Systems and methods for combining radar data - Patents.com

Abstract

To provide a system for analyzing radar data.SOLUTION: A system may include: a frequency generator that is configured to generate a reference frequency signal; a timing module that is configured to generate one or more timing signals; and a plurality of radar modules that is in communication with the frequency generator and timing module. The radar module may be configured to: (i) receive the reference frequency signal and the one or more timing signals; (ii) transmit a first set of radar signals partially based on the reference frequency signal and the one or more timing signals, and (iii) receive a second set of radar signals reflected from a surrounding environment. The system may include a processor that is configured to process the radar signal received by the plurality of radar modules, by coherently combining the radar signal using the phase and time-stamp information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] cross reference This application claims priority to U.S. Provisional Patent Application No. 62 / 840,926, filed April 30, 2019, which is incorporated by reference in its entirety. [Background technology]

[0002] Radio Detection And Ranging (RADIO DETECTION AND RANGING) can be used in many applications, including object detection, distance measurement, direction finding, and mapping. Traditionally, radar has been used in airborne vehicles, satellites, and ships to locate objects and image terrain. In recent years, radar has become increasingly popular in automobiles for applications such as blind spot detection, collision avoidance, and autonomous driving. Unlike optical sensors (such as cameras and Light Detection and Ranging (LIDAR) systems), which are affected by weather and changes in visibility, radar can function in low light conditions, darkness, and all types of weather. Summary of the Invention

[0003] Various limitations of currently available radar systems are recognized herein. To utilize radar, a vehicle may be equipped with multiple radar sensors to detect obstacles and objects in the surrounding environment. However, typically, the multiple radar sensors of current radar systems may process data independently of each other. Systems and methods for processing and combining radar data are provided herein. The performance and robustness of a radar system may be improved by combining data from multiple radar sensors and / or modules prior to recognition, detection, and / or classification of objects or obstacles in the surrounding environment. Still further, the radar systems disclosed herein may be configured to resolve computational ambiguities involved in processing and coherently combining radar data from multiple radar sensors and / or modules to identify nearby objects or obstacles and generate one or more localized maps of the surrounding environment.

[0004] In one aspect, the present disclosure provides a system for analyzing radar data. The system may include a frequency generator configured to generate a reference frequency signal having a reference frequency, a timing module configured to generate one or more timing signals, and a plurality of radar modules in communication with the frequency generator and the timing module. In some embodiments, the plurality of radar modules are configured to: (i) receive the reference frequency signal and the one or more timing signals, (ii) transmit a first set of radar signals including a plurality of outgoing radar pulses based at least in part on (a) the reference frequency signal and (b) the one or more timing signals, and (iii) receive a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in a surrounding environment.

[0005] In some embodiments, the system may further include a processor configured to process the second set of radar signals received separately from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating characteristics of targets, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals, and (ii) timestamp information associated with the second set of radar signals.

[0006] In some embodiments, the system may include at least one housing that includes a frequency generator, a timing module, and a plurality of radar modules. In some embodiments, the at least one housing may be mountable to a vehicle. In some embodiments, the vehicle may include a land vehicle, an air vehicle, or a water vehicle.

[0007] In some embodiments, the frequency generator may include circuitry configured to generate a wave signal, including a sine wave, a square wave, a triangular wave, or a sawtooth wave. The wave signal may have a signal frequency that is predetermined or adjustable in real time.

[0008] In some embodiments, the circuit may include a crystal oscillator, a simple package crystal oscillator, a temperature controlled crystal oscillator, a voltage controlled crystal oscillator, a frequency controlled crystal oscillator, an oven controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0009] In some embodiments, the multiple radar modules may be configured to generate a first set of radar signals using a local oscillator. In some embodiments, the local oscillator may be configured to multiply a reference frequency by one or more frequency multiplication factors. In some embodiments, the local oscillator may include an integer-N phase-locked loop, a fractional-N phase-locked loop, or a frequency multiplier. In some embodiments, the local oscillator may be implemented on-board one radar module of the multiple radar modules. In some embodiments, the radar module may include a radar transmitter and / or a radar receiver. In some embodiments, the local oscillator may be implemented on board or on chip of the radar transmitter and / or radar receiver.

[0010] In some embodiments, the timing module may be configured to transmit one or more timing signals to the multiple radar modules or processors. In some embodiments, the one or more timing signals may include a shared clock signal generated based on an absolute time reference or a local time reference. In some embodiments, the one or more timing signals may include one or more separate timing signals for a processor or one or more radar modules of the multiple radar modules.

[0011] In some embodiments, the timing module may be configured to generate separate timing signals for one or more radar modules of the plurality of radar modules, hi some embodiments, the one or more timing signals may include one or more separate timing signals.

[0012] In some embodiments, the multiple radar modules may be configured to trigger transmission of the first set of radar signals based at least in part on a shared clock signal or one or more timing signals.

[0013] In some embodiments, a radar module of the multiple radar modules may include a timestamp generator configured to mark at least a subset of the multiple incoming radar pulses respectively received by the radar module with one or more timestamps on the one or more timing signals prior to forwarding the multiple incoming radar pulses to the processor.

[0014] In some embodiments, the processor may be configured to generate one or more timestamps for the multiple incoming radar pulses received by the multiple radar modules using a shared clock signal generated by the timing module. In some embodiments, the processor may be configured to generate one or more timestamps for the multiple incoming radar pulses received by the multiple radar modules using the one or more timing signals generated by the timing module.

[0015] In some embodiments, the processor may be configured to use one or more timestamps generated by the timestamp generator or processor to sort multiple incoming radar pulses received from multiple radar modules by date and time.

[0016] In some embodiments, the timing module may be configured to generate a shared clock signal that is based on an absolute time reference or a local time reference.

[0017] In some embodiments, the timing module may be configured to correct one or more timing signals for the one or more radar modules prior to transmitting the one or more corrected timing signals to the one or more radar modules. In some embodiments, the one or more corrected timing signals may include one or more separate timing signals.

[0018] In some embodiments, one or more radar modules of the plurality of radar modules may be configured to (i) modify one or more timing signals received from the timing module, and (ii) trigger transmission of a plurality of outgoing radar pulses using the one or more modified timing signals generated at the one or more radar modules.

[0019] In some embodiments, the one or more modified timing signals may be generated, at least in part, by (a) multiplying the frequency of the shared clock signal by one or more frequency multiplication factors and / or (b) implementing a programmable time delay with respect to the shared clock signal.

[0020] In some embodiments, the processor may be configured to coherently combine the subsets of the multiple incoming radar pulses received by the subset of the multiple radar modules by summing one or more complex signals of the subsets of the multiple incoming radar pulses and a relative phase shift or a relative frequency shift. In some embodiments, the relative phase shift or the relative frequency shift may be a function of the relative spatial positions and / or the relative spatial orientations of the multiple radar modules.

[0021] In some embodiments, the multiple radar modules may be configured to calibrate the second set of radar signals received by the multiple radar modules prior to forwarding the second set of radar signals to the processor. In some embodiments, the multiple radar modules may be configured to (i) apply a correction based on the estimated calibration parameters to the second set of radar signals or (ii) provide the estimated calibration parameters for the second set of radar signals to the processor. In some embodiments, the estimated calibration parameters may be derived from one or more variations in phase, gain, delay, and / or bias observed between two or more incoming radar pulses of the multiple incoming radar pulses. In some embodiments, the estimated calibration parameters may be derived in part from relative spatial positions or relative spatial orientations of the multiple radar modules.

[0022] In some embodiments, the multiple radar modules may be configured to calibrate the second set of radar signals using a known object visible to the multiple radar modules to identify a phase difference between two or more incoming radar pulses of the second set of radar signals received by the multiple radar modules.

[0023] In some embodiments, the phase information may include one or more phase differences observed between two or more incoming radar pulses of the second set of radar signals, where the two or more incoming radar pulses are received (i) by different receive antennas in one radar module, (ii) by different radar modules of the multiple radar modules, and / or (iii) when the vehicle is at different spatial positions or orientations.

[0024] In some embodiments, the processor may be configured to generate an occupancy grid using at least (i) the phase information. In some embodiments, the processor may be further configured to generate an occupancy grid using (ii) relative spatial positions or orientations of the multiple radar modules. In some embodiments, the processor may be further configured to calculate a characteristic of a target using the occupancy grid.

[0025] In some embodiments, one or more radar modules of the plurality of radar modules may be configured to (a) extract raw, unprocessed data from the second set of signals, in part, using (i) the phase information and (ii) the timestamp information, and (b) provide the raw, unprocessed data to a processor for coherent combining.

[0026] In some embodiments, the processor may be configured to calculate a characteristic of the target using at least (i) the phase information, hi some embodiments, the characteristic of the target may be selected from the group consisting of: shape, size, position, orientation, angle of arrival, velocity, acceleration, and radar cross section.

[0027] In some embodiments, a first set of radar signals may be transmitted by a first radar module and a second set of radar signals may be received at a second radar module. In some embodiments, the second set of radar signals may correspond to a subset of the first set of radar signals transmitted by the first radar module and reflected off at least one object in the surrounding environment. In some embodiments, the second radar module may be configured to pre-process the second set of radar signals before providing the second set of radar signals to a processor for coherent combining with an additional second set of radar signals received at a third radar module.

[0028] In another aspect, the present disclosure provides a method for analyzing radar data. In some embodiments, the method may provide a radar system including: (a) (i) a frequency generator; (ii) a timing module; and a plurality of radar modules in communication with the frequency generator and the timing module. In some embodiments, the frequency generator may be configured to generate a reference frequency signal at a reference frequency. In some embodiments, the timing module may be configured to generate one or more timing signals. In some embodiments, the method may further include (b) receiving the reference frequency signal and the one or more timing signals at the plurality of radar modules. In some embodiments, the method may further include (c) using the plurality of radar modules to transmit a first set of radar signals including a plurality of outgoing radar pulses based at least in part on the reference frequency signal and the one or more timing signals. In some embodiments, the method may further include (d) receiving a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in the surrounding environment at the plurality of radar modules.

[0029] In some embodiments, the method may further include using the processor to process the second set of radar signals received respectively from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating characteristics of targets, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals, and (ii) timestamp information associated with the second set of radar signals.

[0030] In some embodiments, the radar system may include at least one housing that includes a frequency generator, a timing module, and multiple radar modules. In some embodiments, the at least one housing may be vehicle mountable. In some embodiments, the vehicle may be a land vehicle, an air vehicle, or a water vehicle.

