Transmit power control for automotive radar sensing

Abstract

A system and method are presented. A plurality of target objects are determined by a radar system. Each target object of the plurality of target objects is associated with a distance value and a velocity value. A power reduction factor is determined using the distance value and the velocity value associated with each target object of the plurality of target objects. A second radar signal is transmitted at a second power level determined by the power reduction factor.

Description

Technical Field

[0001] The present disclosure generally relates to radar systems and associated methods of operation. In one aspect, the present disclosure relates to a radar system configured to modulate the power level of an output signal, which may reduce power consumption and inter-radar system interference. Background Art

[0002] A radar system transmits an electromagnetic signal and receives back reflections of the transmitted signal. A time delay and / or a change in the time delay between the transmitted signal and the received signal may be determined and used to calculate the distance and / or speed of the object causing the reflection, respectively. For example, in automotive applications, an automotive radar system may be used to determine the distance and / or speed of oncoming vehicles and other obstacles.

[0003] Automotive radar systems enable the implementation of advanced driver assistance systems (ADAS) functions that may enable increasingly safer driving and ultimately fully autonomous driving platforms. Such systems use radar systems as the primary sensor for ADAS operation.

[0004] Existing radar systems are configured to transmit radar signals at a fixed and maximum power level to support detection of objects at the maximum range of interest. In addition to increasing the power consumption of the radar sensor, a side effect of this behavior is that it may lead to increased levels of radar-to-radar system interference. Summary of the invention

[0005] In some embodiments of the present system, when a controller of the radar system is notified (e.g., via out-of-band signaling) that another radar system is operating near the radar system, the radar system may be configured to reduce the transmit power of radar signals sent into a sector of the radar system's FOV that includes the other radar system.

[0006] In some aspects, the technology described herein relates to a radar system comprising: at least one transmitter and at least one receiver, wherein the at least one transmitter and the at least one receiver are configured to transmit and receive radar signals; and a radar processor, the radar processor configured to: transmit a first radar signal at a first power level at a first time, wherein the first power level is a maximum power level of a signal transmitted by an automotive radar system; receive a first received signal using the at least one receiver; process the first received signal to identify a plurality of target objects, wherein each of the plurality of target objects is associated with a distance value and a velocity value; determine a power reduction factor using the distance value and the velocity value associated with each of the plurality of target objects; and transmit a second radar signal at a second power level at a second time after the first time, wherein the second power level is determined at least in part by the power reduction factor and the second power level is less than the first power level.

[0007] Illustratively, the power reduction factor is determined by determining a first target object associated with a minimum distance value among the distance values ​​associated with each of the plurality of target objects.

[0008] Exemplarily, the automotive radar system is configured to transmit radar signals at time intervals denoted as Δt, and the power reduction factor is determined by determining a position value of each of the multiple target objects, wherein the position value of each target object is equal to the distance value associated with the target object minus the speed value associated with the target object multiplied by Δt.

[0009] Illustratively, the power reduction factor is equal to a minimum position value among the position values ​​associated with the target object among the plurality of target objects divided by a maximum range value of the automotive radar system.

[0010] For example, the automotive radar processor is configured according to the expression To determine the second power level, where P min is the minimum power level of the signal transmitted by the automotive radar system, P max is the maximum power level, and α is equal to the power reduction factor.

[0011] Illustratively, the distance value and the speed value associated with each target object of the plurality of target objects are determined by processing the received signal.

[0012] Illustratively, the power reduction factor is determined at least in part by a signal-to-noise ratio value associated with a target object of the plurality of target objects.

[0013] In some aspects, the technology described herein relates to a system comprising: a transmitter; a receiver; and a processor, the processor being configured to: use the transmitter to send a first radar signal at a first power level; process a first reflected signal received by the receiver to identify a plurality of target objects; determine a first power reduction factor using the plurality of target objects, wherein the first power reduction factor is associated with a first angular beam steering direction; determine a second power reduction factor using the plurality of target objects, wherein the second power reduction factor is associated with a second angular beam steering direction; use the transmitter to send a second radar signal at a second power level in the first angular direction, wherein the second power level is determined at least in part by the first power reduction factor; and use the transmitter to send a third radar signal at a third power level in the second angular direction, wherein the third power level is determined at least in part by the second power reduction factor.

[0014] Illustratively, at least one of the first power reduction factor and the second power reduction factor is determined by determining a distance value to each of the plurality of target objects.

