Showing papers by "Saab AB published in 2012"

Subsurface imaging radar

Abstract: A method and system for obtaining SAR images with reduced or eliminated surface clutter to detect subsurface targets, the method comprising the following steps: - selecting a first frequency and an incidence angle for the radar signal such that the ratio of surface backscattering to subsurface target backscattering is significantly larger for vertical polarization than for horizontal - obtaining vertically and horizontally polarized SAR images based on the same SAR path exploiting the selected first frequency and viewing angle - weighting and differencing the vertically and horizontally polarized SAR images so that the surface backscattering completely cancels between the two images and only the combination of the target backscattering components remains.

A Joint Statistical and Symbolic Anomaly Detection System: Increasing performance in maritime surveillance

Abstract: The need for improving the capability to detect illegal or hazardous activities and yet reducing the workload of operators involved in various surveillance tasks calls for research on more capable automatic tools. To maximize their performance, these tools should be able to combine automatic capturing of normal behavior from data with domain knowledge in the form of human descriptions. In a proposed Joint Statistical and Symbolic Anomaly Detection System, statistical and symbolic methods are tightly integrated in order to detect the majority of critical events in the situation while minimizing unwanted alerts. We exemplify the proposed system in the domain of maritime surveillance.

Ground target tracking of vehicles in a wireless ground sensor network

Abstract: In this paper data from a wireless unattended ground sensor network is used for tracking vehicles travelling in a road network. A multiple model particle filter algorithm, taking into account the road information, is studied. The algorithm enables tracking of targets driving both on and off road. In the PF algorithm two different dynamic models, a second order linear Gaussian model and a constant velocity model, are used to represent the on and off road motion. In order to handle realistic ground target tracking scenarios, the tracking algorithm is integrated into a multiple-sensor tracking system platform which is able to handle real data from a wireless ground sensor network. The performance of the ground target tracking algorithm is evaluated using real data together with simulated data.

Flexible display system

Abstract: The invention pertains to display method, a computer program for performing the steps of the display method and a display system (1), the display system having for example: at least one display unit (13, 16) arranged to present at least one display image, at least one memory unit (12, 15) comprising information related to for example descriptions of a set of default graphics display objects (W1-W3) and configuration data.The configuration data is arranged to define:at least one transparent display layer (L1-L3), at least one transparent display container (CO0-CO2) associated to the at least one transparent display layer and at least one display mode. Each of said at least one display mode comprising a predetermined selection of one or more of said at least one transparent display container of one or more of said at least one display layer.

Prognostics of thermal fatigue failure of solder joints in avionic equipment

Abstract: A practical method has been suggested for solder joint thermal fatigue prognostics, which enables real-time fatigue calculations based on uncompressed temperature data embedded in a host system that performs safety-critical operations. The accuracy of the prognosticated remaining useful life depends on the level of details captured in the model, and the level of confidence from validation efforts.

Multi-target tracking with background discrimination using PHD filters

Abstract: In this paper, we propose a new double PHD filter for simultaneous multi-target tracking and background discrimination for airborne radar applications. Both the foreground and the background processes are modeled as Poisson point processes, which gives a symmetric formulation of the coupled filters. The differences between foreground and background lie in the assumed target dynamics, and in the sensor detection probabilities. Although there are proposals for PHD filter with adaptive background models in the literature, our filter appears to be novel and also the simplest possible. To implement the filter we use a Gaussian mixture approximation of the intensities, which enables simple and effective ways to extract tracks. For the evaluations we use a simulated target tracking scenario with an airborne radar tracking a number of flying targets over a background of road objects. First, the performance of the Gaussian mixture PHD filter with track extraction is illustrated. Second, the superior ability of the foreground-background PHD filter to suppress clutter and disturbing road traffic is illustrated.

