systems

Control of exhaust systems

Exhaust capture and containment are enhanced by means of automatic or manual side skirts, a sensitive breach detector based on interference effects, a combination of vertical and horizontal edge jets, and/or corner jets that are directed to the center diagonally from corners. Associated control functions are described.




systems

Initiation disruptor systems and methods of initiation disruption

A system that may be used as an initiation disruption system (IDS) according to one embodiment includes an explosive charge; a plurality of particles in a layer at least partially surrounding the explosive charge; and a fire suppressant adjacent the plurality of particles. A method for disabling an object according to one embodiment includes placing the system as recited above near an object; and causing the explosive charge to initiate, thereby applying mechanical loading to the object such that the object becomes disabled. Additional systems and methods are also presented. A device according to another embodiment includes a plurality of particles bound by a binder thereby defining a sidewall having an interior for receiving an explosive; and a fire suppressant adjacent the plurality of particles and binder. Additional systems and methods are also presented.




systems

Systems and methods for localization of tire pressure monitoring system wheel modules

Embodiments relate to unidirectional TPMS utilizing information from a corresponding vehicle system in order to correlate with vehicle speed information to be used in a tire localization methodology. In an embodiment, the vehicle system is an anti-lock brake system (ABS), and the vehicle speed can be used in a localization scheme that reconstructs a +/−1 g ripple with waveform, amplitude, frequency and phase parameters. Because the waveform is known to be sinusoidal (due to the wheel rotation), the amplitude is known to be 2 g peak-to-peak (due to the gravitational +/−1 g), the frequency depends on vehicle speed (which can be estimated from centrifugal force measurements), and an algorithm is discussed herein for determining the phase by correlation, the +/−1 g ripple can be reconstructed and the wheels localized therefrom.




systems

Portable movie screens, systems, and methods of using the same

A portable movie screen includes a screen portion and a frame portion surrounding at least part of the periphery of the screen portion. The screen portion has a screen gain greater than about 0.8 and an elasticity greater than an elasticity of the frame portion. The movie screen includes at least one side connected to the front portion and a receiving space defined at least in part by the front portion and the side portion. The receiving space is configured to selectively receive a support body including at least one sealed chamber and movable between a collapsed configuration and an expanded configuration. The frame portion is configured such that when the support body is in the expanded configuration and positioned in the receiving space, the frame portion tensions the screen portion and substantially maintains the screen portion in a desired shape.




systems

Substrate treatment systems using supercritical fluid

Substrate treatment systems are provided. The substrate treatment systems may include a treating device configured to treat a substrate with a supercritical fluid, and a supplying device configured to supply the supercritical fluid to the treating device. The treating device may include a supercritical process zone in which the substrate is treated with the supercritical fluid, and a pre-supercritical process zone in which the supercritical fluid is expanded and then provided into the supercritical process zone to create a supercritical state in the supercritical process zone.




systems

Systems and methods for connecting an ingot to a wire saw

Systems and methods are disclosed for connecting an ingot to a wire saw with an ingot holder, a bond beam, and a bar. The bar has an angled mating surface that engages a recessed surface formed in a slot of the bond beam. Mechanical fasteners are used to connect the tee bar to the ingot holder. The angle of the mating surface with respect to the recessed surface of the slot prevents deformation of the bond beam and prevents compromising the integrity of the adhesive bond between the ingot and the bond beam.




systems

Systems and methods for producing a hardwearing alloy material

Described herein are systems and methods for producing a hardwearing or wear-resistant material. In one aspect, a first group of materials comprising zirconium dioxide (ZrO2), aluminum oxide (Al2O3), and one or both of calcium oxide (CaO) and yttrium oxide (Y2O3) may be mixed, heated, and cooled to yield a first mixture. The first mixture may be used to generate granules that may then be mixed with a second group of materials comprising iron, nickel, manganese, titanium, carbon, chromium, and optionally, a paraffin, to yield a second mixture. The second mixture may then be compressed, cast, cooled, and heat treated to yield the hardwearing or wear-resistant material.




systems

Method of produced water treatment, method of water reuse, and systems for these methods

A method of produced water treatment in an in-situ recovery method of producing bitumen from oil sand, the method has the steps of: separating bitumen from bitumen-mixed fluid so as to leave produced water, the bitumen-mixed fluid having been recovered from the oil sand wells; and filtering the produced water via a microfiltration membrane made of polytetrafluoroethylene.




