Antenna group system

Abstract

Antenna group system, comprising: a phased array antenna (30) having a first antenna group (40) and a second antenna group (50), a calibration circuit (70), and a foldable power transformer (60); wherein the calibration circuit (70) is electrically connected to the first antenna group (40); wherein the first antenna group (40) is electrically coupled to the second antenna group (50) via the foldable power transformer (60) when the foldable power transformer (60) is arranged in a first position; wherein the foldable power transformer (60) mechanically connects the first antenna group (40) to the second antenna group (50) in the first position and a second position, respectively; and wherein the first antenna group (40) is arranged at an angle with respect to the second antenna group (50) when the foldable power transformer (60) is in the first position.

Description

[0001] In-vehicle radar systems can be used to detect and locate other vehicles, pedestrians, and fixed or moving objects when installed in ground vehicles.

[0002] Antenna arrays used in various applications such as radar, experimental data acquisition, etc., must operate coherently in time, frequency, and phase. Due to changing conditions (such as ambient temperature, humidity, component aging, etc.), regular calibration of the time, gain, and phase of the system's transmit / receive chains is required.

[0003] Accurate calibration of phase, gain, frequency, and related parameters is essential for applying array processing algorithms to estimate radar parameters such as direction of arrival, time delay, Doppler shift, etc. Conventional methods for calibrating an antenna array require a special setup, which may involve disconnecting the antennas or otherwise interfering with them to introduce a calibration signal. Furthermore, automotive radar systems may only be calibrated once during vehicle production. However, during normal system operation, radar systems installed at different locations on a vehicle may be exposed to different ambient temperatures. For example, one section of the radar system may face the sun while another section is in shadow, creating a temperature differential.In such cases, temperature-related phase differences can become noticeable and affect the overall performance of the radar.

[0004] In some cases, antenna arrays have three-dimensional (3D) shapes to improve their spatial resolution in azimuth, elevation, or both. An antenna with a 3D array consists of multiple antenna boards, with one board or assembly rotated at an angle relative to a main board. Such arrangements can present a particular electromechanical challenge during calibration if the calibration signal must be routed to an adjacent antenna array (e.g., a printed circuit board) positioned at an angle to a main board.

[0005] DE 10 2022 120 231 A1 describes a system in a vehicle. The system includes a radar system with a uniform linear array (ULA) of antenna elements and a uniform rectangular array (URA) of antenna elements for receiving the reflected signals resulting from the emitted radio frequency energy. The ULA is arranged perpendicular to the URA. The processing circuitry estimates one or more elevation angles using the reflected signals received by the ULA from antenna elements and estimates an azimuth angle corresponding to each of the one or more elevation angles using the one or more elevation angles and the reflected signals received by the URA from antenna elements. Each of the one or more elevation angles and the corresponding azimuth angle is referred to as an angle of arrival (AOA) of the signals reflected from an object.The control of vehicle operation is based on each AOA of each object.

[0006] DE 102019 123 282 A1 describes a sensor arrangement for detecting an object and a method for forming a sensor opening in sheet metal. The sensor arrangement comprises at least one electromagnetic source for emitting electromagnetic waves. The sensor arrangement also comprises at least one electromagnetic receiver for receiving the electromagnetic waves after reflection from the object and corresponding to detection of the object in the vicinity of the sensor arrangement. Furthermore, the sensor arrangement comprises a filter cover arranged adjacent to and covering the at least one electromagnetic source and the at least one electromagnetic receiver, which filter cover is configured to transmit the electromagnetic waves while reflecting visible light, thereby obscuring the at least one electromagnetic source and the at least one electromagnetic receiver.

[0007] US 2009 / 0 267 835 A1 describes a phased array radar system that mechanically reconfigures its antenna array from a single-sided aperture into two geometrically opposed arrays

[0008] It can be considered a task to provide an improved antenna array system to enable and facilitate real-time phase and gain calibration.

[0009] The concepts described here provide a three-dimensional (3D) antenna array for a vehicle featuring a foldable configuration that enables and facilitates real-time phase and gain calibration. Real-time phase and gain calibration is performed to account for changes in parameters that may occur due to aging and / or real-time environmental fluctuations.

