An improved circuit configuration is disclosed for calibrating and/or verifying the operation of phase shifters in a phased array radar system. In one illustrative embodiment, a method includes: (i) programming a set of phase shifters to convert a radio frequency signal into a set of channel signals; (ii) splitting off a monitor signal from each channel signal while coupling the set of channel signals to a set of antenna feeds; and (iii) while taking the monitor signals in pairs associated with adjacent channels, measuring a relative phase between each pair of monitor signals.

An improved circuit configuration is disclosed for calibrating and/or verifying the operation of phase shifters in a phased array radar system. In one illustrative embodiment, a method includes: (i) programming a set of phase shifters to convert a radio frequency signal into a set of channel signals; (ii) splitting off a monitor signal from each channel signal while coupling the set of channel signals to a set of antenna feeds; and (iii) while taking the monitor signals in pairs associated with adjacent channels, measuring a relative phase between each pair of monitor signals.

A TOF ranging system based on a multi-phase correlation vector synthesis ranging method is presented. The method is a generalized expansion from conventional 2- or 4-phase correlations to arbitrary N-phase correlations in finding in-phase (I) and quadrature-phase (Q) signals of the reflected signal at the receiver, where N is an odd number greater than or equal to 3. The correlation vectors of the output of multi-phase correlators are processed by a zero-force synthesizer to produce optimal I and Q signals, from which the phase delay or ranging information is calculated. Embodiments disclose necessary components in realization of the method, such as half clock shifter, full clock shifter, dual edge reference pulse generator, and correlation integrator. The TOF ranging method enables the construction of finer and more accurate TOF systems like 3D imaging systems, 3D sonar imaging systems, or 3D touchless pointer systems.

Disclosed are methods for checking the operational reliability of a radar-based fill level measurement device, which operates according to the pulse time-of-flight method. The methods include detecting controlled variables of the fill level measurement device, such as the signal amplification or the sampling rate. By comparing the controlled variable with a corresponding limit value, it can be determined whether the fill level measurement device is operationally reliable or whether the operational reliability of the fill level measurement device has been lost with increasing operating times because of the degradation of electrical components. It is also advantageous that, on the basis of the methods according to the invention, it is possible to make a prediction according to the principle of “predictive maintenance” regarding how much remaining operating time is estimated to be left until a possible functional failure of the fill level measurement device.

A radar system operated in a variable power mode includes transmitters, receivers, and a controller. The transmitters transmit digitally modulated signals. The receivers receive radio signals that include transmitted radio signals from the transmitter and reflected from objects in the environment. In addition, an interfering radar signal from a different radar system is received that has been linearly frequency modulated. Each receiver includes a linear frequency modulation canceler that includes a FIR filter, and is configured as a 1-step linear predictor with least mean squares adaptation to attempt to cancel the interfering signal. The prediction is subtracted from the FIR input signal that drives the adaptation and also comprises the canceler output. The controller is configured to control the adaptation on a first receiver. The controller delays the adaptation such that transients at the start of each receive pulse are avoided.

A radar system operated in a variable power mode includes transmitters, receivers, and a controller. The transmitters transmit digitally modulated signals. The receivers receive radio signals that include transmitted radio signals from the transmitter and reflected from objects in the environment. In addition, an interfering radar signal from a different radar system is received that has been linearly frequency modulated. Each receiver includes a linear frequency modulation canceler that includes a FIR filter, and is configured as a 1-step linear predictor with least mean squares adaptation to attempt to cancel the interfering signal. The prediction is subtracted from the FIR input signal that drives the adaptation and also comprises the canceler output. The controller is configured to control the adaptation on a first receiver. The controller delays the adaptation such that transients at the start of each receive pulse are avoided.

A distance measurement apparatus of an embodiment includes a first device provided in a vehicle and a second device provided in a key-fob, and calculates a distance between the vehicle and the key-fob based on carrier phase detection. In at least one of the first device and the second device, transmission powers at which a plurality of first distance measurement signals are respectively transmitted when the key-fob is inside the vehicle are set to be lower than transmission powers at which a plurality of first distance measurement signals are respectively transmitted when the key-fob is outside the vehicle.

A distance measurement apparatus of an embodiment includes a first device provided in a vehicle and a second device provided in a key-fob, and calculates a distance between the vehicle and the key-fob based on carrier phase detection. In at least one of the first device and the second device, transmission powers at which a plurality of first distance measurement signals are respectively transmitted when the key-fob is inside the vehicle are set to be lower than transmission powers at which a plurality of first distance measurement signals are respectively transmitted when the key-fob is outside the vehicle.

Various examples for multi-tone continuous wave detection and ranging are disclosed herein. In some embodiments, an initial signal is generated using initial radio frequency (RF) tones, and is emitted as a multi-tone continuous wave signal. The initial signal is reflected from a target and received as a reflected signal. Resultant RF tones, including a frequency, a phase and a power, are determined from the reflected signal in a frequency domain. A frequency-domain sinusoidal wave is fitted to the resultant RF tones in the frequency domain, and a distance to the target is determined using a modulation of the frequency-domain sinusoidal wave. A phase processing algorithm is applied to generate the target distance and speed by triangulating the range information encoded in the backscattered RF tones.

Radar frequency range signals (e.g., 1 to 100 gigahertz) are often generated by upconverting a reference frequency to a transmission frequency, and a received signal may be downconverted to analyze information encoded on the transmission via modulation. Modulation may be achieved via a fractional frequency divider in a phase-locked loop, but fractional spurs may reduce the signal-to-noise ratio. Additionally, the ramp slope may vary due to phase-locked loop momentum. Instead, a clock generator may generate clock signals for a digital front end comprising a digital signal modulator that generates modulated digital values comprising quadrature representations of a radar modulation signal, which are encoded by a radiofrequency digital-to-analog converter (RF-DAC). The RF-DAC analog signal may be upconverted to a radar frequency and transmitted. A receiver may receive, downconvert, and analyze a reflection of the radar transmission, e.g., to perform range detection based on a frequency ramp encoded by the radar transmission.