Saab AB

About: Saab AB is a company organization based out in Thun, Switzerland. It is known for research contribution in the topics: Antenna (radio) & Signal. The organization has 862 authors who have published 928 publications receiving 8807 citations. The organization is also known as: Saab AB & Svenska Aeroplan AB.

Programming Real-Time Autofocus on a Massively Parallel Reconfigurable Architecture Using Occam-pi

Abstract: Recently we proposed occam-pi as a high-level language for programming massively parallel reconfigurable architectures. The design of occam-pi incorporates ideas from CSP and pi-calculus to facilitate expressing parallelism and reconfigurability. The feasability of this approach was illustrated by building three occam-pi implementations of DCT executing on an Ambric. However, because DCT is a simple and well-studied algorithm it remained uncertain whether occam-pi would also be effective for programming novel, more complex algorithms. In this paper, we demonstrate the applicability of occam-pi for expressing various degrees of parallelism by implementing a significantly large case-study of focus criterion calculation in an auto focus algorithm on the Ambric architecture. Auto focus is a key component of synthetic aperture radar systems. Two implementations of focus criterion calculation were developed and evaluated on the basis of performance. The comparison of the performance results with a single threaded software implementation of the same algorithm show that the throughput of the two implementations are 11x and 23x higher than the sequential implementation despite a much lower (9x) clock frequency. The two designs are, respectively, 29x and 40x more energy efficient.

Method for designing array antennas

Abstract: A method for designing low signature array antennas using a calculation method. The method proposes a way of improving antenna and signature performance of array antennas. According to the method electromagnetic antenna and signature characteristics are specified, an iterative optimizing method is performed to design the antenna to fulfil the specified characteristics, the iterative method is interrupted when a design fulfils the specified characteristics, and the specified characteristics are readjusted in an iterative optimizing method to follow if the specified characteristics not are fulfilled.

Color for moving map cockpit displays

Abstract: Three color schemes (monochrome, dichrome, and polychrome) based on basic principles for color perceptionand cognition were optimized and applied to an electronic map in a horizontal-situation display. Principles forcolor discrimination, symbol coding, and color naming were applied for the super-imposed symbols (targets,waypoints etc) and for the map symbology (land, water, roads). The color codes were tested in a visual searchand detection experiment in a real-time simulation in an air-to-air mission with test pilots as subjects. Thesimulation task was as close as possible to a real-life situation. The pilots had to track a maneuvering targetwithin specified limits. Reaction times for target detection were recorded. After the simulation, the test pilotsgave a subjective estimation ofthe different color schemes. They also estimated them according to situationawareness using a rating technique on cognitive compatibility (CC-SART). All the results, both the objectiveand the subjective show that color schemes are advantageous in comparison to the monochrome code. Thereactions times were significantly lower for the chromatic color codes. The estimated situation awareness washigher for the chromatic schemes and the subjects gave higher preferences to the chromatic codes.Keywords: human factors, aviation, moving map cockpit displays, horizontal-situation displays, electronicmaps, color coding

A Wide Scanning Array of Connected Bowtie Antennas Suitable for Integration in Composite Sandwich Structures With Monte-Carlo Tolerance Analysis

Abstract: A low-profile and wide-scan phased-array antenna of connected cross-bowtie elements is proposed. The design goals and considerations are based on the applications requiring the integration of a large array antenna with composite sandwich structures, such as antennas on aircraft. In a very large array environment (modelled approximately as an infinite array), the main beam of the proposed antenna can be steered up to ±75° at azimuth and ±15° at elevation over bandwidths of 10% and 25% with active reflection coefficients below −10 dB and −5 dB, respectively. A Monte Carlo analysis of critical manufacturing and alignment tolerances shows the desired performance is achieved with the cumulative distribution probability over 80% under the uniformly distributed random combinations of the tolerances. Experimental results of a $7\times 7$ element array prototype agree well with the simulations of this small-scale array case. The experiments show that this small-scale prototype is capable of steering the beam within the range of [−60°, 60°] at azimuth and [−15°, 15°] at elevation with the predicted performance satisfying the targeted application requirements and mechanical constraints. The achieved combination of the wide beam steering performance, relatively low antenna profile, and suitability of its feeding structure for sandwiched electro-mechanical integration makes this design unique with respect to the previously published results.

Synchronization for fh communication

Abstract: The invention provides a method for synchronization of transmitted and received signals in Frequency Hopping (FH) communication systems, the FH communication system comprising a transmitter and a receiver (202), two PN-generators, one located at the transmitting end and one located at the receiving end, in which the clock rate in the receiver (202) is slowed down compared to the clock rate of the transmitter, thus causing a characteristic pattern (304,409,708) and a reversed characteristic pattern (312,410,709), the synchronization being initiated by a start sync signal (208), until obtaining the characteristic patterns (304,409,708,312,410,709) being a measure of the delay between the transmitted and received signal which is used to synchronize the receiver to the transmitted signals.