Radar sensor device and method for operating a radar sensor device, radar system and vehicle

Abstract

The invention relates to a radar sensor device (3) for a vehicle (1), having an optical input (8) for receiving an optical transmission signal (6), a transmitting device (13) for transmitting an electrical radar transmission signal (15) based on the optical transmission signal (6) into an environment (17) of the vehicle (1), a receiving device (14) for receiving an electrical reception signal (16) corresponding to the electrical radar transmission signal (15) and reflected in the environment (17), and an optical ring resonator (19) which generates an optical output signal (11) from the optical transmission signal (6), having a conversion device (20) which is designed to modulate the electrical reception signal (16) into an optical signal which runs in the optical ring resonator (19) or is coupled into the optical ring resonator and to modulate the optical output signal in accordance with the coupled-in electrical reception signal (16). Furthermore, the invention relates to a radar system (2), a vehicle (1) and a method for operating a radar sensor device (3).

Description

Technical Field

[0001] This invention relates to a radar sensor device for vehicles. The radar sensor device has an optical input terminal for receiving optical transmission signals and a transmitting device for transmitting an electrical radar transmission signal based on the optical transmission signals in a vehicle environment. Furthermore, the radar sensor device includes a receiving device for receiving an electrically received signal corresponding to the electrical radar transmission signal and reflected in the environment. The radar sensor device includes an optical ring resonator that generates an optical output signal based on the optical transmission signals.

[0002] Furthermore, the present invention relates to a radar system having at least one radar sensor device and a central electronic computing device. Similarly, the present invention relates to a vehicle equipped with a radar system. Also, the present invention includes a method of operating a radar sensor device. Background Technology

[0003] WO 2017 / 138949 A1 discloses several electro-optic modulators and microwave photonic connections. In an electro-optic modulator, the modulator couples a light source that provides optical power to a high-frequency source that provides high-frequency power. The electro-optic modulator includes a wave marker (Wellenreiter) that receives optical power and a first ring resonator modulator and a second ring resonator modulator that receive high-frequency power.

[0004] Furthermore, US 2020 / 0235703 A1 discloses a high-frequency oscillator having an optical resonator as a ring waveguide. The high-frequency oscillator allows a first wave to propagate in a first direction and a second wave to propagate in a second direction, wherein the second direction is opposite to the first direction. The resonator includes an active optical medium that generates a first ray from the first wave and a second ray from the second wave.

[0005] US 2016 0337041 A1 discloses a device including an optical input configured to receive an optical carrier.

[0006] DE 10 201 6 210 771 B3 discloses a vehicle having a detection device for angle-resolved detection of the vehicle environment by radar method.

[0007] In addition, US 202 / 0 011 432 A1 discloses a coherent lidar system for improving signal-to-noise ratio (SNR).

[0008] In addition, DE 10 201 9 124 553 A1 discloses a chip-level lidar system with improved range. Summary of the Invention

[0009] The technical problem to be solved by this invention is to provide a more compact and efficient radar system for environmental detection for vehicles.

[0010] This problem is addressed by radar sensor devices, radar systems, vehicles, and methods used in transportation.

[0011] One aspect of the present invention relates to a radar sensor device for a vehicle, comprising:

[0012] - An optical input terminal used to receive optical transmission signals.

[0013] - A transmitting device for transmitting optically transmitted radar signals into a vehicle environment.

[0014] - A receiving device for receiving an electrical signal corresponding to an electromagnetic radar transmitted signal and reflected in the environment; and

[0015] - An optical ring resonator that generates an optical output signal based on the optical transmission signal. The optical ring resonator has the following characteristics:

[0016] - A conversion device designed to modulate an electrically received signal into an optical signal operating in an optical ring resonator or coupled into an optical ring resonator, and modulate an optical output signal according to the coupled electrically received signal.

[0017] The radar sensor device of the present invention provides a more compact radar or radar system for vehicles, thereby reducing power requirements. In particular, the radar sensor device has a smaller installation space or space requirement, making it more space-efficient for use in radar systems within vehicles.

[0018] For example, the radar sensor device of the present invention enables the use of standard telecommunications lasers within the radar sensor device. In particular, this eliminates the complex and expensive design of gigahertz circuitry for the frequency interaction of RF signals and optical carriers. After conversion from the terahertz spectral range, the gigahertz signal, in particular, is stabilized. This results in a reduction in chip area compared to conventional electronics. For example, the conversion device replaces the Epic chip. The ring circuitry is particularly easy to implement, where the high quality factor of the optical ring resonator requires low power from the laser, thus compensating for coupling losses, and many chips can be operated with a single source. The gigahertz signal is inherently and stably stable. In particular, low-noise signals can be provided. The signal-to-noise ratio (SNR) can be increased with the aid of the conversion device. In particular, the radar sensor device according to the invention is more sensitive to polarization. Furthermore, the radar sensor device according to the invention requires lower power demands, and in particular, requires less installation space.

[0019] In particular, the transmitting and receiving devices on a single semiconductor chip can be integrated into, for example, CMOS, SiM-CMOS, Bi-CMOS, hybrid Bi-CMOS, or integrated onto a photonics-electronics co-integrated chip using a specific process. Therefore, for example, with the aid of this invention, radar sensor devices can be manufactured in mass production using standardized semiconductor processes.

[0020] In particular, the conversion device of this invention can better realize the connection between the optical fiber loop circuit and multiple photonic semiconductor chips. Currently, microstrip conductor systems are used to achieve high-resolution radar systems in the automotive field. This results in a three-dimensional conductor structure radiating in the millimeter wavelength range, which requires additional three-dimensional mounting space. This can be improved by the radar sensor device of this invention. With this conversion device, the limitation of antenna geometry on the detectable spectrum range can be reduced.

[0021] In particular, the radar sensor device of the present invention can perform frequency conversion from terahertz carrier signal to gigahertz frequency range according to optical signal transmission, and conversely, can modulate and receive gigahertz signal on terahertz carrier signal.