[0010] The invention relates to an antenna array system according to claim 1. The description describes a control unit that may constitute a device for using the system. This description serves to understand the system according to the invention.

[0011] According to the invention, an antenna array system in the form of a phased array antenna comprises a first antenna array and a second antenna array, a calibration circuit, and a foldable power transformer. The calibration circuit is electrically connected to the first antenna array. The first antenna array is electrically coupled to the second antenna array via the foldable power transformer when the foldable power transformer is arranged in a first position. The foldable power transformer mechanically connects the first antenna array to the second antenna array in each of the first position and a second position, wherein the first antenna array is arranged at an angle with respect to the second antenna array when the foldable power transformer is in the first position.

[0012] In one embodiment, the first antenna group is arranged in a horizontal plane and the second antenna group is arranged in a vertical plane when the foldable power transformer is in the first position.

[0013] In one embodiment, the calibration circuit includes an external signal generator configured to generate a pilot signal, wherein the pilot signal is routed to the first antenna group and the foldable power transformer routes the pilot signal to the second antenna group when the foldable power transformer is arranged in the first position.

[0014] In one embodiment, the pilot signal is a short-duration radio frequency (RF) signal having a continuous sine wave.

[0015] In one embodiment, the foldable power transformer has a primary winding, a secondary winding and a ferrite core.

[0016] In one embodiment, the ferrite core has a first end and a second end, while the first end is connected to the second end via a hinge.

[0017] In one embodiment, the primary winding is arranged at the first end of the ferrite core and the secondary winding is arranged at the second end of the ferrite core.

[0018] In one embodiment, the foldable power transformer comprises a primary winding and a secondary winding, wherein the primary winding and the secondary winding are arranged in parallel and spirally wound around a common core element.

[0019] In one embodiment, the foldable power transformer includes a non-ferrite core.

[0020] In one embodiment, the primary winding is arranged to rotate on the common core member relative to the secondary winding.

[0021] In one embodiment, the foldable power transformer comprises a plurality of primary windings having a first number of turns and a plurality of secondary windings having a second number of turns.

[0022] In one embodiment, the first number of turns is equal to the second number of turns.

[0023] In one embodiment, the calibration circuit comprises a first power splitter coupled to the first antenna group via a first directional coupler and a second power splitter coupled to the second antenna group via a second directional coupler.

[0024] For example, a control unit may communicate with the calibration circuit and the external signal generator, the control unit being configured to feed a pilot signal into the first antenna group and the second antenna group via the external signal generator and the calibration circuit. Fig. Figure 1 shows a schematic of a vehicle with a radar system that includes a 3D antenna assembly. Fig. 2 schematically shows an embodiment of a 3D antenna assembly comprising a first antenna group, a second antenna group and a foldable power transformer. Fig. 3 schematically shows an embodiment of a 3D antenna assembly with a first antenna group, a second antenna group, a foldable power transformer and a calibration circuit. The Fig. 4 and Fig. 5 schematically show embodiments of a foldable power transformer that can be used in an embodiment of the 3D antenna assembly.

[0025] With reference to the drawings, in which like reference numerals correspond to the same or similar components, the Fig. 1 to 5, in accordance with the embodiments disclosed herein, schematically illustrate elements of a vehicle 10 having a radar system 20 including a three-dimensional (3D) antenna assembly 30 having a first antenna array 40 and a second antenna array 50 that are mechanically connected and electrically connected using a foldable power transformer 60. A dynamic calibration circuit 70 having an external signal generator 71 is arranged to interact with the 3D antenna assembly 30 to dynamically calibrate the first antenna array 40 and the second antenna array 50 during operation.The vehicle 10 may include, but is not limited to, a ground vehicle in the form of a commercial vehicle, an industrial vehicle, an agricultural vehicle, a passenger car, an aircraft, a watercraft, a train, an off-road vehicle, a personal transporter, a robot, and the like for the purposes of this description. The vehicle 10 advantageously includes a powertrain 12, a telematics system 14, and a navigation system 16, and may also include an advanced driving assistance system (ADAS) 18 that provides some degree of autonomous vehicle control.

