377 research outputs found
Towards coordinated site monitoring and common strategies for mitigation of Radio Frequency Interference at the Italian radio telescopes
We present a project to implement a national common strategy for the
mitigation of the steadily deteriorating Radio Frequency Interference (RFI)
situation at the Italian radio telescopes. The project involves the Medicina,
Noto, and Sardinia dish antennas and comprised the definition of a coordinated
plan for site monitoring as well as the implementation of state-of-the-art
hardware and software tools for RFI mitigation. Coordinated monitoring of
frequency bands up to 40 GHz has been performed by means of continuous
observations and dedicated measurement campaigns with fixed stations and mobile
laboratories. Measurements were executed on the frequency bands allocated to
the radio astronomy and space research service for shared or exclusive use and
on the wider ones employed by the current and under-development receivers at
the telescopes. Results of the monitoring campaigns provide a reference
scenario useful to evaluate the evolution of the interference situation at the
telescopes sites and a case series to test and improve the hardware and
software tools we conceived to counteract radio frequency interference. We
developed a multi-purpose digital backend for high spectral and time resolution
observations over large bandwidths. Observational results demonstrate that the
spectrometer robustness and sensitivity enable the efficient detection and
analysis of interfering signals in radio astronomical data. A prototype
off-line software tool for interference detection and flagging has been also
implemented. This package is capable to handle the huge amount of data
delivered by the most modern instrumentation on board of the Italian radio
telecsopes, like dense focal plane arrays, and its modularity easen the
integration of new algorithms and the re-usability in different contexts or
telescopes.Comment: 39 pages, 10 Figures and 7 Tables. INAF Technical Report n. 149
(2022). http://hdl.handle.net/20.500.12386/3208
Simultaneous Positioning and Communications: Hybrid Radio Architecture, Estimation Techniques, and Experimental Validation
abstract: Limited spectral access motivates technologies that adapt to diminishing resources and increasingly cluttered environments. A joint positioning-communications system is designed and implemented on \acf{COTS} hardware. This system enables simultaneous positioning of, and communications between, nodes in a distributed network of base-stations and unmanned aerial systems (UASs). This technology offers extreme ranging precision ( 5 cm) with minimal bandwidth (10 MHz), a secure communications link to protect against cyberattacks, a small form factor that enables integration into numerous platforms, and minimal resource consumption which supports high-density networks. The positioning and communications tasks are performed simultaneously with a single, co-use waveform, which efficiently utilizes limited resources and supports higher user densities. The positioning task uses a cooperative, point-to-point synchronization protocol to estimate the relative position and orientation of all users within the network. The communications task distributes positioning information between users and secures the positioning task against cyberattacks. This high-performance system is enabled by advanced time-of-arrival estimation techniques and a modern phase-accurate distributed coherence synchronization algorithm. This technology may be installed in ground-stations, ground vehicles, unmanned aerial systems, and airborne vehicles, enabling a highly-mobile, re-configurable network with numerous applications.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201
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