[0022] The radar sensor device of this invention enables the use of a ring resonator in a semiconductor as an antenna structure and photonic-electronic cointegration for frequency modulation. In particular, the proposed radar sensor device can be used in motor vehicles. Specifically, it can be used in, for example, at least partially autonomous motor vehicles, and especially fully autonomous motor vehicles. For such autonomous driving, safe environmental perception is essential, and this perception can be achieved through the radar sensor device of this invention. Therefore, sensors such as radar, lidar, and cameras can be used to detect the surrounding environment. These are examples of potential applications of radar sensors. With the radar sensing device, a 360-degree overall three-dimensional detection of the surrounding environment can be achieved, thereby enabling the detection of all static and dynamic objects.

[0023] Radar sensor devices can serve as an alternative to lidar, as lidar plays a crucial role in redundant and robust environmental detection because this type of sensor can measure distances and angles more accurately and can also be used for classification in environmental detection.

[0024] In particular, radar sensor devices can be used in, for example, at least partially autonomous vehicles, but especially in fully autonomous vehicles. However, safe environmental perception is essential for achieving such autonomous driving. This is achieved through sensors such as radar, lidar, or cameras to detect the surrounding environment. Particularly important is 360-degree three-dimensional detection of the environment to detect all static and dynamic objects. Radar sensor devices can be used for this purpose. LiDAR, in particular, plays a crucial role in redundant and robust environmental detection because this type of sensor can more accurately measure distances in the environment and can also be used for classification. However, these lidar sensors are costly and complex in structure. 360-degree three-dimensional environmental detection is particularly challenging because it either requires many small individual sensors to ensure this, which typically work with many individual light source and detector elements, or it requires large lidar sensors. Furthermore, lidar sensors are susceptible to weather conditions such as rain, fog, or direct sunlight. Radar sensor devices can address this problem.

[0025] Radar sensors or radar sensor devices have been established in automobile manufacturing, providing reliable and fault-resistant data under all weather conditions. Even poor visibility, such as rain, fog, snow, dust, or darkness, has little impact on their perception reliability. However, according to existing technology, the resolution is currently limited, particularly the resolution of currently used tandem radars, which is only around 7 degrees. To meet the requirements of increased automation in automobile manufacturing with safe driving functions, it is envisioned that radar sensor devices provide three-dimensional images with high angular resolution in the range of 0.1 degrees and below, and are highly insensitive to interference from their surrounding environment. Conventional radar technology according to the prior art cannot achieve this because the resolution of such systems is too low. The radar sensor device according to the present invention can advantageously address this challenge.

[0026] Radar sensor devices can be designed as photonic radar sensor devices, achieving increased resolution by co-integrating electronic and photonic components on a single semiconductor chip. Tracking of the FMCW signal, as well as the entire signal processing and evaluation, is performed at a central station. Each transmit and receive module has an electro-photonic co-integrated chip, the so-called Epic chip. Silicon photonics technology is used for cointegration. This allows photonic devices, high-frequency electronics, and digital electronics to be monolithically integrated onto a single chip. The technological innovation of this system lies in using optical carrier signals in the terahertz frequency range to transmit gigahertz signals. The central station, also known as a central electronic computing unit, generates the terahertz optical carrier frequency. At this optical carrier frequency, the signal to be transmitted is modulated to one-eighth of the radar frequency and sent to the antenna chip via optical fiber. Frequency multiplication occurs on the antenna chip, allowing radar radiation to be emitted from it. Signal detection is performed in the reverse manner. All data is processed at the central station.

[0027] However, such an implementation is highly complex in the realization of gigahertz electronics at the chip level. In particular, the frequency doubling that occurs on the chip after detection by a photodiode is technically challenging, posing a significant challenge for generating gigahertz signals with high signal-to-noise ratios and minimal jitter. Therefore, the gigahertz signal must be painstakingly stabilized in further steps. Furthermore, gigahertz electronics are expensive. Moreover, the high power requirements for optical carriers, especially lasers, to generate high-precision gigahertz signals make it difficult to implement a loop with a single phase for radar arrays with many distributed radar semiconductor chips. In particular, two photonic-electronic semiconductor chips are still required for each transmit and receive channel, leading to further cost expenditures. The radar sensor device according to the invention at least partially, and particularly entirely, solves the aforementioned problems.

[0028] In particular, this invention utilizes the fact that in photonic semiconductors, radiation from a laser device is coupled in via an optical interface, and the laser device can also be specifically constructed as a continuous-wave laser. This may relate to the optical transmission signal or carrier signal of a continuous-wave laser. The radiation propagates in a linear waveguide structure within the semiconductor. For example, the semiconductor can be a radar sensor device or a semiconductor chip integrating a radar sensor device. Additional ring waveguide structures, particularly optical ring resonators, are arranged on the semiconductor at a very small distance relative to the linear waveguide structure, such as an optical coupling element. If the distance between the two waveguides is so small that the attenuation field of electromagnetic radiation extends from the linear waveguide to the ring conductor, the radiation from the linear waveguide is coupled into the ring conductor and propagates there. If the optical path length of the ring is chosen to be an integer multiple of the wavelength, the light propagating in the ring conductor will structurally interfere with the coupled attenuation field after one revolution, resulting in reinforcement. Since the interaction region between the linear waveguide and the ring waveguide is within the wavelength range, the interaction duration of the two fields is short, thus only structural interference occurs. This forms an optical ring resonator. Compared to the losses incurred, more laser radiation is coupled into the ring conductor until the power within the resonator reaches saturation. A portion of the light propagating within the ring waveguide is coupled back to the linear waveguide after each cycle and can be used as a signal. The ring resonator monitors the light by appropriately selecting the diameter of the waveguide amplitude and the coupling ratio, thereby forming pulses or pulse trains with high peak intensity from a continuous wave input signal. In semiconductors, the diameter of optical ring resonators ranges from hundreds of micrometers to a few micrometers. The cycle time of the light determines the repetition rate f of the output signal or pulse train. rep .

[0029] The ring resonator formed in this way has q>10 6 The high quality factor results in a peak intensity within the resonator, which can facilitate nonlinear optical processes, also known as multiphoton processes. These occur during the interaction of high-intensity light with matter. The development of the polarization p is an existing model describing the multiphoton processes in light-matter interactions.

