Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

Automotive side object detection sensor blockage detection system and related techniques

Abstract: A system is provided for detecting blockage of an automotive side object detection system (“SODS”) The system includes a blockage detection processor, which is operative to determine whether an RF leakage signal level sensed between transmit and receive antennas of the system substantially match one or more of a plurality of pattern recognition information curves If it is determined that the leakage signal level substantially matches one or more of a plurality of pattern recognition information curves, a blocked condition of the SODS is declared, as may be caused by mud, salt, ice, etc The blockage detection processor is further operative to determine whether the leakage signal exceeds a predetermined blockage threshold level If the leakage exceeds the predetermined blockage threshold level, a blocked condition of the SODS is also declared

Ka-band RF MEMS phase shifters

Abstract: As the need for low-loss phase shifters increases, so does the interest in radio frequency (RF) MEMS as a solution to provide them. In this paper, progress in building low loss Ka-band phase shifters using RF MEMS capacitive switches is demonstrated. Using a switched transmission line 4-bit resonant phase shifter, an average insertion loss of 2.25 dB was obtained with better than 15-dB return loss, a similar 3-bit phase shifter produced an average insertion loss of 1.7 dB with better than 13-dB return loss. Both devices had a phase error of less than 13/spl deg/ in the fundamental states. To our knowledge, these devices represent the lowest loss Ka-band phase shifters reported to date.

Adder/substractor for variable length numbers

Abstract: An adder/subtractor wherein N/2 two bit adders are connected to allow the addition of numbers having N bits, each one of the two bit adders having associated control circuitry adapted: (a) to cause each two bit adder either to add applied bits directly or to add one applied bit and the "two's complement" of the other bit; and (b) to electrically separate any selected ones of the two bit adders from the others.

Distributed signal processing system

Abstract: A distributed, fault-tolerant, self-repairable, reconfigurable signal processing system with redundant elements comprising signal processors, mass memories and input-output controllers interconnected by redundant busses forming a high reliability system. The input-output controller element has redundant busses for interconnecting multiple fault-tolerant distributed signal processing systems into a network configuration. One signal processor element in a system is initially designated as the executive and assigns processing tasks from a mass memory to the other elements or other systems. When a failure is detected, the executive verifies the failure, isolates the faulty element and reassigns the task to another spare element. If another element is not available, the executive reconfigures the system to permit degraded operation using the available elements. The executive element, itself, is fault monitored by one of the other elements which is capable of assuming the role of executive as required. The fault-tolerant and reconfiguration capabilities of the system result from a virtual addressing technique for each element, a distributed bus arbitration method and a two-level distributed operating system.

Calibration of the total infrared luminosity of nearby galaxies from Spitzer and Herschel bands

Abstract: When combined with infrared observations with the Spitzer telescope (3 to 160 μm), the Herschel Space Observatory now fully samples the thermal dust emission up to 500 μm and enables us to better estimate the total infrared-submm energy budget (L_(TIR)) of nearby galaxies. We present new empirical calibrations to estimate resolved and integrated total infrared luminosities from Spitzer and Herschel bands used as monochromatic or combined tracers. We base our calibrations on resolved elements of nearby galaxies (3 to 30 Mpc) observed with Herschel. We perform a resolved spectral energy distribution (SED) modelling of these objects using the Draine & Li dust models and investigate the influence of the addition of Spectral and Photometric Imaging Receiver (SPIRE) measurements in the estimation of L_(TIR). We find that using data up to 250 μm leads to local L_(TIR) values consistent with those obtained with a complete coverage (up to 500 μm) within ±10 per cent for most of our resolved elements. We then study the distribution of energy in the resolved SEDs of our galaxies. The bulk of energy (30–50 per cent) is contained in the [70–160 μm] band. The [24–70 μm] fraction decreases with increasing metallicity. The [160–1100 μm]submillimetre band can account for up to 25 per cent of the L_(TIR) in metal-rich galaxies. We investigate the correlation between the total infrared (TIR) surface brightnesses/luminosities and monochromatic Spitzer and Herschel surface brightnesses/luminosities. The three Photodetector Array Camera and Spectrometer (PACS) bands can be used as reliable monochromatic estimators of the L_(TIR), the 100 μm band being the most reliable monochromatic tracer. There is also a strong correlation between the SPIRE 250 μm and L_(TIR), although with more scatter than for the PACS relations. We also study the ability of our monochromatic relations to reproduce integrated L_(TIR) of nearby galaxies as well as L_(TIR) of z ∼ 1–3 sources. Finally, we provide calibration coefficients that can be used to derive TIR surface brightnesses/luminosities from a combination of Spitzer and Herschel surface brightnesses/fluxes and analyse the associated uncertainties.