An integrated curved structure and winglet strength enhancement

Abstract: The present invention regards a structurally integrated curved structure (13, 13', 13'') comprising a curved transition region (15) being defined between a tip section (42) and a root section (11, 21), an upper and lower composite skin (27, 29) comprising an inner surface (45) fixed to a substructure (31) of said transition region (15), the substructure (31) and skins (27, 29) are, during use of the structure (13, 13', 13''), subjected to a bending moment (M), each skin (27, 29) of said transition region (15) comprises elongated reinforcement fiber-like elements. The lower composite skin (29) comprises reinforcing fibersand/or nano tubes(41, 43), which are oriented transverse to the inner surface (45). The invention also regard sa method for producing the structurally integrated curved structure (13, 13', 13'').

Integral attachment of fiber reinforced plastic rib to fiber reinforced plastic skin for aircraft airfoils

Abstract: The present invention relates to a torsion-box type airfoil structure. The structure (3) being formed by joined structural composite parts (5, 7, 9, 11) made of fiber reinforced plies (19) stacked onto each other. At least a first (11) and a second structural part (5) being joined by embedding a plurality of elongated reinforcement fiber-like elements (17, 17', 23, 23', 23'', 23''') in said first (11) and second (5) structural parts, wherein said fiber-like elements (17, 17', 23, 23', 23'', 23''') connect said parts to each other.

A method for determining threat status for combat aircrafts

Abstract: The invention relates to a method for decision support of a first combat aircraft (1) in a combat situation comprising the steps of: a) detecting (3) a second combat aircraft (2), wherein the second combat aircraft (2) is different from the first combat aircraft (1), b) analyzing (4) the second combat aircraft (2) to determine its type, its sensor capacity and its total weapons capacity, and c) recording (5) the sensor capacity and the total weapons capacity of the second combat aircraft (2) to determine a first geographic zone adapted for defining the detection limit of the second combat aircraft (2) and a second geographic zone adapted for defining a shoot-down limit of the second combat aircraft (2), respectively, wherein the first and the second geographic zone are adapted for decision support of the first combat aircraft (1) in the combat situation with the second combat aircraft (2). In this way, a possibility is provided to assist the pilot in decision support in complicated combat situations while being reliable, fast and easy to handle for the pilot in order to make a quick and efficient decision.

De-icing arrangement and method for de-icing a structural element

Abstract: The present invention relates to a de-icing arrangement (300) and a method for de-icing a structural element. The de-icing arrangement comprises at least one electromagnetic actuator (304), a capacitive storage bank (303), a control unit (301) arranged to provide an excitation pulse (p) to the at least one electromagnetic actuator, and a charging circuit (302) arranged to charge the capacitive storage bank (403). The at least one electromagnetic actuator (304) is arranged to expand in at least one direction when fed with the excitation pulse. The at least one electromagnetic actuator (304) is placed in relation to said structural element so as to apply a mechanical force caused by the expansion on the structural element. The capacitive storage bank (303) comprises a plurality of selectable capacitors of different capacitance and the control unit (301) is arranged to select at least one capacitor for charging having a total capacitance such that current discharge of the capacitive storage bank into the at least one electromagnetic actuator generates a desired distribution between heat and mechanical power.

Dynamic memory access management

Abstract: The invention pertains to a system, a method and a computer program for managing memory access of an avionics control system having at least one control computer (S1-S4) having at least one memory control device (15).The method comprising assigning a memory access of at least one unique memory region (APPM) of at least one memory unit (4) to each of at least one application task or task set (P1, P2). A further step comprises assigning a memory access of at least one application data update task to at least one subregion of one or more of the at least one unique memory region. Further steps consists of writing at least one data parameter to the at least one subregion and de-activating the assigned memory access of said at least one application data update task.

Method and system of mission planning

Abstract: The present invention relates to a method and system for mission planning. The method comprises the steps of: - providing (805) information related to a target scene, said information comprising information related to a plurality of targets, - providing (810) information related to a plurality of resources for target attack, - determining (820) at least one possible attack direction against each target, - determining (830) a target effect associated to attacking the target from each of said determined at least one possible attack direction for each target, - forming (840) a network of possible routes between the targets for the resources, wherein the possible routes are determined based on the possible attack directions related to each target, and - forming (845) the mission plan for fighting the targets based on the determined target effects from the respective attack directions and based on the formed net¬ work of possible routes, wherein each target is fighted a predetermined amount of times.