[0030] P=ε0[X (1) E+X (2) E 2 +X (3) E 3 +X (4) E 4 +…],

[0031] Where p represents the electric pulse, X represents the sensitivity, E represents the electric field, and ε0 represents the electric constant.

[0032] Linear term X with electrical sensitivity (1) The higher-order terms X scale linearly with the electric field, and n>1(n) The relationship between the electric field strength and the frequency of photons is nonlinear. These processes are called multiphoton processes. The number of photons required is X. (n) The nth order. Effects such as harmonics or sum-difference frequency generation require two photons to produce a photon corresponding to the fundamental light frequency, thus inducing second-order nonlinearity in the material. Third-order effects, such as third harmonics or similar, require three photons for third-order frequency conversion. These nonlinear light-matter interactions offer the possibility of nonlinearly modulating the incident light source.

[0033] Therefore, in optical ring resonators, when fully coupled into the ring, the nonlinear refractive index cannot be ignored. For example, due to the Kerr effect, especially at a sensitivity of X... (2) In the case of high peak intensity light interaction in a waveguide, a four-wave mixing process occurs. Due to the increase in intensity in the ring resonator, a degenerate four-wave mixing process occurs first. During this process, the two photons Y of the continuous wave laser... P When absorbed, this is known as optical pumping, where an electron is raised to a virtual or real higher energy level. After a very short time, especially under stimulation, the electron returns to its ground state. It simulates the absorbed energy as a signal photon and an idle sideband photon (Y0, Y0, Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y10, Y10, Y2 ... S and Y I In the form of ), the energy corresponds only to the sum of the photon energies of two photons from the continuous-wave laser. This will generate new spectral units within the ring resonator. The signal and idle sideband photons are correlated in phase, amplitude, and frequency through a coherent formation process. This is achieved by... P To Y S Or Y I The increased frequency conversion causes the ring resonator to become bistable, resulting in slight variances in phase and frequency, thus generating new sidebands. It employs a non-degenerate four-wave mixing method to cascade new frequencies. The newly generated frequencies have fixed phase and frequency relationships with each other, thus the spectral modes are coupled. This mode coupling leads to the development of fundamental solitons, resulting in a pulsed hyperspectral bandwidth that propagates without dispersion within the ring resonator and is reproduced at the resonator frequency frep. Therefore, continuous laser signals, especially optical transmission signals, are pulsed signals with extremely high signal-to-noise ratios (“SNR”) and low time variances.

[0034] To generate pulsed states, other complex waveguide structures can be used. For example, a second waveguide on the opposite side of a ring resonator can be used to couple out the pulse train. Furthermore, an additional resonator ring with coupling points can be used for further coupling between the ring resonators, allowing tuning f... rep The corresponding frequency range. For example, for values ​​of r = 15 μm and r = 5 μm, these ring arrays can generate f respectively.rep =100MHz, especially 80MHz pulses or pulse trains.

[0035] For example, a radar sensor device may have one or more integrated circuits (ICs). For instance, all components of a radar sensor device may be integrated onto a single chip. Alternatively, for example, a transmitting device may be formed as an integrated circuit or chip, and a receiving device may be formed as an integrated circuit or chip.

[0036] In particular, the radar sensor device according to the invention can be used in electromagnetic or optical applications.

[0037] Optical transmission signals can be generated using laser devices, particularly continuous-wave lasers. Based on this optical transmission signal, electrical radar transmission signals can be generated or modulated. This can be transmitted around a vehicle via a transmitting device, transmitting unit, or transmitting module of a radar sensor device. Such transmitted signals can be reflected by objects, for example, around the vehicle. These reflections can be received or detected with the aid of a receiving device or receiving module. For example, a radar sensor device can have multiple receiving channels and / or transmitting channels.

[0038] Therefore, in particular, electronic conversion devices can modulate pulses or optical signals from optical ring resonators such that the output signal or pulse contains at least information about the vehicle environment for environmental detection.

[0039] For example, an optical ring resonator can be part of a switching device. Specifically, the switching device can, for example, control the optical ring resonator.

[0040] With the aid of a conversion device, the optical ring resonator can be used as an antenna. Therefore, radar sensor devices can eliminate the need for an additional antenna because, with the aid of the conversion device, particularly the optical ring resonator, electrical signals can be received and coupled in. Consequently, radar sensor devices can be designed to be more compact.

[0041] In other words, the receiving device and the conversion device are a loop resonator antenna. Therefore, the receiving device, the optical loop resonator, and the conversion device can be collectively referred to as an antenna. Thus, radar sensor devices, especially the receiving module, can operate without a separate receiving antenna. Therefore, the optical loop resonator can be used as either an antenna or a receiving antenna.

[0042] Therefore, no additional components are needed to receive radiation or signals around the vehicle.

[0043] For example, when an external electromagnetic field, especially a transmitted radar signal, encounters a ring structure, particularly an optical ring resonator, it causes temporal modulation of the refractive index within the ring waveguide, particularly the refractive index of the optical ring resonator. This modulates the time-varying period of the light, affecting the pulse repetition rate f. rep It is modulated in time. All characteristics of the external field, especially the environmental characteristics, are thus converted into frequency information of the pulse repetition rate of the output optical signal. These can be evaluated at the central station for environmental detection. By cleverly selecting the resonant dimension, the interaction between the external electromagnetic field and the induced refractive index can be optimized.

[0044] In one embodiment, the conversion device includes an optical coupling element for coupling an electrically received signal into an optical ring resonator, the optical coupling element being directly adjacent to a first side of the optical ring resonator. The optical coupling element can be a linear waveguide or a linear waveguide structure. An optical transmission signal can be coupled into the optical coupling element through an optical input terminal. Therefore, by means of the optical coupling element into which the optical transmission signal is coupled, a received electrically received signal can be coupled into the optical ring resonator. Specifically, an electrically received signal, for example, a gigahertz signal, can be modulated into an optical signal operating in the optical ring resonator. Thus, the electrical signal can be modulated into an optical signal operating in the optical ring resonator based on the optical transmission signal, or coupled into the optical ring resonator.