systems

Systems and processes for improving distillate yield and quality

Systems and processes for improving quality and yield of one or more distillate products generated in a distillation column are disclosed. The system comprises a feed inlet distributor that reduces the amount of liquid entrained in vapor rising from the feed zone of the distillation column, a wash zone collection apparatus having an improved design for collecting slop wax falling from a liquid/vapor contacting structure provided in the wash zone, a recirculation subsystem for recirculating at least a portion of the collected slop wax to the top of the wash zone for distribution as wash oil, and a control subsystem. The feed inlet distributor ensures a horizontal fluid flow path free of transverse surfaces thereby minimizing atomization of liquid droplets entrained in vapor in the feed stream.




systems

GENDER SPECIFIC SYNTHETIC NUTRITIONAL COMPOSITIONS AND NUTRITIONAL SYSTEMS COMPRISING THEM

Gender specific synthetic nutritional compositions for female or male infants up to 1 month of age wherein, the concentration of alanine, and/or histidine, and/or isoleucine, and/or proline, and/or valine is adapted based on that found in HM produced for an infant of the same gender and age, and nutritional systems comprising them.




systems

GENDER SPECIFIC SYNTHETIC NUTRITIONAL COMPOSITIONS AND NUTRITIONAL SYSTEMS COMPRISING THEM

Gender specific synthetic nutritional compositions for infants up to 1 month of age wherein, the total protein content is adapted based on that found in HM produced for infants of the same gender and age, and nutritional systems comprising them.




systems

Methods and systems for in-process quality control during drill-fill assembly

A method for assembling a structure is described. The method includes locating a position in an assembly stack-up where a one-sided fastener is to be installed, drilling a hole through the assembly stack-up at the position, countersinking the hole to a specified depth, operating a calibrated probe to determine at least parameter associated with one or more of the hole and the stack-up proximate the hole, inserting the one-sided fastener into the hole, applying a rotational torque to the one-sided fastener to complete installation of the one-sided fastener, and comparing a measurement of angular displacement required to complete installation of the one-sided fastener to a range of angular displacement indicative of correct installation of the fastener.




systems

Methods and systems for stitching composite materials

A composite material includes a composite body having a composite surface, and a reinforcing element extending through the composite body in a first plurality of stitches and a second plurality of stitches. The first plurality of stitches are aligned relative to the composite surface substantially similarly to each other. The second plurality of stitches are aligned relative to the composite surface substantially dissimilarly to each other.




systems

Systems and methods for creating quilt blocks

Systems and methods for creating quilt blocks are provided. In one embodiment, a method for creating a quilt block with a computerized embroidery machine includes sewing placement stitching on a backing according to a placement stitching pattern provided by instructions for at least partially creating a quilt block comprised of one or more pieces, providing directions for placing one or more pieces of the quilt block on a corresponding portion of the placement stitching on the backing, and sewing the one or more pieces to the backing in accordance with the instructions.




systems

Systems and method for biomass digestion

Provided herein are systems and methods for biomass digestion and products formed thereof. The products include one or more biogases, U.S. Environmental Protection Agency classified Class A Biosolids, and pathogen reduced organic liquid fertilizer. Through the digestion of waste materials using sequential phases in an efficient digestion process, enhanced biomass conversion efficiency and improved output of products (in quantity and/or quality) are obtained with a significant reduction in dwell time in each phase.




systems

METHODS AND SYSTEMS FOR GENERATING SHARED COLLABORATIVE MAPS

Described herein are methods and systems for generating shared collaborative maps for planting or harvesting operations. A method of generating a collaborative shared map between machines includes generating a first map for a first machine based on a first set of data and generating a second map for a second machine based on a second set of data. The method further includes generating at least one shared collaborative map for at least one of the first and second machines based on the first and second maps.




systems

Guide systems for laminated spring assemblies

A patient side-system includes a column with a rail and a counterbalance subsystem. The patient side-system may further include a braking subsystem. The counterbalance subsystem includes a spring assembly coupled at one end to the column with a spring member, and a housing movably coupled to the rail. The housing includes a drum to receive the spring member and a plurality of roller elements to guide a movement of the spring member winding or unwinding on the drum. If present, the braking subsystem includes a first pulley rotatably coupled to the column, a second pulley with a locking mechanism spaced apart from the first pulley and rotatably coupled to the column, and at least one brake cable wrapped around the first pulley and the second pulley with ends coupled to the housing. The locking mechanism can set a position of the housing along the column.




