Unit 2 Unmanned Aircraft Module 1 The UAS Component 1.10 – Sensors for Flight

Sensors for Flight Pilot Static System Static Pressure Uses two main pressures to determine Airspeed and Altitude Static and Dynamic pressure Static Pressure Based on the weight of the atmosphere above and object Usually weight of a single atmosphere is 14.7PSI Weight can be affected by temperature, altitude, and water vapor in condensation A standard unit of measure was created (International Standard Atmosphere)

Sensors for Flight Dynamic pressure Consists of pressure from molecules moving, and forming kinetic energy Loss of kinetic energy creates pressure, called dynamic and ram air pressure Pressure is measured via the pitot tube Must be mounted in and unobstructed and open position. Subtracting static pressure from total pressure will provide dynamic pressure

Sensors for Flight Systems The following systems use the Pitot Static System Airspeed Indicator Vertical Speed Indicator Altimeter

Sensors for Flight Errors When the pitot system becomes blocked by an object, depending on where the blockage is, it will behave differently Blocked Pitot tube, clear static port The airspeed indicator will remain at the last displayed indicated airspeed When the tube is blocked it will act as an altimeter As the aircraft will increases altitude the airspeed will show an increase in altitude as a decrease in airspeed If the static port becomes blocked Several instruments will malfunction and read improperly (Airspeed Indicator, Altitude, and VSI) ASI – at same altitude remain normal, alt increases will produce lower airspeeds, the reverse is true VSI will not respond and Altimeter will lock at the position of the blockage

Sensors for Flight 107.7 Inspection, Testing, and demonstration of compliance A remote pilot in command, owner, or person manipulating the flight controls of a small unmanned aircraft system must, upon request, make available to the Administrator: The remote pilot certificate with a small UAS rating; and Any other document, record, or report required to be kept under the regulations of this chapter. (b) The remote pilot in command, visual observer, owner, operator, or person manipulating the flight controls of a small unmanned aircraft system must, up request, allow the Administrator to make any test or inspection of the small unmanned aircraft system, the remote pilot in command, the person manipulating the flight controls of a small unmanned aircraft system, and if applicable, the visual observer to determine compliance with the part

Sensors for Flight Flux Gate / Magnetometer Magnetometer uses no moving parts to locate magnetic north Uses the principle of a flux gate and the Lorentz force Utilizes a magnet that freely move on three axis Will know the direction of the Earth’s magnetic field at the current location When the magnet is moved the field will reorient the magnet to the correct position Force applied by the field is call the strength

Sensors for Flight Flux Gate / Magnetometer Two electromagnets can be used to detect magnetic north Two bars wrapped with wire in different directions with current applied creates two electromagnets that cancel each other out The Earth’s Magnetic field will create a stronger field on one side A third coil is wrapped around the other wires called a detection field or spring, the earth magnetic field causes a change in the current Arranging three fluxgates on all three axis allows the strength and direction of magnetic north to be determined

Sensors for Flight Gyros Gyroscopic effect is measured using a spinning wheel or disc As the disc speeds up the axis becomes unaffected by outside forces Becomes fixed in space as long as the disc stays in motion Consists of three parts flywheel, outer gimbal and inner gimbal Gimbals allow the frame to rotate in a single axis, two allow freedom in all directions Since the flywheel resists influence from outside influences, it allows the plane to move around the gyro while it remains rigid in space Gyroscopes are used for attitude indicators to determine pitch and roll

Sensors for Flight Inertial measurement Units (IMUs) Used for navigation and calibration purposes Measures states of a static or mobile unit and are low in cost, small, light but still powerful

Sensors for Flight Laser Altimeter Similar to LiDAR used for photomapping and surface detection Uses a short flash of infrared laser radiation to measure distance from the aircraft to the ground As the laser pulse is emitted the instrument records the time the laser pulse takes to reflect off the ground and return to the craft When the sensor receives the light pulse the timer is stopped and distance is calculated using speed of light as a constant

Sensors for Flight Ultrasonic Sensors Use high frequency soundwaves to measure distance between the Sensor and objects Composed of transmitter and receiver Transmitter sends high-frequency waves that are bounced off an object Frequency can vary based on model and type Detects proximity based on simple time-distance formula Good for detecting large objects with hard surfaces, mainly used to detect the ground Soft, round, and small objects are much harder to detect, due to how waver reflect off objects Multiple sensors in a room may interfere sUAS use ultrasonic to detect proximity, altitude is determined by GPS, used mostly in landing for ground distance and detection

Sensors for Flight Angle of Attack Indicator Defines the angle between the chord line of the wing and the direction of the relative wind Allows aircraft to pitch to optimum lift without stalling

Sensors for Flight 107.9 Accident Reporting No later than 10 calendar days after an operation that meets the criteria of either paragraph (a) or (b) of this section, a remote pilot in command must report to the FAA, in a manner acceptable to the Administrator, any operation of the small unmanned aircraft involving at least: Serious injury to any person or any loss of consciousness; or Damage to any property, other than the small unmanned aircraft, unless one of the following conditions is satisfied: The cost of repair (including materials and labor) does not exceed $500; or The fair market value of the property does not exceed $500 in the event of total loss