Abstract: An objective of the invention, focusing on these issues involved in the use of a small, hobby-type, unmanned helicopter, is to develop an autonomous control system comprising autonomous control systems for a small unmanned helicopter, to be mounted on said small unmanned helicopter; a servo pulse mixing/switching unit; a radio-controlled pulse generator; and autonomous control algorithms that are appropriate for the autonomous control of the aforementioned small unmanned helicopter, thereby providing an autonomous control system that provides autonomous control on the helicopter toward target values.

Abstract: A method of and a system for controlling personal air vehicle (PAV) traffic provides a take-off-and-landing zone, and a forward flight zone. The take-off-and-landing zone may be from the ground up to a first altitude. The forward flight zone may be from the first altitude up to a second altitude. A maximum airspeed is provided in the take-off-and-landing zone. Minimum and maximum airspeeds are provided in the forward flight zone. In the forward flight zone there is a single heading for each altitude. Any change in heading must be accompanied by a change in altitude.

Abstract: A system and method for filtering various targets (such as ground vehicles, stationary objects, and aircraft) from display on a display screen within the cockpit of an “Own Ship” aircraft. The system and method withhold from display any non-exempt targets that have an altitude that is either: (1) greater than an upper-threshold altitude; or (2) less than a lower-threshold altitude. The upper-threshold altitude and the lower-threshold altitude may be set to user-specified, customized values as desired to accommodate current flying conditions. In addition, the system and method may also be configured to operate in a plurality of operating modes, each of which features a different upper threshold altitude/lower threshold altitude combination. The system and method are preferably configured to reset certain threshold altitudes to pre-defined default altitudes in response to the aircraft landing.

Abstract: A flight control system moves elevators according to a pilot command summed with an automatic command. The flight control system monitors a set of flight parameters to determine if the flight vehicle is operating inside a permitted envelope. The flight controls system incorporates automatic protections thru the automatic elevator command if the flight vehicle is close to its envelope limits. The exemplary illustrative non-limiting implementation herein provides automatic protections in order to protect the flight vehicle from low speeds, high attitude, stalls and buffetings.

Abstract: The invention relates to a navigation aid method of an aircraft comprising a step for positioning an execution order in a flight plan then in a flight path. When the order is for deferred execution, that is, comprises a condition, estimating the position of the aircraft when the condition associated with the order is satisfied, modifying the flight plan based on the estimated position according to the order, computing a new flight path based on the flight plan.

Abstract: The method includes a preliminary period in which a reference rotorcraft is used that corresponds to a rotorcraft of a particular type, with a series of noise measurements being performed on said rotorcraft (1) in flight using noise sensors (C) disposed on said reference rotorcraft, and with operating domains being determined for the reference rotorcraft in which noise is less than a maximum noise level. Thereafter, the operating point without wind and operating domains with wind are subsequently determined for a rotorcraft of the particular type on the basis of operating domains for the reference rotorcraft.

Abstract: Navigating UAVs in formation, including assigning pattern positions to each of a multiplicity of UAVs flying together in a pattern; identifying a waypoint for each UAV in dependence upon the UAV's pattern position; piloting the UAVs in the pattern toward their waypoints in dependence upon a navigation algorithm, where the navigation algorithm includes repeatedly comparing the UAV's intended position and the UAV's actual position and calculating a corrective flight vector when the distance between the UAV's actual and intended positions exceeds an error threshold. The actual position of the UAV may be taken from a GPS receiver on board the UAV.

Abstract: Methods and systems for linking input control signals, such as control signals used to control aspects of aircraft operation. In one embodiment, the method includes receiving first and second force signals corresponding to first and second forces applied to first and second controllers. The method can further include directing first and second position signals to the first and second controllers to move the first and second controllers to approximately the same positions. Each force signal is transmitted along a signal path, and the signal paths can be linked at a point where the signals on each path correspond to a quantity other that a position of a controller. The signal paths can be linked such that only one of the forces must exceed a threshold value for both controllers to be moved, and if one of the forces is outside a selected limit range, that force can be at least partially discounted.