[0045] In particular, the coupling element and the optical ring resonator can be respectively set on the same integrated circuit and chip.

[0046] Specifically, the various units or devices of a radar sensor apparatus can be co-integrated on photonic and electrophotonic chips. In particular, the conversion device, transmitting device, receiving device, optical ring resonator, and / or optical coupling element can be integrated on an optical carrier substrate. Integration using a polymer substrate is also conceivable. Specifically, the conversion device can be used as an antenna for receiving radiation by means of the optical coupling element and the optical ring resonator. In particular, through the arrangement of the coupling elements, especially the conversion device, the optical ring resonator can be used as an antenna for receiving radiation, particularly electromagnetic radiation.

[0047] In one embodiment, a predetermined coupling distance is further specified between the optical coupling element and the optical ring resonator, wherein the predetermined coupling distance affects the coupling of the electrically received signal into the optical ring resonator. Specifically, the predetermined coupling distance is adjustable, parameterizable, or predetermined. In other words, the coupling element to the optical ring resonator is arranged such that a gap or distance exists between the optical ring resonator and the coupling element. The coupling distance can particularly affect the coupling ratio, thereby affecting the electric or electromagnetic field between the coupling element and the ring resonator.

[0048] For example, the interaction between an external electromagnetic field (e.g., a received signal) and the induced refractive index within a ring resonator can be modulated or altered by adjusting the coupling distance. The modulation depth of the refractive index can be adjusted, particularly optimized, by regulating the coupling distance or gap between the ring waveguide, particularly an optical ring resonator, and the linear waveguide, particularly an optical coupling element. Furthermore, in addition to the distance between the coupling element and the ring resonator, the diameter and / or size of the ring resonator can also be considered to influence or adjust the coupling. Therefore, the interaction between the coupling element and the ring resonator can be adapted or adjusted according to the diameter or size of the ring resonator. Specifically, fine-tuning of the resonance conditions can be achieved by adjusting the diameter of the ring resonator and the coupling distance.

[0049] For example, the coupling distance can be preset in the micrometer or nanometer range. For example, the diameter of the ring resonator varies from 600 μm to 1200 μm. In particular, the coupling distance, and especially the diameter of the ring resonator, can be adapted to various applications, particularly radar applications. For example, a ring resonator with a radius of 600 μm can control frequencies up to 80 GHz.

[0050] In one embodiment, the conversion device has an additional optical coupling element for coupling the generated pulse train from the optical ring resonator. This additional optical coupling element is arranged on a second side of the optical ring resonator opposite to the first side of the optical ring resonator. Therefore, the generated, particularly modulated, optical output signal can be coupled from the optical ring resonator and provided or transmitted to the optical or electrical output of, for example, a radar sensor device via the further optical coupling element. Thus, the modulated optical output signal, particularly including environmental or radar information, can be further processed or transmitted for evaluation. For example, the additional optical coupling element can be a coupling element similar to the original optical coupling element. The additional optical coupling element can be a waveguide. Specifically, the optical coupling element can be arranged or integrated on a carrier substrate or semiconductor chip, such that the ring resonator can be arranged between these two. Specifically, the additional optical coupling element can be spaced apart from the optical ring resonator.

[0051] For example, an optical coupling element, specifically referred to as the first coupling element, can be arranged in parallel with another coupling element, referred to as the second coupling element. Therefore, two different optical coupling elements can be arranged, particularly adjacent to, on two opposite sides of the optical ring resonator. For example, the second coupling element can be located at different points or positions within the optical ring resonator compared to the first coupling element. Specifically, the two coupling elements are arranged opposite each other.

[0052] In particular, an optical ring resonator is a special type of optical resonator. For example, an optical ring resonator consists of several, especially four, mirrors that guide the laser beam into a closed path. The laser beam can be guided onto intersecting paths or onto a quadrilateral path.

[0053] In one embodiment, the optical coupling element is further specified to provide the pulse train as an optical output signal to the optical output terminal of the radar sensor device. Therefore, the modulated pulse train can be provided as an optical output signal to, for example, a central electronic computing device. Thus, additional coupling elements, such as if formed as waveguides, can transmit the pulse train to the optical output terminal or further transmit it.

[0054] In one embodiment, the radar sensor device is further specified as a single-chip microcomputer system or a multi-chip microcomputer system. For example, the radar sensor device can be formed as a single unit, such that, for example, the transmitting device and the receiving device, i.e., the receiving module and the transmitting module, are integrated on a single unit and a single chip. It is also conceivable that the radar sensor device has multiple transmitting modules and receiving modules. This can be considered depending on the application of the radar sensor device.

[0055] In one embodiment, the optical ring resonator is further specified to be either ring-shaped or elliptical. Therefore, optical ring resonators, and especially optical resonators in general, can have various geometries. This may vary depending on the application of the radar sensor device. Thus, offset resonator geometries can be used, allowing radar sensor devices to be used more broadly and independently in radar applications.

[0056] In one embodiment, the optical ring resonator is configured as a miniature ring resonator. Therefore, the optical ring resonator can be designed as a compact, space-saving transducer element. Consequently, radar sensor devices, particularly radar systems, can be used more space-efficiently and compactly.

[0057] Another aspect of the invention relates to a radar system having at least one radar sensing device according to the preceding aspect and a central electronic computing device, wherein the central electronic computing device is configured to generate a transmission optical signal for the radar sensing device and receive an output optical signal, and the central electronic computing device is coupled to the optical input end and optical output end of the radar sensing device respectively via at least one optical fiber (or glass fiber).

[0058] This radar system can be used specifically in motor vehicles or automated systems, or in aviation or space technologies. Further possibilities for the design of the radar system and / or radar sensor device according to the invention can be used for polarization-sensitive detection through shaped antenna geometry.

[0059] Similarly, one application in data transmission could be in the 5G band or beyond. Furthermore, this use of an optical ring resonator as a receiving antenna could be used for data transmission in Car-2-X applications, such as software updates, map updates, and infrastructure signals. Likewise, radar sensor devices can be used as passive detector elements for environmental perception. It is also conceivable that it could be used to detect radiation used for communications, such as radio, telecommunications, satellite communications, or similar camera systems.