systems

Systems and methods for inline sampling

Methods and devices for inline sampling of a bulk material, such as a powder, are provided. The material's bulk density can be determined from samples drawn using methods and devices described herein. One embodiment of a method of sampling a material allows the material to flow through a sampling compartment, closes off the flow of material below the sampling compartment, builds up a column of material through the sampling compartment, shifts the sampling compartment to remove a slice of material in the column, and places the slice of material into a sample container. A device for sampling a material is provided in another embodiment. The device includes an inlet, an outlet aligned with the inlet, and a sample collector. The sample collector can include at least one through hole and be configured to move such that the at least one through hole can be moved into and out of alignment with the inlet and the outlet.




systems

Systems and methods for managing pressure and flow rate

A device for controlling fluid flow pressure and flow rate is disclosed. The device includes a first orifice plate, a second orifice plate housed in a tubular structure. The first orifice plate includes a first orifice of a first diameter (d1) and the first orifice is positioned near an edge of the first orifice plate. The second orifice plate includes a second orifice of a second diameter (d2) and the second orifice is positioned near an edge of the second orifice plate. The tubular structure has an effective diameter (D) comprising the first orifice plate and the second orifice plate placed at perpendicular direction to the fluid flow within the tubular structure, separated by an optimum distance (X).




systems

Vertically integrated systems

Embodiments of the present invention provide an integrated circuit system including a first active layer fabricated on a front side of a semiconductor die and a second pre-fabricated layer on a back side of the semiconductor die and having electrical components embodied therein, wherein the electrical components include at least one discrete passive component. The integrated circuit system also includes at least one electrical path coupling the first active layer and the second pre-fabricated layer.




systems

Marine vehicle systems and methods

Marine vehicle systems and methods are disclosed. The marine vehicle can be buoyancy controlled, enabling efficient, extended use of the marine vehicle. Buoyancy actuation can enable roll, pitch, and yaw of the marine vehicle, as well as translation in any direction. One or more elastic bladders can be disposed on or in the marine vehicle. The bladders can be selectively inflated and deflated to control movement of the marine vehicle.




systems

Optimization of vacuum systems and methods for drying drill cuttings

Systems and methods for separating fluids from drill cuttings. Specifically, the invention relates to shakers that incorporate a vacuum system and methods of operating such systems to effect a high degree of fluid separation. The system and methods are effective across a variety of screen sizes, vacuum flows and vacuum designs.




systems

Systems and methods for efficient microwave drying of extruded honeycomb structures

Systems and methods for efficient microwave drying of extruded honeycomb structures are disclosed. The methods include conveying first and second sets of honeycomb structures in opposite directions through multiple applicator cavities. Each honeycomb structure has a moisture content MC, and the honeycomb structures within each cavity define an average moisture content MCA between 40% and 60% therein. The methods include irradiating the first and second sets of honeycomb structures within the cavities with microwave radiation having an amount of input microwave power PI that results in an amount of reflected microwave power PR from the honeycomb structures, where PR




systems

Tooling assemblies and systems

Press tool assemblies involve separable holder and tip portions. Self-seating structure is incorporated in these assemblies, and can stem from one or both of the separable portions of the assemblies. In use, the self-seating structure facilitates proper positioning and seating of the separable portions in relation to each other, and in some cases, can be used in operatively coupling the portions together. Advantages relating to assembly and disassembly of the tool assemblies, as well as improved structural properties result as a consequence of using the self-seating structure.




systems

FITNESS SYSTEMS AND METHODS THEREOF

Systems and methods for fitness tracking are provided. An exercise apparatus is in networked communication with a fitness tracking computing system. The configuration and location of movable components of the exercise apparatus is determined based on sensors. This information is provided to the fitness tracking computing system via networked communication.




systems

Gas-generating devices with grain-retention structures and related methods and systems

Gas-generating devices with grain-retention structures and related methods and systems are described. In particular, gas-generating devices having at least one retention structure fixed to a frame and positioned between adjacent gas-generant grains arranged in a longitudinal stack. Fire suppression systems comprising such gas-generating devices are also described. Additionally, methods of manufacturing gas-generating devices, as well as methods of generating a gas and methods of suppressing a fire utilizing such gas-generating devices are described.