[0026] The 3D antenna assembly 30, in one embodiment, includes the first antenna array 40, which is arranged at an angle relative to the second antenna array 50 when in use. The external signal generator 71 is used to generate and conduct a radio frequency (RF) pilot signal used by the dynamic calibration circuit 70 to dynamically calibrate the first and second antenna arrays 40, 50 of the 3D antenna assembly 30 during operation. The folding power transformer 60 can be implemented with metal coils, which can form a hinge that facilitates folding the 3D antenna assembly 30 to reduce its profile under certain conditions, such as when entering a parking facility.The concepts described here facilitate a calibration process that includes regular and / or periodic calibration of phase and gain parameters without requiring group reception to be shut down for calibration. The calibration process involves injecting the RF pilot signal into all receive paths, which must be coherent in terms of time, phase, etc.

[0027] The radar system 20 provides information about the location and trajectory of vehicles, pedestrians, and other objects in the vicinity of the vehicle 10, which information is forwarded to the ADAS 18 for use, e.g., to inform the driver and to control the vehicle 10 autonomously.

[0028] The ADAS 18, in one embodiment, includes an on-board control system capable of providing a degree of driving automation. The "operator" is the person responsible for operating the vehicle 10, whether actively participating in controlling one or more vehicle functions or controlling autonomous vehicle operation. Driving automation may include various dynamic driving and vehicle functions. Driving automation may include a degree of automatic control or intervention related to a single vehicle function, such as steering, acceleration, and / or braking, with the operator always having overall control of the vehicle 10. Driving automation may include a degree of automatic control or intervention related to the simultaneous control of multiple vehicle functions, such asSteering, acceleration, and / or braking, wherein the operator constantly has overall control of the vehicle. Driving automation may include the simultaneous automatic control of vehicle functions, including steering, acceleration, and braking, wherein the driver relinquishes control of the vehicle 10 for a certain period of time during the trip. Driving automation may include the simultaneous automatic control of the vehicle's driving functions, including steering, acceleration, and braking, wherein the operator relinquishes control of the vehicle for an entire trip. Driving automation includes hardware and control units configured to monitor the spatial environment in various driving modes to perform various driving tasks during dynamic operation.Driving automation may include, as non-limiting examples, cruise control, adaptive cruise control, lane change warning, intervention and control, automatic parking, acceleration, braking, and the like. The ADAS 18 includes one or more vehicle systems and associated control units that provide a degree of driving automation. The vehicle systems, subsystems, and control units associated with the ADAS 18 are implemented to perform one or more operations associated with autonomous vehicle functions, including, as non-limiting examples, adaptive cruise control (ACC).Adaptive Cruise Control (ACC), a lane guidance and lane keeping operation, a lane change operation, a steering assistance operation, an object avoidance operation, a parking assistance operation, a vehicle braking operation, a vehicle speed and acceleration operation, a vehicle lateral movement operation, e.g. as part of the lane guidance, lane keeping and lane change operations, etc.

[0029] The telematics system 14 is a communication system capable of communicating outside the vehicle to communicate with a communication network system having wireless and wired communication capabilities. The communication outside the vehicle includes short-range vehicle-to-vehicle (V2V) and / or vehicle-to-everything (V2x) communication. This may include communication with an infrastructure monitor, such as a traffic camera, and communication with a nearby pedestrian, etc. Alternatively or additionally, the telematics system 14 may be capable of establishing short-range wireless communication with a handheld device, such as a cellular phone, a satellite phone, or other telecommunications device.In one embodiment, the handheld device is loaded with a software application including a wireless protocol for communicating with the telematics system 14, and the handheld device performs the off-board communication for communicating with an on-board control unit via a communication network, which may be in the form of a satellite, a cellular antenna, and / or another communication mode. The telematics system 14 may also include a Global Positioning System (GPS) sensor that may be used by the navigation system 16.

[0030] The on-board radar system 20 can be configured as a MIMO (Multiple Input / Multiple Output) system that includes the 3D antenna assembly 30.

