Orthorectification of prisma images

Orthorectification is one of the most important satellite imagery pre-processing applications, as it allows to use data, for example, in geographic information systems, making the most of high or medium resolution. Since May 2020, PRISMA (PRecursore IperSpettrale della Missione Applicativa) mission, a project of the Italian Space Agency, has become fully accessible to the community. PRISMA satellite integrates a hyperspectral sensor and a medium-resolution panchromatic sensor. The products are currently available with a declared geolocation accuracy of 200 m, which ASI plans to increase to half pixel in the near future by introducing geometric treatment of the images with Ground Control Points (GCPs). However, the orthorectification of PRISMA images is not a proven and validated procedure, due to the uncertainty of satellite orbital and internal orientation data provided in the metadata file and to the lack of contributions on the subject in literature. In the present work, our contribution on possible strategies for the geometric treatment of PRISMA images is shown. The results obtained by applying the Rational Polynomial Coefficients (RPC) provided with some panchromatic images show coarse rototranslations. For this reason, a procedure was developed to restore conformity between RPCs and the panchromatic image. The best results in terms of accuracy were obtained with the rational polynomials using RPF approach, achieving residuals calculated on the Check Points (CP) in the order of one pixel, better than those supposed by ASI using GCPs. Probably even better results could be obtained with more rigorous information on RPCs or orbital and orientation parameters

Intensive archaeological survey at Piscina Torta:use of a low-cost RTK portable kit to materialise a UTM grid on the ground

We tested the use of a low-cost GPS RTK to set up a grid during the intensive archaeological survey of the Piscina Torta site, in the framework of the Salt and Power project of the University of Groningen. We also suggest not using a local grid but the WGS84 UTM grid and naming the single cells with the coordinates of one of its vertices. This would facilitate the use and exchange of the data (e.g. about the potsherds collected in the cell) among the scientific community

Intensive archaeological survey at Piscina Torta:use of a low-cost RTK portable kit to materialise a UTM grid on the ground

We tested the use of a low-cost GPS RTK to set up a grid during the intensive archaeological survey of the Piscina Torta site, in the framework of the Salt and Power project of the University of Groningen. We also suggest not using a local grid but the WGS84 UTM grid and naming the single cells with the coordinates of one of its vertices. This would facilitate the use and exchange of the data (e.g. about the potsherds collected in the cell) among the scientific community

Intensive archaeological survey at Piscina Torta:use of a low-cost RTK portable kit to materialise a UTM grid on the ground

We tested the use of a low-cost GPS RTK to set up a grid during the intensive archaeological survey of the Piscina Torta site, in the framework of the Salt and Power project of the University of Groningen. We also suggest not using a local grid but the WGS84 UTM grid and naming the single cells with the coordinates of one of its vertices. This would facilitate the use and exchange of the data (e.g. about the potsherds collected in the cell) among the scientific community

Epidemic and timer-based message dissemination in VANETs: A performance comparison

Data dissemination is among the key functions of Vehicular Ad-Hoc Networks (VANETs), and it has attracted much attention in the past decade. We address distributed, efficient, and scalable algorithms in the context of VANETs adopting the paradigm. We introduce an epidemic algorithm for message dissemination. The algorithm, named EPIC, is based on few assumptions, and it is very simple to implement. It uses only local information at each node, broadcast communications, and timers. EPIC is designed with the goal to reach the highest number of vehicles “infected” by the message, without overloading the network. It is tested on different scenarios taken from VANET simulations based on real urban environments (Manhattan, Cologne, Luxembourg). We compare our algorithm with a standard-based solution that exploits the contention-based forwarding component of the ETSI GeoNetworking protocol. On the other hand, we adapt literature based on a connected cover set to assess the near-optimality of our proposed algorithm and gain insight into the best selection of relay nodes as the size of the graph over which messages are spread scales up. The performance evaluation shows the behavior of EPIC and allows us to optimize the protocol parameters to minimize delay and overhead

Intensive archaeological survey at Piscina Torta: use of a low-cost RTK portable kit to materialise a UTM grid on the ground

We tested the use of a low-cost GPS RTK to set up a grid during the intensive archaeological survey of the Piscina Torta site, in the framework of the Salt and Power project of the University of Groningen. We also suggest not using a local grid but the WGS84 UTM grid and naming the single cells with the coordinates of one of its vertices. This would facilitate the use and exchange of the data (e.g. about the potsherds collected in the cell) among the scientific community

Intensive archaeological survey at Piscina Torta:use of a low-cost RTK portable kit to materialise a UTM grid on the ground

We tested the use of a low-cost GPS RTK to set up a grid during the intensive archaeological survey of the Piscina Torta site, in the framework of the Salt and Power project of the University of Groningen. We also suggest not using a local grid but the WGS84 UTM grid and naming the single cells with the coordinates of one of its vertices. This would facilitate the use and exchange of the data (e.g. about the potsherds collected in the cell) among the scientific community

Studio delle possibilità di utilizzo della costellazione Glonass nel suo stato

GLONASS (Global Navigation Satellite System) is a global position satellite system realized by ex- Urss at the same time with the United State’s one. The first launch of satellites went back to 12th October 1982, they completed constellation with 24 satellites in 1997. In the years Russia didn’t have economic force to maintain active the entire constellation. But in 2002 GLONASS relaunching started, that provides 18 satellites before 2007, and it will reach 24 satellites before 2010. The program provides the launch of three or two rockets a year, each one will bring to space two or three satellite. At present (15th September 2006) there are 15 operative GLONASS satellites. The aim of this work is to show the potentiality of the jointed use of GPS and GLONASS satellites by performing an adequate subdivision of the observations collected during a survey in the area of Rome using TOPCON receivers able to acquire data coming from both constellations

First considerations on post processing kinematic GNSS data during a geophysical oceanographic cruise

Differential GNSS positioning on vessels is of considerable interest in various fields of application as navigation aids, precision positioning for geophysical surveys or sampling purposes especially when high resolution bathymetric surveys are conducted. However ship positioning must be considered a kinematic survey with all the associated problems. The possibility of using high-precision differential GNSS receivers in navigation is of increasing interest, also due to the very recent availability of low-cost differential receivers that may soon replace classic navigation ones based on the less accurate point positioning technique. The availability of greater plano-altimetric accuracy, however, requires an increasingly better understanding of planimetric and altimetric reference systems. In particular, the results allow preliminary considerations on the congruence between terrestrial reference systems (which the GNSS survey can easily refer to) and marine reference systems (connected to National Tidegauge Network). In spite of the fluctuations due to the physiological continuous variation of the ship's attitude, GNSS plot faithfully followed the trend of the tidal variations and highlighted the shifts between GNSS plot and the tide gauges due to the different materialization of the relative reference systems