systems

Methods and systems for manufacturing propellants

Methods and systems for mixing propellant formulations are disclosed herein. In one embodiment, a method of mixing a solid propellant formulation includes placing a first component (e.g., a polymer or fuel) and a second component (e.g., an oxidizer of suitable particle size) in a mix vessel. The method further includes mixing the first and second components together by rotating the mix vessel about a first axis and, during at least a portion of the vessel rotation, revolving the vessel about a second axis spaced apart from the first axis. In one embodiment, the first axis can be a vessel spin axis, and the second axis can be spaced apart from the first axis so that the vessel revolves about the second axis in a planetary manner. In another embodiment, the vessel can rotate about the first axis in a first direction while revolving about the second axis in a second direction, opposite to the first direction.




systems

Valve devices, systems, and methods for controlling the distribution of materials

The various embodiments of the present invention are directed to valve devices, systems, and methods for controlling the distribution of materials to multiple locations. The improved valve devices, materials distribution systems, and materials distribution methods disclosed herein are particularly suitable for use in applications where the materials being distributed are, for example but not limited to, non-gaseous fluid materials (e.g., raw liquids, solutions, slurries, colloids, suspensions, and the like) and solid materials having some level of tackiness, moisture content, or like property. The valves, systems, and methods disclosed herein can be operated without having to stop the flow of materials therethrough in order to change the position of the valve from one outlet to another. Further, the valves and systems disclosed herein have few directional changes, therefore there are few, if any, points within the system where the material can get stuck and/or lodged.




systems

Roller rail systems and adjustment brackets therefor

A roller rail system includes an adjustment bracket including a first roller rail assembly support portion and a second roller rail assembly support portion adjacent the first roller rail assembly support portion. The first and second roller rail assembly support portions are each configured to receive a roller rail assembly such that the roller rail assembly slides within the respective first and second roller rail assembly support portion relative to the adjustment bracket. A first roller rail assembly is received by the first roller rail assembly support portion. A second roller rail assembly is received by the second roller rail assembly support portion. The roller rail system has a retracted configuration where leading ends of the first and second roller rail assemblies are closer together and an extended configuration where the leading ends of the first and second roller rail assemblies are further apart.




systems

Inflatable liner systems

An inflatable liner with vibratory function related to lining mining hoppers and other such devices. The inflatable liner has an exterior expandable layer and ceramic wear layer beneath that assists maintaining a long-use-life of the inflatable liner. Use of the air-control device to rapidly inflate and deflate exterior expandable layer vibrates in the exterior expandable layer and assist removing unwanted material/debris from the exterior lining of exterior expandable layer to further maintain a long-life use of the inflatable liner and lower maintenance of the machinery/hopper.




systems

Systems and methods for intermittently colored yarn

Intermittently colored yarns having an intermittent and random dye spacing pattern, and systems and methods of making the same, are disclosed. Such intermittently colored yarns exhibit higher quality and lower manufacturing costs over the known intermittently colored yarns. The intermittent coloring takes place while the yarn is in caterpillar form. Carpets made from such intermittently colored yarns exhibit enhanced aesthetics over carpets made from known intermittently colored yarns. Alternatively, a stain resist, colorless base dye, or bleaching agent can be applied in the same intermittent and random spacing pattern to the intermittently colored yarns prior to subsequent dyeing. This creates a mirror image like color effect to the resulting yarn.




systems

Rope systems and methods for use as a round sling

A rope assembly that is adapted to extend between first and second attachment points comprises a line arranged to define a plurality of loops and at least one pair of organizers. The at least one pair of organizers is configured to engage the line such that line segments of the line between the at least one pair of organizers are maintained in a desired relationship with each other and such that the desired relationship facilitates transfer of loads through the rope assembly between the first and second attachment points.




systems

Safety systems for wireless control for snow plows

A safety system for a wireless snowplow controller makes the wireless controller safer and more effective. The system includes a vehicle, a snowplow, a wireless controller and a tether. The controller wirelessly sends one or more control signs to one or more control modules coupled to the vehicle and/or the snowplow. The control signals may be used to control operation of the snowplow. The controller may be configured such that it is only able to send control signals when it is connected, via the tether, to a power supply coupled to the vehicle.




systems

Retainer systems for ground engaging tools

Disclosed are various exemplary embodiments of a retainer system for a ground engaging tool. The retainer system may include a lock having a lock rotation axis and including an outer surface extending about the lock rotation axis and a retainer bushing having a retainer axis and an inner surface extending about the retainer axis. The inner surface may be configured to rotatably receive the outer surface of the lock. At least a portion of the outer surface may have a varying radius with respect to the lock rotation axis.




