A moving object detection system comprises: a transmission waveform setting section to set a transmission signal in such a way that a frequency of the transmission signal is linearly changed; a transmitting section to transmit the transmission signal; a receiving section to receive a reception signal resulting from a reflection of the transmission signal at an object; a Doppler coefficient estimating section to estimate a Doppler coefficient associated with a movement of the object by performing arithmetic processing on a waveform of the reception signal at a present time point and waveforms of the reception signal at one or more past time points, the one or more past time points being earlier than the present time point by one or more specified periods of time; and an object detection section to detect the object based on the transmission signal, the Doppler coefficient, and the reception signal.

A method of determining a distance to a discontinuity within an object may include the steps of: a) generating a continuous, frequency modulated input signal having a predetermined frequency range and a frequency ramping speed using a signal generator and splitting the input signal into at least a test signal and a reference signal; b) generating an input sound wave based on the test signal and continuously introducing the input sound wave into the object using a transmitter and simultaneously receiving a reflected sound wave reflected by a discontinuity within the object and generating a corresponding return signal using a receiver; c) determining a frequency difference value based on a comparison of the reference signal and the return signal using a controller; and d) automatically determining a distance from the transmitter to the discontinuity within the object based on at least the frequency difference value and the frequency ramping speed.

An object detection device includes a signal generator configured to generate a drive signal including an identification signal for identifying ultrasonic waves, a transmitter configured to transmit an ultrasonic wave as a probe wave in response to the drive signal, a receiver configured to receive the ultrasonic wave to generate a reception signal, and a determiner configured to analyze frequencies of the reception signal to determine whether the received wave is a reflected wave of the probe wave, thereby detecting an object. The drive signal includes a ramp-up signal generated to be followed by the identification signal and is used to ramp up an amplitude of the probe wave. A frequency of the ramp-up signal is set to include a frequency at which a transmission/reception efficiency is higher than a transmission/reception efficiency at each of a maximum frequency of the identification signal and a minimum frequency of the identification signal.

In many applications such as automobiles on busy highways, if a lot of vehicles on road are equipped with Doppler radars to help improve driving safety, no matter human-driven or auto-driven, if the radars use same frequency band, avoiding interference between them is a hard task. Assigning distinct frequencies is one of the solutions, however not only it wastes expensive spectrum resource, but also the task itself to dynamically assign frequency to vehicles randomly come together becomes a hard one to do. The disclosed invention of Doppler group radar will allow radar devices to work together using shared frequency band without interfering one another, without sacrificing performance, and without much increase in costs.

A method for determining a change in a distance, a location prompting method and an apparatus and a system thereof are provided. The method includes: sending, by a receiving terminal, a paring request to a server for the server to forward the paring request to a transmitting terminal, and to allocate a frequency band for the receiving terminal and the transmitting terminal after the transmitting terminal accepts the paring request; acquiring, by the receiving terminal, an acoustic wave signal of a frequency sent by the transmitting terminal, wherein the frequency is determined by the transmitting terminal based on the allocated frequency band; determining, by the receiving terminal, a change in the acquired acoustic wave signal; and determining, by the receiving terminal, a change in a distance between the transmitting terminal and the receiving terminal according to the change in the acquired acoustic wave signal.

A method for determining a change in a distance, a location prompting method and an apparatus and a system thereof are provided. The method includes: sending, by a receiving terminal, a paring request to a server for the server to forward the paring request to a transmitting terminal, and to allocate a frequency band for the receiving terminal and the transmitting terminal after the transmitting terminal accepts the paring request; acquiring, by the receiving terminal, an acoustic wave signal of a frequency sent by the transmitting terminal, wherein the frequency is determined by the transmitting terminal based on the allocated frequency band; determining, by the receiving terminal, a change in the acquired acoustic wave signal; and determining, by the receiving terminal, a change in a distance between the transmitting terminal and the receiving terminal according to the change in the acquired acoustic wave signal.

A method, device and computer program product for controlling the device by tracking a movement of a hand or other objects. The device receives acoustic signals. At least a portion of the received signals are transformed into two-dimensional sinusoids whose frequencies are proportional to an angle-of-arrival (AoA) and a propagation distance of the reflected signals. An AoA-di stance profile is derived based on signals received from the object by evaluating frequencies of the two-dimensional sinusoids. Then, an AoA-di stance pair is derived from the AoA-di stance profile. A current location of the object is determined based on the estimated AoA-di stance pair. The device then performs a command in response to detecting that the user moved to perform the command based on prior and current locations of the object.

A driving support apparatus according to the present disclosure includes a memory and a hardware processor coupled to the memory and a sound wave sensor. The hardware processor is configured to select, as a transmission and reception scheme, either a pulse scheme or a spread spectrum modulation scheme, and control the sound wave sensor with the selected transmission and reception scheme. When the spread spectrum modulation scheme is selected as the transmission and reception scheme, the hardware processor causes the sound wave sensor to successively transmit and receive sound waves by using the spread spectrum modulation scheme.

A frequency modulation continuous wave (FMCW)-based system includes an emitter to transmit at least one linearly modulated wave of radiation to a scene and a receiver to receive a reflection of the transmitted wave from one or multiple objects located at different locations in the scene. The system interferes a copy of the wave outputted by the emitter with the reflection of the transmitted wave received by the receiver to produce a beat signal with spectrum peaks corresponding to reflections from the different locations at the scene. The beat signal is distorted due to the non-linearity of the modulation. The system includes a processor to detect a number of spectrum peaks in the distorted beat signal and, only in response to detecting multiple spectrum peaks, jointly determine coefficients of a basis function approximating the non-linearity of the modulation and distances to the different locations at the scene having the objects causing the reflection resulting in the spectrum peaks in the distorted beat signal.

A method for inspecting a conduit comprising the steps of: emitting an outgoing signal into the conduit to establish an acoustic plane wave within the conduit; and detecting a reflected outgoing signal from the conduit, wherein the outgoing signal is arranged such that low frequency components contribute to more of the outgoing signal, from a time perspective, than high frequency components.