EP3769107A1

EP3769107A1 - Radar sensor head for a radar system

Info

Publication number: EP3769107A1
Application number: EP19701189.3A
Authority: EP
Inventors: Marcel Mayer; Michael Schoor
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2018-03-22
Filing date: 2019-01-17
Publication date: 2021-01-27
Also published as: JP7008838B2; US20200333435A1; MX2020009775A; KR20200135432A; CN111902729A; JP2021518540A; WO2019179669A1; DE102018204377A1; US11536802B2

Abstract

Radar sensor head (100) for a radar system, having: at least one transmitting antenna (10) for generating radar waves and at least one receiving antenna (20) for receiving radar waves; a preprocessing unit (50) for preprocessing received data in a defined manner; an interface (80) for connecting the radar sensor head (100) to a data line (110); and a calibration data device (50, 70) for at least partially calibrating the transmitting antenna (10) and/or the receiving antenna (20), wherein calibration data for the transmitting antenna (10) and the receiving antenna (20) can be stored by means of the calibration data device (50, 70).

Description

description

title

Radar sensor head for a radar system

The invention relates to a radar sensor head for a radar system. The invention further relates to a radar system. The invention further relates to a method for producing a radar sensor head for a radar system.

State of the art

For vehicles with a high level of driver assistance functions or automated driving function, more and more radar sensors are installed. Higher numbers of radar sensors are designed to increase the efficiency of automated or semi-automated case functions over single radar sensors. Previous solutions in this area consist of radar sensors, which perform sensor-extensive data processing of the received radar waves. Thus, the radar sensors can provide data at object or locating level for further evaluation by the vehicle. As a result, the amount of data transmitted to the vehicle can be reduced, but the respective radar sensors must have a higher computing power and a larger memory.

The disadvantage here is that the computing power and the memory size are comparatively unfavorable scalable in terms of increased performance. This results in particular from the fact that, based on a defined requirement on the performance, the microcontroller technology is no longer sufficient for the necessary processing steps of the received radar waves. Therefore, to increase performance, the necessary calculations and analyzes must be performed within the sensor within the framework of microprocessor technologies. This can be detrimental to the price, size and power loss of a radar sensor. Disclosure of the invention

The problem underlying the invention can be seen in proposing a radar sensor head for a radar system which is inexpensive and flexible with regard to the number of elements used.

This object is achieved by means of the subject matter of the independent claims. Advantageous embodiments of the invention are the subject of each dependent subclaims.

According to a first aspect, the object is achieved with a radar sensor head for a radar system, comprising:

at least one transmitting antenna for generating and at least one receiving antenna for receiving radar waves;

a preprocessing unit for defined preprocessing of

Receiving data;

an interface for connecting the Radarsensorkopfs to a data line; and

a calibration data device for at least partial calibration of the transmitting antenna and / or the receiving antenna, calibration data for the transmitting antenna and the receiving antenna being able to be stored by means of the calibration data device.

In this way, partitioning of the overall system by providing a radar sensor head is advantageously made possible. Advantageously, a calibration data device can be implemented in the radar sensor head with little effort, by means of which at least one partial calibration of the

Radar sensor head can be made. In this way it is e.g. possible to carry out an exchange of Radarsensorkopfs during a workshop stay efficiently.

Today's radar sensors are often designed as a fast-chirp radar. This means that many fast FMCW (Frequency Modulated Continuous Wave) ramps are sent to a scan area, which is also referred to as a so-called chirp sequence or a rapid chirp method. After mixing the received radar signals, the baseband signals are filtered, digitized and generally fed to a 2D Fourier transform. Since a subsequent Doppler FFT (fast Fourier transform) can take place only when the data or measurement signals of all ramps or frequencies have been processed, a large memory for buffering the received radar signals is necessary. Moreover, due to the high latency requirement, there is a need for high computing power, which is why hardware accelerators are usually used.

From the aspect that several radar sensors are used in a vehicle, it is advantageous to concentrate the required computing power in at least one central control unit. The respective radar sensors can thus be used as compact and inexpensive radar sensor heads without significant

Be designed power loss. As a result, overall a better price-performance ratio can be achieved and a higher performance of the radar system can be realized.

A proposed radar sensor head includes components for generating and transmitting radar waves, and components for receiving and processing received radar waves. The processing of received

Radar waves is limited to the smallest possible extent or takes place with the least possible effort. In particular, the

Measurement data of the received radar waves are digitized by the analog-to-digital converter and then transmitted with a high bandwidth to the at least one central control unit. The further processing of the digitized measured data from the at least one radar sensor head can then take place in at least one central control device.