systems

Composite smokeless tobacco products, systems, and methods

A smokeless tobacco product includes smokeless tobacco and a polymeric material in intimate contact with the smokeless tobacco and stabilized in conformance to a surface topography of the tobacco's fibrous structures such that the stabilized polymeric material secures the smokeless tobacco together. The smokeless tobacco product has a moisture-permeable porous surface and an overall oven volatiles content of at least 10 weight percent.




systems

Apparatuses, systems, and associated methods for forming porous masses for smoke filter

A system for producing porous masses may include a mold cavity disposed along the material path, at least one hopper before at least a portion of the mold cavity for feeding a matrix material to the material path, a heat source in thermal communication with at least a first portion of the material path, and a cutter disposed along the material path after the first portion of the material path.




systems

PROGRAMMABLE LEVEL SHIFTER FOR LCD SYSTEMS

A programmable level shifter for providing upshifted control signals to an active matrix display based on logic-level control signals received from a timing controller. The programmable level shifter includes a programmable state machine, level-shifting output drivers, and a programming interface. The programmable state machine is configured to receive at least one control signal from a timing controller. The state machine generates, based on said at least one control signal, a plurality of outputs for driving gate drivers of the active matrix display. The level-shifting output drivers convert the plurality of outputs generated by the programmable state machine to a higher-magnitude voltage level. The programming interface facilitates the programming of aspects of the programmable state machine.




systems

Coin counting and/or sorting machines and associated systems and methods

Coin processing apparatuses, such as consumer or commercial coin processing apparatuses for counting and/or sorting coins, are described herein. The apparatuses can include coin conveyors having a plurality of individual coin carriers linked together to form a chain. In some embodiments, each of the coin carriers includes a corresponding pocket that is configured to receive a coin from a coin hopper as the carrier chain passes through the coin hopper during its cycle. The coin carriers can carry the coins past one or more sensors for identification or “discrimination” of the coin denomination. After discrimination, the coins can be knocked from the carrier pockets and into, e.g., a selected coin chute for transfer to a collection bin.




systems

Microplate handling systems and related computer program products and methods

Systems, computer program products, and methods useful for handling or managing microplates are provided.




systems

Fall protection systems and methods

Fall protection systems, methods of installing such systems, and buildings embodying such systems. Such fall protection system extends from structure elements of the building about an encompassed space into which there is risk of a person falling. An open-mesh web is supported from the structure elements and overlies, and extends across, the space. A perimeter band extends about the encompassed space. The perimeter band is secured to the building structure elements about the space and thus entraps the web between the band and the building structure elements. The web may also be supported in the space by supplemental supports, which can be crossing support bands, attached to the structure elements, or intervening e.g. walls within the space. The web is left in place and is covered by internal finish materials whereby the web is captured between internal finish materials and ceiling and/or floor members in the finished building.




systems

Ladders, ladder components, ladder accessories, ladder systems and related methods

Various embodiments of ladders, ladder components, accessories for ladders, ladder systems and related methods are provided. In one embodiment a ladder and platform system is provided having at least two ladders and a platform or plank. The platform or plank has coupling mechanisms that provide adjustable but secure coupling of the platform to the ladders, either with the top cap or with the rungs. Other embodiments include storage devices and paint trays for use with ladders and ladder systems incorporating such devices.




systems

Fuel injection adapters and related systems and methods

A fuel injection adapter can include a primary cavity into which a primary fuel injector can be received and a secondary cavity into which a secondary fuel injector can be received. A channel can provide fluid communication between the primary and secondary cavity, and the primary cavity can be in fluid communication with an outlet of the fuel injection adapter.




systems

Methods and systems for model-based control of gas turbines

Embodiments of systems and methods for tuning a turbine are provided. In one embodiment, a method may include receiving at least one of a measured operating parameter or a modeled operating parameter of a turbine during operation; and tuning the turbine during operation. The turbine may be tuned during operation by applying the measured operating parameter or modeled operating parameter or parameters to at least one operational boundary model, applying the measured operating parameter or modeled operating parameter or parameters to at least one scheduling algorithm, comparing the output of the operational boundary model or models to the output of the scheduling algorithm or algorithms to determine at least one error term, and closing loop on the one error term or terms by adjusting at least one turbine control effector during operation of the turbine.