[0015] Illustratively, the first power reduction factor is equal to a minimum position value among the position values ​​associated with the target object among the plurality of target objects in the first angular direction divided by a maximum range value of the automotive radar system.

[0016] For example, the processor is configured to To determine the second power level, where P min is the minimum power level of the signal transmitted by the automotive radar system, P max is the maximum power level of the signal transmitted by the automotive radar system, and α is equal to the power reduction factor.

[0017] For example, the value P max The signal-to-noise ratio of the first reflected signal is determined at least in part by the signal-to-noise ratio of the first reflected signal.

[0018] Illustratively, the processor is configured to:

[0019] processing the second reflected signal to determine that the second reflected signal is not indicative of any target object; and

[0020] A fourth radar signal is transmitted at a fourth power level equal to a maximum power level of signals transmitted by the automotive radar system.

[0021] In some aspects, the technology described herein relates to a method comprising: determining, by a radar system, a plurality of target objects, wherein each target object of the plurality of target objects is associated with a range value and a velocity value; determining a power reduction factor using the range value and the velocity value associated with each target object of the plurality of target objects; and transmitting a second radar signal at a second power level determined by the power reduction factor.

[0022] Illustratively, the method further includes determining the power reduction factor by at least determining a first target object associated with a minimum distance value among the distance values ​​associated with each of the plurality of target objects.

[0023] Exemplarily, the radar system is configured to transmit radar signals at time intervals denoted as Δt, and the method further comprises determining the power reduction factor by determining a position value for each of the plurality of target objects, wherein the position value for each target object is equal to the distance value associated with the target object minus the speed value associated with the target object multiplied by Δt.

[0024] Illustratively, the method further includes determining the power reduction factor equal to a minimum position value of the position values ​​associated with the target object of the plurality of target objects divided by a maximum range value of the automotive radar system.

[0025] For example, the method further comprises: To determine the second power level, where P min is the minimum power level of the signal transmitted by the radar system, P max is the maximum power level, and α is equal to the power reduction factor.

[0026] For example, the method further comprises determining the value P at least in part from a signal-to-noise ratio in a signal received by the radar system. max .

[0027] For example, the method further comprises determining the distance values ​​and the speed values ​​associated with the plurality of target objects by:

[0028] processing the radar reflection signal to determine said range value and said speed value; and / or

[0029] The distance value and the speed value are retrieved from a database. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] A more complete understanding of the subject matter may be gained by referring to the detailed description and claims when considered in conjunction with the following drawings, wherein like reference numerals refer to similar elements throughout the various figures.

[0031] Figure 1 A simplified schematic block diagram depicting an automotive radar system.

[0032] Figure 2 is a flow chart depicting a method implemented by a controller of a radar system to provide adaptive power control of transmitted signals of the radar system.

[0033] Figure 3-5 Describe the implementation Figure 2 The output of the radar system.

[0034] Figure 6 A method that may be implemented by a controller of a radar system configured to transmit radar signals into one of N sectors (Ω) to provide adaptive power control of a signal transmitter of the radar system by using beam steering is described. DETAILED DESCRIPTION

[0035] The following specific embodiments are merely illustrative in nature and are not intended to limit the embodiments of the subject matter of the present application and the use of such embodiments. As used herein, the words "exemplary" and "example" mean "serving as an example, instance or illustration". Any embodiment or embodiment described herein as exemplary or example should not necessarily be understood as being preferred or advantageous over other embodiments. In addition, it is not intended to be bound by any explicit or implicit theory presented in the aforementioned technical field, background technology or the following specific embodiments.

[0036] Automotive radar systems are used to support advanced driver assistance systems (ADAS) functions such as assisted cruise control, emergency braking, and blind spot monitoring and warning. For these ADAS applications, nearby objects detected by the automotive radar system are usually the most relevant. For example, when performing an emergency braking function, a nearby detected vehicle is more relevant to the braking function than another vehicle in the distance.

[0037] In typical applications, conventional automotive radar systems are configured to transmit at maximum power levels to support object detection at the maximum possible object detection range (e.g., up to 200m for long-range radars). As a result, existing automotive radar systems typically operate at maximum (or very high) power consumption levels. If all automotive radar systems in a particular geographic area (e.g., within a parking lot or on a particular road segment) transmit radar signals at maximum power levels, the likelihood of system-to-system signal interference increases significantly.

[0038] The present disclosure provides an automotive radar system and method that alleviates these deficiencies in existing automotive radar systems by providing an adaptive power control method for an automotive radar system.