[0031] In some embodiments, the frequency generator may include a circuit configured to generate a wave signal including a sine wave, a square wave, a triangular wave, or a sawtooth wave with a signal frequency that is predetermined or adjustable in real time. In some embodiments, the circuit may include a crystal oscillator, a simple package crystal oscillator, a temperature controlled crystal oscillator, a voltage controlled crystal oscillator, a frequency controlled crystal oscillator, an oven controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0032] In some embodiments, the multiple radar modules may be configured to generate the first set of radar signals using a local oscillator configured to multiply a reference frequency by one or more frequency multiplication factors. In some embodiments, the local oscillator may include an integer-N phase-locked loop, a fractional-N phase-locked loop, or a frequency multiplier. In some embodiments, the local oscillator may be implemented on-board one radar module of the multiple radar modules. In some embodiments, the radar module may include a radar transmitter and a radar receiver.

[0033] In some embodiments, the timing module may be configured to transmit one or more timing signals to multiple radar modules or processors. In some embodiments, the one or more timing signals may include a shared clock signal generated based on an absolute time reference or a local time reference.

[0034] In some embodiments, the timing module may be configured to transmit one or more timing signals to the multiple radar modules or processors, hi some embodiments, the one or more timing signals may include one or more separate timing signals for the processor or one or more radar modules of the multiple radar modules.

[0035] In some embodiments, the multiple radar modules may be configured to trigger transmission of the first set of radar signals based at least in part on the one or more timing signals.

[0036] In some embodiments, a radar module of the multiple radar modules may include a timestamp generator configured to mark at least a subset of the multiple incoming radar pulses respectively received by the radar module with one or more timestamps associated with the one or more timing signals prior to forwarding the multiple incoming radar pulses to the processor.

[0037] In some embodiments, the processor may be configured to use the one or more timing signals generated by the timing module to (i) generate one or more timestamps for the multiple incoming radar pulses received by the multiple radar modules, and (ii) sort the multiple incoming radar pulses received by the multiple radar modules by date and time.

[0038] In some embodiments, the processor may be configured to use one or more timestamps generated by the timestamp generator to sort multiple incoming radar pulses received from the multiple radar modules by date and time.

[0039] In some embodiments, the timing module may be configured to modify one or more timing signals for one or more radar modules of the plurality of radar modules prior to transmitting one or more separate timing signals to the one or more radar modules of the plurality of radar modules.

[0040] In some embodiments, a radar module of the multiple radar modules is configured to (i) modify one or more timing signals received from the timing module, and (ii) trigger transmission of a plurality of outgoing radar pulses using the one or more modified timing signals generated at the radar module.

[0041] In some embodiments, the one or more modified timing signals may be generated, at least in part, by (a) multiplying the frequency of the shared clock signal by one or more frequency multiplication factors, or (b) implementing a programmable time delay with respect to the shared clock signal.

[0042] In some embodiments, the processor may be configured to coherently combine the subsets of the incoming radar pulses received by the subset of the radar modules by summing one or more complex signals of the subsets of the incoming radar pulses and a relative phase shift or a relative frequency shift. In some embodiments, the relative phase shift or relative frequency shift may be a function of the relative spatial positions or relative spatial orientations of the radar modules.

[0043] In some embodiments, the multiple radar modules may be configured to calibrate the second set of radar signals received by the multiple radar modules prior to forwarding the second set of radar signals to the processor.

[0044] In some embodiments, the multiple radar modules may be configured to (i) apply a correction to the second set of radar signals based on the estimated calibration parameter or (ii) provide the second set of radar signals to the processor. In some embodiments, the estimated calibration parameter is derived in part from one or more variations in phase, gain, delay, or bias observed between two or more of the multiple incoming radar pulses. In some embodiments, the estimated calibration parameter may be derived in part from relative spatial positions or relative spatial orientations of the multiple radar modules.

[0045] In some embodiments, the multiple radar modules may be configured to calibrate the second set of radar signals using a known object visible to the multiple radar modules to identify a phase difference between two or more incoming radar pulses of the second set of radar signals received by the multiple radar modules.

[0046] In some embodiments, the phase information may include one or more phase differences observed between two or more incoming radar pulses of the second set of radar signals. In some embodiments, the two or more incoming radar pulses may be received (i) by different receive antennas in a radar module, (ii) by different radar modules of multiple radar modules, or (iii) when the vehicle is at different spatial positions or orientations.

[0047] In some embodiments, the processor may be configured to at least (i) generate an occupancy grid using the phase information. In some embodiments, the processor may be further configured to (ii) generate an occupancy grid using relative spatial positions or orientations of the multiple radar modules. In some embodiments, the processor may be further configured to calculate a characteristic of a target using the occupancy grid.

[0048] In some embodiments, a radar module of the multiple radar modules may be configured to (a) extract raw, unprocessed data from the second set of signals, in part, using (i) the phase information and (ii) the timestamp information, and (b) provide the raw, unprocessed data to a processor for coherent combining.

[0049] In some embodiments, the processor may be configured to calculate a characteristic of the target using at least (i) the phase information, hi some embodiments, the characteristic of the target may be selected from the group consisting of: shape, size, position, orientation, angle of arrival, velocity, acceleration, and radar cross section.

[0050] In some embodiments, a first set of radar signals may be transmitted by a first radar module and a second set of radar signals may be received at a second radar module. In some embodiments, the second set of radar signals may correspond to a subset of the first set of radar signals transmitted by the first radar module and reflected from at least one object in the surrounding environment. In some embodiments, the second radar module may be configured to pre-process the second set of radar signals before providing the second set of radar signals to a processor for coherent combining with an additional second set of radar signals received at a third radar module.

[0051] Another aspect of the disclosure provides a non-transitory computer-readable medium containing machine-executable code that, when executed by one or more computer processors, implements any of the methods described above or elsewhere herein.

[0052] Another aspect of the present disclosure provides a system including one or more computer processors and a computer memory coupled to the system, the computer memory including machine executable code that, when executed by the one or more computer processors, performs any of the methods described above or elsewhere herein.

[0053] Further aspects and advantages of the present disclosure will become readily apparent to those skilled in the art from the following detailed description, in which only exemplary embodiments of the present disclosure are shown and described. As will be seen from the following description, the present disclosure may be in other and different embodiments, each of whose details can be modified in various obvious respects, all without departing from the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0054] Incorporation by Reference All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. In the event that any publications and patents or patent applications incorporated by reference conflict with a disclosure contained herein, the present specification is intended to supersede and / or take precedence over any such conflicting material. [Brief description of the drawings]

[0055] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also referred to herein as "drawings" and "figures"), in which:

[0056] [Figure 1] 1 illustrates a schematic diagram of a system for processing data, according to some embodiments. [Diagram 2] 1 illustrates a schematic diagram of a system configured to process radar data from a subset of a plurality of radar modules, according to some embodiments. [Diagram 3] 1 illustrates generally a computer system programmed or configured to carry out the methods provided herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0057] While various embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Numerous modifications, changes, and substitutions may occur to those skilled in the art without departing from the invention. It is understood that various alternatives to the embodiments of the invention described herein may be utilized.

[0058] Whenever the terms "at least," "greater than," or "greater than or equal to" appear before the first number in a series of two or more numerical values, the terms "at least," "greater than," or "greater than or equal to" apply to each number in the series. For example, 1, 2, or 3 or more is equivalent to 1 or more, 2 or more, or 3 or more.

[0059] Whenever the term "no more than," "less than," or "less than or equal to" appears before the first number in a string of two or more numeric values, the term "no more than," "less than," or "less than or equal to" applies to each number in that string. For example, 3, 2, or 1 or less is equivalent to 3 or less, 2 or less, or 1 or less.

[0060] In one aspect, the present disclosure provides a system for analyzing radar data. The system may include: a frequency generator configured to generate a reference frequency signal, a timing module configured to generate one or more timing signals, and a plurality of radar modules in communication with the frequency generator and the timing module. The plurality of radar modules may be configured to (i) receive the reference frequency signal and the one or more timing signals, (ii) transmit a first set of radar signals including a plurality of outgoing radar pulses based at least in part on (a) the reference frequency signal and (b) the one or more timing signals, and (iii) receive a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in a surrounding environment. In some embodiments, the system may further include a processor configured to aggregate and process the second set of radar signals received respectively from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating characteristics of targets, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals, and (ii) timestamp information associated with the second set of radar signals.

[0061] The system may be configured for use in a vehicle. The vehicle may be a self-driving or autonomous vehicle. The vehicle may be operated by a living subject (an animal (e.g., a human)). The vehicle may be stationary, moving, or capable of movement. The vehicle may be any suitable land, air, or water vehicle. A land vehicle may be a motor vehicle or any other vehicle that uses a renewable or non-renewable energy source (e.g., solar, thermal, electrical, wind, oil, etc.) for travel across or in close proximity to the ground, e.g., within 1 meter, 2 meters, 3 meters, etc.). An air vehicle may be a motor vehicle or any other vehicle that uses a renewable or non-renewable energy source (e.g., solar, thermal, electrical, wind, oil, etc.) for travel through the air or space. An aquatic vehicle may be a motor vehicle or any other vehicle that uses a renewable or non-renewable energy source (e.g., solar, thermal, electrical, wind, oil, etc.) for travel across or through water.

[0062] In some embodiments, the vehicle may be a land-bound vehicle and may move across land. Alternatively, or additionally, the vehicle may have the ability to move in the air, on or under water, underground, in the air, and / or in space. The vehicle may be an automobile. The vehicle may be a land-bound vehicle, a ship, an aircraft, and / or a spacecraft. The vehicle may move freely on a flat surface. The vehicle may move freely in two or more dimensions. The vehicle may travel primarily on one or more roads. In some cases, a vehicle as described herein may have the ability to operate in the air or in space. For example, the vehicle may be an airplane or a helicopter.

[0063] In some embodiments, the vehicle may be an unmanned vehicle and may operate without the need for a human operator. In some embodiments, the vehicle may not carry passengers or operators on board at all. In some embodiments, the vehicle may include space in which passengers may ride. In some embodiments, the vehicle may include space for cargo or objects. In some embodiments, the vehicle may include tools that allow the vehicle to interact with the environment (e.g., collect samples, move objects, etc.). In some embodiments, the vehicle may include tools to release objects into the surrounding environment (e.g., light, sound, liquid, and / or insecticide).

[0064] In some embodiments, the vehicle may be an autonomous or semi-autonomous vehicle. An autonomous vehicle may be an unmanned vehicle. An autonomous vehicle may or may not have a passenger or operator. An autonomous vehicle may or may not have a space where a passenger may ride. An autonomous vehicle may or may not have a space for a cargo or object carried by the vehicle. An autonomous vehicle may or may not have tools that allow the vehicle to interact with the environment (e.g., collect samples, move objects, etc.). An autonomous vehicle may or may not have objects (e.g., light, sound, liquid, pesticide, etc.) to be released for dispersal into the environment. An autonomous vehicle may operate without the need for a human operator. An autonomous vehicle may be a fully autonomous vehicle and / or a partially autonomous vehicle.

