Systems and methods for combining radar data

Abstract

The present application relates to systems and methods for combining radar data. The present disclosure provides a system for processing radar data. The system can 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 radar modules can be configured to (i) receive the reference frequency signal and the one or more timing signals, (ii) transmit a first set of radar signals based in part 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 can include a processor configured to process the radar signals received by the plurality of radar modules by coherently combining the radar signals using phase and timestamp information.

Description

[0001] This application is a divisional application of the application filed on March 26, 2020, with application number 202080039126.3 and invention title "System and Method for Combining Radar Data". Cross-referencing

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 840,926, filed April 30, 2019, which is incorporated herein by reference in its entirety for all purposes. background

[0003] Radio detection and ranging (radar) can be used in many applications, including target detection, ranging, direction finding, and mapping. Traditionally, radar has been used in aircraft, satellites, and ships at sea to locate targets 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-based sensors (such as cameras or light detection and ranging (LIDAR) systems) that are affected by weather and visibility variations, radar can potentially operate in low-light conditions, darkness, and all types of weather conditions. Overview

[0004] This paper recognizes the various limitations of currently available radar systems. To utilize radar, vehicles can be equipped with multiple radar sensors to detect obstacles and objects in the surrounding environment. However, the multiple radar sensors in current radar systems typically process data independently of each other. This paper provides systems and methods for processing and combining radar data. The performance and robustness of radar systems can be improved by combining data from multiple radar sensors and / or modules before sensing, detecting, and / or classifying objects or obstacles in the surrounding environment. Furthermore, the radar systems disclosed herein can be configured to resolve computational ambiguities associated with processing and coherently combining radar data from multiple radar sensors and / or modules in order to identify nearby objects or obstacles and generate one or more local maps of the surrounding environment.

[0005] In one aspect, this disclosure provides a system for processing 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 may be configured to: (i) receive the reference frequency signal and one or more timing signals; (ii) transmit a first set of radar signals comprising a plurality of output radar pulses, at least in part based on (a) the reference frequency signal and (b) one or more timing signals; and (iii) receive a second set of radar signals comprising a plurality of input radar pulses reflected from at least one object in the surrounding environment.

[0006] In some embodiments, the system may further include a processor configured to process the second set of radar signals received from a plurality of radar modules, by 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, (a) coherently combining the second set of radar signals, (b) calculating the attributes of the target, or (c) generating an occupancy grid or radar image.

[0007] In some embodiments, the system may further include at least one housing comprising a frequency generator, a timing module, and multiple radar modules. In some embodiments, the at least one housing may be mounted on a vehicle. In some embodiments, the vehicle may include a land vehicle, an air vehicle, or a water vehicle.

[0008] In some embodiments, the frequency generator may include circuitry configured to generate wave signals including sine waves, square waves, triangle waves, or sawtooth waves. The wave signals may have a predetermined or real-time adjustable signal frequency.

[0009] In some embodiments, the circuit may include a crystal oscillator, a simple packaged crystal oscillator, a temperature-controlled crystal oscillator, a voltage-controlled crystal oscillator, a frequency-controlled crystal oscillator, a temperature-controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0010] In some embodiments, 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 one of the radar modules in 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 a board or chip of the radar transmitter and / or radar receiver.

[0011] In some embodiments, the timing module may be configured to send one or more timing signals to a plurality of radar modules or a processor. In some embodiments, the one or more timing signals may include a shared clock signal generated based on an absolute time base or a local time base. In some embodiments, the one or more timing signals may include one or more different timing signals for one or more radar modules of the processor or the plurality of radar modules.

[0012] In some embodiments, the timing module can be configured to generate one or more different timing signals for one or more radar modules. In some embodiments, the one or more timing signals may include one or more different timing signals.

[0013] In some embodiments, multiple radar modules may be configured to trigger the transmission of a first set of radar signals based at least in part on a shared clock signal or one or more timing signals.

[0014] In some embodiments, a radar module among a plurality of radar modules may include a timestamp generator configured to mark at least a subset of the plurality of input radar pulses received by the radar module with one or more timestamps relative to one or more timing signals before forwarding the plurality of input radar pulses to a processor.

[0015] In some embodiments, the processor may be configured to generate one or more timestamps for multiple input radar pulses received by multiple radar modules using a shared clock signal generated by a timing module. In some embodiments, the processor may be configured to generate one or more timestamps for multiple input radar pulses received by multiple radar modules using one or more timing signals generated by a timing module.

[0016] In some embodiments, the processor may be configured to use one or more timestamps generated by a timestamp generator or the processor to sort multiple input radar pulses received from multiple radar modules in chronological order.

[0017] In some embodiments, the timing module can be configured to generate a shared clock signal based on an absolute time base or a local time base.

[0018] In some embodiments, the timing module may be configured to modify one or more timing signals of one or more radar modules before sending one or more modified timing signals to one or more radar modules. In some embodiments, the one or more modified timing signals may include one or more different timing signals.

[0019] In some embodiments, one or more of the multiple radar modules may be configured to (i) modify one or more timing signals received from the timing module, and (ii) use one or more modified timing signals generated at one or more radar modules to trigger the transmission of multiple output radar pulses.

[0020] In some embodiments, 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 multiplication factors and / or (b) implementing a programmable time delay relative to the shared clock signal.

[0021] In some embodiments, the processor may be configured to coherently combine a subset of multiple input radar pulses received by a subset of multiple radar modules by summing one or more complex signals having relative phase shifts or relative frequency shifts from a subset of multiple input radar pulses. In some embodiments, the relative phase shift or relative frequency shift may be a function of the relative spatial position and / or relative spatial orientation of the multiple radar modules.

[0022] In some embodiments, the plurality of radar modules may be configured to calibrate a second set of radar signals received by the plurality of radar modules before forwarding the second set of radar signals to the processor. In some embodiments, the plurality of radar modules may be configured to (i) apply a correction based on estimated calibration parameters to the second set of radar signals, or (ii) provide the processor with the estimated calibration parameters for the second set of radar signals. In some embodiments, the estimated calibration parameters may be derived in part from one or more variations in phase, gain, delay, and / or bias observed between two or more input radar pulses in the plurality of input radar pulses. In some embodiments, the estimated calibration parameters may be derived in part from the relative spatial location or relative spatial orientation of the plurality of radar modules.

[0023] In some embodiments, the plurality of radar modules may be configured to use a known object visible to the plurality of radar modules to calibrate a second set of radar signals in order to identify the phase difference between two or more input radar pulses in the second set of radar signals received by the plurality of radar modules.

[0024] In some embodiments, phase information may include one or more phase differences observed between two or more input radar pulses in a second set of radar signals, wherein the two or more input radar pulses are received by (i) different receiving antennas within a radar module, (ii) different radar modules among a plurality of radar modules, and / or (iii) when the vehicle is in different spatial locations or orientations.

[0025] In some embodiments, the processor may be configured to use at least (i) phase information to generate an occupancy grid. In some embodiments, the processor may also be configured to use (ii) the relative spatial positions or orientations of multiple radar modules to generate an occupancy grid. In some embodiments, the processor may also be configured to use the occupancy grid to calculate target attributes.

[0026] In some embodiments, one or more of the multiple radar modules may be configured to, in part, use (i) phase information and (ii) timestamp information, (a) extract raw, unprocessed data from a second set of signals, and (b) provide the raw, unprocessed data to a processor for coherent combination.

[0027] In some embodiments, the processor may be configured to use at least (i) phase information to calculate the target's attributes. In some embodiments, the target's attributes may be selected from the group consisting of shape, size, position, orientation, angle of arrival, velocity, acceleration, and radar cross-section.

[0028] 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 preprocess the second set of radar signals before providing them to a processor for coherent combination with an additional second set of radar signals received at a third radar module.

[0029] On the other hand, this disclosure provides a method for processing radar data. In some embodiments, the method may include (a) providing a radar system including (i) a frequency generator, (ii) a timing module, and (iii) a plurality of radar modules communicating with the frequency generator and the timing module. In some embodiments, the frequency generator may be configured to generate a reference frequency signal having 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 one or more timing signals at the plurality of radar modules. In some embodiments, the method may further include (c) transmitting a first set of radar signals comprising a plurality of output radar pulses using the plurality of radar modules, at least partially based on the reference frequency signal and one or more timing signals. In some embodiments, the method may further include (d) receiving a second set of radar signals at the plurality of radar modules, the second set of radar signals comprising a plurality of input radar pulses reflected from at least one object in the surrounding environment.

[0030] In some embodiments, the method may further include using a processor to process the second set of radar signals received from multiple radar modules, respectively, by 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, by (a) coherently combining the second set of radar signals, (b) calculating the attributes of the target, or (c) generating an occupancy grid or radar image.

[0031] In some embodiments, the radar system may include at least one housing comprising a frequency generator, a timing module, and multiple radar modules. In some embodiments, at least one housing may be mounted on a vehicle. In some embodiments, the vehicle may be a land vehicle, an air vehicle, or a water vehicle.

[0032] In some embodiments, the frequency generator may include circuitry configured to generate wave signals, including sine waves, square waves, triangle waves, or sawtooth waves, having a predetermined or real-time adjustable signal frequency. In some embodiments, the circuitry may include a crystal oscillator, a simple packaged crystal oscillator, a temperature-controlled crystal oscillator, a voltage-controlled crystal oscillator, a frequency-controlled crystal oscillator, a temperature-controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0033] In some embodiments, multiple radar modules may be configured to generate a 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 one of the radar modules in the multiple radar modules. In some embodiments, the radar module may include a radar transmitter and a radar receiver.

[0034] In some embodiments, the timing module may be configured to send 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 base or a local time base.

[0035] In some embodiments, the timing module may be configured to send one or more timing signals to a plurality of radar modules or a processor. In some embodiments, the one or more timing signals may include one or more different timing signals for one or more radar modules of the processor or the plurality of radar modules.

[0036] In some embodiments, multiple radar modules may be configured to trigger the transmission of a first set of radar signals based at least in part on one or more timing signals.

[0037] In some embodiments, a radar module among a plurality of radar modules may include a timestamp generator configured to mark at least a subset of the plurality of input radar pulses received by the radar module with one or more timestamps relative to one or more timing signals before forwarding the plurality of input radar pulses to a processor.

[0038] In some embodiments, the processor may be configured to use one or more timing signals generated by the timing module to (i) generate one or more timestamps for multiple input radar pulses received by multiple radar modules, and (ii) sort the multiple input radar pulses received by multiple radar modules in chronological order.

[0039] In some embodiments, the processor may be configured to use one or more timestamps generated by a timestamp generator to sort multiple input radar pulses received from multiple radar modules in chronological order.

[0040] In some embodiments, the timing module may be configured to modify one or more timing signals for one or more radar modules before sending one or more different timing signals to one or more radar modules.

[0041] In some embodiments, a radar module among a plurality of radar modules may be configured to (i) modify one or more timing signals received from a timing module, and (ii) use one or more modified timing signals generated at the radar module to trigger the transmission of a plurality of output radar pulses.

[0042] In some embodiments, one or more modified timing signals may be generated at least in part by (a) multiplying the frequency of a shared clock signal by one or more multiplication factors or by (b) implementing a programmable time delay relative to the shared clock signal.