[0039] In the context of the present disclosure, it should be understood that radar systems can be used as sensors in a variety of different applications, including but not limited to automotive radar sensors for road safety and vehicle control systems such as advanced driver assistance systems (ADAS) and autonomous driving (AD) systems.

[0040] In such applications, the radar system is used to measure the radial range to the reflecting object, the relative radial velocity and angular information of the reflecting target, and is characterized by performance criteria such as angular resolution (the minimum distance between two equally large targets that the radar can distinguish and separate from each other at the same range and range rate (or radial velocity) resolution units), sensitivity, false detection rate, etc.

[0041] Typically, a frequency modulated continuous wave (FMCW) modulated radar is used to identify the range, velocity and / or angle of a radar target, such as a car or pedestrian, by transmitting a linear frequency modulated (LFM) waveform from a transmitting antenna, so that a reflected signal from the radar target is received at a receiving antenna and processed to determine the radial range, relative radial velocity and angle (or direction) of the radar target.

[0042] To illustrate the design and operation of a radar system configured in accordance with the present disclosure, reference is now made to Figure 1 , Figure 1 A simplified schematic block diagram of an automotive radar system 100 is depicted. The automotive radar system 100 includes a MIMO radar device 10 connected to a radar controller processor 20. In selected embodiments, the MIMO radar device 10 may be embodied as a field replaceable unit (LRU) or modular assembly designed to be quickly replaced in an operating position. Similarly, the radar controller processor 20 may be embodied as a field replaceable unit (LRU) or modular assembly. Although a single or monostatic MIMO radar device 10 is shown, it should be understood that additional distributed radar devices may be used to form a distributed or multistatic radar. In addition, the depicted radar system 100 may be implemented in the form of an integrated circuit, wherein the LFM MIMO radar device 10 and the radar controller processor 20 are formed by separate integrated circuits or chips or by a single chip, depending on the application.

[0043] Each radar device 10 includes one or more transmit antenna elements TXi and receive antenna elements RXj, respectively connected to one or more radio frequency (RF) transmitter (TX) units 11 and receiver (RX) units 12. For example, each radar device (e.g., 10) is shown as including individual antenna elements (e.g., TX1,i, RX1,j) respectively connected to three transmitter modules (e.g., 11) and four receiver modules (e.g., 12), but these numbers are not limiting, and other numbers are also possible, such as four transmitter modules 11 and six receiver modules 12, or a single transmitter module 11 and / or a single receiver module 12.

[0044] Each radar device 10 also includes a chirp generator 112 configured and connected to supply a chirp input signal to the transmitter module 11. For this purpose, the chirp generator 112 is connected to receive a separate and independent local oscillator (LO) signal 110 and a chirp start trigger signal 111, but the delays are likely to be different due to signal path differences and programmable digital delay elements in the signal paths. A chirp signal 113 is generated and transmitted to multiple transmitters 11, usually according to a predefined transmission schedule, and the chirp signal 113 is filtered at the RF adjustment module 114 and amplified at the power amplifier 115 before being fed to the corresponding transmit antenna TX1,i and radiated. By sequentially using each transmit antenna TX1,i to transmit consecutive pulses in the chirp signal 113, each transmitter element 11 operates in a time multiplexed manner relative to other transmitter elements because these transmitter elements are programmed to transmit exactly the same waveform on a time-separated schedule.

[0045] The radar signal transmitted by the transmitter antenna unit TX1,i, TX2,i may be reflected by an object and a portion of the reflected radar signal reaches the receiver antenna unit RX1,i at the radar device 10. At each receiver module 12, the received (RF) antenna signal is amplified by a low noise amplifier (LNA) 120 and then fed to a mixer 121 where it is mixed with the transmitted chirp signal generated by the RF conditioning module 114. The resulting intermediate frequency signal is fed to a first high pass filter (HPF) 122. The resulting filtered signal is fed to a first variable gain amplifier 123 which amplifies the signal before feeding it to a first low pass filter (LPF) 124. This re-filtered signal is fed to an analog-to-digital converter (ADC) 125 and output by each receiver module 12 as a digital signal D1. In various embodiments, the receiver module compresses the target echoes of the various delayed signals into a plurality of sinusoidal tones, the frequencies of which correspond to the round-trip delays of the echoes.

[0046] Radar system 100 also includes a radar controller processing unit 20 connected to supply input control signals to radar device 10 and to receive therefrom digital output signals generated by receiver module 12 .

