Aptiv Technologies Limited

Aptiv Technologies Ag

Zhengzheng Li

Xin Zhang

Yu Zhang

Mingjian Li

Carlos Alcalde

Christopher D Gianelli

Le Zheng

Kurt J Oster

Yujie Gu

Shawn Shi

James F Searcy

Zhengyu Peng

Carlos A Alcalde

Shuimei Zhang

Xining Yu

Stuart Rogers

Techniques and systems are described for Spatial-Block Code Division Multiplexing (CDM) for MIMO waveforms. A radar system includes multiple transmitters, receivers, and phase shifters. Electromagnetic (EM) signals are transmitted and received in a Spatial-Block CDM scheme. Each spatial block has multiple slots outnumbering the channels. In addition, each slot corresponds to a specific code of phase shifts applied across the channels by the phase shifters during that slot. Fast-Fourier Transformations are applied to reflections of the EM signals to generate complex observations at each of the channels during each slot. Based on the observations, whether a Doppler phase shift exists between two slots can be determined based in part on whether the phase shift has one or multiple possible values. The techniques allow velocities to be resolved, despite a mixed-Doppler interval detected. Analog beamforming is supported; slots can be directed at particular angles to change gain in a field of view.

Spatial-block code division multiplexing (CDM) for multiple input multiple output (MIMO) waveforms

This document describes a radar system to universally detect direct-of-arrival (DoA) and direction-of-departure (DoD) angles in direct-path and multipath reflection conditions. For example, a radar system includes a transmitter and receiver array with a first array forming a minimum redundancy array and a second array forming a sparse uniform linear array. A processor determines, using second-array measurements, estimated angles. The quantity of estimated angles is larger than the quantity of actual angles due to angular ambiguity of the second array. The processor then identifies multiple potential sets of actual angles from among the estimated angles and tests each set under a maximum likelihood criterion using first-array measurements. The DoA and DoD angles are identified as the respective set with a maximum utility function value. In this way, the processor determines actual angles with improved resolution and reduced cost without having to identify whether a direct-path or multipath reflection condition exists.

Radar system to universally detect direction-of-arrival or direction-of-departure angles in direct-path and multipath reflection conditions

Described herein is NLS using a bounded linear initial search space and a fixed grid with pre-calculated variables. Specifically, first and second signals with unknown first and second elevation angles, respectively, are received that have been reflected by an object, with the second signal also having been reflected off the ground. A line of second angles is then established as a function of first angles, a sensor height, and a range to the object. The first angles being bound by a function of the sensor height and the range and a function of the sensor height, the range, and the maximum height. A search algorithm is then used to search for an initial elevation angle pair along the line. The initial elevation angle pair may then be fed into a refinement algorithm (e.g., non-linear least squares) to determine the elevation angles associated with the first and second signals.

NLS using a bounded linear initial search space and a fixed grid with pre-calculated variables

This document describes techniques and systems of a radar system with sequential two-dimensional (2D) angle estimation. The radar system can efficiently estimate angles in two dimensions for detections. For example, a radar system includes a processor and an antenna that can receive electromagnetic energy reflected by one or more objects. The antenna includes a 2D array that includes antenna elements positioned in a first dimension and a second dimension. The processor can determine, using electromagnetic energy received by the 2D array, first angles in the first dimension associated with a detection of the one or more objects. The processor can then steer the 2D array to the first angle to generate a steered 1D array for each first angle. Using the steered 1D array, the processor can determine second angles associated with the first angle for the detection.

Radar system with sequential two-dimensional angle estimation

This document describes techniques and systems of a radar system with paired one-dimensional (1D) and two-dimensional (2D) antenna arrays. Even with fewer antenna elements than a traditional radar system, the paired arrays enable an example radar system to have a comparable angular resolution at a lower cost. For example, the 1D array includes antenna elements positioned in a first direction (e.g., azimuth direction) and spaced by a first distance and a second distance. The 2D array includes at least four other antenna elements positioned in the first direction and a second direction (e.g., elevation direction). The other antenna elements are spaced by a third distance in the second direction and by the sum of the first direction and the second direction in the first direction. A processor can associate, using shared angle estimates, angles in the first direction and the second direction for respective objects.

Radar system with paired one-dimensional and two-dimensional antenna arrays

This document describes techniques, apparatuses, and systems for multi-channel joint interference mitigation. Radar radiation received by a radar system may include interference from other nearby radar systems. The interference can result in reduced sensitivity of the radar system. The techniques, apparatuses, and systems described herein mitigate the interference by identifying a set of samples of the radar radiation with interference. The interference can be estimated and mitigated by comparing this set (e.g., with interference) to a set of samples without interference and suppressing the interference without suppressing the detected signal. Further, the interference can be analyzed to determine if the interference contains detection information of one or more objects (e.g., other vehicles with radar systems causing interference). In this manner, interference mitigation may be obtained without losing information included in the set of samples including interference.

Multi-channel joint interference mitigation

The techniques of this disclosure relate to object range and velocity detections from varying radar pulse repetition times. A device includes a transmitter, a receiver, and a processor. The transmitter is configured to transmit a series of electromagnetic pulses within a frame having a varying pulse repetition time between electromagnetic pulses. A center frequency of the electromagnetic pulses varies by a frequency step. The receiver is configured to receive a series of corresponding reflected electromagnetic pulses reflected from an object. The processor is configured to determine range and velocity information of the object based on the received series of corresponding reflected electromagnetic pulses. By varying the pulse repetition times between consecutive pulses in a radar frame, the radar system may improve a range resolution, particularly in the case of frequency-modulated continuous-wave (FMCW) radar systems.