Abstract: The present invention relates to a device and methods for filtering anti-collision alerts for aircraft having a locating system charting the position of the aircraft and estimating the precision of its position. A navigation system of the aircraft calculates at least the actual speed of the aircraft, the speed instruction and a first deviation between the instruction and the actual speed, and the deviation being compared with a first reference overshoot threshold. An anti-collision system generates alerts. An alarms manager of the aircraft centralizes the alerts transmitted by the terrain anti-collision equipment of the aircraft to the crew. The alerts each posses a coding of the danger level, and the danger levels form part of a first predetermined set. The alert filter according to the invention filters sets of alerts according to the coding of their danger level.

Abstract: A method for transmitting environmental conditions information, comprising, receiving at least some environmental conditions data and/or information, scaling the received environmental conditions data and/or information such that a scaled environmental conditions value is determined for a particular vehicle, and transmitting, in response to a request for environmental conditions information, at least one of the data and/or information relating to the environmental conditions and the dynamic vehicle information.

Abstract: Terrain augmented display symbology improves a pilot's spatial awareness during aircraft approach and landing. The symbology includes a terrain-tracing, three-dimensional centerline that provides a visual cue of terrain elevations along an approach course to a runway. Additionally, the symbology includes terrain-tracing, three-dimensional lateral deviation marks representing deviations from the centerline. The symbology also includes an aircraft symbol shaped like an airplane and pointing towards the direction of travel. The pilot may be able to quickly interpret the terrain augmented display symbology and take actions based on the surrounding terrain elevation.

Abstract: The field of the invention is that of the generation of an aircraft flight plan. The invention more specifically relates to a method of generating a flight plan enabling an aircraft to link a departure airport AD to a destination airport AA. The flight plan consists of a number N?1 of segments SGi, i being an integer number between 2 and N. The index i uniquely identifies the segment SGi of the flight plan linking an auxiliary departure position PADi to an auxiliary arrival position PAAi according to a route Ri. The route Ri is a straight line defined by a list of auxiliary route positions PARi,k, in which k identifies the auxiliary route positions. The routes Ri are stored in a database BDR onboard the aircraft. PAD1 is a geographic position (of the departure airport for example) AD, PAAN is a geographic position (of the arrival airport for example) AA, PAAi and PADi+1 are combined for any integer i between 2 and N?1.

Abstract: Systems and methods for aircraft guidance using a localizer capture criteria for rectilinear displacement data are disclosed. In one embodiment, the method includes determining a rectilinear deviation D between a current aircraft location and a final defined path (FDP) of an aircraft and determining a location at which the aircraft should begin a reposition maneuver based on the rectilinear deviation D. The method starts a reposition maneuver of the aircraft at a location determined based on a relationship between D and characteristics of the aircraft during the reposition maneuver. In some embodiments, the characteristics of the aircraft may include a velocity of the aircraft with respect to ground, an aircraft track angle, a heading of the FDP of the aircraft, a maximum allowed bank angle of the aircraft during a reposition maneuver, and a time allowance for aircraft rollup and rollout.

Abstract: A steering aid system for altitude and horizontal speed of an aircraft (4) includes: a measuring device (22) for delivering a measured signal based on the aircraft altitude and horizontal speed, a common predetermined reference value (26) for the aircraft altitude and horizontal speed, and elements (20) for slaving the signal to the reference value by pitch loop, the elements being adapted to vary automatically the pitch and/or propulsive performance of the lifting members to lock the measured signal to the reference value.

Abstract: A system for enhancing flight safety of a host aircraft receives an adjustment value from a portable memory device; determines a working value of a parameter in accordance with the adjustment value; and provides an advice for threat avoidance in accordance with the working value of the parameter, a terrain database, and an expected climb gradient capability of the host aircraft. The adjustment value may describe an adjustment to at least one of: an aircraft capability parameter, a flight crew capability parameter, a mission parameter, a threat detection technique parameter, a threat advice parameter, or a threat avoidance parameter. Threats include a risk of colliding with other aircraft, colliding with terrain, and encountering adverse weather conditions.