[0043] In some embodiments, the processor may be configured to coherently combine a subset of multiple input radar pulses received by a subset of multiple radar modules by summing one or more complex signals having relative phase shifts or relative frequency shifts. In some embodiments, the relative phase shift or relative frequency shift may be a function of the relative spatial position or relative spatial orientation of the multiple radar modules.

[0044] In some embodiments, the multiple radar modules may be configured to calibrate a second set of radar signals received by the multiple radar modules before forwarding the second set of radar signals to the processor.

[0045] In some embodiments, the plurality of radar modules may be configured to (i) apply corrections based on estimated calibration parameters to a second set of radar signals, or (ii) provide estimated calibration parameters for the second set of radar signals to a processor. In some embodiments, the estimated calibration parameters are derived in part from one or more variations in phase, gain, delay, or bias observed between two or more input radar pulses in a plurality of input radar pulses. In some embodiments, the estimated calibration parameters may be derived in part from the relative spatial positions or relative spatial orientations of the plurality of radar modules.

[0046] In some embodiments, multiple radar modules may be configured to use known objects visible to the multiple radar modules to calibrate a second set of radar signals to identify the phase difference between two or more input radar pulses in the second set of radar signals received by the multiple radar modules.

[0047] In some embodiments, phase information may include one or more phase differences observed between two or more input radar pulses in a second set of radar signals. In some embodiments, the two or more input radar pulses may be received by (i) different receiving antennas within a radar module, (ii) different radar modules among a plurality of radar modules, or (iii) when the vehicle is in different spatial locations or orientations.

[0048] In some embodiments, the processor may be configured to use at least (i) phase information to generate an occupancy grid. In some embodiments, the processor may also be configured to use (ii) the relative spatial positions or orientations of multiple radar modules to generate an occupancy grid. In some embodiments, the processor may also be configured to use the occupancy grid to calculate target attributes.

[0049] In some embodiments, the radar modules among the plurality of radar modules may be configured to, in part, use (i) phase information and (ii) timestamp information, (a) extract raw unprocessed data from a second set of signals, and (b) provide the raw unprocessed data to a processor for coherent combination.

[0050] In some embodiments, the processor may be configured to use at least (i) phase information to calculate the target's attributes. In some embodiments, the target's attributes may be selected from the group consisting of shape, size, position, orientation, angle of arrival, velocity, acceleration, and radar cross-section.

[0051] 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 preprocess the second set of radar signals before providing them to a processor for coherent combination with additional second set of radar signals received at a third radar module.

[0052] Another aspect of this 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.

[0053] Another aspect of this disclosure provides a system comprising one or more computer processors and computer memory coupled thereto. The computer memory includes machine-executable code that, when executed by one or more computer processors, implements any of the methods described above or elsewhere herein.

[0054] Further aspects and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description, in which only illustrative embodiments of the disclosure are shown and described. As will be appreciated, this disclosure is capable of having other and different embodiments, and certain details thereof can be modified in a variety of obvious ways, all without departing from the present disclosure. Accordingly, the drawings and description are to be considered illustrative in nature and not restrictive. By incorporating via reference

[0055] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference to the extent that each individual publication, patent, or patent application is specifically and individually indicated to be incorporated by reference. If any publication, patent, or patent application incorporated by reference contradicts the disclosure contained in this specification, the specification is intended to supersede and / or take precedence over any such contradictory material. Brief description of the attached diagram

[0056] The novel features of the invention are specifically set forth in the appended claims. A better understanding of the features and advantages of the invention will be obtained by referring to the following detailed description and accompanying drawings (also referred to herein as “Figure” and “FIG.”) of illustrative embodiments in which the principles of the invention are utilized, in which: Figure 1 A system for processing radar data according to some embodiments is illustrated schematically.

[0057] Figure 2 A system configured to process a subset of radar data from multiple radar modules is illustrated schematically according to some embodiments.

[0058] Figure 3 A computer system is schematically illustrated as being programmed or otherwise configured to implement the methods provided herein. Detailed description

[0059] Although various embodiments of the 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. Many variations, modifications, and substitutions will occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.

[0060] When the term "at least," "greater than," or "greater than or equal to" precedes the first value in a series of two or more values, the term "at least," "greater than," or "greater than or equal to" applies to each value in the series. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0061] When the term "not exceeding," "less than," or "less than or equal to" precedes the first value in a series of two or more values, the term "not exceeding," "less than," or "less than or equal to" applies to each value in the series. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.

[0062] In one aspect, this disclosure provides a system for processing 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 one or more timing signals; (ii) transmit a first set of radar signals comprising a plurality of output radar pulses, at least partially based on (a) the reference frequency signal and (b) one or more timing signals; and (iii) receive a second set of radar signals comprising a plurality of input radar pulses reflected from at least one object in the surrounding environment. In some cases, the system may also include a processor configured to aggregate and process the second set of radar signals received from the plurality of radar modules, respectively, by (a) coherently combining the second set of radar signals, (b) calculating target attributes, 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.

[0063] This system can be configured for use with vehicles. Vehicles can be self-driving or autonomous. Vehicles can be operated by living beings such as animals (e.g., humans). Vehicles can be stationary, moving, or mobile. The vehicle can be any suitable land, air, or water vehicle. Land vehicles can be electric vehicles or any other vehicles using renewable or non-renewable energy sources (e.g., solar, thermal, electrical, wind, oil, etc.) to move on or close to the ground, for example, within 1, 2, or 3 meters of the ground. Air vehicles can be electric vehicles or any other vehicles using renewable or non-renewable energy sources (solar, thermal, electrical, wind, oil, etc.) to move in the air or in space. Water vehicles can be electric vehicles or any other vehicles using renewable or non-renewable energy sources (solar, thermal, electrical, wind, oil, etc.) to move on or across water.

[0064] In some embodiments, the vehicle may be a land-based vehicle and travel on land. Alternatively or additionally, the vehicle may be capable of traveling on or in water, underground, in the air, and / or in space. The vehicle may be a car. The vehicle may be a land-based vehicle, a boat, an aircraft, and / or a spacecraft. The vehicle may travel freely on a surface. The vehicle may travel freely in two or more dimensions. The vehicle may travel primarily on one or more roads. In some cases, the vehicles described herein may be capable of operating in the air or in space. For example, the vehicle may be an airplane or a helicopter.

[0065] In some embodiments, the vehicle may be an unmanned vehicle and can operate without the need for a human operator. In some embodiments, the vehicle may have no passengers or operator on board. In some embodiments, the vehicle may include space for passengers to sit in. In some embodiments, the vehicle may include space for goods or objects. In some embodiments, the vehicle may include tools that allow the vehicle to interact with its environment (e.g., collect samples, move objects, etc.). In some embodiments, the vehicle may include tools that emit objects (e.g., light, sound, liquids, and / or pesticides) into its surrounding environment.

[0066] In some embodiments, the vehicle may be an automated or semi-automated vehicle. An automated vehicle may be a driverless vehicle. An automated vehicle may or may not have passengers or an operator on board. An automated vehicle may or may not have passenger space. An automated vehicle may or may not have cargo or object loading space. An automated vehicle may or may not have tools that allow the vehicle to interact with its environment (e.g., collect samples, move objects). An automated vehicle may or may not have objects that can be emitted to disperse into the environment (e.g., light, sound, liquids, pesticides, etc.). An automated vehicle may operate without the need for a human operator. An automated vehicle may be a fully automated vehicle and / or a partially automated vehicle.

[0067] In some embodiments, the vehicle may allow one or more passengers to ride on it. The vehicle may include space for one or more passengers to ride in the vehicle. The vehicle may have an interior compartment with space for one or more passengers. The vehicle may have space for a driver. In some embodiments, the vehicle may be operable by a human operator. Alternatively or additionally, the vehicle may be operated using an automated driving system.

[0068] In some embodiments, the vehicle can switch between a manual driving mode and an autonomous driving mode. In manual driving mode, a human driver can operate the vehicle. In autonomous driving mode, an automatic controller can generate signals to operate the vehicle without human driver intervention. In some embodiments, the vehicle can provide driver assistance, where the driver can primarily drive the vehicle manually, but the vehicle can execute certain automated procedures or assist the driver in performing certain procedures (e.g., lane changing, lane merging, stopping, automatic braking). In some embodiments, the vehicle may have a default operating mode. For example, manual driving mode or autonomous driving mode may be the default operating mode.

[0069] This system can be configured to detect and / or classify one or more targets in the surrounding environment. Detecting targets may include identifying the presence of targets near a vehicle. Classifying targets may include determining whether the target is stationary or moving, and / or determining whether the target is located relative to the vehicle in a position that obstructs or partially obstructs the vehicle's path of movement. Targets can be any object outside the vehicle. Targets can be living or inanimate objects. Targets can be pedestrians, animals, vehicles, buildings, signposts, sidewalks, sidewalk curbs, fences, trees, or any object that may obstruct the movement of a vehicle in any given direction. Targets can be stationary, moving, or capable of movement.

[0070] The target can be located in front of, behind, or to the side of the vehicle. The target can be located within approximately 1 meter (m), 2m, 3m, 4m, 5m, 10m, 15m, 20m, 25m, 50m, 75m, or 100m of the vehicle. The target can be located on land, in water, or in the air. The target can be located on or near the path of the vehicle. The target can be oriented in any direction relative to the vehicle. The target can be oriented towards the vehicle or oriented away from the vehicle at an angle from 0 degrees to approximately 360 degrees. In some cases, the target may include multiple targets external to the land vehicle.

[0071] Targets may have measurable or detectable spatial arrangements or characteristics. Spatial arrangement information may include information about the target's position, speed, acceleration, and / or other kinematic properties relative to a land 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 the elevation and / or azimuth angles associated with the input radar signal reflected from the target and received at the vehicle.

[0072] In some embodiments, the target may have a size of at least 0.2 meters, be located in a lateral direction to the land vehicle, and be at least about 1 meter away from the land vehicle. In some embodiments, the target may have a size of at least 0.2 meters, be located in a forward or backward direction to the land vehicle, and be at least about 1 meter away from the land vehicle.

[0073] The surrounding environment can be the location and / or environment where the vehicle can operate. The surrounding environment can be an indoor or outdoor space. The surrounding environment can be an urban, suburban, or rural environment. The surrounding environment can be a high-altitude or low-altitude environment. The surrounding environment can include environments providing low visibility (nighttime, heavy precipitation, fog, airborne particles). The surrounding environment can include targets along the vehicle's path. The surrounding environment can include targets outside the vehicle's path.

