Performance analysis of the Karhunen–Loève Transform for artificial and astrophysical transmissions: denoizing and detection

In this work, we propose a new method of computing the Karhunen–Loève Transform (KLT) applied to complex voltage data for the detection and noise level reduction in astronomical signals. We compared this method with the standard KLT techniques based on the Toeplitz correlation matrix and we conducted a performance analysis for the detection and extraction of astrophysical and artificial signals via Monte Carlo (MC) simulations. We applied our novel method to a real data study-case: the Voyager 1 telemetry signal. We evaluated the KLT performance in an astrophysical context: our technique provides a remarkable improvement in computation time and MC simulations show significant reconstruction results for signal-to-noise ratio (SNR) down to −10 dB and comparable results with standard signal detection techniques. The application to artificial signals, such as the Voyager 1 data, shows a notable gain in SNR after the KLT

Performance analysis of the Karhunen–Loève Transform for artificial and astrophysical transmissions: denoizing and detection

In this work, we propose a new method of computing the Karhunen–Loève Transform (KLT) applied to complex voltage data for the detection and noise level reduction in astronomical signals. We compared this method with the standard KLT techniques based on the Toeplitz correlation matrix and we conducted a performance analysis for the detection and extraction of astrophysical and artificial signals via Monte Carlo (MC) simulations. We applied our novel method to a real data study-case: the Voyager 1 telemetry signal. We evaluated the KLT performance in an astrophysical context: our technique provides a remarkable improvement in computation time and MC simulations show significant reconstruction results for signal-to-noise ratio (SNR) down to −10 dB and comparable results with standard signal detection techniques. The application to artificial signals, such as the Voyager 1 data, shows a notable gain in SNR after the KLT

Project of a multibeam UHF receiver to improve survey capabilities

The Institute of Radioastronomy (IRA-Bologna) of the National Institute for Astrophysics of Italy (INAF – Rome) joined the European group for the Square Kilometer Array Design Study (SKA-DS) in the frame of the FP6 program. One of the goals of the Design Study was the construction and test of a state of the art very small SKA prototype. A segment (1/8) of the N/S arm of the large Northern Cross array (408 MHz+/−8 MHz) was exploited to obtain a prototype array, made up by 8 cylindrical concentrators (23.5 mt×7.5 mt) equipped with 4 receivers each. In this way a 32 receivers array with a total collecting area of about 1400 m2 was obtained. Signals are directly carried from the receivers, located on the focal lines, down to the back end, located in the processing room, via a very cost effective analog optical links. Here a fast back end, presently based on Field Programmable Gate Array (FPGA) Berkeley-Roach boards, takes care of running the required complex algorithms to perform (non-adaptive) multi-beamforming with a 2D FFT. The main advantage of such an already working array is to produce 21 independent 31’×104’ beams located inside a 38 deg2 Field Of View (FoV). Our plan is to search for funds to refit the remaining 56 cylinders of the N/S arm, to dramatically increase both the sensitivity and number of beams (pixels) placed in the same FoV. In this way, it could be possible to perform a deep SETI survey in the UHF band by an about 11.200 m2 antenna (equivalent to a 119 m dish), a 37.6 deg2 FOV and 189 independent beams. The system could be further expanded by installing more receivers on each N/S focal line, increasing the FOV and the number of pixels with the same sensitivity. Assuming that adequate funds could be found for refitting the giant E/W arm as well, an equivalent 180 m dish could be obtained to perform a very deep SETI sky survey with a 120 deg2 FOV at high sensitivity. This would allow a very fast and deep sky survey in the UHF band

Levi-Civita Effect in the polarizable vacuum (PV) representation of general relativity

The polarizable vacuum (PV) representation of general relativity (GR), derived from a model by Dicke and related to the "TH-epsilon-mu" formalism used in comparative studies of gravitational theories, provides for a compact derivation of the Levi-Civita Effect (both magnetic and electric), herein demonstrated.Comment: 8 page

Near Earth Object (NEO) Mitigation Options Using Exploration Technologies

This work documents the advancements in MSFC threat modeling and mitigation technology research completed since our last major publication in this field. Most of the work enclosed here are refinements of our work documented in NASA TP-2004-213089. Very long development times from start of funding (10-20 years) can be expected for any mitigation system which suggests that delaying consideration of mitigation technologies could leave the Earth in an unprotected state for a significant period of time. Fortunately there is the potential for strong synergy between architecture requirements for some threat mitigators and crewed deep space exploration. Thus planetary defense has the potential to be integrated into the current U.S. space exploration effort. The number of possible options available for protection against the NEO threat was too numerous for them to all be addressed within the study; instead, a representative selection were modeled and evaluated. A summary of the major lessons learned during this study is presented, as are recommendations for future work