[0047] In selected embodiments, the radar controller processing unit 20 may be embodied as a microcontroller unit (MCU) or other processing unit configured and arranged for signal processing tasks such as, but not limited to: target identification; calculation of target range, target velocity, and target direction; and generation of control signals. For example, the radar controller processing unit 20 may be configured to generate calibration signals, receive data signals, receive sensor signals, generate spectrum shaping signals (e.g., ramp generation in the case of FMCW radar), and / or enable sequence registration programming or state machine signals for RF (radio frequency) circuits.

[0048] In addition, the radar controller processor 20 can be configured to program the module 11 to operate in a time division manner by sequentially transmitting LFM chirps for coordinated communication between the transmit antennas TX1,i, RX1,j. The result of the digital processing at the radar controller processing unit 20 is that the digital domain signal D1 is processed for subsequent fast time range frequency Fourier transform (FFT) 21, slow time FFT 22 for Doppler compression, constant false alarm rate (CFAR) target detection 23, spatial angle estimation 24 and target tracking process 25, where the results are output 26 to other automotive computing or user interface devices for further processing or display. When performing target detection, the radar controller processor 20 is configured to determine the profile of the reflected radar signal (e.g., range, Doppler, azimuth, elevation and / or radar cross section (rcs) profile), where peaks in the profile indicate potential targets at known ranges.

[0049] During operation of the automotive radar system 100, the radar controller processor 20 sends control signals to various components of the one or more radio frequency (RF) transmitter (TX) units 11 and the receiver (RX) unit 12 to control how radar signals transmitted by the automotive radar system 100 are shaped as transmitted signals and how received signals are processed. In a specific example, the radar controller processor 20 is configured to modulate the power level of the signal transmitted by the one or more radio frequency (RF) transmitter (TX) units 11 by sending control signals to the power amplifier 115 of each of the one or more radio frequency (RF) transmitter (TX) units 11.

[0050] In a typical radar system, radar signals are sent at a fixed power level that is selected to achieve object detection at the maximum range of interest for the radar system. This typically requires that radar signals are always sent at the maximum allowable power level. In addition to increasing the power consumption of conventional radar systems, a side effect of this behavior is an increased likelihood of radar-to-radar interference between surrounding vehicles using similar time, frequency, and space resources. If multiple radar systems are operating at maximum power levels within a constrained location, a radar signal sent by one such radar system may overwhelm or otherwise interfere with a signal being received and processed by another nearby radar system.

[0051] In minimizing these deleterious effects, it is important to note that for radar systems providing ADAS functionality, accurate detection of nearby objects may generally be more relevant to ADAS operation than detection of more distant objects. For example, detecting a first object near the vehicle is generally more important than detecting a second object that is farther away and may be in the same path as the first object. The ADAS system must take action with respect to the first object. At the same time, the more distant second object may not be relevant to the operation of the ADAS system.

[0052] Thus, the present disclosure provides a radar system that includes an adaptive power control mechanism that provides detection of the closest objects in an environment. In certain embodiments, a controller (e.g., Figure 1 The radar controller processor 20 is configured to modulate the power level of the transmitted radar signal based on an analysis of target objects detected in the vicinity of the radar system (e.g., by modifying Figure 1 In an embodiment, the power level of the transmitted signal may be modulated based on object detection characteristics such as an estimated range to a detected object and / or a speed of the detected object in the current radar system sensing time slot.

[0053] In an embodiment of the present system, a radar system (e.g., Figure 1 The automotive radar system 100 has a field of view (FOV) defined by radar signals transmitted by the radar system covering a particular area of ​​interest (e.g., by Figure 1 The radar system is configured to transmit a signal to the radar system by one or more radio frequency (RF) transmitters (TX) units 11) and receive (e.g., by one or more radio frequency (RF) receivers (RX) units 12). During operation, the radar system operates according to a sensing interval Δt, which defines the duration between two radar waveform transmissions used by the radar system to perform object detection. Using these properties, a controller of the radar can implement a method for power modulation according to the present disclosure.

[0054] The example radar system 100 described above is presented in conjunction with a radar system 100 configured as an FMCW radar system. It should be understood that embodiments of the inventive system may be utilized in conjunction with signals received and processed by other types of radar systems to control the transmit power of such radar systems. For example, radar signals processed in conjunction with the inventive system may be received by a radar system configured to process signals encoded by a (dual) phase modulated continuous wave (PMCW), orthogonal frequency division multiplexing (OFDM), or orthogonal time frequency space (OTFS) modulation scheme, or by any other type of radar system configured to process received radar signals and process those signals into identifying attributes of target objects in the vicinity of the radar system (i.e., in the field of view (FOV) of the radar system) based on the processing.