Method and mould system for net moulding of a co-cured, integrated structure

Abstract: The present invention relates to a mould system and a method for net moulding of a co-cured integrated structure (1) comprising a skin (26) provided with stringers(4) and rib feet (2) and with a gap (6) between the stringers (4) and the rib feet (4). The mould system comprises a substantially rectangular frame (12) made of a low heat expanding material,a number of substantially rectangular boxes (8) made of a heat expanding material, connection plates (16) made of a heat expanding material and fastening means (14). By means of the connection plates (16) the gap (6) is obtained. A moulding assembly (64) is created by applying prepregs to the surfaces of the boxes(8), by connecting the boxes (8) to each other and by surrounding the connected boxes (8) with the frame (12). The moulding assembly (64) is treated in a conventional way in an autoclave in order to cure the structure (1). Thereafter the frame (12), the boxes (8) and the connection plates (16) are removed.

Method for integrating an antenna with a vehicle fuselage

Abstract: An antenna frame for reducing radar cross section of a vehicle provided with a flat microstrip patch antenna array comprising a number of microstrip patches arranged in an array pattern, the antenna frame: - being arranged to surround the outer periphery of the flat antenna array - the frame comprising a first conductive sheet; - the first conductive sheet extending from the most peripheral patches and outward in a sloping manner; wherein dielectric and magnetic absorbent material are arranged to improve impedance transition from a point of the antenna to a point on the periphery of the frame, which is also contemplated as adjoining a vehicle fuselage.

An airframe leading edge

Abstract: An airframe leading edge part designed to be replaceable fixed to a structural portion which during use moves through the air. The airframe leading edge part includes first and second longitudinal joint edges adapted to fit the structural portion. At least one joint is provided between the structural portion and at least one of the longitudinal joint edges. The joint is adapted to break in the event of a object strikes and deforms the airframe leading edge part during use. The joint is designed to break at beforehand determined maximum joint strength of the joint. Also a repair method for exchanging a damaged leading edge.

A porous coating applied onto an aerial article

Abstract: The present invention regards an aerial article comprising a composite skin (5), a leading edge (1) facing the airflow (a) during the use of the aerial article (3), an erosion resistant coating (7) comprising a metallic material, and an aerodynamic surface (9). The coating (7) partly or entirely covers the composite skin (5) of the aerial article (3), wherein the coating (7) is of such high porosity that moisture transportation (MT) is permitted from the composite skin (5) to the aerodynamic surface (9) of the coating (7), and of such low porosity that erosion protection of the composite skin (5) still is achieved during said use. It also regards a method of applying an erosion resistant coating (7) comprising a metallic material to a composite skin (5) of an aerial article (3). It is made by providing an erosion resistant coating material (45) onto the composite skin (5) over a selected area of the article (3) wherein the coating is porous. Finally, polishing the outer surface (9) of the coating (7) is made so that a smooth aerodynamic surface is achieved.

Calculating uncertainties in situation analysis for fighter aircraft combat survivability

Abstract: The aim of situation analysis is to assess the relevant objects in the surroundings and interpret their relations and their impact in order for a decision maker to achieve situation awareness and be able to make suitable decisions. However, the information regarding the relevant objects is typically uncertain, which will induce uncertainty in the result from the situation analysis. If the kinematic states of the objects are estimated with a tracking filter, the estimates can be considered as random variables. Furthermore, the situation analysis algorithm is a function of these estimates entailing that the result from the situation analysis is random variable. This paper studies the fighter aircraft domain and a situation analysis algorithm that calculates the combat survivability, i.e., the probability that the aircraft can a fly a route inside hostile territory without getting hit by enemy fire. The survivability of different routes can be compared in order to decide where to fly. However, the uncertainties regarding the threats' positions imply that the survivability is uncertain and can be described as a random variable with a distribution. The unscented transform (UT) is here used for calculating the mean and standard deviation (std) of the survivability in a few scenarios with threats located on the ground. Simulations show that the position uncertainties affect both the mean and std of the survivability and that UT gives similar estimates as a Monte Carlo (MC) approach. UT therefore seems to be a promising approach for calculating the uncertainty in the survivability, which is more computational efficient than MC.