[0065] In some embodiments, the vehicle may allow one or more passengers to board. The vehicle may include space for one or more passengers to board the vehicle. The vehicle may have an interior cabin with space for one or more passengers. The vehicle may have space for a vehicle driver. In some embodiments, the vehicle may have the capability to be driven by a human operator. Alternatively, or additionally, the vehicle may be operated using an autonomous driving system.

[0066] In some embodiments, the vehicle may switch between a manual driving mode in which a human driver may drive the vehicle, and an autonomous driving mode in which an automatic controller may generate signals to operate the vehicle without the need for human driver intervention. In some embodiments, the vehicle may have a driver who primarily operates the vehicle manually, but the vehicle may perform certain automated procedures or provide assistance to the driver in certain instances where the vehicle may perform certain procedures to assist the driver (e.g., lane changes, merging, parking, automatic braking). In some embodiments, the vehicle may have a default mode of operation. For example, the manual driving mode may be the default mode of operation, or the autonomous driving mode may be the default mode of operation.

[0067] The system may be configured to detect and / or classify one or more objects in the surrounding environment. Detecting an object may include identifying the presence of an object in the vicinity of the vehicle. Classifying the object may include determining whether the object is stationary or moving and / or determining whether the object is positioned to obstruct or partially obstruct the path of motion of the vehicle. The object may be anything external to the vehicle. The object may be animate or inanimate. The object may be a pedestrian, an animal, a vehicle, a building, a signpost, a sidewalk, a sidewalk curb, a fence, a tree, or anything that may obstruct a vehicle moving in a given direction. The object may be stationary, moving, or capable of motion.

[0068] The target may be located in front of, behind, or to the side of the vehicle. The target may be located within at least about 1 meter (m), 2 m, 3 m, 4 m, 5 m, 10 m, 15 m, 20 m, 25 m, 50 m, 75 m, or 100 m from the vehicle. The target may be located on land, in water, or in the air. The target may be located on or near the vehicle's path of motion. The target may be oriented in any direction relative to the vehicle. The target may be oriented and directed toward the vehicle. Or, the target may be directed away from the vehicle at an angle ranging from 0 to about 360 degrees. In some cases, the target may include multiple targets external to the vehicle on land.

[0069] A target may have a spatial location or characteristics that can be measured or sensed. Spatial location information may include information about the position, velocity, acceleration, and / or other kinematic properties of the target relative to the ground vehicle. Target characteristics may include information about the target's size, shape, orientation, and / or material properties. Material properties may include the target's reflectivity or radar cross section. In some cases, target characteristics may include a measurement of the target's angle of arrival relative to the vehicle. The angle of arrival may correspond to an elevation angle and / or azimuth angle associated with an incoming radar signal reflected from the target and received at the vehicle.

[0070] In some embodiments, the target may have a dimension of at least 0.2 meters, may be to the side of the land vehicle, and may be at least about 1 meter from the land vehicle. In some embodiments, the target may have a dimension of at least 0.2 meters, may be in front of or behind the land vehicle, and may be at least about 1 meter from the land vehicle.

[0071] The surrounding environment may be a location and / or environment in which the vehicle may operate. The surrounding environment may be an indoor or outdoor space. The surrounding environment may be an urban, suburban, or rural environment. The surrounding environment may be a high altitude or low altitude environment. The surrounding environment may include environments with poor visibility (nighttime, heavy precipitation, fog, particulates in the air). The surrounding environment may include objects on the vehicle's path of travel. The surrounding environment may include objects outside the vehicle's path of travel.

[0072] FIG. 1 illustrates an example of a system (100) for processing radar data. The system (100) may include a frequency generator (110), a timing module (120), and a plurality of radar modules (130-1, 130-2, and 130-3), such as up to an nth radar module (130-n), where n may be any integer greater than 3. In some cases, n may be 4, 5, 6, 7, 8, 9, 10, or more, or may be greater than 10. The frequency generator (110) and the timing module (120) may be operatively coupled to and in communication with the plurality of radar modules. Each radar module of the plurality of radar modules may be configured to transmit a first set of signals based on at least one of a reference frequency signal generated by the frequency generator and a shared clock signal or a timing signal generated by the timing module. In any of the embodiments described herein, the timing signal may include a shared clock signal. In some examples, the timing signal may correspond to (or be associated with) the shared clock signal. Alternatively, in any of the embodiments described herein, the shared clock signal and the timing signal may be two different or separate signals. The timing signal may be provided as a single timing signal, or multiple timing signals. In some cases, two or more of the multiple timing signals may be different. The first set of signals may include multiple outgoing radar pulses (105). Each radar module of the multiple radar modules may be configured to receive a second set of signals reflected from targets (102) in the surrounding environment. The second set of signals may be a subset of the first set of signals transmitted from each radar module of the multiple radar modules and may be generated based on a subset of the first set of signals interacting with the target (102) and / or a subset of the first set of signals reflecting off the target (102). The second set of signals may include multiple incoming radar pulses (106).The system (100) may further include a processor (140) operatively coupled and in communication with each radar module of the plurality of radar modules. Each of the plurality of radar modules may be configured to provide a second set of radar signals and / or a plurality of incoming radar pulses (106) respectively received by each of the plurality of radar modules to the processor (140). The processor (140) may be configured to aggregate and process the second set of radar signals respectively received from the plurality of radar modules by (a) coherently combining the second set of radar signals, (b) calculating a characteristic of a target, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals and (ii) timestamp information associated with the second set of radar signals. In some cases, the processor (140) may be operatively coupled to and in communication with the frequency generator (110) and the timing module (120). In such a case, the processor (140) may be configured to provide feedback data to the frequency generator (110) and the timing module (120). The frequency generator (110) and the timing module (120) may be configured to receive feedback data from the processor (140). The feedback data may include one or more signals derived in part from a second set of radar signals received by the processor (140) from the multiple radar modules. The frequency generator (110) and the timing module (120) may be configured to use the feedback data from the processor (140) to adjust, correct, and / or modify the reference frequency signal, the shared clock signal, and / or one of the multiple timing signals.

[0073] The system may include a frequency generator. The frequency generator may be configured to generate a reference frequency signal. The reference frequency signal may be a wave signal having a reference frequency. The wave signal may include a sine wave, a square wave, a triangular wave, a sawtooth wave, or any combination thereof. In some cases, the reference frequency may be a predetermined reference frequency. In other cases, the reference frequency may be modified or adjustable in real time when one or more radar signals are received and / or transmitted by the multiple radar modules.

[0074] The frequency generator may include a circuit configured to generate a reference frequency signal having a reference frequency, which may include a crystal oscillator, a simple package crystal oscillator, a temperature controlled crystal oscillator, a voltage controlled crystal oscillator, a frequency controlled crystal oscillator, an oven controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0075] The frequency generator may be configured to generate a reference frequency signal having a predetermined reference frequency. The predetermined reference frequency may be at least about 1 Hertz (Hz), 10 Hz, 100 Hz, 1 kilohertz (kHz), 10 kHz, 100 kHz, 1 megahertz (MHz), 10 MHz, 100 MHz, 1 gigahertz (GHz), 10 GHz, 100 GHz, 200 GHz, 300 GHz, or even greater. The predetermined reference frequency may be any frequency between about 1 Hertz (Hz) and about 300 Gigahertz (GHz). In some cases, the predetermined reference frequency may be 1 Megahertz (MHz), 40 MHz, or 4 Gigahertz (GHz). The predetermined reference frequency may be a lower frequency than the frequency of one or more outgoing radar pulses and / or one or more incoming radar pulses.

[0076] In some cases, the frequency generator may be configured to generate a reference frequency signal having a reference frequency that is not predetermined. For example, the reference frequency may be generated by adjusting (e.g., increasing and / or decreasing) a predetermined reference frequency in real time based on feedback data from the processor. The feedback data may include one or more signals derived in part from a second set of radar signals received by the multiple radar modules. The frequency generator may be configured to use the feedback data from the processor to adjust, correct, and / or modify the reference frequency.

[0077] The frequency generator may be in communication with each of the multiple radar modules. The frequency generator may be in communication with the multiple radar modules via wired or wireless connections. The wired connection may be a transmission medium including coaxial cable, waveguide, or twisted pair cable. The wireless connection may be an in-area connection established using connection hardware built into and / or internal to the frequency generator and / or the multiple radar modules. The connection hardware may include wireless transmitters, wireless receivers, antennas, and / or other hardware configured to enable the frequency generator and / or the multiple radar modules to process, transmit, or receive the reference frequency signal.

[0078] The frequency generator may be configured to provide and / or distribute a reference frequency signal to each of the multiple radar modules. The reference frequency signal may be distributed from the frequency generator to each of the multiple radar modules by a wireless connection, a wired connection (e.g., coaxial cable, waveguide, and / or twisted pair cable), or other electrical or electromagnetic transmission medium disclosed herein. The reference frequency signal may be used by each of the multiple radar modules to generate a first set of radar signals.

[0079] In some cases, the frequency generator may be configured to generate a plurality of reference frequency signals, including one or more reference frequency signals. The one or more reference frequency signals may be identical or may not be identical. The frequency generator may be configured to provide and / or distribute one reference frequency signal of the plurality of reference frequency signals to each of the plurality of radar modules. In some cases, the plurality of reference frequency signals may include one or more separate reference frequency signals. In such cases, the frequency generator may be configured to provide and / or distribute a separate reference frequency signal to each of the plurality of radar modules. The one or more separate reference frequency signals may be distributed from the frequency generator to each of the plurality of radar modules by a wired or wireless connection. The one or more separate reference frequency signals may be used by each radar module of the plurality of radar modules to generate a respective first set of radar signals.

[0080] The system may include a timing module. The timing module may be configured to generate at least one of (a) a shared clock signal or (b) a plurality of timing signals. In any of the embodiments described herein, the plurality of timing signals may include a shared clock signal. In some examples, one timing signal of the plurality of timing signals may correspond to (or be associated with) the shared clock signal. Alternatively, in any of the embodiments described herein, the shared clock signal and the plurality of timing signals may be different or distinct types of signals. The timing module may be configured to generate the shared clock signal and / or the plurality of timing signals based on an absolute time reference (e.g., a GPS time receiver) or a local time reference (e.g., a crystal oscillator, a simple package crystal oscillator, a temperature controlled crystal oscillator, a voltage controlled crystal oscillator, a frequency controlled crystal oscillator, an oven controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator).

[0081] The timing module may be configured to generate one or more timing signals. In some embodiments, the one or more timing signals may include a shared clock signal as described elsewhere herein. Alternatively, the shared clock signal may be different or separate from the one or more timing signals. The shared clock signal may be a clock signal shared and / or available by the processor and / or one or more radar modules of the multiple radar modules. The shared clock signal may be a wavy signal (e.g., a square wave) that swings between a high state and a low state at a clock frequency. The clock frequency of the shared clock signal may or may not be a predetermined clock frequency.