As a result, the costs for the respective radar sensor heads can be reduced because less computing power is required in the radar sensor heads. In addition, a lower power loss in the respective

Radarsensorköpfen incurred due to the fewer number of processing steps. Although the computational effort increases in the at least one central control device, in this case the computing power can be scaled more easily or with less effort compared to the costs incurred. In an overall view of the radar system, the radar system according to the invention can be extended inexpensively and flexibly compared to previous solutions and scaled. Furthermore, the higher computing power of the at least one central control device makes it possible to use more complex and powerful algorithms for processing the received radar waves.

With increasing high integration, it is additionally possible to integrate a first processing stage into a high-frequency module such as, for example, a so-called Monolithic Microwave Integrated Circuit (MMIC). This may preferably be an analysis unit for performing a Fourier analysis. For example, the analysis unit can perform a range FFT of the digitized measurement data. Depending on the modulation methods used, other Fourier transforms may also be used. As a rule, this first processing stage can be integrated inexpensively into the existing components of a radar sensor head since the required area in the high-frequency component is very small and there is a small storage requirement. Thus, in the production of the corresponding high-frequency module, the silicon area used can usually remain the same.

A preferred embodiment of the radar sensor head is characterized in that a full calibration can be carried out by means of the calibration data device. Thus, it is advantageously possible to complete the calibration of

Radarsensorkopf perform without using a central control unit.

A further preferred embodiment of the Radarsensorkopfs is characterized in that during the calibration process to defined channels of the

Transmitting antenna and / or the receiving antenna a calibration matrix is applicable. The application of the calibration matrix corresponds to a matrix-vector multiplication, wherein a vector this case a defined number of

Reception channels represented.

Another preferred embodiment of the radar sensor head is characterized in that a frequency correction can be carried out during the calibration process. In this way, a specific type of calibration can be performed, which makes sense, for example, when filter characteristics have to be corrected. A further preferred embodiment of the radar sensor head is characterized in that the calibration data are at least one of the following: typical noise level, antenna properties, amplitude / phase deviations, position of the antenna elements, temperature characteristics, temperature responses. In this way, advantageously different properties of the antennas can be compensated during operation of the radar sensor head or

be adjusted.

A further preferred embodiment of the radar sensor head provides that a Fourier transformation can be carried out by means of the preprocessing unit. In this case, a preprocessing of the received data is carried out, as a result of which a data rate to a downstream central control device is advantageously reduced significantly.

A further preferred embodiment of the radar sensor head is characterized in that the radar waves received by the at least one receiving antenna can be converted into digital measurement data by an analog-to-digital converter and can be marked with at least one time information. In this way, receive sequences can be assigned exactly in time, which supports accurate processing of the measurement data.

In the following, preferred exemplary embodiments of the invention will be explained in more detail on the basis of greatly simplified schematic illustrations.

Showing:

1 shows a schematic representation of a proposed radar sensor head;

Fig. 2 is a schematic representation of a radar system with a

Embodiment of a proposed Radarsensorkopfs; and

Fig. 3 is a schematic representation of a method for producing a Radarsensorkopfs. In the figures, the same constructive elements each have the same reference numerals.

1 shows a schematic illustration of a proposed radar sensor head 100. The radar sensor head 100 has at least one transmitting antenna 10, which can be operated via an associated antenna controller 11. The

Antenna controller 1 1 is coupled inter alia with at least one oscillator or synthesizer 30 for generating a carrier frequency of the radar waves.

Furthermore, at least one receiving antenna 20 with an associated

Antenna controller 21 connected. The antenna controller 21 is functionally connected to an evaluation unit 40, wherein received radar waves by means of an arranged in the evaluation unit 40 A / D converter into digital

Measurement data are converted and then in a first

Processing step by means of a preprocessing unit 50 are transformed.

The radar waves received by the receiving antenna 20 of the radar sensor head 100 can be converted by the analog-to-digital converter into digital measured data and can be marked with at least one time information. As a result, the received radar waves or measurement data can be converted into a digital format and thus processed more easily. Advantageously, the measured data converted into a digital format can be combined with a

Timestamp be provided. For example, each recorded spectrum may be given its own timestamp.

By means of the preprocessing unit 50, a Fourier transformation and / or a calibration can be carried out. Thus, the samples or received radar waves are not transmitted directly after digitizing, but subjected to a first processing process. The fast Fourier transform is preferably a range FFT, which may be adapted to the particular application, wherein the range FFT represents a first dimension of the FFT, in which the Doppler effect plays a minor role and resulting frequency bins almost exclusively are distance-dependent. Since this transformation requires relatively little memory, the Analysis unit 50, for example, manufactured in RFCMOS technology and integrated into an MMIC, such as a high-frequency module of the Radarsensorkopfes 100. Since not all range bins are required due to the anti-aliasing filter, for example 90% or 45% of the bins, the resulting amount of data can be reduced and the FFT simultaneously used as a buffer to reduce peak data rates of the radar sensor head 100.