[0060] In particular, the aforementioned proposed radar system may have radar sensor devices as described in the preceding aspect. Specifically, the radar system may have multiple radar sensor devices.

[0061] Radar sensor devices can be co-integrated transmitting and / or receiving units that use a special structure or arrangement of optical ring resonators as antennas.

[0062] Radar systems are particularly advantageous for use in motor vehicles because they require sensor systems distributed around the vehicle for effective environmental perception. Therefore, multiple radar sensor units can be distributed across the vehicle and networked communicatively via a central electronic computing unit. Consequently, a radar system requires a single, central electronic computing unit, essentially a central station. This central electronic computing unit can power the various radar sensor units via optical transmission signals, and can also receive optical output signals or other signals at the respective optical output terminals of the radar sensor units.

[0063] Specifically, the central electronic computing device is a physically separate unit from the radar sensor device. In particular, the central electronic computing device is not part of the radar sensor device. Unlike the radar sensor device, the central electronic computing device can be a different semiconductor chip or integrated circuit.

[0064] For example, a central electronic computing device can be used to track frequency modulated continuous wave (FMCW) signals and perform the entire signal processing and evaluation. Transmission and reception operations can be performed sequentially using radar sensor devices.

[0065] In particular, the central electronic computing unit can generate carrier frequencies in the terahertz frequency range, especially for optical transmission signals. At this carrier frequency, the signal to be transmitted, especially the optical transmission signal, is modulated with one-eighth of the radar frequency of the radar system, and the optical phase, amplitude modulation, or frequency modulation is sent to the radar sensor device respectively. In this way, an eight-fold frequency is formed, so that radar radiation, especially the radar transmission signal, can be transmitted. Signal detection is performed in the reverse manner. All data is processed at the central station, specifically the central electronic computing unit.

[0066] The central electronic computing unit is coupled to the optical input and output ends of the radar sensor device via one or more optical fibers. Therefore, the optical transmission signal generated by the central electronic computing unit is coupled into the optical fiber and transmitted to the optical input end of the radar sensor device via optical signal transmission. Thus, the transmission of the carrier signal or radar drive signal occurs through the optical transmission path. Specifically, the optical fiber can be an optical fiber line. The central electronic computing unit is also coupled to the optical output end via optical fiber. Thus, the radar sensor device, especially the modulation device of the radar sensor device, can couple the output optical signal into the optical fiber and transmit it to the central electronic computing unit for evaluating the received radar radiation.

[0067] In another embodiment, the central electronic computing device includes a laser device configured to generate an optical transmission signal and couple it into at least one optical fiber coupled to the optical input terminal of the radar sensor device. Furthermore, the central electronic computing device includes an optical receiving unit configured to receive an optical output signal via at least one optical fiber (coupled to the optical output terminal of the radar sensor device).

[0068] In particular, by means of a laser device, especially a continuous-wave laser, the optical transmission signal can be generated or produced based on a carrier signal, especially based on the carrier frequency. For this purpose, electrical control signals can be specifically considered. The optical receiving unit may additionally have an evaluation unit, which can be used to evaluate the output optical signal received from the optical receiving unit.

[0069] For example, a central electronic computing device may have fiber optic output and fiber optic input.

[0070] In a further embodiment, the central electronic computing device is provided with a processing unit, particularly an electronic computing unit, configured to determine the pulse train frequency of the received output optical signal and to determine at least one piece of radar information based on the pulse train frequency.

[0071] In particular, the pulse train frequency can be the pulse repetition rate f rep It is modulated in a pulse train via an optical ring resonator for re-evaluation with the aid of a processing unit, particularly for obtaining radar information. Therefore, the output optical signal contains frequency information of the modulated pulse train. For example, the pulse repetition rate can be evaluated through photocurrent measurement, heterodyne measurement, or homodyne measurement.

[0072] Another aspect of the invention relates to a vehicle having a radar system according to the preceding aspect or an improved design thereof. Specifically, the aforementioned vehicle or motor vehicle includes a radar system according to the preceding aspect.

[0073] Therefore, for example, radar systems can be used for environmental detection in vehicles.

[0074] For example, the vehicle can be a passenger car or a freight car. For example, the vehicle may be highly automated. For example, multiple radar sensor devices can be arranged in an array over a large area inside or on the vehicle. For example, a sparse array configuration can be used.

[0075] For example, multiple individual chip modules or radar sensor devices can be installed in a vehicle and connected to a central electronic computing unit. This can be used, for example, in a vehicle's ADAS (Advanced Driver Assistance System). For instance, radar sensor devices, particularly receiving and / or transmitting modules, can be mounted on the windshield, rear window, roof, or bumper.

[0076] Another aspect of the invention relates to a method for operating a radar sensor device according to any of the foregoing aspects, or an advantageous improvement thereof, wherein the optical transmission signal is coupled into an optical ring resonator according to an attenuation field caused by the optical transmission signal. An optical output signal is generated in the optical ring resonator according to the coupled optical transmission signal through a four-wave mixing process (or four-wave frequency mixing process), and the refractive index of the optical ring resonator is modulated by the coupled electrical receiving signal, thereby modulating the pulse train frequency of the optical output signal.

[0077] In particular, when the optical transmission signal approaches the optical ring resonator at a predetermined coupling distance via an optical coupling element, an attenuation field is advantageously generated. If this distance is specifically chosen to satisfy the resonance condition, the optical transmission signal is completely, and in particular at least partially, coupled into the optical ring resonator by means of the attenuation field acting specifically around the optical coupling element.

[0078] Specifically, using the laser device of the central electronic computing unit, a transmission optical signal is generated through a four-wave mixing process and coupled into an optical ring resonator, resulting in an output optical signal or a pulse train with a pulse repetition rate within the optical ring resonator. The refractive index within the optical ring resonator is modulated by the received electrical signal, particularly by an external electromagnetic field, and the pulse repetition rate of the pulse train is also modulated. Therefore, the pulse repetition rate is modulated in time, such that the frequency of the modulated pulse train is proportional to both the detected radar radiation and the received signal. This can then be evaluated within the central electronic computing unit.