[0082] In some cases, the shared clock signal may have a predetermined clock frequency. The predetermined clock frequency may be at least about 1 Hertz (Hz), 10 Hz, 100 Hz, 1 kilohertz (kHz), 10 kHz, 100 kHz, 1 megahertz (MHz), 10 MHz, 100 MHz, 1 gigahertz (GHz), 10 GHz, 100 GHz, 200 GHz, 300 GHz, or even greater. The predetermined clock frequency may be any frequency between about 1 Hertz (Hz) and about 300 gigahertz (GHz).

[0083] In some cases, the clock frequency of the shared clock signal may not be predetermined. For example, the shared clock signal may be generated by adjusting a predetermined clock frequency in real time based on feedback data from the processor. The feedback data may include one or more signals derived in part from a second set of radar signals received by the multiple radar modules. The timing module may be configured to use the feedback data from the processor to adjust, correct, and / or modify the clock frequency of the shared clock signal.

[0084] The timing module may be configured to provide and / or distribute a shared clock signal to one or more radar modules of the plurality of radar modules. In some cases, the shared clock signal may be used by each of the plurality of radar modules to trigger and / or initiate transmission of a first set of radar signals. The first set of radar signals may be transmitted at different times and / or different pulse repetition frequencies. The pulse repetition frequency may be a rate at which a radar module repeatedly transmits one or more successive outgoing radar pulses. In other cases, the shared clock signal may be used to chronologically order a plurality of incoming radar pulses received by individual radar modules of the plurality of radar modules. Chronologically ordering the plurality of incoming radar pulses may include labeling and / or assigning one or more timestamps to each incoming radar pulse of the plurality of incoming radar pulses received by each of the plurality of radar modules. The one or more timestamps may correspond to a time at which the one or more incoming radar pulses are received by each of the plurality of radar modules. The one or more timestamps may be generated in part based on the shared clock signal.

[0085] The timing module may be configured to generate a plurality of timing signals including one or more timing signals. In some cases, the plurality of timing signals may be generated based at least in part on a shared clock signal or plurality of shared clock signals. In other cases, the plurality of timing signals may be generated independently of a shared clock signal. In such cases, the plurality of timing signals need not be generated using a shared clock signal or plurality of shared clock signals. The plurality of timing signals may include two or more timing signals for two or more radar modules of the plurality of radar modules. The two or more timing signals may or may not be identical to one another.

[0086] The multiple timing signals generated by the timing module may include one or more separate timing signals. In such cases, different radar modules of the multiple radar modules may receive different or separate timing signals. The one or more separate timing signals may be similar or dissimilar to one another in nature. The one or more separate timing signals may include one or more undulating signals (e.g., sine, square, triangular, or sawtooth waves) that swing between high and low states at one or more clock frequencies. In some cases, the one or more clock frequencies may be predetermined clock frequencies. In other cases, the one or more clock frequencies may be modified or adjustable in real time as the one or more radar signals are received and / or transmitted by the multiple radar modules.

[0087] The one or more separate timing signals may have one or more predetermined clock frequencies. The one or more predetermined clock frequencies may be at least about 1 Hertz (Hz), 10 Hz, 100 Hz, 1 kilohertz (kHz), 10 kHz, 100 kHz, 1 megahertz (MHz), 10 MHz, 100 MHz, 1 gigahertz (GHz), 10 GHz, 100 GHz, 200 GHz, 300 GHz, or even greater. The predetermined clock frequency may be any frequency between about 1 Hertz (Hz) and about 300 Gigahertz (GHz).

[0088] In some cases, one or more distinct timing signals of the plurality of timing signals may have one or more clock frequencies that are not predetermined. In such cases, the timing module may be configured to use feedback data from the processor to adjust, correct, and / or modify one or more clock frequencies of the one or more distinct timing signals in real time. The feedback data may include one or more signals derived in part from the second set of radar signals received by the plurality of radar modules.

[0089] The timing module may be configured to generate one or more separate timing signals by modifying at least a subset of the plurality of timing signals generated by the plurality of radar modules. In some cases, generating one or more separate timing signals may include delaying a timing signal for one radar module relative to another timing signal for another radar module of the plurality of radar modules. For example, the timing module may be configured to generate a first separate timing signal that may be used to trigger transmission of a first set of radar signals by the first radar module. The timing module may further be configured to generate a second separate timing signal by implementing a time delay with respect to the first timing signal. The second separate timing signal may be used to trigger transmission of another first set of radar signals by the second radar module. The first radar module and the second radar module may be configured to use the first separate timing signal and the second separate timing signal to transmit their respective first sets of radar signals at different times. In some cases, the one or more separate timing signals may be generated by modifying a clock frequency of one timing signal of the plurality of timing signals. For example, a separate timing signal for a radar module may be generated by multiplying a clock frequency of another timing signal for another radar module by a frequency multiplication factor. In such a case, the first radar module and the second radar module may be configured to use the first separate timing signal and the second separate timing signal to transmit respective first sets of radar signals at different pulse repetition frequencies.

[0090] The timing module may be in communication with the processor and each of the multiple radar modules. The timing module may be in communication with the processor and each of the multiple radar modules via a wired or wireless connection. The timing module may be configured to transmit the multiple timing signals to the processor and / or the multiple radar modules by coaxial cable, waveguide, twisted pair cable, or any other electrical or electromagnetic transmission medium disclosed herein.

[0091] The timing module may be configured to provide a plurality of timing signals, including one or more separate timing signals, to each of the plurality of radar modules. In some cases, the one or more separate timing signals may be used by each of the plurality of radar modules to trigger and / or initiate transmission of a first set of radar signals. The first set of radar signals may be transmitted at different times and / or different pulse repetition frequencies. In other cases, the one or more separate timing signals may be used to chronologically order a plurality of incoming radar pulses received by individual radar modules of the plurality of radar modules. Chronologically ordering the plurality of incoming radar pulses may include labeling and / or assigning one or more timestamps to each incoming radar pulse of the plurality of incoming radar pulses received by each of the plurality of radar modules. The one or more timestamps may correspond to a time at which the one or more incoming radar pulses are received by each of the plurality of radar modules. The one or more timestamps may be generated based in part on the one or more separate timing signals of the plurality of timing signals.

[0092] In some cases, the timing module may be in communication with one or more additional sensors, such as a Global Navigation Satellite System (GNSS) receiver, a Global Positioning System (GPS) receiver, an Inertial Measurement Unit (IMU), or a Light Detection and Ranging (LIDAR) unit. The one or more additional sensors may be in communication with the timing module via a wired or wireless connection. In such cases, the timing module may be configured to transmit a shared clock signal and / or multiple timing signals to the one or more additional sensors.

[0093] The system may include multiple radar modules. The multiple radar modules may include one radar module. The radar module may include a radar transmitter and / or a radar receiver. The radar transmitter may include a transmitting antenna. The radar receiver may include a receiving antenna. The transmitting antenna may be any antenna (dipole, directional, patch, sector, yagi, parabolic, grid) capable of converting an electrical signal into an electromagnetic wave and transmitting the electromagnetic wave. The receiving antenna may be any antenna (dipole, directional, patch, sector, yagi, parabolic, grid) capable of receiving the electromagnetic wave and converting the radio wave radiation into a waving electrical signal. In some cases, the radar module may include one or more transmitting antennas and / or one or more receiving antennas. In some cases, the radar module may have multiple RX and / or TX channels. The radar module may be used to detect one or more targets in the surrounding environment.

[0094] The multiple radar modules may be in communication with the frequency generator and the timing module. The multiple radar modules may be in communication with the frequency generator and the timing module via a wired or wireless connection. Each radar module of the multiple radar modules may be configured to receive a reference frequency signal from the frequency generator. Each radar module of the multiple radar modules may be further configured to receive from the timing module at least one shared clock signal or one timing signal of the multiple timing signals generated by the timing module. In some cases, the timing signal may include a separate timing signal as described elsewhere herein.

[0095] Each radar module of the plurality of radar modules may be configured to transmit a first set of radar signals including a plurality of outgoing radar pulses. The plurality of outgoing radar pulses may include one radar pulse. The radar pulses may be any electromagnetic waves or signals transmitted by the radar module within a frequency range extending from about 1 Hertz (Hz) to about 300 Gigahertz (GHz). In some cases, the plurality of outgoing radar pulses may have a frequency of 24 GHz, 60 GHz, or 79 GHz.

[0096] Each radar module of the plurality of radar modules may be configured to generate a first set of radar signals based in part on a reference frequency signal generated by and received from the frequency generator. For example, the plurality of radar modules may be configured to generate the first set of radar signals by multiplying a reference frequency for the reference frequency signal by one or more frequency multiplication factors.

[0097] In some cases, the multiple radar modules may be configured to generate the first set of respective radar signals in part through the use of a local oscillator, which may be configured to multiply a reference frequency by one or more frequency multiplication factors. The one or more frequency multiplication factors can be about 1,000,000 or less, 100,000 or less, 10,000 or less, 9,000 or less, 8,000 or less, 7,000 or less, 6,000 or less, 5,000 or less, 4,000 or less, 3,000 or less, 2,000 or less, 1,000 or less, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 300 or less, 200 or less, 100 or less, 50 or less, 40 or less, 30 or less, 20 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, 2 or less, 1 or less, 0.75 or less, 0.67 or less, 0.5 or less, 0.33 or less, 0.25 or less, 0.2 or less, 0.1 or less, or less. In some cases, the one or more frequency multiplication factors may be at least about 1.0, 1.25, 1.5, 1.75, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 100000 or more. The local oscillator may be an integer-N phase locked loop, a fractional-N phase locked loop, or a frequency multiplier.

[0098] In some cases, the local oscillator may be mounted on each of the multiple radar modules. In such cases, the local oscillator may be implemented on the same substrate or chip as the radar transmitter and / or radar receiver of each of the multiple radar modules. In other cases, the local oscillator may be located remotely with respect to the multiple radar modules and in communication with the multiple radar modules via wired or wireless connections. The local oscillator may be configured to operate as a common local oscillator for the multiple radar modules. For example, a local oscillator implemented on one radar module of the multiple radar modules may be configured to operate as a local oscillator for another radar module of the multiple radar modules.