Abstract: This method relates to the system of ATM air traffic management with cooperative aircraft provided with a flight management computer FMS, that are linked by a data transmission system ATN to the control authority and that have presented a flight plan to the control authority. It consists in communicating to the control authority via the ATN link, the projections SPWPi,j onto the flight plan LTFP of pseudo-waypoints PWPi,j introduced by the flight management computer FMS during lateral (between two segments of the flight plan) and/or vertical (between two breaks in slope) softened transitions performed by the aircraft at the time of the changes of instructions appearing in the flight plan LTFP. By virtue of this information, the control authority estimates more precisely the actual future position of the aircraft and the changes of instruction, thereby enabling it to increase the safety level in particular for the spacing and separation of traffic.

Abstract: A static longitudinal stability (SLS) system provides an unobtrusive airspeed hold function that reacts to the pilot control inputs into the flight control system and the measured states of the aircraft to engage and disengage smoothly without any explicit mode selection by the pilot. The SLS engages airspeed hold when the aircraft is close to trimmed, non-accelerating state. This logic allows the pilot to either fly close to a desired airspeed and let SLS engage, or trim the aircraft in an accelerating/decelerating maneuver and just wait for the SLS to capture a speed when longitudinal acceleration is small. The SLS is not dependant on the pilot specifically selecting this mode, but rather engages and disengages in response to flight control system status and how the aircraft is being maneuvered.

Abstract: This device furnishes a map for assisting navigation at low-level altitude while representing the zone flown over with points shown in false colors and/or textures or symbols corresponding to the vertical speeds needed to fly over them.

Abstract: Method and device to assist in the piloting of an aircraft in a landing phase. The device (1) comprises means (12) for applying a maximum braking of the aircraft if there is a risk of longitudinal departure from a runway, on a landing.

Abstract: A method for ensuring the safety of an aircraft flying horizontally at low speed includes determining a lower speed threshold for the aircraft, measuring the actual speed of the aircraft and comparing the actual speed with the threshold. When the actual speed reaches the threshold in the decreasing direction, the diving command of the aircraft is limited to a load factor (fg) greater than 0g. According to the invention: a lower speed threshold is determined for the aircraft; the actual speed of the said aircraft is measured; and the said actual speed is compared with the said threshold and, when the said actual speed reaches the said threshold in the decreasing direction, the diving command of the said aircraft is limited to a load factor (fg) greater than 0 g.

Abstract: A method and device for monitoring the validity of a parameter calculated by an anemometric unit of an aircraft may employ a first section for taking into account n first data, each dependent on the parameter being monitored and n being greater than or equal to 1. A second section takes into account p second data that each depends on a value obtained from a data source external to the anemometric unit, where P is greater than or equal to 2. A calculator calculates, for each of the second data, a difference between this second datum and a first datum of the same type. A comparator compares the absolute value of each of the calculated differences with a threshold value. A deducing section deduces from the comparisons that the monitored parameter is invalid if the absolute values of two of the various differences are greater than the corresponding threshold values.

Abstract: An altitude monitoring system for an aircraft, comprising an input unit that makes it possible to receive or enter cleared flight level and cleared maximum and minimum altitudes into the system, and interfaces or other means to gain access to present altitude and speed, said system being provided with a calculator unit for calculating a future altitude and a comparator unit that compare said future altitude with said maximum and minimum altitude limits, and/or with a cleared flight level plus/minus a tolerance, and also an alerting unit capable of issuing a warning to an aircraft pilot of said aircraft a certain time before an altitude limit is violated, said certain time being calculated such that an evasive manoeuvre using a specified load factor can be performed within said certain time with no or little margin.

Abstract: Systems and methods for automatically switching to a track view mode on a vertical view display. The system determines aircraft position relative to a leg of a flight plan and switches display mode for a navigation vertical display to track view mode, if the display mode is in a plan view mode and if the determined relative position is greater than a threshold distance.

Abstract: The inventive device (1) comprises means (2) for determining a control value corresponding to an instruction value representing the actuation of a control member (3) by a pilot, means (5) for controlling an effective control value corresponding to said instruction value which is actually applied to the aircraft, means (6) for automatically controlling the aircraft, means (11) for computing an auxiliary control value, which is closer to the effective controlled vale and means (16) for monitoring the control value and for detecting a pilot induced oscillation, wherein the automatic control is carried out with the aid of the controlled effective value and the auxiliary control value in the case of the detection of the pilot induced oscillation.

