 13.3762°E. The earthquake damaged 3,000 to 11,000 buildings in the medieval city of L'Aquila. Several buildings totally collapsed, 308 people were killed. The post emergency phase till now is just at its beginning step. Conventional surveying techniques using high precision total stations, GNSS receivers and laser scanners for investigations on damaged buildings are always becoming more automated, accurate and operative and even much more fast. Even if these techniques represent instruments of extreme operability there are still many evident limits on their use, especially regarding the survey of both the roofs and the facades of tall buildings or dangerous places, typical on post earthquake situations. So using micro UAVs for surveying in such particular cases, many of these problems can be easily bypassed. In fact, the present work aims on experimenting using multi-rotor micro UAVs, that will allow high quality image capturing on roofs and facades of structures in the old city center of L' Aquila. To obtain actual stereoscopic acquisitions of buildings some conditions on the geometry of acquisition have to be observed, for this reason, taking as a guideline classic flight photogrammetric, a flight planning software was developed. Accurate planning for UAVs acquisitions is very important also considering the reduced autonomy of such vehicles. This can be a strategic point if we want to use UAVs for early damage assessment and also for post event reconstruction planning.