[0099] The multiple radar modules may be configured to modulate the first set of radar signals and / or the multiple outgoing radar pulses prior to transmitting the first set of radar signals and / or the multiple outgoing radar pulses. The modulation may include altering one or more characteristics (e.g., frequency, phase, delay, and / or amplitude) of the first set of radar signals, in part, by using a modulation signal. In some cases, the modulation signal may be a reference frequency signal, a shared clock signal, and / or a timing signal of one of the multiple timing signals generated by the timing module. In other cases, the modulation signal may be any signal generated by a local oscillator (e.g., an integer-N phase-locked loop, a fractional-N phase-locked loop, or a frequency multiplier) of each of the multiple radar modules. The local oscillator may or may not be implemented on-board each of the multiple radar modules. The modulation may be performed using one or more modulation schemes. The one or more modulation schemes may include amplitude modulation, double sideband modulation, single sideband modulation, vestigial sideband modulation, quadrature, quadrature amplitude modulation, angle modulation, frequency modulation, phase modulation, transpose modulation, pulse amplitude modulation, wavelet modulation, fractal modulation, phase shift keying, frequency shift keying, amplitude shift keying, binary phase shift keying, quadrature phase shift keying, differential quadrature phase shift keying, offset quadrature phase shift keying, minimum deviation keying, Gaussian minimum deviation keying, and / or any combination thereof. In some cases, the one or more modulation schemes may implement one or more spreading spectrum techniques, such as chirp spread spectrum, direct sequence spread spectrum, frequency hopping spread spectrum, and / or time hopping spread spectrum. In other cases, the one or more modulation schemes may implement one or more multiplexing techniques, such as space division multiplexing, frequency division multiplexing, time division multiplexing, polarization multiplexing orbital angular momentum multiplexing, and / or code division multiplexing (e.g., code division multiple access (CDMA)).

[0100] The multiple radar modules may be configured to control the rate and / or time of transmission of the first set of radar signals based in part on the shared clock signal or the multiple timing signals. The shared clock signal and / or the multiple timing signals may inform each of the multiple radar modules when to transmit their respective first set of radar signals including the multiple outgoing radar pulses. The shared clock signal and / or the multiple timing signals may inform each of the multiple radar modules how often to transmit their respective first set of radar signals including the multiple outgoing radar pulses. In some cases, each of the multiple radar modules may use a separate timing signal of the shared clock signal or the multiple timing signals to trigger it to transmit its respective first set of radar signals at a desired time or at a desired pulse repetition frequency. In other cases, the multiple radar modules may use the shared clock signal or one timing signal of the multiple timing signals to chronologically sequence the multiple incoming radar pulses received by each radar module of the multiple radar modules. Sequencing the outgoing radar pulses may include assigning one or more timestamps to each incoming radar pulse of the incoming radar pulses received by each of the multiple radar modules. The one or more timestamps may correspond to a time at which the one or more incoming radar pulses are received by each of the multiple radar modules. The one or more timestamps may be generated based in part on a shared clock signal and / or a timing signal of the multiple timing signals.

[0101] In some cases, the multiple radar modules may be configured to directly trigger the transmission of the multiple outgoing radar pulses by using the shared clock signal or the multiple timing signals generated by the timing module. Each of the radar modules of the multiple radars is configured to (i) modify one or more timing signals of the multiple timing signals received from the timing module and (ii) trigger the transmission of the multiple outgoing radar pulses using the multiple modified timing signals generated at each of the multiple radar modules. The multiple modified timing signals may be generated in part by (a) multiplying the frequency of the shared clock signal by one or more frequency multiplication factors and / or (b) implementing a programmable time delay on the shared clock signal. The one or more frequency multiplication factors can be about 1,000,000 or less, 100,000 or less, 10,000 or less, 9,000 or less, 8,000 or less, 7,000 or less, 6,000 or less, 5,000 or less, 4,000 or less, 3,000 or less, 2,000 or less, 1,000 or less, 900 or less, 800 or less, 700 or less, 600 or less, 500 or less, 400 or less, 300 or less, 200 or less, 100 or less, 50 or less, 40 or less, 30 or less, 20 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, 2 or less, 1 or less, 0.75 or less, 0.67 or less, 0.5 or less, 0.33 or less, 0.25 or less, 0.2 or less, 0.1 or less, or less. In some cases, one or more frequency multiplication factors can be at least about 1.0, 1.25, 1.5, 1.75, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 100000 or more.The programmable time delay may be a time delay of 10 seconds, 9 seconds, 8 seconds, 7 seconds, 6 seconds, 5 seconds, 4 seconds, 3 seconds, 2 seconds, 1 second, 0.9 seconds, 0.8 seconds, 0.7 seconds, 0.6 seconds, 0.5 seconds, 0.4 seconds, 0.3 seconds, 0.2 seconds, 0.1 seconds, 0.01 seconds, 1 millisecond (ms), 0.1 ms, 0.01 ms, 1 microsecond (μs), 0.1 μs, 0.01 μs, 1 nanosecond (ns), or less relative to the shared clock signal and / or one of the timing signals generated by the timing module. In some cases, the programmable time delay may be adjusted by each of the multiple radar modules modifying and / or delaying a timing signal received by one of the multiple radar modules relative to another timing signal of the multiple timing signals generated by the shared clock signal and / or timing module.

[0102] Each radar module of the multiple radar modules may be configured to receive a second set of radar signals including a plurality of incoming radar pulses that reflect from the surrounding environment. The plurality of incoming radar pulses may include one radar pulse. The radar pulses may be any electromagnetic waves or signals received by the radar module within a frequency range ranging from about 1 Hertz (Hz) to about 300 Gigahertz (GHz). In some cases, the second set of radar signals may be a subset of the first set of radar signals. Each radar module of the multiple radar modules may be configured to receive a subset of the plurality of outgoing radar pulses transmitted by a transmitting antenna and reflected to a receiving antenna after interacting with external targets in the surrounding environment. In some embodiments, one or more receiving antennas may be used to receive a subset of the plurality of outgoing radar pulses transmitted by one or more transmitting / receiving antennas and reflected to each radar module of the multiple radar modules after interacting with external targets in the surrounding environment. The second set of radar signals received by the multiple radar modules may convey information regarding the distance or range of the targets relative to the vehicle. Information regarding the distance or range of a target relative to the vehicle may be based on the round trip time delay of one or more incoming radar pulses, or the phase of one or more incoming radar pulses. The round trip time delay may provide a spatial resolution that correlates to the bandwidth of the system.

[0103] In some cases, the first set of radar signals may be transmitted by a first radar module and the second set of radar signals may be received at a second radar module. The second radar module may be another radar module different from the first radar module of the multiple radar modules. The second radar module may be operatively coupled to and / or in communication with the first radar module. In some cases, the second set of radar signals may be associated with the first set of radar signals. The second set of radar signals may correspond to a subset of the first set of radar signals transmitted by the first radar module and reflected from the surrounding environment.

[0104] In some cases, the second radar module may be configured to preprocess the second set of radar signals before providing the second set of radar signals to a processor for coherent combining with the additional second set of radar signals received at the third radar module. The additional second set of radar signals may be a separate second set of radar signals received at the third radar module. The third radar module may be different from the second radar module. In some cases, preprocessing the second set of radar signals may include modulating one or more characteristics (e.g., frequency, phase, delay, and / or amplitude) of the second set of radar signals. In other cases, preprocessing the second set of radar signals may include demodulating the second set of radar signals. As described elsewhere herein, demodulating the second set of radar signals may include extracting one or more signals (e.g., information-bearing electronic signals) from the second set of radar signals and / or a plurality of incoming radar pulses of the second set of radar signals.

[0105] The phase of one or more incoming radar pulses may provide spatial resolution relative to a carrier frequency of the first and / or second set of radar signals. In some cases, the carrier frequency may be 79 GHz. The phase information may encompass ambiguities that may be resolved using a phase difference between two or more incoming radar pulses received at different spatial points. For example, the two or more incoming radar pulses may be received at different transmit and / or receive antennas. In some cases, the two or more incoming radar pulses may be received at different positions and / or orientations of the vehicle.

[0106] In some cases, each of the multiple radar modules may be configured to transmit, receive, and process the second set of radar signals and / or the multiple incoming radar pulses received independently by each of the multiple radar modules. Processing the second set of radar signals and / or the multiple incoming radar pulses may include demodulating the second set of radar signals and / or the multiple incoming radar pulses. Demodulating the second set may include extracting one or more signals (e.g., information-carrying electronic signals) from the second set of radar signals and / or the multiple incoming radar pulses. In some cases, the demodulation may be performed using a direct conversion receiver. The direct conversion receiver may demodulate the incoming radar pulses using synchronous detection triggered by a local oscillator having a frequency identical to or very close to the frequency of the incoming radar pulses. In such a case, the second set of radar signals and / or the incoming radar pulses may be mixed down to a baseband signal. The baseband signal may be a complex baseband signal with real and imaginary components. The complex baseband signal may include a common mode signal and a quadrature signal. The multiple radar modules may be configured to transmit the complex baseband signal to a processor for signal aggregation and / or signal processing. The complex baseband signal may be transmitted to the processor in either analog or digital form. The complex baseband signal may be processed by the multiple radar modules and / or the processor in either analog or digital form. In other cases, the demodulation may be performed using a superheterodyne receiver. The superheterodyne receiver may demodulate the incoming radar pulses by using a frequency mixer to convert the frequency of the incoming radar pulses to an intermediate frequency. In such a case, demodulation of the first set of radar signals may include shifting the second set of radar signals to an intermediate frequency. The intermediate frequency may be generated by mixing the frequency of the second set of radar signals with a reference frequency or with a frequency of a signal generated by a local oscillator of each of the multiple radar modules.In some cases, the incoming radar pulses may be mixed down to a non-zero intermediate frequency. In such cases, the multiple radar modules may be configured to transmit the incoming radar pulses mixed down to the non-zero intermediate frequency to a processor for signal aggregation and / or signal processing. The incoming radar pulses mixed down to the non-zero intermediate frequency may be transmitted to the processor in either analog or digital form. The incoming radar pulses mixed down to the non-zero intermediate frequency may be processed by the multiple radar modules and / or processor in either analog or digital form.

[0107] In any of the embodiments disclosed herein, the system may further include a processor configured to aggregate and / or process a second set of radar signals received respectively from the plurality of radar modules. The processor may include a computer processor, an application specific IC, a graphic processing unit, or a field programmable gate array. Aggregating the second set of radar signals may include collecting one or more of the plurality of incoming radar pulses received by at least a subset of the plurality of radar modules. Processing the second set of radar signals may include summing two or more of the plurality of incoming radar pulses together, coherently combining two or more of the plurality of incoming radar pulses based on one or more characteristics (e.g., frequency, phase, delay, and / or amplitude) of the radar signal, calculating one or more characteristics or features of targets in the surrounding environment using data from two or more of the plurality of incoming radar pulses, and / or generating an occupancy grid.