[0079] In another embodiment of a further aspect, the pulse train frequency is specified to be modulated based on the diameter of the optical ring resonator and / or the coupling ratio between the optical coupling element and the optical ring resonator. The modulation of the pulse repetition rate of the optical output signal can be influenced by the diameter of the ring resonator or the geometry or size of the ring resonator. The coupling distance between the coupling element and the optical ring resonator is also important.

[0080] In a further embodiment, it is specified that at least one piece of information from the electrically received signal is converted into frequency information of the pulse train frequency by modulating the pulse train frequency. Therefore, at least one piece of radar information, particularly information about the environment of the vehicle, can be converted into information in the pulse train frequency, which can then be evaluated in a central electronic computing unit. In particular, the optical signal within the ring resonator is modulated according to the electrically received signal, particularly an external electric field. In this case, the refractive index can be modulated, for example, by a received signal configured as a 77 GHz signal, causing a change in the frequency of the pulse sequence or pulse train.

[0081] Embodiments of certain aspects of the invention are advantageous embodiments of other aspects. In particular, each embodiment of a particular aspect can be regarded as an advantageous embodiment of all other aspects. This also applies in reverse manner.

[0082] Advantageous designs for radar sensor devices should be considered advantageous designs for radar systems, vehicles, and methods. Therefore, radar sensor devices, radar systems, and vehicles possess practical features that allow for the implementation of the method or its advantageous design.

[0083] The present invention also includes improvements to the radar system, vehicle, and method according to the invention, which have the features already described related to the improvements to the radar sensor device of the invention. For this reason, corresponding improvements to the radar system, vehicle, and method of the invention will not be described herein.

[0084] The present invention also includes combinations of features of the embodiments described. Attached Figure Description

[0085] The following describes embodiments of the present invention. In the accompanying drawings:

[0086] Figure 1 A schematic diagram of a vehicle equipped with a radar system is shown.

[0087] Figure 2 Show Figure 1 A schematic diagram of the radar system block diagram;

[0088] Figure 3 As shown Figure 2 The diagram shows a radar system receiving device.

[0089] Figure 4 Show Figure 3 Another schematic diagram of the receiving direction;

[0090] Figure 5 Show Figure 3 Another embodiment of the receiving direction; and

[0091] Figure 6 Show Figure 1 An embodiment of a radar system with multiple coupled receiving directions. Detailed Implementation

[0092] The embodiments explained below are preferred embodiments of the present invention. In the embodiments, the described components represent individual, independently conceived features of the present invention, which also independently improve the present invention, and therefore can be considered as part of the present invention individually or in combinations different from those shown. Furthermore, the described embodiments may be supplemented by other features among those already described in the present invention.

[0093] In the diagram, components with the same function are labeled with the same reference symbol.

[0094] Figure 1 A schematic diagram of a vehicle 1 is shown, which may be a motor vehicle. For example, vehicle 1 includes a radar system 2.

[0095] For example, radar system 2 can be a sensor system or an environmental sensor system for vehicle 1. For this purpose, radar system 2 can be networked and communicate with, for example, one or more driver assistance systems or other vehicle systems. For example, radar system 2 can be a radar sensor, a lidar sensor, or other types of sensors, particularly sensors for vehicles. Besides its use in vehicle 1, radar system 2 can also be used in non-vehicle systems.

[0096] Figure 2An example view of radar system 2 is shown. Radar system 2 may have at least a radar sensor device 3 and a central electronic computing device 4. For example, the radar sensor device 3 and the central electronic computing device 4 may be separate and physically distinct units. The central electronic computing device is a central unit. For example, the central electronic computing device 4 may generate an electrical control signal, which can be used to drive or control a laser device 5. For example, the laser device 5 may be a continuous wave laser. With the aid of the laser device 5, an optical transmission signal and a carrier signal 6 may be generated separately. In particular, the optical transmission signal 6 may be referred to as an optical carrier signal in the terahertz frequency range. The central electronic computing device 4 may, for example, generate an optical carrier frequency. At this optical carrier frequency, the signal to be transmitted is modulated to one-eighth of the radar frequency and transmitted, for example, to the radar sensor device 3. In this way, the frequency can be increased eightfold. Again, with the aid of the radar sensor device 3, signals in the gigahertz frequency range can be received and transmitted to the central electronic computing device 4.

[0097] For example, the central electronic computing device 4 can be coupled to the optical input terminal 8 and optical output terminal 9 of the radar sensor device 3 via at least one optical fiber 7. Therefore, bidirectional signal transmission can be performed between the central electronic computing device 4 and the radar sensor device 3.

[0098] The central electronic computing device 4 may also include an optical receiving unit 10, which is configured to receive the optical output signal 11 provided by the optical output terminal 9 of the radar sensor device 3. Therefore, the central electronic computing device 4 can be coupled to the radar sensor device 3 via an optical fiber or an electronic interface such as Ethernet. In particular, multiple radar sensor devices can be coupled to the central electronic computing device 4. For example, the central electronic computing device 4 may each have a processing unit 12 and a processing unit that can process the received optical output signal. Therefore, signal detection and subsequent data processing can be performed on the received output signal 11.

[0099] In particular, the central electronic computing device 4 may have or provide all necessary control signals, data processing signals, modules and interfaces.

[0100] For example, in addition to the optical input terminal 8 and the optical output terminal 9, the radar sensor device 3 may also have a transmitting device 13 and a receiving device 14. Therefore, the radar sensor device 3 has a receiving module and / or a transmitting module. Specifically, the transmitting device 13 and the receiving device 14 can be integrated on the same chip. It is also conceivable that they are located on different semiconductor chips.

[0101] With the aid of the transmitting device 13, an electrical radar transmission signal 15 based on the optical transmission signal 6 can be transmitted to the environment 17 of the vehicle 1. Therefore, depending on the optical transmission signal 6, a corresponding radar signal 15 can be transmitted. Now, if this signal 15 is reflected in the environment 17 by an object such as a road user, road, tree, or other object, an electrical receiving signal 16 corresponding to the electrical radar transmission signal 15 and reflected in the environment 17 can be received.