[0074] Figure 1An example of a system 100 for processing radar data is shown. System 100 may include a frequency generator 110, a timing module 120, and multiple radar modules 130-1, 130-2, 130-3, etc., up to the nth radar module 130-n, where n can be any integer greater than 3. In some cases, n may be greater than or equal to 4, 5, 6, 7, 8, 9, 10, or more. The frequency generator 110 and timing module 120 may be operatively coupled to and communicate with the multiple radar modules. Each of the multiple 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 timing signal generated by the timing module. In any embodiment described herein, the timing signal may include the shared clock signal. In some cases, the timing signal may correspond to (or be associated with) the shared clock signal. Alternatively, in any embodiment described herein, the shared clock signal and the timing signal may be two independent or different signals. The timing signal may be provided as a single timing signal or as 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 output radar pulses 105. Each of the multiple radar modules may be configured to receive a second set of signals reflected from a target 102 in the surrounding environment. The second set of signals may be a subset of the first set of signals emitted by each of the multiple radar modules and may be generated based on a subset of the first set of signals interacting with and / or reflected from the target 102. The second set of signals may include multiple input radar pulses 106. System 100 may also include a processor 140 operatively coupled to and communicating with each of the multiple radar modules. Each of the multiple radar modules may be configured to provide the processor 140 with the second set of radar signals and / or the multiple input radar pulses 106 received by each of the multiple radar modules, respectively. Processor 140 may be configured to aggregate and process second-group radar signals received from multiple radar modules, using at least (i) phase information associated with the second-group radar signals and (ii) timestamp information associated with the second-group radar signals, by (a) coherently combining the second-group radar signals, (b) calculating target attributes, or (c) generating an occupancy grid or radar image. In some cases, processor 140 may be operatively coupled to and in communication with frequency generator 110 and timing module 120. In these cases, processor 140 may be configured to provide feedback data to frequency generator 110 and timing module 120. Frequency generator 110 and timing module 120 may be configured to receive feedback data from processor 140. The feedback data may include one or more signals derived in part from the second-group radar signals received by processor 140 from the multiple radar modules.The frequency generator 110 and timing module 120 can be configured to use feedback data from the processor 140 to adjust, correct, and / or modify a timing signal among a reference frequency signal, a shared clock signal, and / or multiple timing signals.

[0075] The system may include a frequency generator. The frequency generator can be configured to generate a reference frequency signal. The reference frequency signal can be a wave signal with a reference frequency. The wave signal can include a sine wave, square wave, triangle wave, sawtooth wave, or any combination thereof. In some cases, the reference frequency can be a predetermined reference frequency. In other cases, the reference frequency can be modified or adjusted in real time when multiple radar modules are transmitting and / or receiving one or more radar signals.

[0076] A frequency generator may include circuitry configured to generate a reference frequency signal having a reference frequency. This circuitry 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, a temperature-controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0077] The frequency generator can be configured to generate a reference frequency signal with a predetermined reference frequency. The predetermined reference frequency can be at least about 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz, 10 MHz, 1 GHz, 10 GHz, 100 GHz, 200 GHz, 300 GHz, or more. The predetermined reference frequency can be any frequency between about 1 Hz and about 300 GHz. In some cases, the predetermined reference frequency can be 1 MHz, 40 MHz, or 4 GHz. The predetermined reference frequency can be a frequency lower than the frequency of one or more output radar pulses and / or one or more input radar pulses.

[0078] In some cases, a frequency generator can be configured to generate a reference frequency signal with a non-predetermined reference frequency. For example, a reference frequency can be generated by adjusting (e.g., increasing and / or decreasing) a predetermined reference frequency in real time based on feedback data from a processor. The feedback data may include one or more signals derived in part from a second set of radar signals received by multiple radar modules. The frequency generator can be configured to use the feedback data from the processor to adjust, correct, and / or modify the reference frequency.

[0079] The frequency generator can communicate with each of multiple radar modules. The frequency generator can communicate with multiple radar modules via wired or wireless connections. Wired connections can be transmission media including coaxial cables, waveguides, or twisted-pair cables. Wireless connections can be local connections established using connection hardware built into and / or within the frequency generator and / or multiple radar modules. Connection hardware may include radio transmitters, radio receivers, antennas, and / or any other hardware configured to allow the frequency generator and / or multiple radar modules to process, transmit, or receive reference frequency signals.

[0080] The frequency generator can be configured to provide and / or distribute a reference frequency signal to each of a plurality of radar modules. The reference frequency signal can be distributed from the frequency generator to each of the plurality of radar modules via a wireless connection, a wired connection (e.g., coaxial cable, waveguide, and / or twisted-pair cable), or any other electrical or electromagnetic transmission medium disclosed herein. Each of the plurality of radar modules can use the reference frequency signal to generate a first set of radar signals.

[0081] In some cases, a frequency generator can be configured to generate multiple reference frequency signals, including one or more reference frequency signals. The one or more reference frequency signals may be the same or different. The frequency generator can be configured to provide and / or distribute the reference frequency signals from the multiple reference frequency signals to each of the multiple radar modules. In some cases, the multiple reference frequency signals may include one or more different reference frequency signals. In these cases, the frequency generator can be configured to provide and / or distribute different reference frequency signals to each of the multiple radar modules. One or more different reference frequency signals can be distributed from the frequency generator to each of the multiple radar modules via a wired or wireless connection. One or more different reference frequency signals can be used by each of the multiple radar modules to generate its corresponding first set of radar signals.

[0082] The system may include a timing module. The timing module may be configured to generate at least one of the following: (a) a shared clock signal or (b) multiple timing signals. In any embodiment described herein, the multiple timing signals may include a shared clock signal. In some cases, a timing signal among the multiple timing signals may correspond to (or be associated with) a shared clock signal. Alternatively, in any embodiment described herein, the shared clock signal and the multiple timing signals may be separate or different types of signals. The timing module may be configured to generate the shared clock signal and / or multiple 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 packaged crystal oscillator, a temperature-controlled crystal oscillator, a voltage-controlled crystal oscillator, a frequency-controlled crystal oscillator, a temperature-controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator).

[0083] The timing module can 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 from or independent of the one or more timing signals. The shared clock signal may be a clock signal shared with and / or available for use by one or more radar modules of the processor and / or the multiple radar modules. The shared clock signal may be a wave signal (e.g., a square wave) that oscillates between high and low states at a clock frequency. The clock frequency of the shared clock signal may or may not be a predetermined clock frequency.

[0084] In some cases, the shared clock signal may have a predetermined clock frequency. The predetermined clock frequency can be at least about 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz, 10 MHz, 1 GHz, 10 GHz, 100 GHz, 200 GHz, 300 GHz, or more. The predetermined clock frequency can be any frequency between about 1 Hz and about 300 GHz.

[0085] In some cases, the clock frequency of the shared clock signal may not be predetermined. For example, the shared clock signal can 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 multiple radar modules. The timing module can be configured to use the feedback data from the processor to adjust, correct, and / or modify the clock frequency of the shared clock signal.

[0086] A timing module can be configured to provide and / or distribute a shared clock signal to one or more radar modules. In some cases, each of the radar modules can use the shared clock signal to trigger and / or initiate the transmission of a first set of radar signals. The first set of radar signals can be transmitted at different times and / or at different pulse repetition frequencies. The pulse repetition frequency can be the rate at which a radar module repeatedly transmits one or more consecutive output radar pulses. In other cases, the shared clock signal can be used to chronologically sequence multiple input radar pulses received by each corresponding radar module in the multiple radar modules. Chronologically sequenced multiple input radar pulses can include marking and / or assigning one or more timestamps to each of the multiple input radar pulses received by each of the multiple radar modules. One or more timestamps can correspond to the time when each of the multiple radar modules receives one or more input radar pulses. One or more timestamps can be generated in part based on the shared clock signal.

[0087] A timing module can be configured to generate multiple timing signals, including one or more timing signals. In some cases, the multiple timing signals may be generated at least partially based on a shared clock signal or a multiple of a shared clock signal. In other cases, the multiple timing signals may be generated independently of the shared clock signal. In these cases, it is not necessary to use a shared clock signal or a multiple of a shared clock signal to generate the multiple timing signals. The multiple timing signals may include two or more timing signals for two or more radar modules in a plurality of radar modules. The two or more timing signals may be the same as each other or different.

[0088] Multiple timing signals generated by the timing module may include one or more different timing signals. In these cases, different radar modules among the multiple radar modules may receive different or identical timing signals. The one or more different timing signals may be substantially similar to each other or dissimilar to each other. The one or more different timing signals may include one or more wave signals (e.g., sine waves, square waves, triangle waves, or sawtooth waves) oscillating 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 adjusted in real time while one or more radar signals are being transmitted and / or received by multiple radar modules.

[0089] One or more different timing signals may have one or more predetermined clock frequencies. One or more predetermined clock frequencies may be at least about 1 Hz, 10 Hz, 100 Hz, 1 kHz, 10 kHz, 100 kHz, 1 MHz, 10 MHz, 1 GHz, 10 GHz, 100 GHz, 200 GHz, 300 GHz, or more. One or more predetermined clock frequencies may be any frequency between about 1 Hz and about 300 GHz.

[0090] In some cases, one or more different timing signals among a plurality of timing signals may have one or more non-predetermined clock frequencies. In these cases, the timing module can be configured to use feedback data from the processor to adjust, correct, and / or modify one or more clock frequencies of one or more different timing signals in real time. The feedback data may include one or more signals derived in part from a second set of radar signals received by a plurality of radar modules.

[0091] A timing module can be configured to generate one or more distinct timing signals by modifying at least a subset of multiple timing signals generated for multiple radar modules. In some cases, generating one or more distinct timing signals may include delaying a timing signal for one radar module relative to another timing signal used for another radar module. For example, the timing module can be configured to generate a first distinct timing signal that can be used to trigger a first radar module to transmit a first set of radar signals. The timing module can also be configured to generate a second distinct timing signal by implementing a time delay relative to the first timing signal. The second distinct timing signal can be used to trigger a second radar module to transmit another set of first radar signals. The first and second radar modules can be configured to transmit their respective first sets of radar signals at different times using the first and second distinct timing signals. In some cases, one or more distinct timing signals can be generated by modifying the clock frequency of one of the multiple timing signals. For example, distinct timing signals for a radar module can be generated by multiplying the clock frequency of another timing signal used for another radar module by a frequency multiplication factor. In these cases, the first radar module and the second radar module can be configured to transmit their respective first set of radar signals using a first different timing signal and a second different timing signal at different pulse repetition frequencies.

[0092] The timing module can communicate with the processor and each of the multiple radar modules. The timing module can communicate with the processor and each of the multiple radar modules via wired or wireless connections. The timing module can be configured to send multiple timing signals to the processor and / or multiple radar modules via coaxial cable, waveguide, twisted pair cable, or any other electrical or electromagnetic transmission medium disclosed herein.

[0093] A timing module can be configured to provide each of a plurality of radar modules with multiple timing signals, including one or more different timing signals. In some cases, one or more different timing signals can be used by each of the plurality of radar modules to trigger and / or initiate the transmission of a first set of radar signals. The first set of radar signals can be transmitted at different times and / or at different pulse repetition frequencies. In other cases, one or more different timing signals can be used to chronologically sequence multiple input radar pulses received by each corresponding radar module of the plurality of radar modules. Chronologically sequenced multiple input radar pulses can include marking and / or assigning one or more timestamps to each of the multiple input radar pulses received by each of the plurality of radar modules. One or more timestamps can correspond to the time when each of the plurality of radar modules receives one or more input radar pulses. One or more timestamps can be generated in part based on one or more different timing signals of the plurality of timing signals.

[0094] In some cases, the timing module can communicate 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 lidar unit. One or more additional sensors can communicate with the timing module via wired or wireless connections. In these cases, the timing module can be configured to send a shared clock signal and / or multiple timing signals to one or more additional sensors.