[0108] The processor may be configured to process the second set of radar signals received from the multiple radar modules by coherently combining at least a subset of the multiple incoming radar pulses. Coherently combining at least a subset of the multiple incoming radar pulses may include summing two or more incoming radar pulses using at least (i) phase information (e.g., phase difference) associated with the second set of radar signals and / or (ii) timestamp information associated with the second set of radar signals. The phase information may include one or more phase differences observed between two or more incoming radar pulses of the second set of radar signals. In any of the embodiments described herein, the two or more incoming radar pulses used to determine the phase difference may correspond to two or more incoming radar pulses received (i) by different receive antennas in one radar module, (ii) by different radar modules of the multiple radar modules, and / or (iii) when the vehicle is in different spatial positions or orientations. For example, the two or more incoming radar pulses may be received from one side of the vehicle by a first radar module and from another side of the vehicle by a second radar module. Alternatively, the two or more incoming radar pulses may include a first incoming radar pulse received by the first radar module when the vehicle is at a first spatial location and / or a first orientation and a second incoming radar pulse received by the second radar module when the vehicle is at a second spatial location and / or a second orientation. The timestamp information may include information of when one or more incoming radar pulses of the multiple incoming radar pulses are received by each radar module of the multiple radar modules. In some cases, the timestamp information may include information of when one or more outgoing radar pulses of the multiple outgoing radar pulses are transmitted by each radar module of the multiple radar modules. The timestamp information may be generated by a processor.

[0109] The processor may be configured to coherently combine a subset of the plurality of incoming radar pulses received by the subset of the plurality of radar modules. Coherently combining the subset of the plurality of incoming radar pulses may include summing two or more complex baseband signals derived from the subset of the plurality of incoming radar pulses. Before the two or more complex baseband signals are coherently combined, at least one of the two or more complex baseband signals may be modulated with a relative phase shift or a relative frequency shift. The relative phase shift may be a measurement of a phase difference between two or more incoming radar pulses of the subset of the plurality of incoming radar pulses received by the subset of the plurality of radar modules. In some cases, the relative phase shift may be a measurement of a phase difference between a first set of radar signals transmitted by the transmit antenna and a second set of radar signals received by the receive antenna. The relative frequency shift may be a measurement of a frequency difference between two or more incoming radar pulses of the subset of the plurality of incoming radar pulses received by the subset of the plurality of radar modules.

[0110] The relative phase shift and / or the relative frequency shift may be a function of a relative spatial position and / or a relative spatial orientation of one of the multiple radar modules. For example, in some cases, the relative phase shift and / or the relative frequency shift may be a function of one or more relative constant distances between two or more of the multiple radar modules. The one or more relative constant distances may be at least about 1 millimeter (mm), 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 10 centimeters (cm), 100 cm, or at least about 1 meter in any direction. The one or more relative constant distances may have a tolerance based on a predefined threshold. The predefined threshold may be associated with a percentage of the wavelength of the outgoing or incoming radar pulse, or a fraction of the wavelength of the outgoing or incoming radar pulse. In other cases, the relative frequency shift and / or the relative phase shift may be a function of an angle between a first direction of alignment of one radar module of the plurality of radar modules and a second direction of alignment of another radar module of the plurality of radar modules. The angle between the first direction of alignment and the second direction of alignment may range from about 0 degrees to about 360 degrees in the XY, XZ, and / or YZ planes. The angle between the first direction of alignment and the second direction of alignment may be at least about 0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, 135 degrees, 140 degrees, 150 degrees, 160 degrees, 170 degrees, 180 degrees, 190 degrees, 200 degrees, 210 degrees, 220 degrees, 225 degrees, 230 degrees, 240 degrees, 250 degrees, 260 degrees, 270 degrees, 280 degrees, 290 degrees, 300 degrees, 310 degrees, 315 degrees, 320 degrees, 330 degrees, 340 degrees, 350 degrees, 360 degrees, or any angle between 0 degrees and 360 degrees. In some cases, the relative spatial positions and / or relative spatial orientations of multiple radar modules may be known a priori.In other cases, the relative spatial positions and / or relative spatial orientations of multiple radar modules may be estimated by an online, external calibration algorithm.

[0111] As described above, in some cases, a first set of radar signals may be transmitted by a first radar module, and a second set of radar signals associated with the first set of radar signals may be received at a second radar module. The second radar module may be another radar module of the multiple radar modules different from the first radar module. The second set of radar signals may correspond to a subset of the first set of radar signals transmitted by the first radar module and reflected from the surrounding environment. The second radar module may be configured to pre-process the second set of radar signals before providing the second set of radar signals to a processor for coherent combining with one or more radar signals received at the third radar module. The third radar module may be different from the second radar module. The third radar module may be different from the first radar module. The processor may be configured to (i) coherently combine the second set of preprocessed radar signals with (ii) one or more separate radar signals received by the plurality of radar modules, or a subset thereof.

[0112] The processor may be configured to calculate one or more properties or characteristics of a target in the surrounding environment using data derived from the two or more radar signals. The properties or characteristics of the target may include a shape, size, radar cross section, angle of arrival, position, orientation, velocity, and / or acceleration of the target relative to the vehicle. The two or more radar signals may include a subset of the multiple incoming radar pulses received by the multiple radar modules. The two or more radar signals may be derived by applying a phase or frequency shift to the subset of the multiple incoming radar pulses received by the multiple radar modules.

[0113] The processor may be configured to use the raw data to calculate an angle of arrival of one or more targets in the vicinity of the vehicle. The raw data may include unprocessed data associated with one or more incoming radar pulses of the multiple incoming radar pulses. The raw data may include data that has not been demodulated, calibrated, or corrected to account for variations and / or errors in phase, gain, delay, and / or bias. The angle of arrival may be calculated based in part on a relationship between the angle of arrival and a phase difference measured between two receive antennas of the multiple radar modules. The relationship may be given by the following equation:

[0114]

number

[0115] The processor may be configured to use the raw data to calculate a velocity of one or more targets in the vicinity of the vehicle. The velocity may be calculated based in part on a relationship between the velocity and a phase difference measured between two incoming radar pulses received by a receive antenna of the radar module. The relationship may be given by the following equation:

[0116]

number

[0117] In some cases, the processor may be configured to modify one or more of the multiple incoming radar pulses before calculating a characteristic or signature of the target. For example, the processor may be configured to (i) modify one or more incoming radar pulses by applying a phase or frequency shift, and / or (ii) coherently combine two or more incoming radar pulses before calculating the angle of arrival or velocity of the target.

[0118] In some cases, the processor and / or each of the multiple radar modules may be configured to generate an occupancy grid using at least the phase information. The occupancy grid may be a visual representation of the surrounding environment in which the radar system operates. The occupancy grid may represent when one or more objects in space are detected in relation to the position and / or orientation of the vehicle. The occupancy grid may represent the presence of one or more objects in the surrounding environment and in the vicinity of the vehicle. The occupancy grid may indicate the position and / or orientation of the one or more objects relative to the position and / or orientation of the vehicle. The vehicle may be stationary or in motion. In some cases, the occupancy grid may be generated and / or updated based on the movement of the vehicle through the surrounding environment.

[0119] In some cases, the processor and / or each of the multiple radar modules may be further configured to generate an occupancy grid using the relative spatial positions and / or relative spatial orientations of the multiple radar modules. The relative spatial positions of the multiple radar modules may include one or more relative constant distances between two or more of the multiple radar modules. The one or more relative constant distances may be at least about 1 millimeter (mm), 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 10 centimeters (cm), 100 cm, or at least about 1 meter in any direction. The one or more relative constant distances may have a tolerance based on a predefined threshold. The predefined threshold may be associated with a percentage of the wavelength of the outgoing or incoming radar pulse, or a fraction of the wavelength of the outgoing or incoming radar pulse. The relative spatial orientation of the multiple radar modules may require an angle between a first direction of alignment of one radar module of the multiple radar modules and a second direction of alignment of another radar module of the multiple radar modules. The angle between the first direction of alignment and the second direction of alignment may range from about 0 degrees to about 360 degrees in the XY plane, the XZ plane, and / or the YZ plane. The angle between the first direction of alignment and the second direction of alignment can be at least about 0 degrees, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 45 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, 135 degrees, 140 degrees, 150 degrees, 160 degrees, 170 degrees, 180 degrees, 190 degrees, 200 degrees, 210 degrees, 220 degrees, 225 degrees, 230 degrees, 240 degrees, 250 degrees, 260 degrees, 270 degrees, 280 degrees, 290 degrees, 300 degrees, 310 degrees, 315 degrees, 320 degrees, 330 degrees, 340 degrees, 350 degrees, 360 degrees, or any angle between 0 degrees and 360 degrees.

[0120] In some cases, the processor and / or each of the multiple radar modules may be configured to generate one or more occupancy grids using round trip delay information associated with the second set of radar signals and / or the multiple incoming radar pulses. In such cases, the processor and / or each of the multiple radar modules may be configured to maintain phase information associated with the second set of radar signals and / or the multiple incoming radar pulses after generating the one or more occupancy grids. The processor and / or each of the multiple radar modules may be configured to combine the one or more occupancy grids generated by each of the multiple radar modules into a wide-area occupancy grid using (i) the relative spatial positions and / or relative spatial orientations of the multiple radar modules and (ii) one or more phase differences between two or more incoming radar pulses received by each of the multiple radar modules.

[0121] In some cases, the processor may be configured to receive raw unprocessed data from the multiple radar modules. In such cases, the multiple radar modules may be configured to (a) extract raw unprocessed data from the second set of signals and / or the multiple incoming radar pulses, and (b) provide the raw unprocessed data associated with the second set of radar signals and / or the multiple incoming radar pulses to the processor without generating any occupancy grid. In such cases, the processor may be configured to combine the raw unprocessed data received from the multiple radar modules and subsequently generate one or more occupancy grids based on the raw unprocessed data associated with the second set of radar signals and / or the multiple incoming radar pulses. The processor may be configured to combine the raw unprocessed data based in part on phase information and / or timestamp information associated with the second set of radar signals and / or the multiple incoming radar pulses.

[0122] In some cases, the processor may be configured to determine one or more features or characteristics of targets in the vicinity of the vehicle using a perception algorithm. The perception algorithm may be an algorithm configured to (i) process one or more complex baseband signals derived from a subset of the plurality of incoming radar pulses and / or (ii) combine two or more complex baseband signals derived from the subset of the plurality of incoming radar pulses. The perception algorithm may be configured to calculate one or more features (e.g., size, shape, position, orientation, angle of arrival, or material properties such as reflectivity or radar cross section) or one or more kinematic properties (e.g., velocity or acceleration) of targets in the surrounding environment.

[0123] The perception algorithm may be configured to calculate and / or derive one or more features or one or more kinematic characteristics of the target by interpreting and / or analyzing the radar image generated by the processor. The radar image may be generated, in part, by aggregating and / or processing by the processor at least a subset of the second set of radar signals received by at least a subset of the plurality of radar modules. The radar image may be an occupancy grid and / or a local map. The local map may be a visual representation of a surrounding environment in which the vehicle may operate. The local map may include information associated with the location, orientation, attitude, and / or kinematic characteristics of the vehicle as the vehicle moves through the surrounding environment. The local map may include data regarding the location, orientation, attitude, and / or kinematic characteristics of one or more targets in the surrounding environment. The local map may visually represent the location and orientation, and / or movement of the vehicle correlated to the location and / or movement of one or more targets in the surrounding environment.

