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Secure architecture for embedded systems

September 15, 2015
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Conference Paper
Author:
Mankuan Michael Vai
…
Published in:
HPEC 2015: IEEE Conf. on High Performance Extreme Computing, 15-17 September 2015.
Topic:
embedded computing
R&D area:
R&D group:

Summary

Devices connected to the internet are increasingly the targets of deliberate and sophisticated attacks. Embedded system engineers tend to focus on well-defined functional capabilities rather than "obscure" security and resilience. However, "after-the-fact" system hardening could be prohibitively expensive or even impossible. The co-design of security and resilience with functionality has to overcome a major challenge; rarely can the security and resilience requirements be accurately identified when the design begins. This paper describes an embedded system architecture that decouples secure and functional design aspects.
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Summary

Devices connected to the internet are increasingly the targets of deliberate and sophisticated attacks. Embedded system engineers tend to focus on well-defined functional capabilities rather than "obscure" security and resilience. However, "after-the-fact" system hardening could be prohibitively expensive or even impossible. The co-design of security and resilience with functionality has...

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Secure architecture for embedded systems

Vehicle-mounted STAR antenna isolation performance

July 19, 2015
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Conference Paper
Author:
Kenneth E. Kolodziej
…
Published in:
IEEE Antennas and Propagation Society Int. Symp. 2015, 19-25 July 2015.
Topic:
antennas
R&D area:
R&D group:

Summary

Vehicle-to-vehicle communication systems promise enhanced safety for passengers, but require access to a crowded wireless spectrum to enable their data links. Simultaneous Transmit and Receive (STAR) systems can facilitate this spectrum access by increasing the number of users within a given frequency band. Since high isolation is needed for STAR system operation, the effect of mounting a STAR antenna on a vehicle is investigated in this paper. The omni-directional antennas isolation performance was measured to be 53 dB at 2.45 GHz across a 60 MHz bandwidth, which confirms that the vehicle does not significantly degrade isolation performance.
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Summary

Vehicle-to-vehicle communication systems promise enhanced safety for passengers, but require access to a crowded wireless spectrum to enable their data links. Simultaneous Transmit and Receive (STAR) systems can facilitate this spectrum access by increasing the number of users within a given frequency band. Since high isolation is needed for STAR...

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Vehicle-mounted STAR antenna isolation performance

Inductance of circuit structures for MIT LL superconductor electronics fabrication process with 8 niobium layers

June 1, 2015
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Journal Article
Author:
Sergey K. Tolpygo
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Published in:
IEEE Trans. Appl. Supercond., Vol. 25, No. 3, 1 June 2015, 1100905.
Topic:
integrated circuit
R&D area:
R&D group:

Summary

Inductance of superconducting thin-film inductors and structures with linewidth down to 250 nm has been experimentally evaluated. The inductors include various striplines and microstrips, their 90 degree bends and meanders, interlayer vias, etc., typically used in superconducting digital circuits. The circuits have been fabricated by a fully planarized process with 8 niobium layers, developed at MIT Lincoln Laboratory for very-large-scale superconducting integrated circuits. Excellent run-to-run reproducibility and inductance uniformity of better than 1% across 200-mm wafers have been found. It has been found that the inductance per unit length of stripline and microstrip line inductors continues to grow as the inductor linewidth is reduced deep into the submicron range to the widths comparable to the film thickness and magnetic field penetration depth. It is shown that the linewidth reduction does not lead to widening of the parameter spread due to diminishing sensitivity of the inductance to the linewidth and dielectric thickness. The experimental results were compared with numeric inductance extraction using commercial software and freeware, and a good agreement was found for 3-D inductance extractors. Methods of further miniaturization of circuit inductors for achieving circuit densities >10^6 Josephson junctions per cm^2 are discussed.
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Summary

Inductance of superconducting thin-film inductors and structures with linewidth down to 250 nm has been experimentally evaluated. The inductors include various striplines and microstrips, their 90 degree bends and meanders, interlayer vias, etc., typically used in superconducting digital circuits. The circuits have been fabricated by a fully planarized process with...

