Methods for calibrating an emission rate measurement of a gas are provided. The methods involve discharging a reference gas that is the same or a different composition than a subject gas. If the same or similar, then a combined emission rate of the reference and subject gas is measured, as well as an emission rate of the subject gas only. A deviation, or an one or more adjusted parameter, of the combined and subject gas measurement from the reference gas discharge rate is used to calibrate the subject gas measurement. If the reference gas is different, the emission rates of the subject and reference gas are measured, and a deviation, or an one or more adjusted parameter, of the measured rate from the discharge rate of the reference gas is used in calibrating the subject gas measurement. The methods may also use a modified 2-D tracer measurement as a reference.

Adjusting emulated encoder frequencies in an example embodiment can include determining a difference between an encoder count and a theoretical encoder count and adjusting a frequency of an emulated encoder signal to mitigate at least some of the difference between the encoder count and the theoretical encoder count.

An angular velocity detection circuit includes: an angular velocity signal generation unit that generates an angular velocity signal on the basis of an output signal of a differential amplifier unit that differentially amplifies a signal based on an output signal of a first conversion unit and a signal based on an output signal of a second conversion unit; and a correction signal generation unit that generates a correction signal for reducing an offset of the angular velocity signal which occurs due to leakage signals which are respectively included in the first detection signal and the second detection signal on the basis of a signal based on drive oscillation of the angular velocity detection element. The correction signal is input to a circuit that is located on a first signal path ranging from the first detection electrode of an angular velocity detection element to the differential amplifier unit.

An angular velocity detection circuit includes: an angular velocity signal generation unit that generates an angular velocity signal on the basis of an output signal of a differential amplifier unit that differentially amplifies a signal based on an output signal of a first conversion unit and a signal based on an output signal of a second conversion unit; and a correction signal generation unit that generates a correction signal for reducing an offset of the angular velocity signal which occurs due to leakage signals which are respectively included in the first detection signal and the second detection signal on the basis of a signal based on drive oscillation of the angular velocity detection element. The correction signal is input to a circuit that is located on a first signal path ranging from the first detection electrode of an angular velocity detection element to the differential amplifier unit.

Methods and apparatus to control a torque threshold for hands on/off detection are disclosed. An example apparatus includes memory including instructions, and one or more processors to execute the instructions to cause the one or more processors to at least compare a velocity of a rack to at least one of a first velocity threshold or a second velocity threshold, adjust a first torque threshold in response to the velocity of the rack satisfying the first velocity threshold, adjust a second torque threshold in response to the velocity of the rack satisfying the second velocity threshold, compare a torque between the rack and a steering shaft to the first torque threshold and the second torque threshold, and detect a hands off condition in response to the torque between the rack and the steering shaft not satisfying the first torque threshold or the second torque threshold.

If a controller determines the calculation of a measured vehicle body velocity is possible, the controller calculates the measured vehicle body velocity as an estimated vehicle body velocity to conduct update processing for a K table and an AB table. If the controller determines the calculation of the measured vehicle body velocity is impossible, the controller extracts a conversion coefficient from the K table based on a detected running state while extracting a sensitivity coefficient and an offset coefficient from the AB table based on the temperature by a temperature sensor. The vehicle mounted apparatus calculates an axle pulse-based vehicle body velocity from the extracted conversion coefficient while calculating an acceleration-based vehicle body velocity from the extracted sensitivity coefficient and offset coefficient. The vehicle mounted apparatus calculates the estimated vehicle body velocity by weighting the calculation values of the axle pulse-based vehicle body velocity and the acceleration-based vehicle body velocity.

The invention relates to a method for filtering an input signal (3b, 4b, 5b) relative to a physical variable of a turbine engine (9), the input signal being digitised, the method implementing frequency filtering of said signal in a computer (6) of a control system (7) of said turbine engine (9), said signal being provided at the input of the computer, a digital derivative of said signal being intended for being used by the control system (7), characterised in that it involves: —detecting an amplitude variation of said variable on said input signal, by a step of generating a second derivative signal (S) of the input signal and a step of comparing a value of the second derivative value of the input signal with at least one predetermined threshold (S.sub.1 . . . S.sub.n); and —adapting the frequency filtering of said input signal as a function of the detected amplitude variation of said variable, by a step of controlling a controlled filter (PB.sub.11) capable of applying frequency filtering to the input signal, so that the controlled filter applies or does not apply the frequency filtering as a function of a result of the comparison step.

The present disclosure provides methods and systems for fault detection for a speed sensing system of a multi-engine rotorcraft. A shaft speed for a first engine and a rotor speed for at least one rotor of the multi-engine rotorcraft are obtained. The shaft speed is compared to the rotor speed. When the shaft speed is greater than the rotor speed, a first fault in the speed sensing system is detected and a first speed sensing system fault signal is issued. When the shaft speed is less than the rotor speed, a determination is made regarding whether the first engine is coupled the at least one rotor based on a fuel flow to the first engine. A second fault in the speed sensing system is detected and a second speed sensing system fault signal is issued responsive to determining that the first engine is coupled to the at least one rotor.

A method of monitoring at least first and second inertial measurement units, the first inertial measurement unit and the second inertial measurement unit being connected to the same electronic processor circuit and being arranged to determine both a specific force vector in an accelerometer measurement reference frame and also rotation data concerning turning of the accelerometer measurement reference frame relative to an inertial reference frame; the electronic processor circuit performs the steps of projecting the specific force vectors into an inertial reference frame by using the rotation data; comparing the two specific force vectors as projected into said reference frame with each other in order to determine a difference between them; and monitoring variation in this difference over time.

Method and apparatus are disclosed for GNSS statistical speed calibration An example vehicle includes a wheel, a speed sensor for determining a first vehicle speed, an inertial sensor, and a processor. The processor may be configured for determining a second vehicle speed based on information from the inertial sensor and information from a satellite based system, determining that a difference between the first and second vehicle speeds is statistically significant, and responsively adjusting a value of the radius of the wheel.