[0055] Figure 2 is a description of the radar system controller (e.g. Figure 1 The radar controller processor 20 of the automotive radar system 100 is implemented to provide a signal transmitter (e.g., Figure 1 Flow chart of a method 200 for adaptive power control of one or more radio frequency (RF) transmitter (TX) units 11).

[0056] In step 202, at an initial time t0, the controller turns on the power amplifier (eg, Figure 1 The power amplifier 115 of the radar system is configured to transmit radar signals at a default power level P0. In most applications, the default power level will be the maximum power level (i.e., P0) at which the radar system is allowed to transmit radar signals. max ). This is the default behavior of the radar system because, by transmitting at maximum power, the radar system is configured to detect max Objects within.

[0057] In step 204, signals including reflections of the radar signal sent in step 202 are received by the radar system (e.g., via one or more radio frequency (RF) receiver (RX) units 12). In step 206, those reflected signals are processed (e.g., via a series of Fourier transforms and other analyses) to identify a set of target objects from which the signal was reflected. For each target object, a range and velocity are determined. Thus, in step 206, a data set comprising K objects is determined, where each object is associated with a range value R K and speed value V K However, in other embodiments, the range value and the speed value may be generated by an external database, or retrieved from a third-party data source that processes movement data of multiple target objects in a particular geographic area. Therefore, in this step, the range value and the speed value may be retrieved from the data source rather than generated via processing of the radar signal data.

[0058] In step 208, the set of objects identified in step 206 is further analyzed to determine a power reduction factor (α) used to modulate the power level of the signal transmitted by the radar system. Specifically, in step 208, the controller is configured to determine the value αi using the following equation:

[0059]

[0060] According to equation (1), the value αi is equal to the minimum distance of the closest object in the set of detected objects (taking into account the movement due to the detected speed) divided by the maximum range R of the radar system max ratio.

[0061] Using the value α determined for the current time interval i i (i.e., α i ), in step 212, in the next time interval (ie, time interval i+1), the controller configures the radar system to use the value α determined at least in part in step 210 i The power signal level determined is sent. A scalar β value between the current estimate and the previous estimate of the power reduction value may optionally be used (e.g., via α i+1 =(1-β)α i-1 +βα i ) to smooth the power reduction value. In an embodiment, this involves configuring the radar system to transmit in time interval i+1 at a power level determined according to the following equation:

[0062]

[0063] In equation (2), P min represents the minimum power level of radar signals that the radar system can transmit to ensure reliable object detection given a noisy environment, even if not reliable over the entire range of the system. Thus, in step 212, the radar system is configured to transmit at a reduced power level that still enables detection of objects closest to the radar system.

[0064] Method 200 then returns to step 204 where the radar system repeats step 204 for received reflection signals generated by the radar signal sent in step 212 .

[0065] Referring to method 200, when the target object set is empty (for example, no target object is detected in the reflected signal), the power level P i+1 Set to maximum. This returns the radar system to operating at full power to increase the likelihood that the radar system will detect the target object.

[0066] Other situations may cause the radar system to resume full power operation. For example, if it is determined that the vehicle is changing orientation significantly (so that the radar system is presented with a completely new scene) or the car is approaching a complex environment (e.g., an intersection), the radar system may resume operation at full power.

[0067] To illustrate the operation of method 200, Figure 3 Plotted at the initial time t i The output of the radar system during the period is shown in scene 300. In scene 300, the vertical axis represents the distance to the detected objects, while the horizontal axis represents the speed of those detected objects. As shown in scene 300, the radar system has detected three objects 302, 304, and 306. The three objects are detected by the radar system at an initial time t according to step 202 of method 200. i At full power (P max ) transmits a radar signal. This maximum power level is depicted by graph 308. The vertical axis of graph 308 represents the power level of the radar signal transmitted by the radar system, while the horizontal axis represents time. Figure 3 As depicted by the curve diagram 308 in FIG. , the radar signal transmitted at time t i The power level is set to the maximum value P max .

[0068] Then, the reflected signals are received and processed (e.g., in steps 204 and 206) to detect objects 302, 304, and 306. Then, the distance and speed of the detected objects are analyzed according to equation (1) of method 200 and step 210 to determine the value α i .