A realistic roadmap for the introduction of dynamic spectrum management in military tactical radio communication

Abstract: Cognitive radio (CR) technology has to date not been adopted by the military even though more than a decade has passed since its inception. This paper describes how cognitive radio and associated dynamic spectrum management (DSM) procedures can be introduced in military tactical radio communication. CR and DSM address key challenges that face future military tactical radio communication and their successful introduction can reduce or even overcome current spectrum scarcity and deployment difficulty. A DSM roadmap is introduced where military users develop trust in, and experience with, these novel technologies in manageable steps. The first step in this DSM roadmap involves the introduction of a military band dedicated for CRs and subsequent steps gradually increase the spectrum that may be utilized for military cognitive operation. A high-level vision of how existing military spectrum management procedures will change in the future with the introduction of DSM is also presented resulting in a significant reduction in the workload of spectrum management personnel.

Combined antenna, antenna array and method for using the antenna array

Abstract: An antenna including a dipole antenna element having central feeding points, a common mode rejection filter, a first length of a two-conductor transmission line, and a common mode rejection filter arranged and connected between a far end of the first length of the two-conductor transmission line and the feeding points of the dipole antenna element. The first length of the two-conductor transmission line is arranged to extend from a ground plane to a first height where the first length of the two-conductor transmission line is connected to the common mode rejection filter.

Expectation maximization algorithm for calibration of ground sensor networks using a road constrained particle filter

Abstract: Target tracking in ground sensor networks requires an accurate calibration of sensor positions and orientations, as well as sensor offsets and scale errors. We present a calibration algorithm based on the EM (expectation maximization) algorithm, where the particle filter is used for target tracking and a non-linear least squares estimator is used for estimation of the calibration parameters. The proposed algorithm is very simple to use in practice, since no ground truth of the target position and time synchronization are needed. In that way, opportunistic targets can also be used for calibration. For road-bound targets, a road-constrained particle filter is used to increase the performance. Tests on real data shows that a sensor position accuracy of a couple of meters is obtained from only one passing target.

A method for resource allocation in mission planning

Abstract: The present invention relates to a method for planning attacking to optimize the use of own available resources and effecting attacking of targets in a target area (15) based upon information on own resources available for attacking and information on protected and non-protected targets located in the target area. The method comprises collecting different attack tactics in a first library (5) and collecting strategies to defend a target area to be attacked in a second library (6), allotting each target (16, 17, 18) in the target area (15) a reward value, evaluating different attack tactics for a chosen defend tactic to find an optimal attack tactic having highest possible collected reward value, the found optimal attack tactic being used to create an attack plan involving information on inter alia resources needed, targets to attack and attacking directions The object of the invention is to obtain a more effective use of available resources.

Airborne network extension cluster

Abstract: The object of the present invention is to provide an over-the-horizon communication system comprising at least two end nodes, the end nodes being configuredto receive and transmit communication signals, and providing communication between the at least two end nodes. The system further comprises at least two, in the troposphere and/or stratosphere airborne, network extension nodes that are communicatively connected to the end nodes and wherein the end nodes are arranged for bidirectional or unidirectional communication with the network extension nodes and the network extension nodes are arranged for bidirectional or unidirectional communication between the individual network extension nodes and bidirectional or unidirectional communication with the end nodes.

An erosion protection strip for a leading edge of an airfoil article

Abstract: The invention regards an airfoil article including a composite skin (5) forming a leading edge (4), the composite skin (5) being during use subjected to an airflow (a) meeting the leading edge (4) at stagnation points (SP), where the airflow (a) being divided into a first (a1) and second (a2) airflow, and at which stagnation points (SP) the airflow swirls. The leading edge (4) comprises a flush elongated member (9, 9'…9''''', 30, 32, 36, 38, 39), the elongated member having an extension being parallel with an imaginary line (IL) intersecting with the stagnation points (SP). The elongated member is arranged primarily for erosion protection.