Abstract: An aircraft performance degradation detection system may include information sources, a central unit connected to the information sources, and a warning device that is connected to the central unit. Using information received from the information sources, the central unit computes the current weight and drag of the aircraft and computes a theoretical drag based on the current weight. The current and theoretical drags are compared, and a determination is made regarding performance degradation based on the comparison.

Abstract: The invention relates to a method of piloting a rotorcraft having a plurality of engines for driving at least one lift and propulsion rotor, in which method, so long as the rotorcraft has not reached an optimum climb speed (OCS), a pitch attitude control signal (Upitch) is determined that is adapted so that the rotorcraft accelerates in application of a profile (P1, P2, P3) that varies as a function of the elapsed time and as a function of the operating state of the engines (OEI/AEO).

Abstract: A control system (12) for controlling velocity and attitude of a dynamic system (20) includes a velocity controller configured to receive a desired velocity command and output a velocity error in the form of Euler angle commands to an attitude controller system. The attitude controller system includes a converter (14) configured to receive the Euler angle commands and output a desired quaternion based on the Euler angle commands. The attitude controller system further includes an attitude error generator (16) configured to receive the desired quaternion and an estimated quaternion indicative of an estimated velocity and attitude of the dynamic system (20) and to output attitude errors associated with the dynamic system (20). The attitude controller system also includes an attitude controller (18) configured to receive the attitude errors and to output error commands to the dynamic system (20) based on the attitude errors.

Abstract: A method of and a system for controlling personal air vehicle (PAV) traffic provides a take-off-and-landing zone, and a forward flight zone. The take-off-and-landing zone may be from the ground up to a first altitude. The forward flight zone may be from the first altitude up to a second altitude. A maximum airspeed is provided in the take-off-and-landing zone. Minimum and maximum airspeeds are provided in the forward flight zone. In the forward flight zone there is a single heading for each altitude. Any change in heading must be accompanied by a change in altitude.

Abstract: Systems, computer program products, and methods for displaying navigation performance based flight path deviation information during the final approach segment to a runway and during landing of non-precision flight modes are provided. Improved graphical depictions of navigation performance based flight path deviation information provide pilots and flight crew members with clear, concise displays of the dynamic relationship between ANP and RNP, mode and aspect of flight and related procedures, intersecting flight paths, and current actual flight path deviation from a predefined flight path during the final approach segment to a runway and during landing. For example, an enhanced IAN display may include NPS-type deviation scales to show RNP/ANP relationships and predetermined RNP markers to alert the pilots and flight crew members that the FMC has transitioned from an NPS display for RNAV (LNAV/VNAV) flight procedures to an enhanced IAN display for a non-precision (non-xLS) approach and/or landing.

Abstract: The control device (1) comprises means (2) for determining a roll objective, and means (6) for calculating, on the basis of this roll objective, a deflection order which is applied exclusively to ailerons (11) of the aircraft.

Abstract: It is an object of the present invention to provide a system that is used to provide support so that a pilot can perform flight operations that reduce noise pollution, by devising this system so that noise conditions on the ground are calculated and displayed on the basis of map information for the flight area in which facilities and the like are described, environmental conditions in the flight area such as the wind direction and wind velocity, or the temperature and density of the atmosphere, and noise generation data for the aircraft itself.

Abstract: A precision approach guidance system that provides flying craft guidance information during a precision approach to a landing site and methods associated therewith are provided. In one embodiment, the system includes: an inertial navigation system, an onboard ranging sensor, a terrain database storing previously identified position-referenced terrain information associated with the landing site, and a position determining process. The position determining process repetitively determines a corrected position of the flying craft during the precision approach based at least in part on attitude and velocity information from an inertial navigation system, current position-referenced terrain information based on measurements from an onboard ranging sensor, and previously identified position-referenced terrain information from the terrain database.

Abstract: A portable communication device detects a current speed of travel of the portable communication device independent of any vehicle temporarily transporting the portable communication device. A speed based setting controller of the portable communication device compares the current speed to at least one threshold value set at the portable communication device. Responsive to the current speed exceeding the threshold value, the speed based setting controller automatically assigns a separate speed based setting to a current setting for each feature assigned to the threshold value, wherein each current setting for each feature designates the operability of that feature within the portable communication device, such that the current setting for each feature adjusts with a speed of travel as detected by the portable communication device.