[0124] The perception algorithm may be configured to use output information calculated and / or generated by the processor (e.g., the occupancy grid and / or characteristics of the target, such as the target's speed or angle of arrival) to calculate high-level characteristics of the target. For example, the perception algorithm may be configured to use the occupancy grid and the target's speed and / or the target's angle of arrival to calculate the shape, dimensions, material properties (e.g., reflectivity), and / or radar cross section of the target. In some cases, the perception algorithm may be configured to use the occupancy grid and / or one or more characteristics or features of the target to generate one or more decisions regarding how to correct and / or adjust a path of movement of the vehicle through the surrounding environment to avoid targets that may obstruct or partially obstruct the path of movement of the vehicle.

[0125] The perception algorithm may be configured to classify one or more targets detected by the system. For example, the perception algorithm may be configured to determine whether one or more targets are moving or stationary. Or, the perception algorithm may be configured to determine whether one or more targets obstruct or partially obstruct the motion path of a vehicle moving through the surrounding environment.

[0126] The perception algorithm may be configured to track one or more characteristics (e.g., size, shape, location, orientation, angle of arrival, or material properties such as reflectivity or radar cross section) and / or one or more kinematic properties (e.g., velocity or acceleration) of a target. Tracking one or more characteristics and / or one or more kinematic properties of a target may include measuring changes in the one or more characteristics and / or one or more kinematic properties over a predetermined period of time. In some cases, the perception algorithm may be configured to track the position and / or motion of one or more targets in the vicinity of the vehicle while the vehicle moves through the surrounding environment.

[0127] The perception algorithm may be configured to refine the measurements and / or estimate a feature or characteristic of the target (e.g., a target's speed and / or angle of arrival) prior to being calculated by the processor. Refining the measurements or estimating the feature or characteristic of the target may include updating the measurements or estimates based on a plurality of incoming radar pulses received by one or more of the plurality of radar modules. In some cases, refining the measurements or estimating the feature or characteristic of the target may include updating the measurements or estimates based on feedback data. The feedback data may include one or more signals derived in part from a second set of radar signals received by the processor from the plurality of radar modules.

[0128] In some cases, the processor may be configured to process the second set of radar signals received from each of the multiple radar modules by coherently combining the second set of radar signals using timestamp information associated with the first set of radar signals and / or the second set of radar signals. The timestamp information may include information about when one or more incoming radar pulses of the multiple incoming radar pulses are received by each radar module of the multiple radar modules. In some cases, the timestamp information may include information about when one or more outgoing radar pulses of the multiple outgoing radar pulses are transmitted by each radar module of the multiple radar modules. The timestamp information may be generated by the processor or a timestamp generator.

[0129] In some cases, the multiple radar modules may be configured to forward the multiple incoming radar pulses to the processor for a signal set (e.g., a set of the multiple incoming radar pulses and / or a set of a second set of radar signals received by each of the multiple radar modules). In such a case, the processor may be configured to generate timestamps for the multiple incoming radar pulses received by each of the multiple radar modules using a shared clock signal generated by the timing module. The timestamps generated by the processor may be generated relative to one or more ticks of the shared clock signal. In some cases, the processor may be configured to use the timestamps generated by the processor to chronologically sort the multiple incoming radar pulses received by each of the multiple radar modules.

[0130] In other cases, each of the multiple radar modules may include a timestamp generator. The timestamp generator may be configured to label at least a subset of the multiple incoming radar pulses received by each of the multiple radar modules with a timestamp associated with a shared clock or timing signal associated with each of the multiple radar modules. In some cases, the timestamp generator may be configured to timestamp at least a subset of the multiple incoming radar pulses received by each of the multiple radar modules before the multiple radar modules forward the multiple incoming radar pulses for the signal set to the processor. In such a case, the processor may be configured to use the timestamps generated by the timestamp generator to chronologically sort the multiple incoming radar pulses received by each of the multiple radar modules.

[0131] In some cases, the multiple radar modules may be configured to forward the multiple incoming radar pulses to the processor for a signal set (e.g., a set of the multiple incoming radar pulses and / or a set of the second set of radar signals received by each of the multiple radar modules). In some cases, the multiple radar modules may be configured to calibrate the second set of radar signals received by each of the multiple radar modules prior to forwarding the second set of radar signals to the processor.

[0132] In some cases, the multiple radar modules may be configured to apply corrections to the second set of radar signals based on the estimated calibration parameters. Alternatively, the multiple radar modules may be configured to provide the processor with the estimated calibration parameters for the second set of radar signals without applying any corrections to the second set of radar signals. In such cases, the processor may be configured to correct and / or compensate the second set of radar signals using the estimated calibration parameters received from the multiple radar modules. The estimated calibration parameters may be derived in part from one or more variations in phase, gain, delay, frequency and / or bias observed between two or more of the multiple incoming radar pulses. In some cases, the estimated calibration parameters may be derived in part based on relative spatial positions or relative spatial orientations of the multiple radar modules.

[0133] In some cases, the multiple radar modules may be configured to calibrate the second set of radar signals using a known object visible to each of the multiple radar modules to identify phase, gain, delay, frequency and / or bias differences between two or more incoming radar pulses of the second set of radar signals received by each of the multiple radar modules. Each radar module may use a calibration procedure. The calibration procedure may include factory calibration, lab calibration, and / or an online (e.g., real-time) calibration algorithm. A calibration procedure used for one radar module of the multiple radar modules may or may not be similar in nature to a calibration procedure used for another radar module of the multiple radar modules. A calibration procedure used for one radar module of the multiple radar modules may or may not differ from a calibration procedure used for another radar module of the multiple radar modules.

[0134] FIG. 2 illustrates a system configured to process radar data from a subset of the radar modules (130-1, 130-2, and 130-3). The radar modules (130-1, 130-2, and 130-3) may be mounted on any side of the vehicle (104) or on one or more sides of the vehicle (104) (e.g., the front side, rear side, side, top side, or bottom side of the vehicle). The front side of the vehicle is the side facing the general direction of vehicle travel, while the rear side (or rear side) may be the side not facing the general direction of vehicle travel. The rear side may be opposite the front side of the vehicle. The front side of the vehicle may point in the forward direction of vehicle travel. The rear side of the vehicle may point in the rearward direction (e.g., reverse) of vehicle travel. The side side may include the left and / or right side of the vehicle. The vehicle may or may not be configured to move and / or translate perpendicular to the side of the vehicle. In some cases, the multiple radar modules (130-1, 130-2, and 130-3) may be mounted between two adjacent sides of the vehicle (104). The multiple radar modules (130-1, 130-2, and 130-3) may be oriented to detect one or more targets (102) in front of, behind, on the side of, above, below, or near the vehicle (104). In some cases, each of the multiple radar modules (130-1, 130-2, and 130-3) may be configured to be mounted on the same or different sides of the vehicle (104). For example, one or more radar modules (130-1, 130-2, and 130-3) may be mounted on the top, bottom, front, rear, or side of the vehicle (104). In some cases, each of the multiple radar modules (130-1, 130-2, and 130-3) may be configured to be mounted in the same or different orientations.For example, one or more radar modules (130-1, 130-2, and 130-3) may be oriented to detect one or more targets (102) in front of the vehicle (104), behind the vehicle (104), to the side of the vehicle (104), above the vehicle (104), and / or below the vehicle (104).

[0135] As illustrated in FIG. 2 , the multiple radar modules (130-1, 130-2, and 130-3) may be configured to transmit a first set of radar signals including multiple outgoing radar pulses (105-1, 105-2, and 105-3) based in part on a reference frequency signal and at least one of a shared clock signal or a timing signal of the multiple timing signals. The reference frequency signal may be generated by a frequency generator (110) operably coupled and in communication with each of the multiple radar modules. The shared clock signal and the timing signal of the multiple timing signals may be generated by a timing module (120) operably coupled and in communication with each of the multiple radar modules. The multiple radar modules (130-1, 130-2, and 130-3) may be configured to receive a second set of radar signals including multiple incoming radar pulses (106-1), (106-2), and (106-3). The multiple radar modules (130-1, 130-2, and 130-3) may be operatively coupled to and in communication with a processor (140). The multiple radar modules (130-1, 130-2, and 130-3) may be configured to provide a second set of radar signals and / or multiple incoming radar pulses (106-1), (106-2), and (106-3) respectively received by each of the multiple radar modules to the processor (140). The processor (140) may be configured to aggregate and / or process the second set of radar signals respectively received from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating characteristics of targets, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals, and (ii) timestamp information associated with the second set of radar signals.In some cases, the processor (140) may be configured to coherently combine a subset (106-1) and (106-2) of the multiple incoming radar pulses received by a subset (130-1) and (130-2) of the multiple radar modules by summing a relative phase shift or a relative frequency shift and one or more composite signals of the subsets (106-1) and (106-2) of the multiple incoming radar pulses. In some cases, the multiple radar modules (130-1, 130-2, and 130-3) may be configured to calibrate a second set of radar signals using an object (e.g., a target (102)) visible to one or more of the multiple radar modules to identify a phase difference between two or more incoming radar pulses (106-1), (106-2), and (106-3) received by each of the multiple radar modules (130-1, 130-2, and 130-3). In some cases, the processor (140) may be operatively coupled to and in communication with the frequency generator (110) and the timing module (120). In such cases, the processor (140) may be configured to provide feedback data to the frequency generator (110) and the timing module (120). The frequency generator (110) and the timing module (120) may be configured to receive feedback data from the processor (140). The feedback data may include one or more signals derived in part from a second set of radar signals received by the processor (140) from the multiple radar modules. The frequency generator (110) and the timing module (120) may be configured to use the feedback data from the processor (140) to adjust, correct, and / or modify a reference frequency signal, a shared clock signal, and / or a timing signal of the multiple timing signals.

[0136] Another different aspect of the present disclosure provides a method for processing radar data. The method may include providing a radar system including a frequency generator, a timing module, and a plurality of radar modules in communication with the frequency generator and the timing module. The frequency generator may be configured to generate a reference frequency signal having a reference frequency. The timing module may be configured to generate one or more timing signals. The method may further include receiving the reference frequency signal and the one or more timing signals at the plurality of radar modules. The method may further include using the plurality of radar modules to transmit a first set of radar signals including a plurality of outgoing radar pulses based at least in part on (a) the reference frequency signal and (b) the one or more timing signals. The method may further include receiving a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in a surrounding environment at the plurality of radar modules. In some cases, the method may further include using the processor to aggregate and / or process the second set of radar signals respectively received from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating a characteristic of a target, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals and (ii) timestamp information associated with the second set of radar signals.