[0031] The 3D antenna assembly 30 is arranged as a phased array antenna comprising a first antenna array 40 and a second antenna array 50 that are mechanically interconnected and electrically connected to a foldable power transformer 60. The external signal generator 71 of the calibration circuit 70 is coupled to the first antenna array 40. The 3D antenna assembly 30 includes a transmitter array, a receiver array, a dynamic calibration circuit 70, and a signal construction control unit 80. The elements of the onboard radar system 20 can be configured to operate as a non-linear frequency modulated (NLFM) system in one embodiment.The transmission frequency and associated operating parameters for the NLFM system are selected to achieve the desired values ​​for range, distance resolution, angular resolution, and velocity resolution for the expected operating environment of the vehicle 10. The NLFM system is designed to generate and transmit tansec waveforms that resolve the beam skew error by compensating for the additional phase variation of the skew error.

[0032] In one embodiment, the first antenna group 40 is arranged in a horizontal position in the vehicle, and the second antenna group 50 can be arranged in either a horizontal position (when stowed) or a vertical position (when active).

[0033] The foldable power transformer 60 facilitates the mechanical folding of the second antenna group 50 and also enables real-time calibration of the phase and gain parameters of each path via the calibration circuit 70, online, without having to disable the group reception for calibration.

[0034] The 3D antenna assembly 30 comprises one or more assemblies rotated at an angle to each other. The folding power transformer 60 is used to route the RF pilot signal from the calibration circuit 70 to adjacent assemblies and boards. The folding power transformer 60 can be implemented with metal coils that form a hinge, allowing the 3D antenna assembly 30 to be folded when needed.

[0035] Fig. Figure 2 schematically shows an embodiment of the 3D antenna assembly 30, including the first antenna group 40, the second antenna group 50, the foldable power transformer 60, and the external signal generator 71 of the calibration circuit 70.

[0036] The first antenna group 40 comprises a first plurality of antennas 42a, 42b, ... 42m arranged in a nominal horizontal plane and all electrically connected to the calibration circuit 70.

[0037] The second antenna group 50 comprises a second plurality of antennas 52a, 52b, ... 52n arranged in a nominal vertical plane and all electrically connected to the external signal generator 71 via the foldable power transformer 60.

[0038] Fig. Figure 3 schematically shows further details of an embodiment of the 3D antenna assembly 30, including the first antenna group 40, the second antenna group 50, the foldable power transformer 60, and the calibration circuit 70.

[0039] The first antenna group 40 includes the first plurality of antennas 42a, ... 42m, where "m" represents the numerical number of the first plurality of antennas 42. The first plurality of antennas 42a, ... 42m are all electrically connected to the calibration circuit 70. The calibration circuit 70 includes a 1-to-(m+1) power divider 72 connected to the external signal generator 71, a plurality of directional couplers 76a, ..., 76m, and a plurality of receivers 77a, ..., 77m, all of which are connected to a signal construction control unit 80. The directional couplers 76a, ..., 76m are each implemented as first and second transmission elements arranged in parallel and close enough to each other so that energy passing through one is coupled into the other. When used in this manner, the directional couplers 76a, ... 76m simultaneously feed the RF pilot signal into the signals received from the antennas 42a, ...42m and processed by the multitude of receivers 77a, ... 77m.

[0040] The second antenna group 50 includes the second plurality of antennas 52a, ... 52n, where "n" represents the numerical number of the second plurality of antennas 52. The second plurality of antennas 52a, ... 52n are all electrically connected to the calibration circuit 70. The calibration circuit 70 includes a 1-to-(n) power splitter 74, a plurality of directional couplers 75a, ..., 75n, and a plurality of receivers 73a, ... 73n, all of which are in communication with the signal construction control unit 80. The directional couplers 75a, ... 75n are each implemented as first and second transmission elements arranged in parallel and positioned close enough to each other that energy passing through one is coupled into the other. When used in this manner, the directional couplers 75a, ...75n simultaneously feed the RF pilot signal into the signals detected by the antennas 52a, ...52n and received by the plurality of receivers 73a, ...73n can be processed.