Object range and velocity detection from varying radar pulse repetition times

This document describes techniques, apparatuses, and systems for a wave-shaped ground structure for antenna arrays. A radar system may include a ground structure with a first surface having a wave shape and a second surface opposite the first surface. The ground structure includes multiple antenna arrays separated in a longitudinal direction on the first surface. Each antenna array includes one or more antenna elements configured to emit or receive electromagnetic (EM) energy. The ground structure also includes antenna feeds separated in the longitudinal direction on the second surface and operably connected to the antenna arrays. The wave shape of the ground structure configures the radar system to provide an antenna radiation pattern that provides a uniform radiation pattern among the antenna arrays. The wave shape can also be configured to provide an asymmetrical radiation pattern or a narrow beamwidth for specific applications.

Wave-shaped ground structure for antenna arrays

An illustrative example embodiment of a detector device, which may be useful on an automated vehicle, includes an array of detectors arranged in one dimension. The array includes a plurality of first detectors and a plurality of second detectors. The first detectors respectively have one of the second detectors between the first detector and an adjacent one of the first detectors. The first detectors respectively are spaced from the one of the second detectors by a first distance. The one of the second detectors are respectively spaced from the adjacent one of the first detectors by a second distance that is larger than the first distance. The first detectors are spaced from each other by a third distance that is a sum of the first and second distance. The second detectors are also spaced from each other by the third distance.

Angle finding for a detector having a paired staggered array

This document describes techniques and systems for frequency division multiplexing (FDM) with polyphase shifters. A radar system can include transmitters, receivers, polyphase shifters, and a processor. The transmitters emit electromagnetic (EM) signals in an FDM scheme, and the receivers detect EM signals reflected by objects. The received EM signals include multiple channels. The processor controls the polyphase shifters to introduce phase shifts to the EM signals. The processor can also divide a Doppler-frequency spectrum of the received EM signals into multiple sectors representing a respective frequency range. Each channel is associated with a respective sector. The processor can determine, using non-coherent integration across the sectors, potential detections of the objects, including aliased and actual detections. The processor can then determine the actual detections. In this way, the described FDM techniques with polyphase shifters can resolve Doppler ambiguities in received EM signals.

Frequency division multiplexing with polyphase shifters

This document describes techniques and systems of a radar system with modified orthogonal linear antenna subarrays and an angle-finding module. The described radar system includes a first one-dimensional (1D) (e.g., linear) subarray; a second 1D subarray positioned orthogonal to the first 1D subarray; and a two-dimensional (2D) subarray. Using electromagnetic energy received by the first 1D subarray and the second 2D subarray, azimuth angles and elevation angles associated with one or more objects can be determined. The radar system associates, using electromagnetic energy received by the 2D subarray, pairs of an azimuth angle and an elevation angle to the respective objects. In this way, the described systems and techniques can reduce the number of antenna elements while maintaining the angular resolution of a rectangular 2D array with similar aperture sizing.

Radar system with modified orthogonal linear antenna subarrays

This document describes techniques and systems directed at slow-time modulation for multiple radar channels. A set of transmit channels are modulated using code sequences to phase-modulate transmission signals. A second set of transmit channels are modulated using the same codes for phase modulation as well as using a frequency phase shift. Demodulation is achieved by multiplying received signals by the code sequences. Fast Fourier transforms (FFT) are applied to the received signals to generate a range-Doppler map for each receive channel. A non-coherent integration is performed on the range-Doppler maps to form a range-Doppler average map. The range-Doppler average map is shifted by the frequency phase shift, and the minimal of the range-Doppler average map and the shifted range-Doppler average map is retained. These techniques may reduce the impact of signal residue and increase angular resolution by enabling multiple transmit channels to be utilized.

Slow-time modulation for multiple radar channels

This document describes techniques and systems of a radar system with an angle-finding process for sparse uniform arrays. The described radar system includes a processor and an antenna that can receive electromagnetic energy reflected by objects in the surrounding environment. The antenna includes a one-dimensional (1D) or two-dimensional (2D) sparse array. The processor can determine, using the received electromagnetic energy, a signal subspace associated with the objects that includes an invariance equation. Using an estimated solution to the invariance equation, the processor determines a solution to the invariance equation. The solution to the invariance equation is used to determine angular phases associated with the objects. The processor can then determine, using the angular phases, angles associated with the objects. In this way, the described angle-finding process enables the radar system with a sparse array to efficiently determine angles associated with objects without blind spots.

Angle-finding process for sparse uniform arrays

This document describes techniques and systems for independent transmit and receive channel calibration for multiple-input multiple-output (MIMO) systems. Antenna responses are collected from each virtual channel of a MIMO system at an angle respective to an object. The transmit components and the receive components of the virtual channels are separated and organized into vectors (one for the transmit components and one for the receive components). Calibration values for elements of the vectors are computed and maintained in a transmit calibration matrix and a receive calibration matrix, respectively. Together, the transmit calibration matrix and the receive calibration matrix may include fewer elements than a calibration matrix for the virtual channels and, therefore, may require less memory and fewer computations to calibrate a MIMO system than using other calibration techniques. As such, described is a less expensive and less complex way to calibrate MIMO system by accurately approximating an ideal antenna array.

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Agoura Hills, CA, United States of America

Zhengzheng Li