[0095] This system may include multiple radar modules. Each 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 can be any antenna capable of converting electrical signals into electromagnetic waves and transmitting those waves (dipole antenna, directional antenna, patch antenna, sector antenna, Yagi antenna, parabolic antenna, grid antenna). The receiving antenna can be any antenna capable of receiving electromagnetic waves and converting radio frequency radiated waves into electrical signals (dipole antenna, directional antenna, patch antenna, sector antenna, Yagi antenna, parabolic antenna, grid antenna). In some cases, a radar module may include one or more transmitting antennas and / or one or more receiving antennas. In some cases, a radar module may have multiple receive RX and / or transmit TX channels. The radar module can be used to detect one or more targets in the surrounding environment.

[0096] Multiple radar modules can communicate with a frequency generator and a timing module. These modules can communicate via wired or wireless connections. Each radar module can be configured to receive a reference frequency signal from the frequency generator. Each radar module can also be configured to receive a shared clock signal or at least one of a plurality of timing signals generated by the timing module. In some cases, the timing signals can be different timing signals as described elsewhere herein.

[0097] Each of the multiple radar modules can be configured to transmit a first set of radar signals comprising multiple output radar pulses. The multiple output radar pulses can include radar pulses. The radar pulses can be any electromagnetic wave or signal transmitted by the radar module in a frequency range from approximately 1 Hz to approximately 300 GHz. In some cases, the multiple output radar pulses may have frequencies of 24 GHz, 60 GHz, or 79 GHz.

[0098] Each of the multiple radar modules can be configured to generate a first set of radar signals in part based on a reference frequency signal generated by and received from the frequency generator. For example, each radar module can be configured to generate the first set of radar signals by multiplying the reference frequency associated with the reference frequency signal by one or more frequency multiplication factors.

[0099] In some cases, each of the multiple radar modules can be configured to generate a first set of radar signals corresponding to each radar module, in part, using a local oscillator. The local oscillator can be configured to multiply the reference frequency by one or more harmonic factors. One or more harmonic factors can be less than or equal to approximately 1,000,000, 100,000, 10,000, 9,000, 8,000, 7,000, 6,000, 5,000, 4,000, 3,000, 2,000, 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.75, 0.67, 0.5, 0.33, 0.25, 0.2, 0.1, or fewer. 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, 1000000, or more. The local oscillator can be an integer N phase-locked loop, a fractional N phase-locked loop, or a frequency multiplier.

[0100] In some cases, a local oscillator can be implemented on each of multiple radar modules. In these cases, the local oscillator can be implemented on the same board or chip as the radar transmitter and / or radar receiver in each of the multiple radar modules. In other cases, the local oscillator can be located remotely from the multiple radar modules and communicate with the multiple radar modules via wired or wireless connections. The local oscillator can be configured to operate as a common local oscillator for the multiple radar modules. For example, a local oscillator implemented on one of the multiple radar modules can be configured to operate as the local oscillator for another of the multiple radar modules.

[0101] Multiple radar modules can be configured to modulate a first set of radar signals and / or multiple output radar pulses before transmitting the first set of radar signals and / or multiple output radar pulses. Modulation may include partially altering one or more properties of the first set of radar signals (e.g., frequency, phase, delay, and / or amplitude) by using a modulating signal. In some cases, the modulating signal may be a reference frequency signal, a shared clock signal, and / or a timing signal among multiple timing signals generated by a timing module. In other cases, the modulating 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 each of the multiple radar modules. Modulation may be performed using one or more modulation schemes. One or more modulation schemes may include amplitude modulation, double-sideband modulation, single-sideband modulation, vestigial sideband modulation, quadrature amplitude modulation, angle modulation, frequency modulation, phase modulation, transposition 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 shift keying, Gaussian minimum shift keying, and / or any combination thereof. In some cases, one or more modulation schemes may implement one or more spread spectrum techniques, such as linear frequency modulation spread spectrum, direct sequence spread spectrum, frequency hopping spread spectrum, and / or time hopping spread spectrum. In other cases, 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)).

[0102] Multiple radar modules can be configured to control the timing and / or transmission rate of a first set of radar signals, partially based on a shared clock signal or multiple timing signals. The shared clock signal and / or multiple timing signals can instruct each of the multiple radar modules when to transmit its respective first set of radar signals, comprising multiple output radar pulses. The shared clock signal and / or multiple timing signals can instruct each of the multiple radar modules at the frequency for transmitting its corresponding first set of radar signals, comprising multiple output radar pulses. In some cases, each of the multiple radar modules can use a different timing signal from the shared clock signal or multiple timing signals to trigger the transmission of 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 can use the shared clock signal or multiple timing signals to chronologically sequence multiple input radar pulses received by each respective radar module. Sequencing the multiple output radar pulses can include assigning one or more timestamps to each of the multiple input radar pulses received by each of the multiple radar modules. One or more timestamps can correspond to the time when one or more input radar pulses were received by each of the multiple radar modules. One or more timestamps may be generated in part based on a shared clock signal and / or a timing signal from multiple timing signals.

[0103] In some cases, multiple radar modules can be configured to directly trigger the transmission of multiple output radar pulses using a shared clock signal or more timing signals generated by a timing module. In other cases, each of the multiple radar modules can be configured to (i) modify one or more timing signals received from the timing module, and (ii) trigger the transmission of multiple output radar pulses using multiple modified timing signals generated at each of the multiple radar modules. The multiple modified timing signals can be generated in part by (a) multiplying the frequency of the shared clock signal by one or more frequency multiplication factors and / or by (b) implementing a programmable time delay relative to the shared clock signal. One or more harmonic factors may be less than or equal to approximately 1,000,000, 100,000, 10,000, 9,000, 8,000, 7,000, 6,000, 5,000, 4,000, 3,000, 2,000, 1,000, 900, 800, 700, 600, 500, 400, 300, 200, 100, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.75, 0.67, 0.5, 0.33, 0.25, 0.2, 0.1, or less. In some cases, one or more harmonic 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, 1000000, or more. The programmable time delay can be a 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 a shared clock signal and / or another timing signal among multiple timing signals generated by the timing module. In some cases, the programmable time delay can be adjusted by each of the multiple radar modules by modifying and / or delaying a timing signal received by one of the multiple radar modules relative to a shared clock signal and / or another timing signal among multiple timing signals generated by the timing module.

[0104] Each of the multiple radar modules can be configured to receive a second set of radar signals, which includes multiple input radar pulses reflected from the surrounding environment. The multiple input radar pulses can include radar pulses. The radar pulses can be any electromagnetic wave or signal received by the radar module in a frequency range of approximately 1 Hz to approximately 300 GHz. In some cases, the second set of radar signals can be a subset of the first set of radar signals. Each of the multiple radar modules can be configured to receive a subset of multiple output radar pulses emitted by a transmitting antenna and reflected back to a receiving antenna after interacting with an external target in the surrounding environment. In some embodiments, one or more receiving antennas can be used to receive a subset of multiple output radar pulses emitted by one or more transmitting antennas and reflected back to each of the multiple radar modules after interacting with an external target in the surrounding environment. The second set of radar signals received by the multiple radar modules can carry information about the distance or range of the target relative to a vehicle. This information about the distance or range of the target relative to a vehicle can be based on the round-trip time delay of one or more input radar pulses, or the phase of one or more input radar pulses. The round-trip time delay can provide spatial resolution relative to the system bandwidth.

[0105] In some cases, a first set of radar signals can be transmitted by a first radar module, and a second set of radar signals can be received at a second radar module. The second radar module can be another radar module, different from the first radar module, among a plurality of radar modules. The second radar module can communicate with and / or be operatively coupled to the first radar module. The second set of radar signals can be associated with the first set of radar signals. The second set of radar signals can correspond to a subset of the first set of radar signals transmitted by the first radar module and reflected from the surrounding environment.

[0106] In some cases, the second radar module can be configured to preprocess the second set of radar signals before providing them to the processor for coherent combination with an additional second set of radar signals received at the third radar module. The additional second set of radar signals may be a different set of second 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 attributes of the second set of radar signals (e.g., frequency, phase, delay, and / or amplitude). 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-carrying electronic signals) from the second set of radar signals and / or multiple input radar pulses of the second set of radar signals.

[0107] The phase of one or more input radar pulses can provide spatial resolution relative to the carrier frequency of a first and / or second set of radar signals. In some cases, the carrier frequency can be 79 GHz. Phase information may contain ambiguities, which can be resolved using the phase difference between two or more input radar pulses received at different spatial points. For example, two or more input radar pulses may be received at different transmitting and / or receiving antennas. In some cases, two or more input radar pulses may be received at different vehicle locations and / or orientations.

[0108] In some cases, each of multiple radar modules can be configured to independently transmit, receive, and process a second set of radar signals and / or multiple input radar pulses received separately by each of the multiple radar modules. Processing the second set of radar signals and / or multiple input radar pulses may include demodulating the second set of radar signals and / or multiple input radar pulses. Demodulation may include extracting one or more signals (e.g., electronic signals carrying information) from the second set of radar signals and / or multiple input radar pulses. In some cases, a direct conversion receiver can be used to perform demodulation. The direct conversion receiver can use synchronization detection driven by a local oscillator whose frequency is the same as or very close to the frequency of the input radar pulses to demodulate the input radar pulses. In these cases, the second set of radar signals and / or input radar pulses can be down-mixed to baseband signals. The baseband signals can be complex baseband signals with real and imaginary parts. Complex baseband signals may include in-phase signals and quadrature-phase signals. Multiple radar modules can be configured to send complex baseband signals to a processor for signal aggregation and / or signal processing. Complex baseband signals can be sent to the processor in analog or digital form. Complex baseband signals can be processed in analog or digital form by multiple radar modules and / or processors. In other cases, a superheterodyne receiver can be used to perform demodulation. A superheterodyne receiver can demodulate the input radar pulse by using a mixer to convert the frequency of the input radar pulse to an intermediate frequency (IF). In these cases, demodulating the first set of radar signals may include shifting a second set of radar signals to the IF. The IF can be generated by mixing the frequency of the second set of radar signals with a reference frequency or the frequency of a signal generated by a local oscillator of each of the multiple radar modules. In some cases, the input radar pulse can be down-mixed to a non-zero IF. In these cases, multiple radar modules can be configured to send the down-mixed non-zero IF input radar pulse to a processor for signal aggregation and / or signal processing. The down-mixed non-zero IF input radar pulse can be sent to the processor in analog or digital form. The down-mixed non-zero IF input radar pulse can be processed in analog or digital form by multiple radar modules and / or processors.

[0109] 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 from a plurality of radar modules, respectively. The processor may include a computer processor, an application-specific integrated circuit, a graphics processing unit, or a field-programmable gate array. Aggregating the second set of radar signals may include collecting one or more of a plurality of input radar pulses received by at least a subset of the plurality of radar modules. Processing the second set of radar signals may include adding two or more of the plurality of input radar pulses, coherently combining two or more of the plurality of input radar pulses based on one or more attributes of the radar signals (e.g., frequency, phase, delay, and / or amplitude), calculating one or more attributes or features of a target in the surrounding environment using data derived from two or more of the plurality of input radar pulses, and / or generating an occupancy grid.