[0041] The external signal generator 71 generates and transmits the RF pilot signal to the 1-to-(m+1) power splitter 72. The 1-to-(m+1) power splitter 72 divides the RF pilot signal into m+1 signals, which are transmitted to the first plurality of antennas 42a, ... 42m of the first antenna group 40, and also generates a second electrical power signal, which is transmitted to the 1-to-(n) power splitter 74 via the folding power transformer 60 and a phase control circuit 90. The 1-to-(n) power splitter 74 divides the second electrical power signal into n signals, which are transmitted to the second plurality of antennas 52a, ... 52n of the second antenna group 50.

[0042] In some cases, the calibration signal (local oscillator / LO signal) split between the first and second power dividers 72, 74 is too weak to be received by the second power divider 74 due to various design constraints. In such cases, the signal may need to be amplified. An amplifier introduces an unknown phase shift. The phase-locked loop 90 includes a selectable phase-locked loop to account for the unknown phase shift during the calibration process.

[0043] Fig. Figure 4 schematically shows an embodiment of the foldable power transformer 60 that can be used in an embodiment of the 3D antenna assembly 30 described herein. The foldable power transformer 60 includes a split ferrite core 61 having a first end 62 and a second end 63, the first and second ferrite ends 62, 63 being connected by hinges 64 and locking mechanisms 65. Primary windings 66, consisting of Np turns and originating from the calibration circuit 70 and the first antenna group 40, are shown at the first end 62 of the split ferrite core 61, and secondary windings 67, consisting of Ns turns and coupled to the second antenna group 50, are shown at the second end 63 of the ferrite core 61.

[0044] Fig. 5 schematically shows an embodiment of the foldable power transformer 560 used in an embodiment of the 3D antenna assembly 30 described with reference to Fig. 2. The hinged power transformer 560 is arranged with primary windings 561 and secondary windings 562, wherein the primary windings 561 and the secondary windings 562 are arranged in parallel and spirally wound around a common core element 563. The common core element 563 may be cylindrically shaped and is arranged to act as a hinge 564. In one embodiment, the common core element 563 is made of a ferritic material, e.g., steel. In one embodiment, the common core element 563 is made of a non-ferritic material, e.g., a polymer. In one embodiment, the primary windings 561 are embodied as Np turns and the secondary windings 562 as Ns turns. In one embodiment, the Np turns of the primary windings 561 are equivalent to the Ns turns of the second windings 562.

[0045] A radar calibration process includes one or more algorithms executed in or by the signal constructor control unit 80 to control elements of the calibration circuit 70 and the radar system 20 to dynamically calibrate the radar system 20 during its ongoing operation. The radar calibration process includes generating the RF pilot signal via the external signal generator 71 and directing the RF pilot signal to the first plurality of antennas 42a, ... 42m and the second plurality of antennas 52a, ..., 52n during a portion of the idle periods. The RF pilot signal is simultaneously injected into all receive channels 77, 73 of the antenna groups 40, 50 using the first and second power splitters 72, 74. The RF pilot signal is injected into each of the channels via directional couplers 76, 75.The RF pilot signal may experience different delays and attenuations in the receive channels of the antenna array due to imbalances in the circuitry of the receive channels, which can be caused by manufacturing variations, aging, temperature, etc. If the RF pilot signal is a continuous sine wave (CW), a delay difference between the channels that is shorter than one cycle of the RF pilot signal will manifest as a phase shift and a variation in signal gain. The phase shift can be estimated relative to a reference channel, which is one of the receive channels.The calibration process includes introducing gain and phase shift adjustments for each of the receive channels to eliminate the effects of inter-channel delays and attenuations to enable coherent signal reception in a signal build-up controller of the on-board radar system 20 related to the location and trajectory of vehicles, pedestrians, and other objects in the vicinity of the vehicle 10.