systems

TRANSIENT CURRENT-PROTECTED THRESHOLD SWITCHING DEVICES SYSTEMS AND METHODS

Threshold switching devices demonstrating transient current protection through both insulation and repair current mechanisms, including associated systems and methods, are provided and discussed.




systems

SLOT ALLOCATION IN TIME DIVISION DUPLEX SYSTEMS

Various communication systems may benefit from managing signal interference. For example, certain wireless communication systems may benefit from a dynamic time division duplex system involving slot allocation. A method includes allocating, by an access point, in a time division duplex frame a plurality of radio resource slots, each one of the plurality of radio resource slots being allocated for a downlink or an uplink transmission, and determining that the allocation of the downlink or uplink transmission should be changed. The method also includes applying a permutation pattern to re-allocate at least one of the plurality of radio resource slots for the downlink or uplink transmission.




systems

Method, Apparatus, Server, and Systems of Time-Reversal Technology

A time-reversal wireless system comprising a first wireless transceiver of a time-reversal client, one or more second wireless transceiver and/or a time-reversal client with the first wireless transceiver. The first wireless transceiver of the time-reversal client is wirelessly coupled to the one or more second wireless transceiver through a wireless broadband multipath channel associated with a space. The time-reversal client contains the first wireless transceiver. The time-reversal client also contains a processor and a memory configured to obtain a set of channel state information (CSI) in a channel probing phase, and/or to obtain a set of location-specific signatures based on the set of CSI and/or a time reversal operation in a channel probing phase. The set of CSI is captured when one or more probing signal is sent either from the first wireless transceiver to each of the at least one second wireless transceiver, or from each of the at least one second wireless transceiver to the first wireless transceiver, through the wireless broadband multipath channel associated with the space. A channel passband with bandwidth W0 is associated with the wireless broadband multipath channel. A first passband with bandwidth W1 is associated with the first wireless transceiver. The W1 is not larger than W0 such that the first passband is part of the channel passband. One or more second passband is associated with the one or more second wireless transceiver such that a bandwidth W2 associated with each of the one or more second passband is not larger than W1 such that the each of the one or more second passband is part of the first passband. Each of the set of CSI include a channel impulse response, a channel frequency response, and/or another channel state data of the wireless broadband multipath channel.




systems

Systems and methods for fabricating biased fabric

In one embodiment, a biased fabric is supplied. The biased fabric supply has a first specified width and a first bias angle of warp yarns relative to weft yarns. At least one overfeed roller configured to overfeed fabric from the biased fabric supply at an overfeed rate is provided. At least one spreading arm configured to stretch the fabric to a second specified width and a fabric oven configured to heat the biased fabric supply to a specified temperature and output a balanced crimp and/or elongation biased fabric are also provided.




systems

Inclination angle compensation systems and methods

An inclination angle compensation system for determining an inclination angle of a machine is disclosed. The inclination angle compensation system may have a non-gravitational acceleration estimator configured to estimate a non-gravitational acceleration of a machine based on an estimated inclination angle and an acceleration output from a forward acceleration sensor. The inclination angle compensation system may also have an inclination angle sensor corrector configured to receive an inclination angle output from an inclination angle sensor, determine an inclination angle sensor acceleration based on the inclination angle output, and calculate a corrected inclination angle of the machine based on the non-gravitational acceleration and the inclination angle sensor acceleration.




systems

Systems and methods for sailboat mast alignment

Systems and methods for sailboat mast alignment are provided. In some embodiments, a system for alignment of a sailboat mast comprises a mounting bracket configured for attachment to the mast, and one or more lasers pivotally connected to the mounting bracket to enable the one or more lasers to be positioned at an index angle relative to the mast on both sides of the mast.




systems

Systems and methods for providing aircraft heading information

Systems and methods for providing aircraft heading information are provided. In one embodiment, an attitude heading reference device comprises: at least one interface for receiving heading information from one or more IRUs; at least one set of gyroscopes and accelerometers; a memory device for storing data representing heading information received via the at least one interface; and a heading calculator coupled to the at least one interface, the at least one set of gyroscopes and accelerometers, and the memory device. The heading calculator generating a heading output signal based on heading information when reliable heading information is received over the at least one interface; the heading calculator generating the heading output signal based on data from the memory device regarding previously reliable heading information and an output of the at least one set of gyroscopes and accelerometers when reliable heading information is not received over the at least one interface.