An approach for providing a lower cost real time location system in less trafficked areas of a building. This approach uses on-board audio capabilities of a mobile device to receive a room response trace resulting from a self-generated acoustic signal. By comparing the room response trace to a modeled room response trace, the location of the mobile device is determined.

An object detection system includes a plurality of object detection devices disposed at predetermined intervals. Each object detection device includes a transmission unit configured to transmit a transmission wave on which frequency modulation based on chirp signals that change in a frequency pattern different from that of an initial signal is performed subsequently to frequency modulation based on the initial signal so as to be in a mode different from those in the object detection devices including the adjacent object detection devices, a reception unit configured to receive a reception wave as the transmission wave returned in response to reflection on an object, and a detection processing unit configured to detect information related to the object based on information acquired as a result of transmission and reception of the transmission wave and the reception wave.

Techniques for range finding for an unmanned aerial system are described. As one example, an unmanned aerial system includes at least one motor to provide propulsion, a piezoelectric acoustic actuator having a resonant frequency, a piezoelectric acoustic sensor having the resonant frequency, and a controller to modulate a fixed amplitude and fixed frequency, at the resonant frequency, carrier wave according to a pseudo-random sequence of bits to produce a modulated wave sequence having a respective section of the carrier wave for each bit of the bits of the pseudo-random sequence having a first value, and a respective section of the carrier wave for each bit of the bits of the pseudo-random sequence having a second value, transmit the modulated wave sequence from the piezoelectric acoustic actuator, receive a reflected wave sequence including a reflection of the modulated wave sequence with the piezoelectric acoustic sensor, determine a delay time between the transmit and the receive of the modulated wave sequence based on the reflected wave sequence received by the piezoelectric acoustic sensor and the modulated wave sequence transmitted by the piezoelectric acoustic actuator, and modify power provided to the at least one motor based on the delay time.

In an ultrasonic detection system that uses frequency-modulation coding to distinguish emitted bursts from multiple transducers, a receiver associated with a transducer uses dynamic thresholding to discriminate valid echoes from system and environmental noise in multiple envelope signals produced by multiple correlators. The time-varying dynamic thresholds are generated from the mean of noise in a respective envelope derived from the output of a respective correlator. Multiple thresholds can be combined together such that a single time-varying threshold is applied to all correlators' envelopes. Such thresholding has the benefits of a constant false-alarm rate with regard to detection of echoes (as opposed to false triggering from noise), and, owing to finer-resolution and adaptive thresholds, can detect targets or obstacles as further distances and with greater time responsiveness.

A survey system including a multibeam echo sounder having a single projector array and a single hydrophone array constructs a multi-component message for ensonifying multiple fans and deconstructs a corresponding message echo for use in analyzing the returns from each fan.

A sonar survey system including a multibeam echo sounder using plural transmit projectors and plural receive hydrophones, wherein beams with associated magnitudes are received such that the largest magnitude beam(s) are identified as characterizing beam(s) and data associated with these characterizing beam(s) is used as a compressed characterization of the ensonified space.

A proximity detection method for detecting absorptive and reflective proximal objects using ultrasound signals and an associated electronic device are provided. The electronic device includes an audio codec, and an acoustics module having a microphone and a speaker. The method includes the steps of: utilizing the speaker to emit an ultrasound signal encoded by the audio codec; utilizing the microphone to sense to generate an incoming ultrasound signal associated with the emitted ultrasound signal; decoding the incoming ultrasound signal into ultrasound waves; and analyzing the ultrasound waves to detect the proximity of a proximal object.

A survey system including a multibeam echo sounder and a beam selector for selecting beams with the largest amplitudes.

A survey system including a multibeam echo sounder having a single projector array and a single hydrophone array constructs a multi-signal message and deconstructs a corresponding multi-signal echo to substantially simultaneously perform multiple survey missions.

A survey system including a multibeam echo sounder having a single projector array and a single hydrophone array constructs a multi-component message for ensonifying multiple fans and deconstructs a corresponding message echo for use in analyzing the returns from each fan.