In a drive device for driving an ultrasonic transmitter, a drive signal generating unit generates a drive signal for driving the ultrasonic transmitter, based on a base signal having a plurality of unit frequency signals arranged in a time series, corresponding to respective codes forming a code sequence. When a first unit frequency signal and a second unit frequency signal chronologically adjacent to it are switched in a discontinuously switching state that is different from a continuously switching state where the first and second unit frequency signals are switched such that a target frequency for a transmission frequency changes continuously at a substantially constant rate, the drive signal generating unit shifts the frequency in at least a switching portion immediately after start of the second unit frequency signal, in a same direction as a direction of frequency change from the first unit frequency signal to the second unit frequency signal.

A system for searching for underground entities in ground of an area, including a search probe configured to generate and deliver an acoustic signal into the ground of the area, wherein the acoustic signal uses a low frequency signal so that wavelengths of the acoustic signal are between 0.01-500 times the depth to the sought underground entity, two or more sensors positioned on the ground at about an equal distance from the search probe at different angles, an analysis device that receives measurements from the two or more sensors in the form of a measured echo signal responsive to the delivered acoustic signal, wherein said analysis device designates pairs of sensors and subtracts their echo signals to identify a difference indicating the existence of an underground entity.

A method comprising: providing an autonomous vehicle (AV) with a first estimated position of a target; directing the AV to travel toward the first estimated position at a constant velocity; receiving echo signals of transmitted sonar signals, the echo signals indicating a range and an azimuth of the target; determining a depth difference of the AV and the target based on the received echo signals, the depth difference being determined based on changes to the range and azimuth of the target over time; and in response to a depth difference existing, re-directing the AV toward a second estimated position of the target generated from the depth difference.

A method and apparatus for processing a transceiver signal (115) detected by a transceiver (110). The method includes obtaining (51) a processed signal from the transceiver signal (115), the processed signal having frames (200, 300) corresponding to respective time intervals (t1, t2, t3, t4), wherein the frames define bins (210, 310) configured according to a quantized resolution (dr) of the transceiver signal (115). The method further includes obtaining (S2) data related to a relative motion of the transceiver (110) during a time interval (t1, t2, t3, t4) and initializing (S3) a residual distance to zero. For each frame (200, 300) and each respective time interval (t1, t2, t3, t4) the method further includes determining (S4) a shift distance (ds1, ds3) corresponding to a sum of the residual distance and a distance value (d1, d2) corresponding to a relative motion of the transceiver (110) in the respective time interval (t1, t2, t3, t4) and rounding (S5) the determined shift distance (ds1, ds3) with respect to the distance resolution (dr) to a rounded shift distance. The method then further includes updating (S6) the residual distance based on a difference between the determined shift distance (ds1, ds3) and the rounded shift distance, and generating (S7) an adjusted frame (304) by shifting the bins (310) of the frame by the rounded shift distance to account for relative transceiver motion with respect to the object (150) in the respective time interval. The method finally includes processing (S8) the signal by integrating bin values (210, 310) over the adjusted frames (300).

Conventional gesture detection approaches demand large memory and computation power to run efficiently, thus limiting their use in power and memory constrained edge devices. Present application/disclosure provides a Spiking Neural Network based system which is a robust low power edge compatible ultrasound-based gesture detection system. The system uses a plurality of speakers and microphones that mimics a Multi Input Multi Output (MIMO) setup thus providing requisite diversity to effectively address fading. The system also makes use of distinctive Channel Impulse Response (CIR) estimated by imposing sparsity prior for robust gesture detection. A multi-layer Convolutional Neural Network (CNN) has been trained on these distinctive CIR images and the trained CNN model is converted into an equivalent Spiking Neural Network (SNN) via an ANN (Artificial Neural Network)-to-SNN conversion mechanism. The SNN is further configured to detect/classify gestures performed by user(s).

A method for measuring, using a radar or sonar, the velocity with respect to the ground of a carrier moving parallel to the ground, includes the following steps: a) orienting the line of sight of the radar or sonar toward the ground; b) emitting a plurality of radar or sonar signals (P.sub.1-P.sub.N) that are directed toward the ground, and acquiring respective echo signals (E.sub.1-E.sub.N); c) processing the acquired echo signals so as to obtain, for one or more echo delay values, a corresponding Doppler spectrum; d) for the or at least one the echo delay value, determining a high cut-off frequency of the corresponding Doppler spectrum; and e) computing the velocity of the carrier with respect to the ground on the basis of the one or more high cut-off frequencies. A system allowing such a method to be implemented.

A system, apparatus, and method can tune a sensor to filter unwanted reflections or echoes of sound waves from a vegetation layer covering a ground surface in favor of reflections or echoes of sound waves from the ground surface. Such tuning can include adjusting a width of the sound waves output by the sensor. A distance from the sensor to the ground surface underlying the vegetation layer can be determined using the reflections or echoes of the sound from the ground surface based on the sound waves output from the sensor at the adjusted width.

A method for detecting a ground echo signal of an ultrasonic sensor of a vehicle. The ultrasonic sensor emits a signal at a first frequency or having a first frequency profile, the signal is reflected by a roadway surface and the reflected signal is received by the ultrasonic sensor and/or by an additional ultrasonic sensor. The received echo signal is filtered with the aid of a matched filter, the matched filter being adapted to the emitted signal and having a characterizing frequency. In this way a ground echo signal is determined from the filtered signal. The instantaneous vehicle speed is determined and an expected Doppler shift of the reflected signal is determined as a function of the instantaneous vehicle speed. The first frequency or the first frequency profile and/or the characterizing frequency of the matched filter is/are adapted as a function of the Doppler shift to be expected.

A method for detecting a ground echo signal of an ultrasonic sensor of a vehicle. The ultrasonic sensor emits a signal at a first frequency or having a first frequency profile, the signal is reflected by a roadway surface and the reflected signal is received by the ultrasonic sensor and/or by an additional ultrasonic sensor. The received echo signal is filtered with the aid of a matched filter, the matched filter being adapted to the emitted signal and having a characterizing frequency. In this way a ground echo signal is determined from the filtered signal. The instantaneous vehicle speed is determined and an expected Doppler shift of the reflected signal is determined as a function of the instantaneous vehicle speed. The first frequency or the first frequency profile and/or the characterizing frequency of the matched filter is/are adapted as a function of the Doppler shift to be expected.

A system, apparatus, and method can tune a sensor to filter unwanted reflections or echoes of sound waves from a vegetation layer covering a ground surface in favor of reflections or echoes of sound waves from the ground surface. Such tuning can include adjusting a width of the sound waves output by the sensor. A distance from the sensor to the ground surface underlying the vegetation layer can be determined using the reflections or echoes of the sound from the ground surface based on the sound waves output from the sensor at the adjusted width.