[0102] For example, the transmitting device 13 for transmitting may have at least one antenna 18 or antenna element.

[0103] For example, the transmitted radar signal 15 and the received signal 16 can be in the terahertz frequency range or the gigahertz frequency range. Therefore, with the aid of radar system 2, frequency conversion of the terahertz carrier signal, particularly the transmitted signal 6, to the gigahertz frequency range can be performed for transmission. Conversely, modulation can be performed on the terahertz carrier signal to perform the reception of the gigahertz signal.

[0104] In particular, in order to design compact and space-saving radar sensor devices 3 for various applications, the receiving device 14 does not have a conventional antenna and antenna structure compared to the prior art. In this regard, an optical ring resonator 19 is used. For example, a conversion device 20 can be provided for this purpose. It can be designed as a separate unit or as part of the receiving device 14. In particular, the conversion device 20 can be integrated on, for example, an optical carrier substrate, a polymer substrate, a photonic chip, or an electrophotonic chip. The transmission signal 6 can be transmitted separately by means of an optical coupling element 21 or a linear waveguide. The transmission signal 6 can be coupled to the coupling element 21 by means of an input terminal 8. Specifically, the coupling element 21 is arranged adjacent to one side of the optical ring resonator 19, particularly directly adjacent to one side of the optical ring resonator 19. Specifically, the optical coupling element 21 and the ring resonator 19 are arranged relative to each other at a predetermined coupling distance 23 (compare). Figure 4 Therefore, the coupling element 21 and the ring resonator 19 have a gap and a distance from each other, respectively. In particular, the coupling element 21 and the ring resonator 19 do not contact each other. The coupling ratio between the coupling element 21 and the ring resonator 19 can be specified, defined, or set according to the coupling distance 23.

[0105] For example, the transmitted signal 6 can propagate within the coupling element 21. In the interaction region 24, where a specific distance 23 exists, the optical transmitted signal 6 generates an attenuation field 25, thereby coupling the transmitted signal 6 into the optical ring resonator 19. After one cycle within the optical ring resonator 19, the newly coupled field and the field already located within the ring resonator 19 structurally interfere. Thus, amplitude modulation can be generated. A small portion can be coupled out. By increasing the intensity within the optical ring resonator 19, a fundamental soliton is formed, which can be coupled out in the form of a pulse train 26 or an optical output signal (11). Here, a pulse train 26 dependent on the coupled optical transmitted signal 6 can be generated in the ring resonator 19 by means of a four-wave mixing process. Now, as an external electromagnetic field, i.e., the received signal 16 encounters the ring resonator 19 or the ring resonator structure, it induces modulation of the time-varying refractive index within the ring resonator 19. Thus, the time of travel of the light within the ring resonator 19 can be modulated. Thus, the pulse repetition rate f of the output optical signal 11 can be modulated. rep Time modulation is then performed. All characteristics of the external field, i.e., environmental information or radar information, can be converted into pulse repetition rate f. rep Or, in other words, the frequency information of the pulse train. Specifically, the pulse repetition rate f. rep The diameter 27 of the optical ring resonator 19 can be used for comparison. Figure 4 The electromagnetic radiation reception can be modulated by the coupling distance 23 or the coupling ratio between the optical coupling element 21 and the optical ring resonator 19. Therefore, depending on the application and / or radar system, the reception of electromagnetic radiation can be adjusted or adapted by a special arrangement of the ring resonator 19 and the coupling element 21.

[0106] By modulating the pulse train frequency f rep It can convert at least one piece of information from the electrically received signal 16 into the pulse train frequency f of the pulse train 26. rep The frequency information can be evaluated in the central electronic computing unit 4 to detect the environment. By individually selecting the resonator dimension of the ring resonator 19, the interaction between the electromagnetic field and the induced refractive index in the ring resonator 19 can be adjusted or changed.

[0107] Specifically, here, the optical ring resonator 19 is used as a passive device for receiving electromagnetic radiation.

[0108] In addition, another optical coupling element 28, different from coupling element 21, is provided. This is specifically used to couple the generated optical signal 16 from the ring resonator 19. The additional coupling element 28 is disposed adjacent to the second side 29 opposite to the first side 22 of the ring resonator 19. Thus, the ring resonator 19 is disposed between the two coupling elements 21 and 28. The two coupling elements 21 and 28 are spaced apart from each other and also spaced apart from the ring resonator 19. Therefore, the coupling elements 21 and 28 and the ring resonator 19 do not contact each other.

[0109] Specifically, a further coupling element 28, which can be formed as a linear waveguide, can be used to provide an optical output signal 11 to the optical output terminal 9. This signal can then be transmitted to a central electronic computing device 4 for processing and evaluation. In particular, the output optical signal 11 can be evaluated by a processing unit 12. The processing unit 12 can then determine the pulse train frequency f from the optical output signal 11. rep For example, heterodyne or homodyne measurements can be performed. This can be achieved by using the photodiode of processing unit 12 to evaluate the photocurrent of the output optical signal 11. The photocurrent can be compared with f rep It is directly proportional, so at least radar information can be obtained or determined.

[0110] exist Figure 5 An embodiment is shown in which the conversion device 20, specifically the optical ring resonator 19, is integrated at the chip level. For example, EPIC, photonic ICs, multi-chip solutions, or flip-chip solutions can be used. In particular, in Figure 5 The receiving device 14 of the radar sensor device 13 is shown again. For this purpose, for example, a modulation unit 30 can be provided to perform modulation of the pulse train 26. In addition, a diagnostic unit 31 can be used for processing and / or evaluation purposes.

[0111] exist Figure 6 In the middle, once again based on Figure 5 The diagram now shows the integration or fabrication of multiple detector units, particularly receiver unit 14, on semiconductor chip 32. This can be implemented as a single-chip microcontroller system or a dual-chip microcontroller system, for example. Therefore, multiple detector units can be integrated on one or more chips. This is particularly advantageous for applications in vehicle 1, as multiple receiver units can be distributed across vehicle 1.

[0112] Therefore, data can be combined and processed in the central electronic computing unit 4. Thus, continuous processing is also possible.

