Methods and systems for estimating a distance between an acoustic sensor and an acoustic reflector in a conduit are disclosed. One such method includes using the acoustic sensor to measure a combined acoustic signal that comprises an originating acoustic signal propagating along the conduit and an echo signal. The echo signal is generated by the originating acoustic signal reflecting off the acoustic reflector after propagating past the acoustic sensor. A frequency domain representation of the combined acoustic signal is determined and the echo signal is identified by identifying in the frequency domain representation periodic oscillations having a peak-to-peak difference between 0.75 Hz and 1500 Hz. The distance between the acoustic sensor and the acoustic reflector is determined from the velocity of the echo signal and a time required for the echo signal to propagate between the acoustic sensor and the acoustic reflector.

A receiver method and apparatus provides a more efficient computation and application of optimal filters. Range and Doppler processing in the receiver are decoupled and, as a result, computational complexity required for both filter computation and filtering stages are significantly reduced. In one embodiment, a response to an emitted signal is demodulated and sampled to provide baseband samples. The response includes a component due to interaction of the emitted signal with a target, The baseband samples are filtered in a bank of N parallel range filters to provide N filter outputs for each of the baseband samples. For one or more Doppler phase shifts , a discrete Fourier transform of the N filter outputs is computed to produce Doppler components that may be analyzed to determine at least one of a presence, range and speed of the target.

A system includes a computer including a processor and a memory, the memory storing instructions executable by the processor to actuate a brake valve to drain a brake cylinder and then actuate the brake valve to isolate the brake cylinder and hold a brake pedal in a retracted position.

A system includes a computer including a processor and a memory, the memory storing instructions executable by the processor to actuate a brake valve to drain a brake cylinder and then actuate the brake valve to isolate the brake cylinder and hold a brake pedal in a retracted position.

An ultrasonic input includes two or more ultrasonic transceiver units having transducers separated from each other by a predetermined spacing and a processor coupled to the transceiver units. In some implementations one unit transmits while two receive and in other implementations one unit transmits and receives while the other just receives. The transmitter sends an ultrasonic pulse and first and second receivers receive echoes of the ultrasonic pulse from an object. The processor and/or transceiver units use first and second receive signals to determine first and second time-of-flight (ToF) measurements corresponding to times between transmitting an ultrasonic pulse and receiving an echo of the ultrasonic pulse.

A semi-autonomous or autonomous mowing vehicle with a sensor that detects the boundary between a first, relatively higher surface, such as the un-mowed vegetation and a second, a relatively lower surface, such as the mowed vegetation, and a controller for steering the semi-autonomous or autonomous vehicle along detected boundary. The detected boundary is based on height differential between the two surfaces and two methods are discussed. For one, the boundary between the two surfaces is detected using a plurality of non-contact distance measuring sensors aligned in same direction, and processes these distance measuring sensors for determining the distance sensors that measure said first relatively higher surface and the distance sensors that measure the second relatively lower surface. For two, the boundary between the two surfaces is detected using a plurality of rotatable contact members on a rotating shaft and a plurality of slip clutches, each slip clutch associated with each contact member coupling the shaft to the contact member in rotating engagement, and processes the internal sensors for detecting impeded rotation of said contact members do to slippage of said clutches in response to contact with said first surface, relatively higher surface, but not contact with said second surface, a relatively lower surface.

A device and method for determining the three-dimensional position of an object. The device comprises at least one transmitter that is adapted to emit a signal; at least three receivers, wherein the at least three receivers and the at least one transmitter are preferably arranged within a first plane, wherein a first receiver and a second receiver are preferably arranged along a first straight line, and a third receiver is preferably arranged at a distance from the first straight line; and a processor that is configured to determine at least three propagation times, wherein the respective propagation time is a time required by the signal from the transmitter via the object to the respective receiver, and wherein the processor is further configured to determine the three-dimensional position of the object on the basis of the determined propagation times as well as on the basis of the arrangement of the transmitter and the receivers.

The invention concerns a tank (1) of fluid (4) for a motor vehicle (3), comprising a body (5) arranged to receive the fluid (4) and a system (9) for measuring a parameter of the fluid (4) in the tank (1) from an acoustic wave. According to the invention, the acoustic wave (6) is generated by another system (7), the main function of which is not that of emitting an acoustic wave.

A system where a large number of underwater devices can transmit their precise position relative to a fixed underwater beacon, by transmitting two short duration, precisely timed acoustic tones (pings). The arrival time of the pulses at the fixed underwater transceiver beacon will relay the transmitter's precise position relative to that beacon. The two pings code for two numbers; either the range and bearing or an X, Y coordinate of each object with respect to the beacon. Data messages can be sent to and received from the beacon, used for command, control and status. The pulses can be a single frequency and have duration of around a 1 ms and operate one or many frequencies to allow multiple cycles to be overlapped in time. This coding scheme allows many devices to send the data simultaneously in the cycle for group tracking from last position or as independent cycles for unambiguous tracking. The transducers used in the system can be omni-directional hydrophones. The tracking grid size is a function of the acoustic frequency chosen and range from 1000 m for 40 KHz and 6000 m for 8 kHz. The system requires that all nodes in the system keep precise synchronized time.

Various embodiments of the present invention are directed towards a system and methods for generating three dimensional (3D) images with increased composite vertical field of view and composite resolution for a spinning three-dimensional sensor, based on actuating the sensor to generate a plurality of sensor axis orientations as a function of rotation of the actuator. The output data from the sensor, such as a spinning LIDAR, is transformable as a function of the actuator angle to generate three dimensional imagery.