A system and method for generating communications waveforms that can operate in congested frequency spaces and in applications in which the receiver is moving with respect to the transmitter is provided. In one or more examples, each symbol to be encoded and transmitted is converted into a sequence of frequency chirps. The sequence of frequencies used by the sequence of chirps is based on the symbol that is to be encoded. Each chirp can have a center frequency, and the frequency can be swept over the duration of the chirp. In this way each chirp can have a varying frequency over the duration of the chirp, but the phase of the chirp can be continuous throughout the duration of the chirp. The bandwidth and sweep rate of the chirp can be based on the expected maximum velocity of the receiver and the transmitter relative to one another.

The target detection accuracy of a radar apparatus is improved. The radar apparatus includes transmission circuitry, which, in operation, transmits a transmission signal using a plurality of transmit antennas, and reception circuitry, which, in operation, receives using a plurality of receive antennas a reflected wave signal that is the transmission signal reflected by an object, in which the plurality of transmit antennas include at least one first transmit antenna and a plurality of second transmit antennas, and, in a first direction, an absolute value of a difference between, on one hand, a spacing between the at least one first transmit antenna and a phase center of those of the plurality of second transmit antennas which are used for beam synthesis, and, on another hand, a spacing between adjacent receive antennas of the plurality of receive antennas is a defined value based on a wavelength of the plurality of transmission signals.

Techniques and apparatuses are described that implement a smart-device-based radar system capable of performing symmetric Doppler interference mitigation. The radar system employs symmetric Doppler interference mitigation to filter interference artifacts caused by the vibration of the radar system or the vibration other objects. This filtering operation incorporates the interference artifact within the noise floor, without significantly attenuating reflections from a desired object. This mitigation can filter each radar frame independently without a priori knowledge about the frequency or amplitude of the vibration. The filtering operation is also independent of the Doppler sampling frequency and can handle aliasing. By filtering the interference artifacts, the radar system produces fewer false detections in the presence of vibrations and can detect objects that would otherwise be masked by the interference artifact.

A radar antenna calibration method includes: forming a detection matrix from signals detected by an arrangement of receive antennas in response to chirps transmitted by an arrangement of transmit antennas, the detection matrix having multiple rows corresponding to the chirps, multiple columns corresponding to a signal sample, and multiple planes corresponding the receive antennas; deriving a range matrix by performing a frequency transform on a portion of each row of the detection matrix; extracting a slice of the range matrix, with different rows of the slice being associated with different chirps and with different receive antennas; deriving a velocity matrix from the extracted slice by performing a frequency transform on a portion of each column of the extracted slice; analyzing the velocity matrix to determine a current peak width; and adjusting, based on the current peak width, phase shifts associated with one or more of the receive antennas.

An example radar system includes a transmission array and a reception array, each aligned as a linear array. The radar system also includes a transmitter configured to cause transmission of radar signals having a center frequency by the transmission array. The radar system also includes a receiver configured to receive radar signals having the center frequency that are received by the reception array. The radar system also includes a processor configured to process received radar signals from the receiver, and adjust the center frequency from a first center frequency to a second center frequency. The adjusting of the center frequency from the first center frequency to the second center frequency causes the frequency-dependent transmission radiation pattern of the transmission array to tilt in a first direction and the frequency-dependent reception radiation pattern of the reception array to tilt in an opposite direction from the first direction.

Device for determining the mixing ratio of a mixture of at least two different fluids, the device comprising: a pipe section with a measuring region; wherein the mixture flows through the measuring region; a radar sensor system with a radar sensor chip arranged on an outer wall of the pipe section. The radar sensor system is configured to: irradiate frequency-modulated millimeter-radar waves (f.sub.S) in a specified frequency range (f) into the measuring region; receive millimeter-radar waves (f.sub.R) backscattered by the mixture; determine a frequency-dependent reflection coefficient (.sub.f) for the specified frequency range (f) using the backscattered millimeter-radar waves (f.sub.R); and calculate or allocate the mixing ratio from the determined frequency-dependent reflection coefficient (.sub.f).

A radar apparatus is provided with a data calculation unit, a first threshold calculation unit, a second threshold calculation unit, a detection threshold calculation unit and a peak detecting unit. The data calculation unit performs a frequency analysis of the reception signal to produce complex data. The first threshold calculating unit adds a predetermined addition value to a power value of the average data where the complex data is averaged to calculate a first threshold. The second threshold calculation unit calculates a second threshold based on a noise power. The detection threshold calculation unit calculates, for each frequency bin, a larger value of the first threshold and the second threshold to be the detection threshold.

A radar system including a transmit antenna for transmitting a radio frequency (RF) signal or a radar signal and a receive antenna for receiving a plurality of reflected signals created by a plurality of targets reflecting the RF signal or radar signal. The reflected signals include noise. The radar system also includes an analog-to-digital converter (ADC) that digitizes or samples the reflected signals to provide a digitized or sampled noisy input signal. The radar system further includes a reservoir computer that receives the noisy input signal. The reservoir computer includes a time-varying reservoir and is configured to de-noise the noisy input signal and provide a range measurement for each of the plurality of targets.

A vehicle, radar system for a vehicle, and method of determining a radial velocity of an object via the radar system. The radar system includes a transmitter, receiver and processor. The transmitter transmits a source signal towards an object, and the receiver for receives a reflection of the source signal from the object. The processor obtains a Doppler measurement related to a radial velocity of the object, wherein the Doppler measurement includes a Doppler ambiguity, obtains a range walk rate for the radial velocity of the object, and resolves the Doppler ambiguity of the Doppler measurement using the range walk rate to obtain the radial velocity of the object.

Embodiments are presented herein of apparatuses, systems, and methods for a wireless device to perform sensing applications using communication signals. The first wireless device may determine to perform a sensing application and to perform the sensing application using a communication signal to be transmitted to a second device. In other words, the first wireless device may use a transmission that is scheduled for communication purposes to additionally perform sensing of one or more types. Example sensing or radar-like applications include estimating distance, motion, and/or angle to one or more objects or structures in the vicinity of the first wireless device. After transmitting the communication signal to the second wireless device, the first wireless device may receive a reflection of the communication signal. The first wireless device may use the reflection to perform the sensing application.