[0110] The processor can be configured to process a second set of radar signals received from multiple radar modules by coherently combining at least a subset of multiple input radar pulses. The coherent combination of the multiple input radar pulses may include adding two or more input radar pulses together 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 input radar pulses in the second set of radar signals. In any embodiment described herein, the two or more input radar pulses used to determine the phase difference may correspond to two or more input radar pulses that (i) are received by different receiving antennas within a radar module, (ii) are received by different radar modules among the multiple radar modules, and / or (iii) are received when the vehicle is in different spatial locations or orientations. For example, the two or more input radar pulses may be received by a first radar module on one side of the vehicle and a second radar module on the other side of the vehicle. Alternatively, two or more input radar pulses may include a first input radar pulse received by the first radar module when the vehicle is in a first spatial position and / or a first orientation, and a second input radar pulse received by the first radar module when the vehicle is in a second spatial position and / or a second orientation. Timestamp information may include information about when one or more of the input radar pulses were received by each of the multiple radar modules. In some cases, timestamp information may include information about when one or more of the output radar pulses were transmitted by each of the multiple radar modules. The timestamp information may be generated by a processor.

[0111] The processor can be configured to coherently combine a subset of multiple input radar pulses received by a subset of multiple radar modules. Coherently combining the subset of multiple input radar pulses may include summing two or more complex baseband signals derived from the subset of multiple input 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 using a relative phase shift or a relative frequency shift. The relative phase shift may be a measurement of the phase difference between two or more input radar pulses in the subset of multiple input radar pulses received by the subset of multiple radar modules. In some cases, the relative phase shift may be a measurement of the phase difference between a first set of radar signals transmitted by a transmitting antenna and a second set of radar signals received by a receiving antenna. The relative frequency shift may be a measurement of the frequency difference between two or more input radar pulses in the subset of multiple input radar pulses received by the subset of multiple radar modules.

[0112] The relative phase shift and / or relative frequency shift can be a function of one or more relative spatial positions and / or one or more relative spatial orientations of multiple radar modules. For example, in some cases, the relative phase shift and / or relative frequency shift can be a function of one or more relative fixed distances between two or more of the multiple radar modules. One or more relative fixed distances can be at least about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 10 cm, 100 cm, or 1 meter in any direction. One or more relative fixed distances can have a tolerance based on a predefined threshold. The predefined threshold can be associated with a percentage of the wavelength of the output radar pulse or the input radar pulse, or with a percentage of a fraction of the wavelength of the output radar pulse or the input radar pulse. In other cases, the relative phase shift and / or relative frequency shift can be a function of the angle between a first alignment direction of one radar module and a second alignment direction of another radar module among the multiple radar modules. The angle between the first alignment direction and the second alignment direction can range from approximately 0 degrees to approximately 360 degrees in the XY plane, XZ plane and / or YZ plane. The angle between the first alignment direction and the second alignment direction can be at least approximately 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 value between 0 and 360 degrees. In some cases, the relative spatial positions and / or relative spatial orientations of multiple radar modules can be known a priori. In other cases, the relative spatial positions and / or relative spatial orientations of multiple radar modules can be estimated using online external calibration algorithms.

[0113] 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 different from the first radar module among a plurality of radar modules. 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 preprocess the second set of radar signals before providing them to a processor for coherent combination with one or more radar signals received at a third radar module. The third radar module may be different from the second radar module. The processor may be configured to coherently combine (i) the preprocessed second set of radar signals with (ii) one or more different radar signals received by a plurality of radar modules or a subset thereof.

[0114] The processor can be configured to calculate one or more attributes or characteristics of a target in the surrounding environment using data derived from two or more radar signals. Target attributes or characteristics may include the target's shape, size, radar cross-section, angle of arrival, position, orientation, velocity, and / or acceleration relative to a vehicle. The two or more radar signals may include a subset of multiple input radar pulses received by multiple radar modules. Two or more radar signals can be derived by applying phase shift or frequency shift to the subset of multiple input radar pulses received by multiple radar modules.

[0115] The processor can be configured to calculate the angle of arrival (Angle of Arrival) of one or more targets near a vehicle using raw data. The raw data may include unprocessed data associated with one or more input radar pulses from a plurality of input 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 offset. The Angle of Arrival can be calculated in part based on the relationship between the Angle of Arrival and the phase difference measured between two receiving antennas of a plurality of radar modules. This relationship can be given by: in θ λ is the angle of arrival, L is the distance between the two receiving antennas, and λ is the wavelength associated with the radar pulse transmitted and / or received by the radar module. It is the phase difference measured between the two receiving antennas.

[0116] The processor can be configured to calculate the speed of one or more targets near the vehicle using raw data. The speed can be calculated in part based on the relationship between the speed and the phase difference measured between two input radar pulses received by the receiving antenna of the radar module. This relationship can be given by the following equation: in v It's speed. λ It is the wavelength associated with the radar pulse received by the radar module. T is the phase difference measured between two input radar pulses received by the receiving antenna of the radar module. C It is the time between consecutive input radar pulses received by the receiving antenna of the radar module.

[0117] In some cases, the processor can be configured to modify one or more of a plurality of input radar pulses before calculating the properties or characteristics of the target. For example, the processor can be configured to (i) modify one or more input radar pulses by applying phase shift or frequency shift, and / or (ii) coherently combine two or more input radar pulses before calculating the target’s angle of arrival or velocity.

[0118] In some cases, each of the processor and / or multiple radar modules can be configured to generate an occupancy grid using at least phase information. The occupancy grid can be a visual representation of the surrounding environment in which the radar system operates. The occupancy grid can indicate where one or more objects are detected in space relative to the position and / or orientation of a vehicle. The occupancy grid can indicate the presence of one or more objects in the surrounding environment and near the vehicle. The occupancy grid can show the position and / or orientation of one or more objects relative to the vehicle. The vehicle can be stationary or moving. In some cases, the occupancy grid can 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 fixed distances between two or more of the multiple radar modules. One or more relative fixed distances may be at least approximately 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 10 cm, 100 cm, or 1 meter in any direction. One or more relative fixed distances may have a tolerance based on a predefined threshold. The predefined threshold may be associated with a percentage of the wavelength of the output radar pulse or the input radar pulse, or with a fraction of the wavelength of the output radar pulse or the input radar pulse. The relative spatial orientation of the multiple radar modules may include an angle between a first alignment direction for one of the multiple radar modules and a second alignment direction for another of the multiple radar modules. The angle between the first alignment direction and the second alignment direction can range from approximately 0 degrees to approximately 360 degrees in the XY plane, XZ plane and / or YZ plane. The angle between the first alignment direction and the second alignment direction 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 value between 0 degrees and 360 degrees.

[0120] In some cases, each of the processor and / or multiple radar modules can be configured to generate one or more occupancy grids using round-trip delay information associated with a second set of radar signals and / or multiple input radar pulses. In these cases, each of the processor and / or multiple radar modules can be configured to store phase information associated with the second set of radar signals and / or multiple input radar pulses after generating one or more occupancy grids. Each of the processor and / or multiple radar modules can be configured to combine one or more occupancy grids generated by each of the multiple radar modules into a global 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 input radar pulses received by each of the multiple radar modules.

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

[0122] In some cases, the processor can be configured to use a perception algorithm to determine one or more features or attributes of a target near the vehicle. The perception algorithm can be configured to (i) process one or more complex baseband signals derived from a subset of multiple input radar pulses and / or (ii) combine two or more complex baseband signals derived from a subset of multiple input radar pulses. The perception algorithm can be configured to calculate one or more features of a target in the surrounding environment (e.g., size, shape, position, orientation, angle of arrival, or material properties such as reflectivity or radar cross-section) or one or more kinematic attributes (e.g., velocity or acceleration).

[0123] The perception algorithm can be configured to calculate and / or derive one or more features or one or more kinematic attributes of a target by analyzing and / or interpreting radar images generated by a processor. The radar images can be generated by the processor, in part, by aggregating and / or processing at least a subset of a second set of radar signals received by at least a subset of multiple radar modules. The radar images can be occupies a grid and / or a local map. The local map can be a visual representation of the surrounding environment in which vehicles can be maneuvered. The local map can include data relating to the vehicle's position, orientation, attitude, and / or kinematic attributes as the vehicle moves through the surrounding environment. The local map can also include data relating to the position, orientation, attitude, and / or kinematic attributes of one or more targets in the surrounding environment. The local map can visually represent the position, orientation, and / or motion of a vehicle relative to one or more targets in the surrounding environment.

[0124] Perception algorithms can be configured to use output information computed and / or generated by a processor (e.g., attributes of the occupying grid and / or the target, such as the target's velocity or angle of arrival) to calculate higher-order properties of the target. For example, a perception algorithm can be configured to use the occupying grid and the target's velocity and / or the target's angle of arrival to calculate the target's shape, size, material properties (e.g., reflectivity), and / or radar cross-section. In some cases, a perception algorithm can be configured to use one or more attributes or features of the occupying grid and / or the target to generate one or more decisions about how to correct and / or adjust the vehicle's path as it passes through its surroundings to avoid targets that may obstruct or partially obstruct the vehicle's path.

[0125] The perception algorithm can be configured to classify one or more targets detected by the system. For example, the perception algorithm can be configured to determine whether one or more targets are moving or stationary. Alternatively, the perception algorithm can be configured to determine whether one or more targets obstruct or partially obstruct the movement path of vehicles traveling through the surrounding environment.

[0126] Perception algorithms can be configured to track one or more features of a target (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). Tracking one or more features and / or one or more kinematic properties of a target may include measuring changes in one or more features and / or one or more kinematic properties over a predetermined time period. In some cases, perception algorithms can be configured to track the position and / or movement of one or more targets near a vehicle as the vehicle moves through its surroundings.

[0127] The perception algorithm can be configured to refine measurements and / or estimates of target features or attributes (e.g., target velocity and / or angle of arrival) previously calculated by the processor. Refining the measurements or estimates of target features or attributes may include updating the measurements or estimates based on one or more of a plurality of input radar pulses received by a plurality of radar modules. In some cases, refining the measurements or estimates of target features or attributes may include updating the measurements or estimates based on feedback data. The feedback data may include one or more signals that are partially derived by the processor from a second set of radar signals received from the plurality of radar modules.

[0128] In some cases, the processor can be configured to process a second set of radar signals received from 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 of the multiple input radar pulses were received by each of the multiple radar modules. In some cases, the timestamp information may include information about when one or more of the multiple output radar pulses were emitted by each of the multiple radar modules. The timestamp information may be generated by the processor or a timestamp generator.

[0129] In some cases, multiple radar modules can be configured to forward multiple input radar pulses to a processor for signal aggregation (e.g., aggregation of multiple input radar pulses and / or aggregation of a second set of radar signals received by each of the multiple radar modules). In these cases, the processor can be configured to generate timestamps for the multiple input radar pulses received by each of the multiple radar modules using a shared clock signal generated by a timing module. The timestamps generated by the processor can be generated relative to one or more ticks of the shared clock signal. In some cases, the processor can be configured to use the timestamps generated by the processor to chronologically sequence the multiple input 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 mark at least a subset of multiple input radar pulses received by each of the multiple radar modules with a timestamp relative to a shared clock signal or a 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 input radar pulses received by each of the multiple radar modules before the multiple radar modules forward the multiple input radar pulses to the processor for signal aggregation. In these cases, the processor may be configured to use the timestamps generated by the timestamp generator to chronologically order the multiple input radar pulses received by each of the multiple radar modules.