[0137] Computer Systems Another aspect of the present disclosure provides a computer system programmed or configured to implement the method of the present disclosure. Figure 3 shows a computer system (301) programmed or configured to implement a method for processing radar data. The computer system (301) may be configured to: generate a reference frequency signal at a reference frequency using a frequency generator; generate one or more timing signals using a timing module; provide the reference frequency signal and the one or more timing signals to a plurality of radar modules; transmit using the plurality of radar modules a first set of radar signals including a plurality of outgoing radar pulses based at least in part on (a) the reference frequency signal and (b) the one or more timing signals; and receive using the plurality of radar modules a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in the surrounding environment. In some cases, the computer system (301) may be configured to aggregate and / or process the second set of radar signals received respectively from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating a characteristic of a target, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals and (ii) timestamp information associated with the second set of radar signals. The computer system (301) may be an electronic device of a user or a computer system located remotely relative to the electronic device. The electronic device may be a mobile electronic device.

[0138] The computer system (301) may include a central processing unit (CPU, herein "processor" and "computer processor") (305), which may be a single-core processor or a multi-core processor, or multiple processors for parallel processing. The computer system (301) also includes memory or memory locations (310) (e.g., random access memory, read-only memory, flash memory), electronic storage (315) (e.g., hard disk), communication interfaces (320) (e.g., network adapters) for communicating with one or more other systems, and peripherals (325), such as cache, other memory, data storage devices, and / or electronic display adapters. The memory (310), storage (315), interface (320), and peripherals (325) communicate with the CPU (305) via a communication bus (solid line), such as a motherboard. The storage (315) may be a data storage device (or data repository) for storing data. The computer system (301) may be operatively coupled to a computer network ("network") (330) using a communication interface (320). The network (330) may be the Internet, an Internet and / or an extranet, or an intranet and / or an extranet in communication with the Internet. The network (330) may in some cases be a telecommunications and / or data network. The network (330) may include one or more computer servers, which may enable distributed computing, such as cloud computing. The network (330) may in some cases implement a peer-to-peer network with the computer system (301), thereby enabling devices coupled to the computer system (301) to act as clients or servers.

[0139] The CPU (305) can execute a sequence of machine-readable instructions, which may be embodied in a program or software. The instructions may be stored in a memory location, such as the memory (310). The instructions may be directed to the CPU (305), which may then program or configure the CPU (305) to implement the methods of the present disclosure. Examples of operations performed by the CPU (305) may include fetch, decode, execute, and writeback.

[0140] The CPU 305 may be part of a circuit, such as an integrated circuit, that may include one or more other components of the system 301. In some cases, the circuit is an application specific integrated circuit (ASIC).

[0141] The storage device (315) can store files such as drivers, libraries, and saved programs. The storage device (315) can store user data, such as user preferences and user programs. The computer system (301) may optionally include one or more additional data storage devices external to the computer system (301), such as located on a remote server in communication with the computer system (301) over an intranet or the Internet.

[0142] The computer system (301) can communicate with one or more remote computer systems through the network (330). For example, the computer system (301) can communicate with a remote computer system of a user (e.g., an end user, a consumer, a driver, a vehicle operator, etc.). Examples of remote computer systems include a personal computer (e.g., a portable PC), a slate or tablet PC (e.g., an Apple® iPad, a Samsung® Galaxy Tab), a phone, a smartphone (e.g., an Apple® iPhone, an Android-enabled device, a Blackberry®), or a personal digital assistant. The user can access the computer system (301) through the network (330).

[0143] Methods as described herein may be implemented by machine (e.g., computer processor) executable code stored in an electronic storage location of the computer system (301), such as memory (310) or electronic storage (315). The machine executable or machine readable code may be provided in the form of software. During use, the code may be executed by the processor (305). In some cases, the code may be retrieved from storage (315) and stored in memory (310) where it is readily accessible by the processor (305). In some circumstances, the electronic storage (315) may be omitted and the machine executable instructions are stored in memory (310).

[0144] The code may be precompiled and configured for use with a machine having a processor adapted to execute the code, or may be compiled at run-time. The code may be provided in a programming language that can be selected to enable the code to be executed in a precompiled or compiled at run-time manner.

[0145] Aspects of the systems and methods provided herein, such as the computer system (301), may be embodied in programming. Various aspects of the technology may be considered "goods" or "products" typically in the form of machine (or processor) executable code and / or associated data carried or embodied in some type of machine-readable medium. The machine executable code may be stored in electronic storage such as memory (e.g., read-only memory, random access memory, flash memory) or hard disk. A "storage" type medium may include any or all of the tangible memory of the computer, processor, etc., or their associated modules, such as various semiconductor memories, tape drives, disk drives, etc., that may provide non-transitory storage for software programming at any one time. All or portions of the software may be communicated from time to time over the Internet or various other communications networks. Such communication may, for example, enable loading of the software from one computer or processor to another, for example, from a management server or host computer to the computer platform of an application server. Thus, other types of media that may carry software elements include optical, electrical, and electromagnetic waves, such as those used over wired and land-based optical communication networks between local devices, and various air links. The physical elements that carry such waves, such as wired or wireless links, optical links, etc., may also be considered media that carry software. As used herein, unless limited to non-transitory tangible "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution.

[0146] Thus, a machine-readable medium such as a computer-executable code may take many forms, including but not limited to a tangible storage medium, a carrier wave medium, or a physical transmission medium. Non-volatile storage media include optical or magnetic disks, such as any of the storage devices in any computer(s), such as may be used to implement the databases, etc., shown in the figures. Volatile storage media include dynamic memory, such as the main memory of such a computer platform. Tangible transmission storage media include coaxial cables, copper wire and optical fibers, including the wires that comprise a bus within a computer system. Carrier wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Thus, common forms of computer readable media include, for example, a floppy disk, a flexible disk, a hard disk, a magnetic tape, any other magnetic medium, a CD-ROM, a DVD or DVD-ROM, any other optical medium, punch cards paper tape, any other physical storage medium having a pattern of holes, a RAM, a ROM, a PROM and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave carrying data or instructions, a cable or link carrying such a carrier wave, or any other medium from which a computer can read programming code and / or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.

[0147] The computer system (301) may include or communicate with an electronic display (335) including a user interface (UI) (340), for example, to provide a portal for monitoring one or more objects, obstacles, and / or targets detected by the radar system. In some cases, the portal may be used to render, view, monitor, and / or manipulate one or more occupancy grid maps generated by the processor and / or multiple radar modules. The portal may be provided through an application programming interface (API). A user or entity may also interact with various elements of the portal through the UI. Examples of UIs include, without limitation, graphical user interfaces (GUIs) and web-based user interfaces.

[0148] The disclosed methods and systems may be implemented by one or more algorithms. The algorithm may be implemented by software when executed by a central processing unit (305). The algorithm may be configured to generate, using a frequency generator, a reference frequency signal at a reference frequency, generate, using a timing module, one or more timing signals, provide the reference frequency signal and the one or more timing signals to a plurality of radar modules, transmit, using the plurality of radar modules, a first set of radar signals including a plurality of outgoing radar pulses based at least in part on (a) the reference frequency signal and (b) the one or more timing signals, and receive, using the plurality of radar modules, a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in the surrounding environment. In some cases, the algorithm may be configured to aggregate or process the second set of radar signals received respectively from the multiple radar modules by (a) coherently combining the second set of radar signals, (b) calculating characteristics of targets, or (c) generating an occupancy grid or radar image using at least (i) phase information associated with the second set of radar signals, and (ii) timestamp information associated with the second set of radar signals.

[0149] While preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the present invention be limited by the specific examples provided herein. While the present invention has been described with reference to the foregoing specification, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Many modifications, changes, and substitutions will occur to those skilled in the art without departing from the present invention. Furthermore, it will be understood that all aspects of the present invention are not limited to the specific depictions, configurations, or relative proportions set forth herein, which depend upon a variety of conditions and variables. It is to be understood that various alternatives to the embodiments of the present invention described herein may be utilized in the practice of the present invention. It is therefore contemplated that the present invention shall cover any such alternatives, modifications, variations, or equivalents. It is intended that the following claims define the scope of the present invention, and that methods and structures within the scope of the claims and their equivalents are covered thereby.

Claims

1. 1. A system for processing radar data, the system comprising: A plurality of radar modules; a frequency generator communicatively coupled to each radar module of the plurality of radar modules, the frequency generator configured to generate a reference frequency signal having a reference frequency; a timing module communicatively coupled to each radar module of the plurality of radar modules, to generate a shared clock signal based on an absolute or local time reference; generating one or more timing signals including said shared clock signal; A timing module comprising: Including, Each radar module of the plurality of radar modules comprises: modifying the one or more timing signals received from the timing module to generate modified one or more timing signals; and transmitting a first set of radar signals including a plurality of emitted radar pulses using a reference frequency signal and the modified one or more timing signals. The system is configured.

2. further comprising a processor communicatively coupled to each radar module of the plurality of radar modules; Each radar module of the plurality of radar modules is further configured to receive a second set of radar signals including a plurality of incoming radar pulses reflected from at least one object in a surrounding environment; 2. The system of claim 1, wherein the processor is configured to generate a second set of processed radar signals based on the second set of radar signals and one or more characteristics of the plurality of incoming radar pulses.

3. The processor, coherently combining one or more of the plurality of incoming radar pulses based on phase and amplitude information associated with the one or more incoming radar pulses; or summing two or more of the plurality of incoming radar pulses based on amplitude information associated with one or more of the incoming radar pulses.

3. The system of claim 2, configured to generate the second set of processed radar signals by:

4. the processor is further configured to improve resolution or sensitivity to detect a presence or characteristic of one or more objects in the surrounding environment based on the second set of processed radar signals; The system of claim 2 , wherein the one or more objects includes the at least one object.

5. the processor is further configured to detect a presence or characteristic of a selected object within the surrounding environment based on the second set of the processed radar signals; The system of claim 2 , wherein the selected object spans one or more fields of view corresponding to one or more radar modules of the plurality of radar modules.

6. The processor is further configured to detect a presence or characteristic of a movable object in the surrounding environment based on the second set of the processed radar signals; The system of claim 2 , wherein the movable object is moving or has moved between two or more fields of view corresponding to two or more radar modules of the plurality of radar modules.

7. The system of claim 2 , wherein the one or more characteristics include a phase, an amplitude, a frequency, a delay, or a timing associated with the plurality of incoming radar pulses.

8. The system of claim 2 , further comprising a visualization module configured to generate a visual representation of the surrounding environment based on the second set of processed radar signals.

9. 10. The system of claim 8, wherein the visual representation is derived from or associated with a data representation of the surrounding environment generated from a radar view of one or more radar modules of the plurality of radar modules.

10. The processor, identifying a relative position and orientation of at least one radar module of the plurality of radar modules; and Rotating or translating at least a portion of the radar data acquired using the plurality of radar modules to align the radar data with a global coordinate system. The system of claim 2 , further configured to calibrate the plurality of radar modules by:

11. 3. The system of claim 2, further comprising a light detection and ranging (LIDAR) unit communicatively coupled to the timing module, the LIDAR unit configured to obtain image data of the surrounding environment.

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