[0069] Figure 4 The next time interval (i.e., t0+1) is depicted in FIG. In time interval t0+1, according to step 212 of method 200, the power level of the radar signal transmitted by the radar system is reduced according to equation (2). The reduced power level is indicated by graph 308, where i The power level depicted is reduced in time interval t0+1 compared to the power level in t0+1. At the reduced power level, the radar system is only able to detect objects 304 and 306 in scene 300. Object 302 is no longer detected.

[0070] This process is repeated in future time intervals. A new value α is determined based on the detected objects 304 and 306 according to equation (1). i+1 .

[0071] Figure 5 The next time interval (i.e., t0+2) is depicted in . In time interval t0+2, the value α is used i+1The power level of the radar signal transmitted by the radar system is reduced according to equation (2). The reduced power level is indicated by a graph 308, wherein i Compared to the power level in +1, the power level depicted in the time interval t i +2. At the reduced power level, the radar system is only able to detect object 306 in scene 300. Objects 302 and 304 are no longer detected. This process can be repeated until no target objects are detected (in which case the radar system resumes operating at the maximum power level P max The radar signal is sent until an object is detected) or the transmitted power level reaches a certain minimum power threshold (P min )until.

[0072] Return to Figure 2 In some embodiments, method 200 may be further modified to account for the variable radar cross section (RCS) of target objects. Specifically, objects with smaller RCS tend to reflect radar signals at lower magnitudes than other objects that may have larger RCS. This may reduce the overall signal-to-noise ratio (SNR) of signals reflected by low RCS target objects compared to the SNR of signals reflected by high RCS target objects. Therefore, it may be necessary to send radar signals to objects with lower RCS at a higher power level than when sending radar signals to target objects with higher RCS in order to increase the SNR in any reflected signals.

[0073] Although it is impractical to directly measure the RCS of a target object, the SNR of the signal reflected from the object is a good indicator of the RCS of the object. Therefore, the power level of the signal transmitted according to the method 200 described above can be modified according to the target SNR value or the measured SNR value of the received signal.

[0074] Therefore, the default power (eg, P max ) can be based on the maximum detectable range of the radar system (R max ) and a predetermined minimum SNR value (SNR min ) to choose. That is, P max It can be limited by the following expression:

[0075] P max =f(R max ,SNR min ) (3)

[0076] Using the relationship provided by the radar problem, equation (3) can be rewritten as:

[0077] P max ~SNR min *R max 4(4)

[0078] This relationship can be used to further modify equation (1) to determine the value of the power scaling factor α that takes into account the SNR of the received reflected signal. The relationship is shown in the following equation:

[0079]

[0080] Using Equation 5 to calculate the power scaling factor α in different time intervals, method 200 may be as follows Figure 2 , to calculate the power scaling factor and determine the transmit power to be used by the radar system in the upcoming time slot (e.g., via equation (2)). Using the SNR of the reflected signal, equation (5) allows a higher power radar signal to be sent when the SNR of the nearest target object is low, and allows a lower power radar signal to be sent when the SNR of the nearest target object is high.

[0081] In another embodiment of the present system and method, the radar system may include multiple transmit antennas and receive antennas configured to cover different areas or sectors of interest using a combination of transmitted radar signals and received radar signals. Figure 1 The automotive radar system 100 is configured, wherein the radar system 100 includes two or more transmitting antenna elements TXi and receiving antenna elements RXj connected to one or more radio frequency (RF) transmitter (TX) units 11 and receiver (RX) units 12, respectively.

[0082] Figure 2 The power control method 200 may be suitable for use in conjunction with a radar system having multiple transmitters and receivers. Specifically, the method 200 may be modified to implement transmit power control of signals sent to multiple angular regions or sectors within the FOV of the radar system. For example, a multi-transmitter / receiver radar system may be configured to scan an area of ​​interest comprising k sectors. Using beamforming, the radar system iteratively sends radar signals into k scanning regions, thereby enabling the radar system to detect objects that may be present in each of the k scanning regions. At any particular time, the radar system may be configured to scan only a single sector. Therefore, radar signals sent to perform scans of different sectors may be sent at different power levels, so that a different power level may be used for each scanning sector.

[0083] Figure 6 The depiction may be implemented by a controller of a radar system configured to transmit a radar signal into one of N sectors (Ω) to provide a signal transmitter (eg, Figure 1 A method 600 for adaptive power control of one or more radio frequency (RF) transmitter (TX) units 11).