[0046] The term "control unit" and related terms such as control module, module, controller, control device, processor, and similar terms refer to one or various combinations of application-specific integrated circuits (ASICs), electronic circuits, central processing units, e.g., microprocessors, and associated non-transitory memory components in the form of memory and storage devices (read-only memory, programmable read-only memory, random access memory, hard disk, etc.). The non-transitory memory component is capable of storing machine-readable instructions in the form of one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices, signal conditioning and buffer circuits, and other components accessible by one or more processors to provide the described functionality.Input / output circuits and devices include analog-to-digital converters and related devices that monitor inputs from sensors, where such inputs are monitored at a preset sampling frequency or in response to a triggering event. Software, firmware, programs, instructions, control routines, code, algorithms, and similar terms refer to sets of instructions executable by control units, including calibrations and lookup tables. Each control unit executes control routine(s) to provide the desired functions. The routines may be executed at regular intervals, such as every 100 microseconds during ongoing operation. Alternatively, the routines may be executed in response to a triggering event.Communication between controllers and communication between controllers, actuators, and / or sensors may be via a direct-wired point-to-point connection, a networked communication bus connection, a wireless connection, or any other suitable communication link. Communication includes the exchange of data signals in any suitable form, e.g., electrical signals over a conductive medium, electromagnetic signals over air, optical signals over fiber optics, and the like. The data signals may be discrete, analog, or digitized analog signals representing inputs from sensors, actuator commands, and communication between control units. The term "signal" refers to a physically perceptible indicator that conveys information and may be a suitable waveform (e.g.,electrical, optical, magnetic, mechanical or electromagnetic), such as direct current, alternating current, sine waves, triangular waves, square waves, vibrations and the like, which can propagate through a medium.

[0047] The teachings may be described herein in terms of functional and / or logical block components and / or various processing steps. Such block components may consist of hardware, software, and / or firmware components configured to perform the specified functions. Embodiments consistent with the present description may be embodied as a device, method, or computer program product. Accordingly, the present description may take the form of a pure hardware variant, a pure software variant (including firmware, resident software, microcode, etc.), or a variant combining software and hardware aspects, generally referred to herein as a "module" or "system."Furthermore, the present description may take the form of a computer program product embodied in a tangible medium of expression in which computer-usable program code is embodied.

Claims

[1] Antenna array system comprising: a phased array antenna (30) having a first antenna group (40) and a second antenna group (50), a calibration circuit (70), and a foldable power transformer (60); wherein the calibration circuit (70) is electrically connected to the first antenna group (40); wherein the first antenna group (40) is electrically coupled to the second antenna group (50) via the foldable power transformer (60) when the foldable power transformer (60) is arranged in a first position; wherein the foldable power transformer (60) mechanically connects the first antenna group (40) to the second antenna group (50) in the first position and a second position, respectively; and wherein the first antenna group (40) is arranged at an angle with respect to the second antenna group (50) when the foldable power transformer (60) is in the first position. [2] The antenna array system of claim 1, wherein the first antenna array (40) is arranged in a horizontal plane and the second antenna array (50) is arranged in a vertical plane when the foldable power transformer (60) is arranged in the first position. [3] Antenna array system according to claim 1: wherein the calibration circuit (70) includes an external signal generator (71) and wherein the external signal generator (71) is configured to generate a pilot signal; wherein the pilot signal is supplied to the first antenna group (40); and wherein the foldable power transformer (60) transmits the pilot signal to the second antenna group (50) when the foldable power transformer (60) is arranged in the first position. [4] The antenna array system of claim 3, wherein the pilot signal comprises a short-term radio frequency (RF) pilot signal having a continuous sine wave. [5] Antenna array system according to claim 1, wherein the foldable power transformer (60) has a primary winding (66), a secondary winding (67) and a ferrite core (61). [6] Antenna array system according to claim 5, wherein the ferrite core (61) has a first end (62) and a second end (63), while the first end (62) is coupled to the second end (62) via a hinge (64). [7] Antenna array system according to claim 6, wherein the primary winding (66) is arranged at the first end (62) of the ferrite core (61) and the secondary winding (67) is arranged at the second end (63) of the ferrite core (61). [8] Antenna array system according to claim 1, wherein the foldable power transformer (560) comprises a primary winding (561) and a secondary winding (562), the primary winding (561) and the secondary winding (562) being arranged in parallel and spirally wound around a common core element (563). [9] The antenna array system of claim 8, wherein the foldable power transformer (560) includes a non-ferrite core.

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