Abstract: The invention concerns a method and a device for constructing a low-altitude flight path to be followed by an aircraft. The device (1) comprises a database (3) containing a terrain profile concerning the terrain to be flown over by the aircraft, a set of data sources (5), first means (6) for determining a lateral trajectory of the flight path, and second means (7) for determining a vertical trajectory of the flight path, said second means (7) being formed to as to determine the vertical trajectory during the aircraft flight, successively as the flight proceeds, segment by segment, and comprising an element (14) for retrieving from the database (3) a profile section, and an element (15) for determining a vertical trajectory segment, using the retrieved profile section, based on the climb-out and let-down performances of the aircraft derived from said set (5) of data sources.

Abstract: A method and system for determining a location of a vehicle, the method comprises determining reception location data within a first cell of a work area for a vehicle. A reception quality estimator estimates reception quality data for the corresponding reception location data for the first cell. Optical location data is determined within a first cell of a work area for a vehicle. An optical quality estimator estimates optical quality data for the corresponding optical location data for the first cell. A data processor selects at least one of the reception location data and the optical location data as refined location data associated with the first cell based on the estimated reception quality data and estimated optical quality data.

Abstract: A field unit for warning of a danger of collision between an aircraft and an obstacle, in particular a topographical ground obstacle or an obstacle formed by a mast, building or aerial cable structure, comprises a multi-part tubular mast having devices for fixing a solar panel and a radar antenna; an elongate radar antenna in an environment-protective casing, which, with an electronics unit, forms a radar system for synthesized radar detection of an aircraft in a radar coverage area; a central processing unit for identifying on the basis of information from the radar system an aircraft which is in a zone of the radar coverage area and which on the basis of radar information such as direction, distance and/or speed computes a collision danger area; and a high-intensity light system and radio transmitter system that can be activated by the central processing unit upon detection of an aircraft in a collision danger area.

Abstract: A system, method, and computer program product are provided for monitoring for high energy landing approaches and advising a flight crew of an aircraft. Specific aircraft energy is predicted at a touchdown zone of a runway. The predicted specific energy is compared with predetermined threshold specific energy. An alert is generated when the predicted specific energy is at least the predetermined threshold specific energy. The present invention improves flight crew awareness of an impending problem with a landing approach, such as a high energy approach, provides an advisory when probability of an unsuccessful approach is significant, and allows a margin from stable approach criteria while avoiding increased aural and visual clutter in the flight deck.

Abstract: A flight guidance system providing perspective flight guidance symbology using positioning and terrain information provides increased pilot situational awareness of the pilot's aircraft. The guidance system uses a positioning system and a detailed mapping system to provide a perspective display for use in an aircraft. A precision pathway flight guidance (PFG) symbology set is thereby displayed on a pilot display. The PFG symbology set includes broken line symbols representing an open tunnel and providing flow field data, a half-bracket symbol to indicate that the aircraft is no longer in the open tunnel represented by the broken line symbols and a quickened flight path vector (QFPV) symbol to provide the pilot with predictive flight path information. A flight director system and tunnel generator component provide for updating the displayed PDFG symbology set based upon current aircraft conditions (e.g., aircraft position) and stored flight path information.

Abstract: A system and a method for providing a continuous, semi-continuous and/or repetitive aural signal to an aircraft pilot indicative of a difference between a set value and an actual value for one or more flight characteristics of the aircraft.

Abstract: A method for transmitting environmental conditions information, which includes receiving at least some environmental conditions information, scaling the received information such that a scaled environmental conditions value is determined for a particular vehicle, receiving an environmental conditions threshold value, comparing the scaled value to the received threshold value, determining whether the scaled value is greater than the received threshold value, and transmitting, if the scaled value is greater than the received threshold value, at least some of the information.

Abstract: A signal is received from an off limits facility and it is determined from the signal whether an aircraft is within a distance of the off limits facility. The course and/or flight of the aircraft is changed if the aircraft is within the distance of the off limits facility. A signal is received from an airport and it is determined from the signal whether an aircraft will be allowed to take off from the airport. The aircraft is prevented from taking off if the signal from the airport indicates that the aircraft should be prevented from taking off. A signal is received from a satellite and it is determined from the signal whether an aircraft is within a distance of an off limits facility. The course and/or flight of the aircraft if the aircraft is changed if the aircraft is within the distance of the off limits facility.