[0084] In step 602, the first sector Ω of the total number of sectors N is selected. k In step 604, the controller determines that the radar signal will be sent to the current sector Ω k Therefore, the controller determines whether the current sector Ω has been previously k Determine the value of α k (e.g., as a result of a previous iteration of method 600). If so, the power level is set to the value α k (e.g., according to equation (2)). Alternatively, if Ω has not yet been determined for the current sector k Set the value of α k , the power level is set to the default power level. In most applications, the default power level will be the maximum power level (i.e., P max ). This is the default behavior of the radar system because by max The radar system is configured to detect the maximum range R of the radar system. max object.

[0085] In step 606, the radar system transmits a radar signal to sector Ω at the power level determined in step 604. k In step 608, signals including reflections of the radar signal sent in step 202 are received by the radar system (e.g., via one or more radio frequency (RF) receiver (RX) units 12) from sector N. In step 610, those reflected signals are processed (e.g., via a series of Fourier transforms and other analyses) to identify a set of target objects from which the signal was reflected. For each target object, for the current sector Ω k Determine the range and speed. Therefore, in step 610, a data set including K objects is determined, where each object is associated with a range value R K , speed value V K 、Azimuth value θ K and elevation value Associated.

[0086] In step 612, the set of K objects identified in step 206 is further analyzed to determine a value α for modulating the power level of a signal transmitted by the radar system for later transmission. k Specifically, in step 208, the controller is configured to use the following equation for the current time slot i and in the current sector Ω k Determine the value α in:

[0087]

[0088] In equation (6), Δt represents the radar system configured to send radar signals to the current sector Ω k The duration of the time interval in . According to equation (6), the value α i (Ω k ) is equal to the current sector Ω k The minimum distance of the closest object in the set of detected objects (taking into account the movement due to the detected speed) divided by the maximum range R of the radar system max Although equation (6) describes the scaling within an angular sector in the azimuth domain, it should be noted that the scaling can be extended to the elevation domain.

[0089] For the current time interval i and the current sector Ω k Determine the value α i (Ω k ), the method moves to the step in step 616, in which the counter k is incremented to select the next sector Ω k +1. The method then moves to step 602 and repeats for the next (and subsequent) sectors Ω. When all sectors have been processed in the manner described, the method repeats by incrementing again within all potential sectors Ω.

[0090] Referring to method 600, when the target object set for a particular sector is empty (eg, no target object is detected in the reflected signal of the sector), the power level (ie, P) used for subsequent signal transmission in the sector is set to i+1 ) to maximum. This returns the radar system to operating at full power to increase the likelihood that the radar system will detect the target object.

[0091] In summary, for a radar system configured with multiple scanning zones, method 600 is arranged to cause the radar system to sequentially send radar signals into different sectors. Based on the detection of target objects in each sector, the signal power level sent to each sector can be fine-tuned for each sector (e.g., via a power scaling factor α) so as to be sent at the minimum power level capable of detecting nearby target objects. The benefit of this method is that the method can further reduce interference to other radar systems nearby.

[0092] Figure 6The method provides a number of benefits, including the ability of the radar system to reduce the transmit power of signals in various sectors of the FOV of the radar system. For example, if a car is traveling along a road where a guardrail or other structure extends along the side of the vehicle, the radar system will transmit radar signals to that FOV sector at a significantly reduced power level because the guardrail will be located near the vehicle, enabling the low-power radar signal to monitor the distance to the guardrail. By reducing the power of the signal transmitted at the guardrail (or other nearby target object), the risk of the radar system detecting a ghost target object is reduced.

[0093] Although examples have been described with reference to automotive radar systems, the systems and methods described herein may be implemented in conjunction with other types of radar systems.

[0094] The preceding detailed description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments.

[0095] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any embodiment described herein as exemplary is not necessarily to be construed as preferred or advantageous over other embodiments. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, or detailed description.

[0096] The connecting lines shown in the various figures included herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may exist in the embodiments of the subject matter. In addition, certain terms may also be used herein only for reference purposes, and therefore these terms are not intended to be restrictive, and unless the context clearly indicates, the terms "first", "second" and other such numerical terms referring to the structure do not imply an order or sequence.

[0097] As used herein, "node" means any internal or external reference point, connection point, junction, signal line, conductive element, etc., at which a given signal, logic level, voltage, data pattern, current or quantity exists. In addition, two or more nodes may be implemented by one physical element (and two or more signals may be multiplexed, modulated, or otherwise distinguished despite being received or output at a common node).