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

[0132] In some cases, multiple radar modules can be configured to apply corrections to a second set of radar signals based on estimated calibration parameters. Alternatively, multiple radar modules can be configured to provide the processor with estimated calibration parameters for the second set of radar signals without applying any corrections. In these cases, the processor can be configured to modify and / or correct the second set of radar signals using the estimated calibration parameters received from the multiple radar modules. The estimated calibration parameters can be derived in part from one or more variations in phase, gain, delay, frequency, and / or offset observed between two or more input radar pulses. In some cases, the estimated calibration parameters can be derived in part based on the relative spatial position or relative spatial orientation of the multiple radar modules.

[0133] In some cases, multiple radar modules can be configured to calibrate a second set of radar signals using a known object visible to each of the multiple radar modules, in order to identify phase, gain, delay, frequency, or offset differences between two or more input radar pulses in the second set of radar signals received by each of the multiple radar modules. Each radar module can use a calibration process. The calibration process may include factory calibration, laboratory calibration, and / or online (e.g., real-time) calibration algorithms. The calibration process for one of the multiple radar modules may or may not be substantially similar to the calibration process for another of the multiple radar modules. The calibration process for one of the multiple radar modules may or may not differ from the calibration process for another of the multiple radar modules.

[0134] Figure 2A system configured to process radar data from a subset of multiple radar modules 130-1, 130-2, and 130-3 is illustrated. The multiple radar modules 130-1, 130-2, and 130-3 can be mounted on any side of a vehicle 104, or on one or more sides of the vehicle 104 (e.g., the front, rear, lateral, top, or bottom side of the vehicle). The front side of the vehicle can be the side facing the general direction of travel of the vehicle, while the rear (or back) side can be the side not facing the general direction of travel of the vehicle. The rear side can be opposite to the front side of the vehicle. The front side of the vehicle can point in the forward direction of travel of the vehicle. The rear side of the vehicle can point in the backward direction of travel of the vehicle (e.g., reversing). The lateral side can include the left and / or right side of the vehicle. The vehicle can be configured to move and / or translate orthogonally to the lateral sides of the vehicle. In some cases, multiple radar modules 130-1, 130-2, and 130-3 may be mounted between two adjacent sides of 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, to the side of, above, below, or near 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 side or different sides of 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 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 directed to detect one or more targets 102 in front of, behind, to the side of, above and / or below the vehicle 104.

[0135] like Figure 2As shown, multiple radar modules 130-1, 130-2, and 130-3 can be configured to transmit a first set of radar signals, including multiple output radar pulses 105-1, 105-2, and 105-3, based in part on a reference frequency signal and a shared clock signal, and at least one of a plurality of timing signals. The reference frequency signal can be generated by a frequency generator 110, which is operatively coupled to and communicates with each of the multiple radar modules. The shared clock signal and the timing signals from the plurality of timing signals can be generated by a timing module 120, which is operatively coupled to and communicates with each of the multiple radar modules. The multiple radar modules 130-1, 130-2, and 130-3 can be configured to receive a second set of radar signals, including multiple input radar pulses 106-1, 106-2, and 106-3. The multiple radar modules 130-1, 130-2, and 130-3 can be operatively coupled to and communicate with a processor 140. Multiple radar modules 130-1, 130-2, and 130-3 can be configured to provide a second set of radar signals and / or multiple input radar pulses 106-1, 106-2, and 106-3 received respectively by each of the multiple radar modules to processor 140. Processor 140 can be configured to aggregate and / or process the second set of radar signals received from the multiple radar modules, respectively, by 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, through (a) coherently combining the second set of radar signals, (b) calculating target attributes, or (c) generating an occupancy grid or radar image. In some cases, processor 140 can be configured to coherently combine subsets 106-1 and 106-2 of the multiple input radar pulses received by subsets 130-1 and 130-2 of the multiple radar modules by summing one or more complex signals having relative phase shifts or relative frequency shifts. In some cases, multiple radar modules 130-1, 130-2, and 130-3 can be configured to calibrate a second set of radar signals using one or more visible objects (e.g., target 102) to identify the phase difference between two or more input 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, processor 140 can be operatively coupled to and communicate with frequency generator 110 and timing module 120. In these cases, processor 140 can be configured to provide feedback data to frequency generator 110 and timing module 120. Frequency generator 110 and timing module 120 can be configured to receive feedback data from 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 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 timing signal among a reference frequency signal, a shared clock signal, and / or multiple timing signals.

[0136] Another aspect of this 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 one or more timing signals at the plurality of radar modules. The method may further include transmitting a first set of radar signals, comprising a plurality of output radar pulses, using the plurality of radar modules, at least in part based on (a) the reference frequency signal and (b) one or more timing signals. The method may further include receiving a second set of radar signals at the plurality of radar modules, the second set of radar signals comprising a plurality of input radar pulses reflected from at least one object in the surrounding environment. In some cases, the method may further include using a processor that aggregates and / or processes second-group radar signals received from multiple radar modules, using at least (i) phase information associated with the second group of radar signals and (ii) timestamp information associated with the second group of radar signals, by (a) coherently combining the second group of radar signals, (b) calculating the attributes of the target, or (c) generating an occupying grid or radar image.

[0137] Computer System Another aspect of this disclosure provides a computer system that is programmed or otherwise configured to implement the methods of this disclosure. Figure 3A computer system 301 is shown, which is programmed or otherwise configured to implement a method for processing radar data. The computer system 301 may be configured to generate a reference frequency signal having a reference frequency using a frequency generator; generate one or more timing signals using a timing module; provide the reference frequency signal and one or more timing signals to multiple radar modules; transmit a first set of radar signals comprising multiple output radar pulses using the multiple radar modules, based at least in part on (a) the reference frequency signal and (b) one or more timing signals; and receive a second set of radar signals at the multiple radar modules, the second set of radar signals comprising multiple input 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 from the multiple radar modules, respectively, by 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, through (a) coherently combining the second set of radar signals, (b) calculating target attributes, or (c) generating an occupancy grid or radar image. Computer system 301 can be a user's electronic device or a computer system located remotely relative to the electronic device. The electronic device can be a mobile electronic device.

[0138] Computer system 301 may include a central processing unit (CPU, also referred to herein as a “processor” and “computer processor”) 305, which may be a single-core or multi-core processor, or multiple processors for parallel processing. Computer system 301 also includes memory or memory location 310 (e.g., random access memory, read-only memory, flash memory), electronic storage unit 315 (e.g., hard disk), communication interface 320 for communicating with one or more other systems (e.g., network adapter), and peripheral devices 325 such as cache, other memory, data storage devices, and / or electronic display adapters. Memory 310, storage unit 315, interface 320, and peripheral devices 325 communicate with CPU 305 via a communication bus (solid line) such as a motherboard. Storage unit 315 may be a data storage unit (or data repository) for storing data. Computer system 301 may be operatively coupled to computer network (“network”) 330 by means of communication interface 320. Network 330 may be the Internet, the Internet of Things, and / or an extranet, or an intranet and / or extranet communicating with the Internet. In some cases, network 330 is a telecommunications and / or data network. Network 330 may include one or more computer servers, which can support distributed computing, such as cloud computing. In some cases, with the aid of computer system 301, network 330 can implement a peer-to-peer network, which enables devices coupled to computer system 301 to operate as clients or servers.

[0139] CPU 305 can execute a series of machine-readable instructions, which can be embodied in a program or software. The instructions can be stored in a memory location, such as memory 310. The instructions can be directed to CPU 305, which can then be programmed or otherwise configured to implement the methods of this disclosure. Examples of operations performed by CPU 305 can include reading, decoding, executing, and writing back.

[0140] CPU 305 may be part of a circuit, such as an integrated circuit. One or more other components of system 301 may be included in this circuit. In some cases, the circuit is an application-specific integrated circuit (ASIC).

[0141] Storage unit 315 may store files, such as drivers, libraries, and saved programs. Storage unit 315 may store user data, such as user preferences and user programs. In some cases, computer system 301 may include one or more additional data storage units located outside of computer system 301, such as on a remote server that communicates with computer system 301 via an intranet or the Internet.

[0142] Computer system 301 can communicate with one or more remote computer systems via network 330. For example, computer system 301 can communicate with a remote computer system belonging to a user (e.g., an end user, consumer, driver, vehicle operator, etc.). Examples of remote computer systems include personal computers (e.g., portable PCs), tablet PCs (e.g., Apple® iPad, Samsung® Galaxy Tab), telephones, smartphones (e.g., Apple® iPhone, Android-enabled devices, Blackberry®), or personal digital assistants. Users can access computer system 301 via network 330.

[0143] The methods described herein can be implemented using machine-executable code (e.g., a computer processor) stored in an electronic storage location (e.g., memory 310 or electronic storage unit 315) of the computer system 301. The machine-executable code or machine-readable code can be provided in software form. During use, the code can be executed by the processor 305. In some cases, the code can be retrieved from storage unit 315 and stored in memory 310 for rapid access by the processor 305. In some cases, electronic storage unit 315 can be omitted, and the machine-executable instructions can be stored in memory 310.

[0144] The code can be pre-compiled and configured for use with machines having processors suitable for executing it, or it can be compiled during runtime. The code can be provided in the form of a programming language, which can be selected to enable the code to be executed either pre-compiled or as-compiled.

[0145] Several aspects of the systems and methods provided herein (such as computer system 301) can be embodied in a programmable manner. Various aspects of the technology can be considered as “products” or “articles of manufacture” typically presented in the form of machine (or processor) executable code and / or associated data carried or embodied in a machine-readable medium. Machine-executable code can be stored in electronic storage units such as memory (e.g., read-only memory, random access memory, flash memory) or hard disks. “Storage” media can include any or all tangible memory of computers, processors, etc., or related modules thereof, such as various semiconductor memories, tape drives, disk drives, etc., which can provide non-transitory storage for software programming at any time. All or part of the software can sometimes be communicated via the Internet or other telecommunications networks. For example, such communication can enable the loading of software from one computer or processor to another, such as from a management server or host computer platform to an application server. Therefore, another type of medium capable of carrying software elements includes light waves, radio waves, and electromagnetic waves used through physical interfaces between local devices, through wired and fiber optic terrestrial networks, and on various air links. Physical elements carrying such waves, such as wired or wireless links, optical links, etc., can also be considered as media carrying software. As used herein, unless limited to non-transitory, tangible "storage" media, the term "readable medium" for a computer or machine refers to any medium involved in providing instructions to a processor for execution.

[0146] Therefore, machine-readable media (such as computer-executable code) can take many forms, including but not limited to tangible storage media, carrier media, or physical transmission media. Non-volatile storage media include (e.g., optical discs or disks, such as any storage device in any computer, etc.) such as those used to implement databases as shown in the accompanying figures. Volatile storage media include dynamic memory, such as the main memory of a computer platform. Tangible transmission media include coaxial cables; copper wires and optical fibers, including wires that form buses within a computer system. Carrier transmission media can take the form of electrical or electromagnetic signals, or sound or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Therefore, common forms of computer-readable media include, for example: floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, DVDs or DVD-ROMs, any other optical media, punched card tapes, any other physical storage media with punched patterns, RAM, ROM, PROM and EPROM, FLASH-EPROM, any other memory chips or cartridges, carrier waves for transmitting data or instructions, cables or links for transmitting such carrier waves, or any other medium from which a computer can read programming code and / or data. Many of these forms of computer-readable media can participate in delivering one or more sequences of one or more instructions to a processor for execution.