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Inductance of circuit structures for MIT LL superconductor electronics fabrication process with 8 niobium layers

Simultaneous transmit and receive (STAR) system architecture using multiple analog cancellation layers

May 17, 2015
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Conference Paper
Author:
Kenneth E. Kolodziej
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Published in:
2015 IEEE MTT-S Int. Microwave Symp. (IMS 2015) 17-22 May 2015.
Topic:
wireless
R&D area:
R&D group:

Summary

Simultaneous Transmit and Receive operation requires a high amount of transmit-to-receive isolation in order to avoid self-interference. This isolation is best achieved by utilizing multiple cancellation techniques. The combination of adaptive multiple-input multiple-output spatial cancellation with a high-isolation antenna and RF canceller produces a novel system architecture that focuses on cancellation in the analog domain before the receiver's low-noise amplifier. A prototype of this system has been implemented on a moving vehicle, and measurements have proven that this design is capable of providing more than 90 dB of total isolation in realistic multi path environments over a 30 MHz bandwidth centered at 2.45 GHz. Index Terms-Adaptive systems, full-duplex wireless communication, interference cancellation, multiaccess communication, simultaneous transmit and receive, STAR.
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Summary

Simultaneous Transmit and Receive operation requires a high amount of transmit-to-receive isolation in order to avoid self-interference. This isolation is best achieved by utilizing multiple cancellation techniques. The combination of adaptive multiple-input multiple-output spatial cancellation with a high-isolation antenna and RF canceller produces a novel system architecture that focuses on...

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Simultaneous transmit and receive (STAR) system architecture using multiple analog cancellation layers

Hyperspectral Microwave Atmospheric Sounder (HyMAS) - new capability in the CoSMIR/CoSSIR scanhead

March 7, 2015
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Conference Paper
Author:
Lawrence M. Hilliard
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Published in:
2015 IEEE Aerospace Conf., 7-14 March 2015.
Topic:
sensing
R&D area:
R&D group:

Summary

MIT Lincoln Laboratory and NASA's Goddard Space Flight Center have teamed to adapt an existing instrument platform, the CoSMIR/CoSSIR system for atmospheric sensing, to develop and demonstrate a new capability in a hyperspectral microwave atmospheric sounder (HyMAS). This new sensor comprises a highly innovative intermediate frequency processor (IFP), that provides the filtering and digitization of 52 radiometric channels and the interoperable remote component (IRC) adapted to CoSMIR, CoSSIR, and HyMAS that stores and archives the data with time tagged calibration and navigation data. The first element of the work is the demonstration of a hyperspectral microwave receiver subsystem that was recently shown using a comprehensive simulation study to yield performance that substantially exceeds current state-of-the-art. Hyperspectral microwave sounders with ~100 channels offer temperature and humidity sounding improvements similar to those obtained when infrared sensors became hyperspectral. Hyperspectral microwave operation is achieved using independent RF antenna/receiver arrays that sample the same area/volume of the Earth's surface/atmosphere at slightly different frequencies and therefore synthesize a set of dense, finely spaced vertical weighting functions. The second, enabling element is the development of a compact 52-channel Intermediate Frequency processor module. A principal challenge of a hyperspectral microwave system is the size of the IF filter bank required for channelization. Large bandwidths are simultaneously processed, thus complicating the use of digital back-ends with associated high complexities, costs, and power requirements. Our approach involves passive filters implemented using low-temperature co-fired ceramic (LTCC) technology to achieve an ultra-compact module that can be easily integrated with existing RF front-end technology. This IF processor is applicable to other microwave sensing missions requiring compact IF spectrometry. The unit produces 52 channels of spectral data in a highly compact volume (
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Summary

MIT Lincoln Laboratory and NASA's Goddard Space Flight Center have teamed to adapt an existing instrument platform, the CoSMIR/CoSSIR system for atmospheric sensing, to develop and demonstrate a new capability in a hyperspectral microwave atmospheric sounder (HyMAS). This new sensor comprises a highly innovative intermediate frequency processor (IFP), that provides...

