Sextant Avionique

Sextant Avionque

Michel Torregrosa

Bertrand Morbieu

Henri Fima

An accelerometer includes a silicon capacitive detector and an electronic device for measuring the capacitive unbalance of the detector, providing an output voltage representative of the acceleration. To avoid the perturbations caused by the stray capacitances present in the detector, there is provided a compensation system for injecting into the measurement system a predetermined correcting electric signal so that the output voltage of the accelerometer is substantially proportional to the ratio between the difference and the sum of the capacitances of the detector's capacitors.

Capacitive accelerometer with a circuit for correcting stray capacitance

An electrostatically servo-controlled pendular micro-sensor includes a pendular element disposed so as to respond to a force representative of a physical quantity to be measured. To avoid the drifts affecting the stability of the micro-sensor, generated by the existence of unstable parasitic voltages that impair the voltages provided by a system servo-controlling the pendular element, the electrostatic forces generated to draw back the pendular element through servo-control voltages have a zero mean value. The control voltages are periodic voltages or series of electric signals of equal durations, each having, preferably, a zero mean value.

Servo-controlled pendular micro-sensor

A system is disclosed for measuring the angle of incidence of an aircraft, comprising at least one probe with a laser generator having a monochromatic emission spectral line, an optical emission system, an optical system receiving a monochromatic radiation back-scattered by the aerosols, means for pumping the laser generator, a detection interferometer receiving a part of the emitted laser beam and the back-scattered radiation and means for determining, after beating of the emitted beam and back-scattered beam, the Doppler frequency of the back-scattered beam and deriving therefrom the air speed along the axis of the emitted laser beam, in which system the optical emission system is adapted so as to focus the emitted beam on an air slice distant from the aircraft, the laser generator is disposed in the vicinity of the skin of the aircraft, the pumping means and the interferometer are moved inside the aircraft and the frequency of the laser spectral line is adapted so that the connections between the probe, on the one hand, and the pumping means and the interferometer, on the other, are made from monomode optical fibers with polarization maintenance.

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Beaumont Les Valence, France

Michel Torregrosa