[0147] Computer system 301 may include or communicate with an electronic display 335, the electronic display 335 including a user interface (UI) 340 for providing, for example, a portal for monitoring one or more objects, obstacles, and / or targets detected by a radar system. In some cases, the portal may be used to present, view, monitor, and / or manipulate one or more occupancy grid maps generated by a processor and / or multiple radar modules. The portal may be provided via an application programming interface (API). Users or entities may also interact with various elements in the portal through the UI. Examples of UIs include, but are not limited to, graphical user interfaces (GUIs) and web-based user interfaces.

[0148] The methods and systems disclosed herein can be implemented by one or more algorithms. The algorithms can be implemented in software after execution by a central processing unit 305. The algorithm can be configured to generate a reference frequency signal with a reference frequency using a frequency generator; generate one or more timing signals using a timing module; provide the reference frequency signal and one or more timing signals to multiple radar modules; transmit a first set of radar signals comprising multiple output radar pulses using multiple radar modules, based at least in part on (a) the reference frequency signal and (b) one or more timing signals; and receive a second set of radar signals at multiple radar modules, the second set of radar signals comprising multiple input radar pulses reflected from at least one object in the surrounding environment. In some cases, the algorithm can be configured to aggregate and / or process the second set of radar signals received from multiple radar modules, respectively, by 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, through (a) coherently combining the second set of radar signals, (b) calculating target attributes, or (c) generating an occupancy grid or radar image.

[0149] While preferred embodiments of the 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. The invention is not intended to be limited to the specific examples provided herein. Although the invention has been described with reference to the foregoing description, the description and illustration of the embodiments herein are not intended to be construed in a limiting sense. Many variations, alterations, and substitutions will now occur to those skilled in the art without departing from the invention. Furthermore, it should be understood that all aspects of the invention are not limited to the specific descriptions, configurations, or relative proportions set forth herein, which depend on a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. Therefore, it is contemplated that the invention should also cover any such alternatives, modifications, variations, or equivalents. The appended claims are intended to define the scope of the invention and thus cover the methods and structures and their equivalents within the scope of these claims.

[0150] Various aspects of this disclosure may be implemented in one or more of the following embodiments: Project 1) A system for processing radar data, comprising: 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 communicating with the frequency generator and the timing module, wherein 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 comprising a plurality of output 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 comprising a plurality of input radar pulses reflected from at least one object in the surrounding environment.

[0151] Project 2) The system according to Project 1) further includes: A processor configured to process the second set of radar signals received from the plurality of radar modules, respectively, by 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, through (a) coherently combining the second set of radar signals, (b) calculating the attributes of the target, or (c) generating an occupied grid or radar image.

[0152] Project 3) The system according to Project 1) or 2) further includes at least one housing, the at least one housing including the frequency generator, the timing module and the plurality of radar modules, wherein the at least one housing is capable of being mounted on a vehicle.

[0153] Project 4) The system according to Project 1), wherein the frequency generator includes circuitry configured to generate wave signals including sine waves, square waves, triangle waves, or sawtooth waves, the signal frequency of the wave signals being predetermined or adjustable in real time, wherein the circuitry includes a crystal oscillator, a simple packaged crystal oscillator, a temperature-controlled crystal oscillator, a voltage-controlled crystal oscillator, a frequency-controlled crystal oscillator, a temperature-controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0154] Project 5) The system according to Project 1), wherein the plurality of radar modules are configured to generate the first set of radar signals using a local oscillator, the local oscillator being configured to multiply the reference frequency by one or more frequency multiplication factors, wherein the local oscillator includes an integer N phase-locked loop, a fractional N phase-locked loop, or a frequency multiplier.

[0155] Project 6) The system according to Project 5) wherein the local oscillator is implemented on a radar module among the plurality of radar modules, and wherein the radar module includes a radar transmitter and a radar receiver.

[0156] Project 7) The system according to Project 2) wherein the timing module is configured to send one or more timing signals to the plurality of radar modules or the processor, wherein the one or more timing signals include a shared clock signal generated based on an absolute time base or a local time base.

[0157] Item 8) The system according to Item 2) wherein the timing module is configured to send one or more timing signals to the plurality of radar modules or the processor, wherein the one or more timing signals include one or more different timing signals for the processor or one or more of the plurality of radar modules.

[0158] Project 9) The system according to Project 1), wherein the plurality of radar modules are configured to trigger the transmission of the first set of radar signals at least in part based on the one or more timing signals.

[0159] Project 10) The system according to Project 2) wherein the radar module of the plurality of radar modules includes a timestamp generator configured to mark at least a subset of the plurality of input radar pulses received by the radar module with one or more timestamps relative to the one or more timing signals before forwarding the plurality of input radar pulses to the processor.

[0160] Project 11) The system according to Project 2), wherein the processor is configured to use the one or more timing signals generated by the timing module to (i) generate one or more timestamps for the plurality of input radar pulses received by the plurality of radar modules, and (ii) sort the plurality of input radar pulses received by the plurality of radar modules in chronological order.

[0161] Item 12) The system according to Item 10) wherein the processor is configured to use the one or more timestamps generated by the timestamp generator to sort the plurality of input radar pulses received from the plurality of radar modules in chronological order.

[0162] Item 13) The system according to Item 8) wherein the timing module is configured to modify the one or more timing signals of the one or more radar modules among the plurality of radar modules before sending the one or more different timing signals to one or more of the plurality of radar modules.

[0163] Item 14) The system according to Item 7) wherein a radar module of the plurality of radar modules is configured to (i) modify one or more timing signals received from the timing module, and (ii) trigger the transmission of the plurality of output radar pulses using one or more modified timing signals generated at the radar module.

[0164] Item 15) The system according to Item 14) wherein the one or more modified timing signals are generated at least in part by (a) multiplying the frequency of the shared clock signal by one or more multiplication factors or by (b) implementing a programmable time delay relative to the shared clock signal.

[0165] Project 16) The system according to Project 2) wherein the processor is configured to coherently combine a subset of the plurality of input radar pulses received by a subset of the plurality of radar modules, the coherent combination being achieved by summing one or more complex signals having a relative phase shift or a relative frequency shift of the subset of the plurality of input radar pulses, wherein the relative phase shift or the relative frequency shift is a function of the relative spatial position or relative spatial orientation of the plurality of radar modules.

[0166] Project 17) The system according to Project 2), wherein the plurality of radar modules are configured to calibrate the second set of radar signals received by the plurality of radar modules before forwarding the second set of radar signals to the processor.

[0167] Item 18) The system according to Item 17) wherein the plurality of radar modules are configured to (i) apply correction to the second set of radar signals based on estimated calibration parameters, or (ii) provide the processor with the estimated calibration parameters for the second set of radar signals.

[0168] Project 19) The system according to Project 18) wherein the estimated calibration parameters are derived in part from one or more variations in phase, gain, delay or bias observed between two or more of the plurality of input radar pulses.

[0169] Project 20) The system according to Project 18) wherein the estimated calibration parameters are derived in part from the relative spatial positions or relative spatial orientations of the plurality of radar modules.

[0170] Project 21) The system according to Project 17) wherein the plurality of radar modules are configured to calibrate the second set of radar signals using known objects visible to the plurality of radar modules in order to identify the phase difference between two or more input radar pulses in the second set of radar signals received by the plurality of radar modules.

[0171] Item 22) The system according to Item 2) wherein the phase information includes one or more phase differences observed between two or more input radar pulses in the second set of radar signals, wherein the two or more input radar pulses are (i) received by different receiving antennas within a radar module, (ii) received by different radar modules among the plurality of radar modules, or (iii) received when the vehicle is in different spatial locations or orientations.

[0172] Item 23) The system according to Item 22) wherein the processor is configured to use at least the phase information (i) to generate an occupancy grid.

[0173] Item 24) The system according to Item 23) wherein the processor is further configured to generate the occupancy grid using (ii) the relative spatial positions or orientations of the plurality of radar modules.

[0174] Item 25) The system according to Item 23) wherein the processor is further configured to use the occupancy grid to calculate the attribute of the target.

[0175] Item 26) The system according to Item 22) wherein the radar module of the plurality of radar modules is configured to partially use (i) the phase information and (ii) the timestamp information to (a) extract raw unprocessed data from the second set of radar signals and (b) provide the raw unprocessed data to the processor for coherent combination.

[0176] Item 27) The system according to Item 2) wherein the processor is configured to use at least (i) the phase information to calculate the attribute of the target, wherein the attribute of the target is selected from the group consisting of shape, size, position, orientation, angle of arrival, velocity, acceleration and radar cross-section.

[0177] Project 28) The system according to Project 1) wherein the first set of radar signals is transmitted by a first radar module and the second set of radar signals is received at a second radar module.

[0178] Item 29) The system according to Item 28) wherein the second set of radar signals corresponds to a subset of the first set of radar signals emitted by the first radar module and reflected from the at least one object in the surrounding environment.

[0179] Item 30) The system according to Item 28) wherein the second radar module is configured to preprocess the second set of radar signals before providing the second set of radar signals to the processor for coherent combination with an additional second set of radar signals received at the third radar module.

[0180] Project 31) The system according to Project 3) wherein the means of transport is a land vehicle, an air vehicle or a water vehicle.

[0181] Item 32) A method for processing radar data, comprising: (a) A radar system is provided, including (i) a frequency generator, (ii) a timing module, and (iii) a plurality of radar modules communicating with the frequency generator and the timing module, wherein the frequency generator is configured to generate a reference frequency signal having a reference frequency, and wherein the timing module is configured to generate one or more timing signals. (b) Receive the reference frequency signal and the one or more timing signals at the plurality of radar modules; (c) Based at least in part on the reference frequency signal and the one or more timing signals, using the plurality of radar modules to transmit a first set of radar signals comprising a plurality of output radar pulses; and (d) Receive a second set of radar signals at the plurality of radar modules, the second set of radar signals comprising a plurality of input radar pulses reflected from at least one object in the surrounding environment.

[0182] Item 33) The method according to Item 32) further includes using a processor to process the second set of radar signals received from the plurality of radar modules, respectively, by 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, through (a) coherently combining the second set of radar signals, (b) calculating the attributes of the target, or (c) generating an occupancy grid or radar image.

[0183] Item 34) The method according to Item 32) or 33) wherein the radar system includes at least one housing, the at least one housing including the frequency generator, the timing module and the plurality of radar modules, wherein the at least one housing is capable of being mounted on a vehicle.

[0184] Item 35) The method according to Item 32) wherein the frequency generator includes a circuit configured to generate a wave signal including a sine wave, a square wave, a triangle wave, or a sawtooth wave, the wave signal having a predetermined or real-time adjustable signal frequency, wherein the circuit includes a crystal oscillator, a simple packaged crystal oscillator, a temperature-controlled crystal oscillator, a voltage-controlled crystal oscillator, a frequency-controlled crystal oscillator, a temperature-controlled crystal oscillator, a ring oscillator, an inductor-capacitor (LC) oscillator, or a resistor-capacitor (RC) oscillator.

[0185] Item 36) According to the method of Item 32), wherein the plurality of radar modules are configured to generate the first set of radar signals using a local oscillator, the local oscillator being configured to multiply the reference frequency by one or more frequency multiplication factors, wherein the local oscillator includes an integer N phase-locked loop, a fractional N phase-locked loop, or a frequency multiplier.