[0113] Optionally, an electronic back-end 33 for data processing can be integrated on chip 32. Therefore, data preprocessing, such as future extraction, classification via machine learning, hardware acceleration, or partial integration of the functions of the central electronic computing device 4, can be performed.

[0114] In particular, the radar system 2 according to the invention, and especially the radar sensor device 3 according to the invention, allows the use of a ring resonator to receive gigahertz or terahertz radiation. The ring resonator and the optical driving element or readout element can be integrated into a semiconductor structure.

[0115] Therefore, ring resonator receivers can be used for environmental detection (radar or lidar).

[0116] Reference character list

[0117] 1. Transportation

[0118] 2 Radar System

[0119] 3. Radar sensor device

[0120] 4. Central electronic computing unit

[0121] 5. Laser device

[0122] 6. Optical transmission signal

[0123] 7. Optical Fiber

[0124] 8 Optical Input Terminal

[0125] 9. Optical output terminal

[0126] 10 Receiving Unit

[0127] 11. Optical output signal

[0128] 12 processing units

[0129] 13 Launching device

[0130] 14 Receiving device

[0131] 15. Radar transmission signals

[0132] 16 Electrically received signals

[0133] 17 Environment

[0134] 18 antennas

[0135] 19 Optical Ring Resonator

[0136] 20 Conversion device

[0137] 21 Optical coupling element

[0138] 22. First side of the ring resonator

[0139] 23 Coupling distance

[0140] 24. Interaction Zone

[0141] 25 Decay Field

[0142] 26 pulse trains

[0143] 27. Diameter of the ring resonator

[0144] 28 Other optical coupling elements

[0145] 29. Second side of the ring resonator

[0146] 30 Modulation Units

[0147] 31 Diagnostic Unit

[0148] 32 Semiconductor chips

[0149] 33 Backend

[0150] f rep The pulse train frequency of a pulse train.

Claims

1. A radar sensor device (3) for a vehicle (1), comprising: - Optical input terminal (8), used to receive optical transmission signals (6); - Transmitting device (13) for transmitting an electrical radar transmission signal (15) based on an optical transmission signal (6) into the environment (17) of the vehicle (1); - A receiving device (14) for receiving an electrical received signal (16) corresponding to an electrical radar transmitted signal (15) and reflected in the environment (17); and - An optical ring resonator (19) that generates an optical output signal (11) based on the optical transmission signal (6); Its features are, - A conversion device (20) is designed to couple an electrical received signal (16) into an optical ring resonator and modulate an optical output signal according to the coupled electrical received signal (16).

2. The radar sensor device (3) according to claim 1, Its features are: The conversion device (20) has an optical coupling element (21) for coupling the electrically received signal (16) into the optical ring resonator (19), the optical coupling element (21) being directly adjacent to the first side (22) of the optical ring resonator (19).

3. The radar sensor device (3) according to claim 2, Its features are: There is a predetermined coupling distance (23) between the optical coupling element (21) and the optical ring resonator (19), wherein the predetermined coupling distance (23) affects the coupling of the electrically received signal (16) into the optical ring resonator (19).

4. The radar sensor device (3) according to claim 2 or 3, Its features are: The conversion device (20) has an additional optical coupling element (28) for coupling the generated optical output signal (11) out from the optical ring resonator (19). The additional optical coupling element (28) is arranged on the second side (29) of the optical ring resonator (19) opposite to the first side (22) of the optical ring resonator (19).

5. The radar sensor device (3) according to claim 4, Its features are: The additional optical coupling element (28) is designed to provide the output optical signal (11) to the optical output terminal (9) of the radar sensor device (3).

6. The radar sensor device (3) according to claim 1, Its features are: The radar sensor device (3) is designed as a single-chip microcomputer system or a multi-chip microcomputer system.

7. The radar sensor device (3) according to claim 1, Its features are: The optical ring resonator (19) has a ring or elliptical shape.

8. The radar sensor device (3) according to claim 1, Its features are: The optical ring resonator (19) is designed as a miniature ring resonator.

9. A radar system (2) comprising at least one radar sensor device (3) according to any one of claims 1 to 8 and a central electronic computing device (4), wherein - The central electronic computing unit (4) is configured to generate optical transmission signals (6) for the radar sensor device (3) and receive optical output signals (11), and - The central electronic computing device (4) is coupled to the optical input end (8) and optical output end (9) of the radar sensor device (3) via at least one optical fiber (7).

10. The radar system (2) according to claim 9, Its features are: - The central electronic computing device (4) has a laser device (5) configured to generate an optical transmission signal (6) and couple it into at least one optical fiber (7), which is coupled to the optical input end (8) of the radar sensor device (3), and - The central electronic computing device (4) has an optical receiving unit (10) configured to receive an optical output signal (11) through at least one optical fiber coupled to the optical output terminal (9) of the radar sensor device (3).

11. The radar system (2) according to claim 10, Its features are: The central electronic computing device (4) has a processing unit (12) configured to determine the pulse train frequency (f) of the received output optical signal (11). rep ), and according to the pulse train frequency (f rep Determine at least one radar information.

12. A means of transport having a radar system (2) according to any one of claims 9 to 11.

13. A method of operating a radar sensor device (3) according to any one of claims 1 to 8, wherein - Based on the attenuation field (25) caused by the optical transmission signal (6), the optical transmission signal (6) is coupled into the optical ring resonator (19). - Through a four-wave mixing process, an optical output signal (11) is generated in the optical ring resonator (19) based on the coupled optical transmission signal (6), and - The refractive index of the optical ring resonator (19) is modulated by the coupled electrical receiving signal (16), thereby modulating the pulse train frequency (frep) of the optical output signal (11).

14. The method according to claim 13, Its features are: The pulse train frequency (frep) of the output optical signal (11) is modulated according to the diameter (27) of the optical ring resonator (19) and / or the coupling ratio between the optical coupling element (21) and the optical ring resonator (19).

15. The method according to claim 13 or 14, Its features are: By modulating the pulse train frequency (frep), at least one piece of information of the electrically received signal (16) is converted into frequency information of the pulse train frequency (frep).

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