A method of determining a filling level of a product in a tank, comprising the steps of: generating an electromagnetic transmit signal exhibiting a measurement sweep across a time series of piece-wise constant frequencies being within a measurement frequency range starting at a first frequency, and ending at a second frequency higher than the first frequency, a difference between frequencies in each pair of adjacent frequencies in the frequency range being equal to the first frequency; guiding the transmit signal towards and into the product in the tank; guiding an electromagnetic reflection signal back towards the transceiver; mixing the reflection signal with an electromagnetic reference signal, resulting in a mixer output indicative of a difference between the reflection signal and the reference signal; forming a measurement signal based on the mixer output; and determining the filling level based on the measurement signal.

Apparatus and associated methods relate to enabling a radar system to use different sensing mechanisms to estimate a distance from a target based on different detection zones (e.g., far-field and near-field). In an illustrative example, a curve fitting method may be applied for near-field sensing, and a Fourier transform may be used for far-field sensing. A predetermined set of rules may be applied to select when to use the near-field sensing mechanism and when to use the far-field mechanism. The frequency of a target signal within a beat signal that has less than two sinusoidal cycles may be estimated with improved accuracy. Accordingly, the distance of a target that is within a predetermined distance range (e.g., two meters range for 24 GHz ISM band limitation) may be reliably estimated.

The disclosure provides a method for estimating the nondirectional wave spectrum from the sea echoes of multiple HF radar frequencies. The method includes: dividing the radar detection area into a plurality of fan-shaped units at an equal range interval and angle interval according to the distance resolution and the angular resolution of an HF radar; obtaining the Doppler spectrum from the sea echo of a single radar frequency at a fan-shaped unit by performing the first fast Fourier transform (FFT) in distance dimension, the second FFT in Doppler frequency dimension and the digital beamforming; extracting the positive first-order peak and the negative first-order peak from the aforementioned Doppler spectrum by the peak-searching method; and selecting the stronger first-order peak σ.sub.R.sup.(1)(ω) ; dividing the second-order spectrum on the stronger first-order peak side into an inner second-order spectrum and an outer second-order spectrum.

The present disclosure relates to distance measurement methods and apparatuses. One example method includes receiving multiple first echo signals, determining multiple first spectrum data groups based on the multiple first echo signals, performing normalization processing on a signal strength value corresponding to each distance value comprised in each first spectrum data group to obtain a normalized signal strength value corresponding to each distance value, determining, based on a normalized signal strength value, a variance value of a signal strength value corresponding to each distance value comprised in the multiple first spectrum data ggroups, and determining a distance between a target obstacle on the to-be-measured object and the transmitting origin based on the variance value of the signal strength value corresponding to each distance value comprised in the multiple first spectrum data groups.

A method for interference reduction between radar units. The method is performed by a radar unit and comprises: receiving one or more radar frames, wherein the one or more radar frames correspond to one or more respective time intervals during which the radar unit was activated to transmit and receive signals to produce data samples of the one or more radar frames; and determining whether the one or more radar frames have a higher presence of data samples that are subject to interference from other radar units in a first half of their corresponding time intervals than in a second, later, half of their corresponding time intervals. In case the presence is higher in the first half of their corresponding time intervals, a scheduled time interval of an upcoming radar frame to be produced by the radar unit is postponed, and otherwise it is advanced.

False alarms in RADAR processing are reduced. One or more transforms may be performed to generate an array of spectrum values for a first domain spanning at least one of a range axis, a direction of arrival (DoA) axis, or a velocity axis. One or more spectrum values may be obtained from the array of spectrum values, wherein for each of the one or more spectrum values, (1) the spectrum value is associated with a range estimate, and (2) the spectrum value exceeds a range-dependent maximum threshold established based on a quartic function of the range estimate. The one or more spectrum values identified as exceeding the range-dependent maximum threshold may be excluded, or one or more reduced-magnitude values obtained, to generate an array of modified spectrum values for the first domain, used to generate a range estimate, a DoA estimate, or a velocity estimate, or any combination thereof.

A radar system, apparatus, architecture, and method are provided for generating a transmit reference or chirp signal to produce a plurality of transmit signals having different frequency offsets from the transmit reference signal for encoding and transmission as N radio frequency encoded transmit signals which are reflected from a target and received at a receive antenna as a target return signal that is down-converted to an intermediate frequency signal and converted by a high-speed analog-to-digital converter to a digital signal that is processed by a radar control processing unit which performs fast time processing steps to generate a range spectrum comprising N segments which correspond, respectively, to the N radio frequency encoded transmit signals transmitted over the N transmit antennas.

A digital self-injection-locked (SIL) radar includes a digital SIL oscillator, a wireless signal transceiver and a digital frequency demodulator. The digital SIL oscillator generates a digital output signal. The wireless signal transceiver is electrically connected to the digital SIL oscillator to convert the digital output signal into a wireless signal for transmission to a target, receives a reflected signal from the target, and converts the reflected signal into a digital injection signal for injection into the digital SIL oscillator. Accordingly, the digital SIL oscillator operates in an SIL state and generates a digital oscillation signal. The digital frequency demodulator is electrically connected to the digital SIL oscillator to receive and demodulate the digital oscillation signal into a digital demodulation signal.

The present disclosure provides a circuitry for radar detection data disambiguation for a mobile platform. The circuitry is configured to obtain radar detection data from a radar sensor mounted on the mobile platform, wherein the radar detection data indicate, for each of a plurality of targets, a radial velocity and an angle of arrival; estimate, based on the radar detection data, an ego-motion of the mobile platform; and determine an unambiguous radial velocity value of a target of the plurality of targets based on the ego-motion and the radar detection data.

A radar system for tracking UAVs and other low flying objects utilizing wireless networking equipment is provided. The system is implemented as a distributed low altitude radar system where transmitting antennas are coupled with the wireless networking equipment to radiate signals in a skyward direction. A receiving antenna or array receives signals radiated from the transmitting antenna, and in particular, signals or echoes reflected from the object in the skyward detection region. One or more processing components is electronically coupled with the wireless networking equipment and receiving antenna to receive and manipulate signal information to provide recognition of and track low flying objects and their movement within the coverage region. The system may provide detection of objects throughout a plurality of regions by networking regional nodes, and aggregating the information to detect and track UAVs and other low flying objects as they move within the detection regions.