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Hyperspectral Microwave Atmospheric Sounder (HyMAS) - new capability in the CoSMIR/CoSSIR scanhead

Simultaneous transmit and receive antenna isolation improvement in scattering environments

July 6, 2014
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Conference Paper
Author:
Kenneth E. Kolodziej
…
Published in:
APS/URSI 2014, IEEE Int. Symp. on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 6-11 July 2014.
Topic:
antennas
R&D area:
R&D group:

Summary

Simultaneous transmit and receive (STAR) systems require high isolation between the transmitter and receiver to avoid self-interference. Antenna isolation degradation stems from errors in the physical construction and beamformer design, as well as reflections from scattering objects in the environment. An RF canceller subsystem can be inserted at the antenna feeds to improve the isolation in the presence of reflecting objects by 30 dB over 30 MHz centered at 2.45 GHz. This results in 90 dB of effective antenna isolation when paired with a high-isolation antenna that exhibits omni-directional radiation patterns, signifying that STAR systems can be practically deployed.
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Summary

Simultaneous transmit and receive (STAR) systems require high isolation between the transmitter and receiver to avoid self-interference. Antenna isolation degradation stems from errors in the physical construction and beamformer design, as well as reflections from scattering objects in the environment. An RF canceller subsystem can be inserted at the antenna...

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Simultaneous transmit and receive antenna isolation improvement in scattering environments

Wideband antenna array for simultaneous transmit and receive (STAR) applications

July 6, 2014
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Conference Paper
Author:
William F. Moulder
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Published in:
2014 IEEE Int. Symp. on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 6-11 July 2014.
Topic:
antennas
R&D area:
R&D group:

Summary

A wideband antenna array for Simultaneous Transmit and Receive (STAR) applications is presented. The design is comprised of a ring array of TEM horns, and a monocone at the array's center. When the array is phased with the first order circular mode, it is isolated from the monocone. Thus, the array may be used in reception while the monocone is used in transmission, or vice versa. The array and monocone both produce quasi-omnidirectional patterns in the azimuthal planes. Simulations suggest that the design operates across an 8.4 : 1 bandwidth. This wide bandwidth is possible through the use of a novel capacitive feed employed in the TEM horn array.
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Summary

A wideband antenna array for Simultaneous Transmit and Receive (STAR) applications is presented. The design is comprised of a ring array of TEM horns, and a monocone at the array's center. When the array is phased with the first order circular mode, it is isolated from the monocone. Thus, the...

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Wideband antenna array for simultaneous transmit and receive (STAR) applications

Secondary Surveillance Phased Array Radar (SSPAR): initial feasibility study

February 6, 2014
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Project Report
Author:
Mark E. Weber
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Published in:
MIT Lincoln Laboratory Report ATC-416
Topic:
radar
R&D area:
R&D group:

Summary

The U.S. Federal Aviation Administration is deploying Automatic Dependent Surveillance-Broadcast (ADS-B) to provide next-generation surveillance derived through down- and cross-link of global positioning satellite (GPS) navigation data. While ADS-B will be the primary future surveillance system, FAA recognizes that backup surveillance capabilities must be provided to assure that air traffic control (ATC) services can continue to be provided when individual aircraft transponders fail and during localized, short-duration GPS outages. This report describes a potential ADS-B backup capability, Secondary Surveillance Phased Array Radar or SSPAR. SSPAR will interrogate aircraft transponders and receive replies using a sparse, non-rotating array of approximately 17 omnidirectional (in azimuth) antennae. Each array element will transmit and receive independently so as to form directional transmit beams for transponder interrogation, and support high-resolution direction finding for received signals. Because each SSPAR element is independently digitized, transponder returns from all azimuths can be equipped with Traffic Alert and Collision Avoidance System (TCAS) and ADS-B avionics to reduce spectrum usage and maintain the high surveillance update rate (~1 per second) achieved by ADS-B. Recurring costs for SSPAR will be low since it involves no moving parts and the number of array channels is small. This report describes an SSPAR configuration supporting terminal operations. We consider interrogation and receive approaches, antenna array configuration, signal processing and preliminary performance analysis. An analysis of SSPAR's impact on spectrum congestion in the beacon radar band is presented, as are concepts for integrating SSPAR and next generation primary radar to improve the efficiency and accuracy of aircraft and weather surveillance.
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Summary