[0098] The foregoing description refers to elements or nodes or features being "connected" or "coupled" together. As used herein, unless otherwise expressly stated, "connected" means that one element is directly joined to another element (or is directly communicated with another element), and not necessarily mechanically joined. Likewise, unless otherwise expressly stated, "coupled" means that one element is directly or indirectly joined to another element (or is directly or indirectly communicated with another element electrically or otherwise), and not necessarily mechanically joined. Thus, although the schematic diagrams shown in the figures depict an exemplary arrangement of elements, additional intervening elements, devices, features, or components may be present in the embodiments of the depicted subject matter.

[0099] Although at least one exemplary embodiment has been presented in the foregoing specific embodiments, it should be understood that there are a large number of variations. It should also be understood that one or more exemplary embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. In fact, the foregoing specific embodiments will provide a convenient guide for implementing the described one or more embodiments to those skilled in the art. It should be understood that various changes may be made to the function and arrangement of elements without departing from the scope defined by the claims, and the scope defined by the claims includes known equivalents and foreseeable equivalents at the time of filing this patent application.

Claims

1. A radar system, characterized in that: include: at least one transmitter and at least one receiver, wherein the at least one transmitter and the at least one receiver are configured to transmit and receive radar signals; as well as A radar processor, the radar processor being configured to: transmitting a first radar signal at a first power level at a first time, wherein the first power level is a maximum power level of a signal transmitted by the radar system, receiving a first received signal using the at least one receiver, processing the first received signal to identify a plurality of target objects, wherein each target object in the plurality of target objects is associated with a distance value and a velocity value, determining a power reduction factor using the distance value and the speed value associated with each target object of the plurality of target objects, and A second radar signal is transmitted at a second time after the first time at a second power level, wherein the second power level is determined at least in part by the power reduction factor and is less than the first power level.

2. The radar system according to claim 1, characterized in that The automotive radar system is configured to transmit radar signals at time intervals denoted as Δt, and the power reduction factor is determined by determining a position value for each of the plurality of target objects, wherein the position value for each target object is equal to the distance value associated with the target object minus the speed value associated with the target object multiplied by Δt.

3. The radar system according to claim 1, characterized in that The automotive radar processor is configured according to the expression To determine the second power level, where P min is the minimum power level of the signal transmitted by the automotive radar system, P max is the maximum power level, and α is equal to the power reduction factor.

4. A system, characterized in that: include: Transmitter; Receiver; as well as A processor configured to: transmitting, using the transmitter, a first radar signal at a first power level, processing a first reflected signal received by the receiver to identify a plurality of target objects, determining a first power reduction factor using the plurality of target objects, wherein the first power reduction factor is associated with a first angular beam steering direction; determining a second power reduction factor using the plurality of target objects, wherein the second power reduction factor is associated with a second angular beam steering direction; transmitting, using the transmitter, a second radar signal in the first angular direction at a second power level, wherein the second power level is determined at least in part by the first power reduction factor; as well as A third radar signal is transmitted using the transmitter in the second angular direction at a third power level, wherein the third power level is determined at least in part by the second power reduction factor.

5. The system according to claim 4, characterized in that At least one of the first power reduction factor and the second power reduction factor is determined by determining a distance value to each of the plurality of target objects.

6. The system according to claim 4, characterized in that The processor is configured to To determine the second power level, where P min is the minimum power level of the signal transmitted by the automotive radar system, P max is the maximum power level of the signal transmitted by the automotive radar system, and α is equal to the power reduction factor.

7. The system according to claim 4, characterized in that The processor is configured to: processing the second reflected signal to determine that the second reflected signal is not indicative of any target object; and A fourth radar signal is transmitted at a fourth power level equal to a maximum power level of signals transmitted by the automotive radar system.

8. A method, characterized in that include: determining, by the radar system, a plurality of target objects, wherein each target object of the plurality of target objects is associated with a distance value and a velocity value, determining a power reduction factor using the distance value and the speed value associated with each target object of the plurality of target objects; as well as A second radar signal is transmitted at a second power level determined by the power reduction factor.

9. The method according to claim 8, characterized in that The radar system is configured to transmit radar signals at time intervals denoted as Δt, and the method further includes determining the power reduction factor by determining a position value for each of the plurality of target objects, wherein the position value for each target object is equal to the distance value associated with the target object minus the speed value associated with the target object multiplied by Δt.

10. The method according to claim 8, characterized in that In addition, the expression To determine the second power level, where P min is the minimum power level of the signal transmitted by the radar system, P max is the maximum power level, and α is equal to the power reduction factor.

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