Abstract: An engine thrust management system comprising an engine control device, an aircraft flight manual, a flight management device and a cockpit instrument device. The engine control device is operable to calculate a percent maximum available thrust parameter and a percent indicated thrust parameter. The aircraft flight manual is operable to calculate a required thrust parameter. The flight management device is operable to calculate a percent thrust setting target parameter and a percent commanded thrust parameter. The percent commanded thrust is the amount of thrust requested by an aircraft operator. The percent commanded thrust is varied by the operator according to the value of the percent thrust setting target parameter and the value of the percent indicated thrust parameter in order to produce optimal thrust.

Abstract: A lane-keep control system for a host-vehicle is arranged to execute a lane-keep control for moving the host-vehicle in a traveling lane, to determine whether there is an approaching-vehicle behind the host-vehicle, to increase an intervention threshold when there is the approaching vehicle behind the host-vehicle, and to suspend the lane-keep control when a steering control indicative value due to driver intervention is greater than the intervention threshold.

Abstract: An aircraft system for reducing the airspeed of an aircraft as it passes through a preselected altitude includes an automatic throttle system including a computer, a device for inputting a preselected altitude and a preselected airspeed into the computer. An altimeter provides the current altitude of the aircraft and an aircraft instrument provides the current air speed and the vertical speed of the aircraft. The computer in response to the current altitude and vertical speed of the aircraft generates a signal to retard the throttles when the current altitude, the current air speed of the aircraft is equal to 2 times the vertical speed plus a preselected altitude.

Abstract: A device and a method determine an offset value which represents the offset of the output signal of a vehicle sensor, the sensor detecting at least one motion of a vehicle, and the output signal is analyzed at at least two different points in time. An additional signal is determined independently of the output signal, this signal also representing the motion of the vehicle. An arrangement is provided for analyzing the characteristic of the output signal, which depends on the longitudinal velocity of the vehicle, and the characteristic of the additional signal, which also depends on the longitudinal velocity of the vehicle, in order to determine the offset value.

Abstract: A terrain warning system includes an indicator to inform a pilot of a proposed degree of flight parameters for safely clearing terrain. An aural message may identify a vertical speed that may be used to safely traverse terrain to the pilot. A visual indicator on a display informs the pilot of a vertical speed or climb angle to traverse terrain. The display may be a vertical speed indicator also capable of displaying traffic advisories.

Abstract: In a lateral terrain map for avionics displays, a terrain relief contrast adjustment parameter, based on a statistical terrain roughness measure, is used to compute optimal terrain presentation for current display conditions. The contrast adjustment parameter allows situation dependent map presentation to enhance, for example, caution and warning situations, or de-emphasize the terrain map features for balanced presentation along with foreground symbology, while reducing computational resource requirements.

Abstract: A system and method for determining the vertical integrity of an altitude component of an aircraft navigational signal through the use of a receiver-autonomous vertical integrity monitoring (RAVIM) algorithm. The system and methods also provide timely warning to vehicle operators if the integrity of the signal is unacceptable or unknown. The system and methods are capable of determining the vertical integrity of an incoming signal without relying upon data embedded within the incoming signal itself. In addition, the system and methods of the present invention provide vertical integrity to vehicle operators in instances, such as when the specific aircraft navigational signal is not operating, when the specific aircraft navigational signal is not available in a particular region, or when an aircraft is operating outside the geographic area covered by the specific aircraft navigational signal system.

Abstract: A method and apparatus to record and process operations information from aircraft for the purpose of improving maintenance processes, improving security, and accident investigation is described. Information recorded from aircraft operations includes equipment operational data, images of people and equipment, and sound information. This digital information that is recorded is a result of, in some cases, sampling an analog signal. In other cases, the digital information is a result of many information processing steps to improve the usefulness of the information while using a minimum quantity of data. This invention includes steps to compress the quantity of data while producing the most useful information. The digital information may be recorded aboard the aircraft in any of several data storage media, or the information may be transmitted from the aircraft, or a combination of storage aboard the aircraft and transmission may be used.

Abstract: Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.