[0186] Item 37) According to the method of Item 36), wherein the local oscillator is implemented on the radar modules of the plurality of radar modules, and wherein the radar module includes a radar transmitter and a radar receiver.

[0187] Item 38) According to the method of Item 33), wherein the timing module is configured to send one or more timing signals to the plurality of radar modules or the processor, wherein the one or more timing signals include a shared clock signal generated based on an absolute time base or a local time base.

[0188] Item 39) According to the method of Item 33), wherein the timing module is configured to send the one or more timing signals to the plurality of radar modules or the processor, wherein the one or more timing signals include one or more different timing signals for the processor or one or more of the plurality of radar modules.

[0189] Item 40) The method according to Item 32) wherein the plurality of radar modules are configured to trigger the transmission of the first set of radar signals at least in part based on the one or more timing signals.

[0190] Item 41) According to the method of Item 33), wherein the radar module of the plurality of radar modules includes a timestamp generator configured to mark at least a subset of the plurality of input radar pulses received by the radar module with one or more timestamps relative to the one or more timing signals before forwarding the plurality of input radar pulses to the processor.

[0191] Item 42) The method according to Item 33) wherein the processor is configured to use the one or more timing signals generated by the timing module to (i) generate one or more timestamps for the plurality of input radar pulses received by the plurality of radar modules, and (ii) sort the plurality of input radar pulses received by the plurality of radar modules in chronological order.

[0192] Item 43) The method according to Item 41), wherein the processor is configured to use the one or more timestamps generated by the timestamp generator to sort the plurality of input radar pulses received from the plurality of radar modules in chronological order.

[0193] Item 44) The method according to Item 39) wherein the timing module is configured to modify the one or more timing signals of the one or more radar modules among the plurality of radar modules before sending the one or more different timing signals to one or more of the plurality of radar modules.

[0194] Item 45) According to the method of Item 38), wherein the radar module of the plurality of radar modules is configured to (i) modify one or more timing signals received from the timing module, and (ii) trigger the transmission of the plurality of output radar pulses using one or more modified timing signals generated at the radar module.

[0195] Item 46) According to the method of Item 45), wherein the one or more modified timing signals are generated at least in part by (a) multiplying the frequency of the shared clock signal by one or more multiplication factors or by (b) implementing a programmable time delay relative to the shared clock signal.

[0196] Item 47) The method according to Item 33) wherein the processor is configured to coherently combine a subset of the plurality of input radar pulses received by a subset of the plurality of radar modules, the coherent combination being achieved by summing one or more complex signals having a relative phase shift or a relative frequency shift of the subset of the plurality of input radar pulses, wherein the relative phase shift or the relative frequency shift is a function of the relative spatial position or relative spatial orientation of the plurality of radar modules.

[0197] Item 48) The method according to Item 33) wherein the plurality of radar modules are configured to calibrate the second set of radar signals received by the plurality of radar modules before forwarding the second set of radar signals to the processor.

[0198] Item 49) According to the method of Item 48), wherein the plurality of radar modules are configured to (i) apply correction based on 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.

[0199] Item 50) The method according to Item 49) wherein the estimated calibration parameters are derived in part from one or more variations in phase, gain, delay or bias observed between two or more of the plurality of input radar pulses.

[0200] Project 51) The method according to Project 49) wherein the estimated calibration parameters are derived in part from the relative spatial positions or relative spatial orientations of the plurality of radar modules.

[0201] Item 52) The method according to Item 48) wherein the plurality of radar modules are configured to calibrate the second set of radar signals using known objects visible to the plurality of radar modules in order to identify the phase difference between two or more input radar pulses in the second set of radar signals received by the plurality of radar modules.

[0202] Item 53) According to the method of Item 33), wherein the phase information includes one or more phase differences observed between two or more input radar pulses in the second set of radar signals, wherein the two or more input radar pulses are (i) received by different receiving antennas within a radar module, (ii) received by different radar modules among the plurality of radar modules, or (iii) received when the vehicle is in different spatial locations or orientations.

[0203] Item 54) The method according to Item 53) wherein the processor is configured to use at least the phase information (i) to generate an occupancy grid.

[0204] Item 55) The method according to Item 54) wherein the processor is further configured to generate the occupancy grid using (ii) the relative spatial positions or orientations of the plurality of radar modules.

[0205] Item 56) The method according to Item 54), wherein the processor is further configured to use the occupied grid to calculate the attribute of the target.

[0206] Item 57) According to the method of Item 53), wherein the radar module of the plurality of radar modules is configured to partially use (i) the phase information and (ii) the timestamp information to (a) extract raw unprocessed data from the second set of radar signals and (b) provide the raw unprocessed data to the processor for coherent combination.

[0207] Item 58) The method according to Item 33) wherein the processor is configured to use at least (i) the phase information to calculate the attribute of the target, wherein the attribute of the target is selected from the group consisting of shape, size, position, orientation, angle of arrival, velocity, acceleration, and radar cross-section.

[0208] Project 59) The method according to Project 32) wherein the first set of radar signals is transmitted by the first radar module and the second set of radar signals is received at the second radar module.

[0209] Item 60) The method according to Item 59) wherein the second set of radar signals corresponds to a subset of the first set of radar signals emitted by the first radar module and reflected from the at least one object in the surrounding environment.

[0210] Item 61) The method according to Item 59) wherein the second radar module is configured to preprocess the second set of radar signals before providing the second set of radar signals to the processor for coherent combination with an additional second set of radar signals received at the third radar module.

[0211] Item 62) The method according to Item 34) wherein the means of transport is a land vehicle, an air vehicle, or a water vehicle.

Claims

1. A system for processing radar data, comprising: Multiple radar modules are configured to: (i) transmit a first set of radar signals comprising multiple output radar pulses based at least in part on a reference frequency signal and one or more timing signals, and (ii) receive a second set of radar signals comprising multiple input radar pulses reflected from at least one object in the surrounding environment. A frequency generator configured to generate the reference frequency signal having a reference frequency; A timing module configured to generate the one or more timing signals; as well as A processor that is common to the plurality of radar modules and communicates with each of the plurality of radar modules, wherein the processor is configured to aggregate and process the second set of radar signals received by the plurality of radar modules; The timing module is configured to send one or more timing signals to the plurality of radar modules or the processor, wherein the one or more timing signals include a shared clock signal generated based on an absolute time reference or a local time reference. The radar module among the plurality of radar modules is configured to: (i) modify one or more timing signals received from the timing module; and (ii) trigger the transmission of the plurality of output radar pulses using one or more modified timing signals generated at the radar module.

2. The system according to claim 1, wherein, The processor is configured to process the second set of radar signals using one or more attributes of the plurality of input radar pulses, wherein the one or more attributes include phase, amplitude, frequency, delay, or timing associated with the plurality of input radar pulses.

3. The system according to claim 2, wherein, The processor is configured to process the second set of radar signals by coherently combining one or more of the plurality of input radar pulses based at least in part on phase and amplitude information associated with the one or more input radar pulses.

4. The system according to claim 2, wherein, The processor is configured to process the second set of radar signals by incoherently combining one or more of the plurality of input radar pulses based at least in part on amplitude information associated with the one or more input radar pulses.

5. The system according to claim 1, wherein, At least two or more of the plurality of radar modules have the same or overlapping fields of view.

6. The system according to claim 1, wherein, At least two or more of the plurality of radar modules have non-overlapping fields of view.

7. The system according to claim 1, wherein, The processor is also configured to use the processed second set of radar signals to improve the resolution or sensitivity of detecting the presence or attributes of one or more objects in the surrounding environment, wherein the one or more objects include the at least one object.

8. The system according to claim 1, wherein, The processor is also configured to detect the presence or attributes of a selected object within the surrounding environment, wherein the selected object spans one or more fields of view corresponding to one or more of the plurality of radar modules.

9. The system according to claim 8, wherein, The processor is configured to recognize the selected object as a single physical object.

10. The system according to claim 1, wherein, The processor is also configured to detect the presence or attributes of a movable object in the surrounding environment, wherein the movable object has moved or has moved between two or more fields of view corresponding to two or more of the plurality of radar modules.

11. The system according to claim 10, wherein, The processor is configured to recognize the movable object as a single physical object.

12. The system of claim 1, further comprising a visualization module configured to generate a visual representation of the surrounding environment using at least the processed second set of radar signals.

13. The system according to claim 12, wherein, The visual representation is obtained from, or associated with, a data representation of the surrounding environment generated from multiple radar fields of view.

14. The system according to claim 13, wherein, The data representation of the surrounding environment includes a panoramic view from approximately 90 degrees to approximately 360 degrees.

15. The system according to claim 1, wherein, The plurality of radar modules are calibrated by: (i) identifying the relative position and orientation of at least one of the plurality of radar modules; and (ii) rotating or translating at least a portion of the radar data obtained using the plurality of radar modules to align the radar data with a global coordinate system.

16. The system of claim 1, further comprising an image-based sensor in communication with the processor, wherein, The image-based sensor is configured to acquire image data of the surrounding environment.

17. The system according to claim 16, wherein, The processor is configured to process the second set of radar signals in such a way as to: (i) combine at least a subset of the plurality of input radar pulses based at least in part on the image data, or (ii) enhance the second set of radar signals with the image data.

18. The system according to claim 17, wherein, The processor is also configured to process the second set of radar signals based at least in part on the position or orientation of the image-based sensors relative to the plurality of radar modules.

19. The system according to claim 18, wherein, The image-based sensor is calibrated by adjusting its position or orientation relative to the plurality of radar modules.

20. The system according to claim 18, wherein, The plurality of radar modules are calibrated by adjusting the position or orientation of at least one of the radar modules relative to the image-based sensor.

21. The system according to claim 18, wherein, The processor is configured to align (a) image data obtained using the image-based sensor with (b) one or more data representations of the surrounding environment generated using the plurality of radar modules in the following manner: (c) rotate or translate the image data relative to the one or more data representations.

22. The system according to claim 18, wherein, The processor is configured to align (a) image data obtained using the image-based sensor with (b) one or more data representations of the surrounding environment generated using the plurality of radar modules in the following manner: (c) rotate or translate the one or more data representations relative to the image data.

23. The system according to claim 16, wherein, The image-based sensor and the plurality of radar modules are aligned relative to each other such that the field of view of the image-based sensor at least partially overlaps with the field of view of one or more of the plurality of radar modules.

24. The system according to claim 16, wherein, The image-based sensor and the plurality of radar modules are configured to detect selected objects within the surrounding environment and identify the selected objects as the same physical object.

25. The system according to claim 16, wherein, The image-based sensor includes a camera or a light detection and ranging (LIDAR) unit.

26. The system according to claim 16, wherein, The processor is configured to calculate one or more physical or kinematic properties of one or more selected objects in the surrounding environment, based at least in part on information received from the image-based sensors and the plurality of radar modules.

27. The system according to claim 1, wherein, The system is configured to be installed on a vehicle, and wherein the processor is configured to combine radar signals received by the plurality of radar modules based at least in part on the position or movement of the vehicle in the surrounding environment.

28. The system according to claim 1, wherein, The system is configured to be installed on a vehicle, and wherein the processor is configured to generate one or more data representations of the surrounding environment based on: (i) one or more radar signals received by the plurality of radar modules, and (ii) the movement of the vehicle within the surrounding environment.

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