The U.S. Federal Aviation Administration is deploying Automatic Dependent Surveillance-Broadcast (ADS-B) to provide next-generation surveillance derived through down- and cross-link of global positioning satellite (GPS) navigation data. While ADS-B will be the primary future surveillance system, FAA recognizes that backup surveillance capabilities must be provided to assure that air traffic...

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Secondary Surveillance Phased Array Radar (SSPAR): initial feasibility study

Adaptive RF canceller for transmit-receive isolation improvement

January 19, 2014
  |
Conference Paper
Author:
Kenneth E. Kolodziej
…
Published in:
2014 IEEE Radio and Wireless Symposium (RWS), 19-23 January 2014.
Topic:
antennas
R&D area:
R&D group:

Summary

For effective operation, Simultaneous Transmit and Receive (STAR) systems require high isolation between the transmitted signals and the receiver input, the absence of which can lead to the saturation of a receiver's front end. This paper presents an adaptive RF canceller used to improve isolation. The canceller is configured as an RD tapped delay line with four taps, each with independent amplitude and phase weights that are tuned by a Dithered Linear Search algorithm. This canceller produces 30 dB of signal cancellation over a 20 MHz bandwidth centered at 2.45 GHz in an isolated environment. When combined with a high-isolation antenna, an overall STAR system isolation of 90 dB is achieved, while also maintaining omnidirectional transmit and receive antenna patterns.
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Summary

For effective operation, Simultaneous Transmit and Receive (STAR) systems require high isolation between the transmitted signals and the receiver input, the absence of which can lead to the saturation of a receiver's front end. This paper presents an adaptive RF canceller used to improve isolation. The canceller is configured as...

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Adaptive RF canceller for transmit-receive isolation improvement

Insensitivity of the rate of ion motional heating to trap-electrode material over a large temperature range

January 16, 2014
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Journal Article
Author:
John Chiaverini
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Published in:
Phys. Rev. A, At. Mol. Opt. Phys., Vol. 89, No. 1, 2014, 012318.
Topic:
advanced materials
R&D area:
R&D group:

Summary

We present measurements of trapped-ion motional-state heating rates in niobium and gold surface-electrode ion traps over a range of trap-electrode temperatures from approximately 4 K to room temperature (295 K) in a single apparatus. Using the sideband-ratio technique after resolved-sideband cooling of single ions to the motional ground state, we find low-temperature heating rates more than two orders of magnitude below the room-temperature values and approximately equal to the lowest measured heating rates in similarly sized cryogenic traps. We find similar behavior in the two very different electrode materials, suggesting that the anomalous heating process is dominated by non-material-specific surface contaminants. Through precise control of the temperature of cryopumping surfaces, we also identify conditions under which elastic collisions with the background gas can lead to an apparent steady heating rate, despite rare collisions.
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Summary

We present measurements of trapped-ion motional-state heating rates in niobium and gold surface-electrode ion traps over a range of trap-electrode temperatures from approximately 4 K to room temperature (295 K) in a single apparatus. Using the sideband-ratio technique after resolved-sideband cooling of single ions to the motional ground state, we...

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Insensitivity of the rate of ion motional heating to trap-electrode material over a large temperature range
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