A method of operating an acoustic resonance fluid flow sensor. The method comprises emitting an acoustic stimulus signal comprising a plurality of frequencies into an acoustic resonance cavity of the acoustic resonance fluid flow sensor, sensing an acoustic response signal within the acoustic resonance cavity and deriving the phases or equivalent group delays of one or more frequency components of a frequency spectrum of the acoustic response signal.

In one embodiment, a system includes a vehicle, one or more probes coupled to the vehicle, and a controller. The vehicle is operable to traverse a distance. The one or more probes are operable to measure wind pressure and generate one or more wind pressure measurements. The controller is operable to receive the one or more wind pressure measurements from the one or more probes, determine a wind angle relative to the vehicle using the one or more wind pressure measurements, and determine a wind speed relative to the vehicle using the one or more wind pressure measurements and the wind angle.

A method of measuring the speed of a fluid, comprising the successive steps of: causing the processor component to emit at the same emission time both a first electrical excitation signal that is applied as input to a first transducer and also a second electrical excitation signal that is applied as input to a second transducer, such that the first transducer generates a first ultrasonic signal and such that the second transducer generates a second ultrasonic signal; putting the processor component on standby; reactivating the processor component after a predetermined standby duration; causing the first ultrasonic signal to be acquired by the second transducer and then by the processor component, and causing the second ultrasonic signal to be acquired by the first transducer and then by the processor component; using a value DToF to estimate the speed of the fluid.

An acoustic airspeed sensor system can include at least one acoustic transmitter configured to provide an acoustic pulse, a plurality of acoustic receivers including at least a first acoustic receiver, a second acoustic, receiver, and a third acoustic receiver, each positioned at a first radial distance from the at least one acoustic transmitter. The first acoustic receiver, the second acoustic receiver, and the third acoustic receiver are each configured to receive the acoustic pulse at a first time, a second time, and a third time, respectively, and output a first receiver signal, a second receiver signal, and a third receiver signal respectively. The system can include a computation unit operatively connected to the acoustic receivers and configured to generate a propagation function. The computation unit is further configured to determine true air speed based upon a receiver signals and the propagation function.

An acoustic airspeed sensor system can include at least one acoustic transmitter configured to provide an acoustic pulse, a plurality of acoustic receivers including at least a first acoustic receiver, a second acoustic, receiver, and a third acoustic receiver, each positioned at a first radial distance from the at least one acoustic transmitter. The first acoustic receiver, the second acoustic receiver, and the third acoustic receiver are each configured to receive the acoustic pulse at a first time, a second time, and a third time, respectively, and output a first receiver signal, a second receiver signal, and a third receiver signal respectively. The system can include a computation unit operatively connected to the acoustic receivers and configured to generate a propagation function. The computation unit is further configured to determine true air speed based upon a receiver signals and the propagation function.

Systems and devices for airflow measurements in rooms and air delivery ducts with low-cost, low-power, accurate, calibration-free, and compact wireless airflow sensors are provided. The system uses room and duct flow sonic anemometers and processing to measure air velocities and temperatures as well as allow control over the environmental conditioning systems. The anemometers use arrays of transmitter/receivers to simultaneously measure multiple sound paths and determine velocity vectors and volumetric flow paths. By transmitting in both directions along the paths between transceivers, differential times of flight (TOF) are measured. These determine both the velocity and temperature of the air along each path.

In one embodiment, a system includes a vehicle, one or more probes coupled to the vehicle, and a controller. The vehicle is operable to traverse a distance. The one or more probes are operable to measure wind pressure and generate one or more wind pressure measurements. The controller is operable to receive the one or more wind pressure measurements from the one or more probes, determine a wind angle relative to the vehicle using the one or more wind pressure measurements, and determine a wind speed relative to the vehicle using the one or more wind pressure measurements and the wind angle.

In one embodiment, a system includes a vehicle, one or more probes coupled to the vehicle, and a controller. The vehicle is operable to traverse a distance. The one or more probes are operable to measure wind pressure and generate one or more wind pressure measurements. The controller is operable to receive the one or more wind pressure measurements from the one or more probes, determine a wind angle relative to the vehicle using the one or more wind pressure measurements, and determine a wind speed relative to the vehicle using the one or more wind pressure measurements and the wind angle.

A method of determining flow speed in a low pressure environment. The method includes obtaining bi-directional acoustic data from a plurality of transducer pairs as a fluid moves relative to the plurality of transducer pairs. The method further includes measuring phase lags corresponding to the bi-directional acoustic data, and determining bi-directional flight times using the phase lags. Additionally, the method includes calculating a flow speed of the fluid corresponding to each transducer pair from the bi-directional flight times. The method includes correcting for at least one of temperature effects, pressure effects, and wake effects, using a system model. The method further includes generating a report including the flow speed of the fluid.

A method of measuring the speed of a fluid, comprising the successive steps of: causing the processor component to emit at the same emission time both a first electrical excitation signal that is applied as input to a first transducer and also a second electrical excitation signal that is applied as input to a second transducer, such that the first transducer generates a first ultrasonic signal and such that the second transducer generates a second ultrasonic signal; putting the processor component on standby; reactivating the processor component after a predetermined standby duration; causing the first ultrasonic signal to be acquired by the second transducer and then by the processor component, and causing the second ultrasonic signal to be acquired by the first transducer and then by the processor component; using a value DToF to estimate the speed of the fluid.