A comparison of joint/independent state particle filters for tracking closely spaced targets in clutter

Abstract: In this paper, we present an overview of the literature for particle filtering under measurement origin uncertainty with an emphasize on single scan data association algorithms. We compare some of the existing and newly proposed joint state particle filtering algorithms for the closely spaced target tracking problem. Both maximum a posteriori (MAP) and minimum mean square error (MMSE) estimation outputs of four different algorithms are compared. We also include MMSE outputs of a non-joint (independent) state particle filter and Kalman filter in the comparison as a baseline.

A countermass container for use in a recoilless weapon and a recoilless weapon comprising such a countermass container

Abstract: A countermass container for use in a recoilless weapon. The countermass container includes an envelope encloses a countermass. A recoilless weapon includes a barrel accommodating an ammunition unit, a propellant charge and a countermass container. The countermass container includes an envelope enclosing a countermass. The barrel includes a front end opening for firing the ammunition unit out of the barrel and a rear end opening for ejecting the envelope and countermass of the counter mass container. The envelope is divided into a front section and a rear section. The rear section of the envelope has a weaker construction than the front section of the envelope to more easily crack than the front section of the envelope. Splines are provided at the front section to create ducts.

An approach to life consumption monitoring of solder joints in operating temperature environment

Abstract: This paper elaborates the 3T-approach to life consumption monitoring of solder joints in operating temperature environment without requiring simplification of operating loads

A method for determining a direction to a signal-emitting object

Abstract: The present invention relates to a method for determining a direction to a signal-emitting object by means of a platform comprising at least two antennas separated by a known distance. The method comprises said steps of: receiving, with each of said at least two antennas, a signal from said signal-emitting object at first positions, determining a first phase relation of said signal between said at least two antennas, - receiving, with each of said at least two antennas, a signal from said signal-emitting object at at least second positions, determining at least a second phase relation of said signal between said at least two antennas, characterised by the steps of: determining change(s) in position(s) of at least one antenna of said at least two antennas, and determining a direction to a signal-emitting object based on said first phase relation, said at least second phase relation and said change(s) in position(s) of said at least one antenna. The invention further relates to a platform performing a determination of a direction to a signal-emitting object.

A method for variable control of a zone sensor in a combat aircraft

Abstract: The invention relates to a method for controlling a sensor in a combat aircraft (1) comprising the steps of: a) determining (3) direction and size of a defence zone around the combat aircraft (1) based on a plurality of characteristic parameters of an enemy combat aircraft (2), b) determining (4) direction and size of at least one offence zone around the combat aircraft (1) based on the plurality of characteristic parameters of the enemy combat aircraft (2), and c) controlling (5) the sensor in the combat aircraft (1) according to emission level and detection capacity within at least one of the defence zone and the at least one offence zone. In this way, the sensors are controlled reliably and thus the pilot can act and react mission-oriented.

Power conversion system

Abstract: A power converter system suitable to provide a load with electrical power, the system comprising; an input voltage terminal; an output voltage terminal; a first power converter unit; a second power converter unit; an input relay unit; an output relay unit; a control unit; wherein the control unit is configured to control the input relay unit and the output relay unit such that the first and second power converter units are engaged alternating at subsequent power ups of the voltage input terminal.

A method for duel handling in a combat aircraft

Abstract: The invention relates to a method for decision support of a first combat aircraft in a duel situation with a second combat aircraft. The method comprises the steps of: a) determining (3) a first plurality of combat value parameters of the first combat aircraft (1) and determining (3) a second plurality of combat value parameters of the second combat aircraft (2), wherein the second combat aircraft (2) is different to the first combat aircraft (1), b) analyzing (4) the first and the second plurality of combat value parameters determined in the previous step (step a)) by fitting the first and the second plurality of combat value parameters to a predefined model, and c) combining (5) the first plurality of combat value parameters analyzed in the previous step (step b) ) to calculate a first value and combining (5) the second plurality of combat value parameters analyzed in the previous step (step b) ) to calculate a second value, wherein the first value and the second value are compared to each other to determine the optimum success probability data of the first combat aircraft (1) and of the second combat aircraft (2) adapted for decision support in the duel situation. In this way, a reliable and fast tool for the pilot is provided while the tool is easy to handle and assists the pilot in order to make a quick and efficient decision in duel situations.