In addition, a calibration data unit 70, in which calibration data are kept available, can be identified in the radar sensor head 100. The calibration data can be at least one of the following: typical noise level of the antennas, antenna properties, amplitudes / phase deviations of the antennas, position of antenna elements, temperature characteristics or characteristics of the antennas.

By the calibration data, e.g. Antenna properties that are due to a technological manufacturing process, be adapted or compensated. This makes it possible to perform at least a partial calibration of the transmitting and / or receiving antenna of the Radarsensorkopfs 100, wherein alternatively, a full calibration of said antennas is possible.

For example, the calibration may be good enough for processing steps to detection, but not for angle estimation. Here, however, the amount of data is advantageously already reduced by the detection.

The determination of the calibration data takes place once in the production, whereby the application of the calibration data takes place during the operational operation of the radar sensor head 100. By means of the calibration data, a processing of signals or a suitable control of the antennas can be carried out, whereby a full calibration does not have to be performed by the downstream central control device (not shown).

Deviations of the antenna pattern from an ideal antenna pattern can be described by so-called "global calibration matrices" which describe deviations caused by phase and amplitude errors as well as by feedback between the channels (see also FIG

Dissertation M. Schoor, "High Resolution Angle Estimation for Automotive Radar Systems", 2010). These calibration matrices describe the deviations caused by phase and amplitude errors as well as couplings between individual channels of the antennas. This type of calibration can be carried out directly in the sensor head 100, which means that, as far as the faults permit, the central control device 120 no longer needs to take into account the hardware characteristics. Ideally, all relevant hardware characteristics may be provided by the sensor head 100 in this manner.

As a result, a radar sensor head 100 is realized, whose main function is the radar front end with digitization of the received signal. After the analog-to-digital conversion, the processing can take place with as little effort as possible, wherein the data is transmitted to the central control device 120 with high bandwidth and processed there.

This advantageously reduces the costs in the radar sensor head 100, since less computing power is required there and less power loss occurs at an unfavorable location (for example due to the installation location in the vehicle), with the computing power advantageously being outsourced to the central control device 120. There, the computing power scales significantly better compared to the costs, so that overall an advantageous outsourcing of computing power is achieved in the central control device 120. This allows the execution of computation algorithms that require significantly more computational power than could be available in a single sensor.

The radar sensor head 100 also has a connection 80 to a broadband data line (not shown) via which data is transmitted to the central control device (not shown).

FIG. 2 shows a basic block diagram of a radar system 200 for a vehicle realized with the proposed radar sensor head 100.

It is provided that the transformed digital measurement data is transmitted to a central control device 120 via a broadband data line 110. The transmitted digital measured data is assigned a time stamp by means of the first control unit 60 arranged in the radar sensor head 100 and likewise transmitted to the central control device 120. If the signal processing takes place in the central control device 120, then the calibration data must be present there. The calibration data are used by the central control device 120 in the signal processing, for example, by a detection unit 150 arranged there. However, the calibration of the antennas 10, 20 can also take place at least partially in the sensor head 100.

The central controller 120 may receive and further process the transmitted digital measurement data, e.g. by means of a memory 130, a transformation unit 140 for performing a Doppler FFT and a second control unit 160, which interacts functionally with the first control unit 60 of the radar sensor head 100. The timestamps transmitted with the measurement data allow them to be precisely timed.

The radar system 200 may, for example, be configured as a chirp sequence radar, but may also be operated with other types of modulation. Alternative radar methods may be, for example, slow FMCW radars without a post-Doppler FFT, PN radars (pseudo-noise) with an analyzer as a correlator bank, or an OFDM radar with an analyzer to perform spectral division.

Due to the proposed provision of the calibration data in the radar sensor head 100, the computational effort in the at least one central control device 120 can be reduced. In addition, a data volume to be transmitted via the data line 110 can thereby be reduced.

In the radar system 200, the at least one time information can be generated by a first control unit 60 arranged in the radar sensor head 100. The first control unit 60 can, for example, receive and convert 10 transmitted control commands via the data line 110 and provide the digitized measured data with precise time information. Furthermore, the first control unit 60 can be used for controlling the at least one radar sensor head 100 and, for example, for monitoring control or cycle control. In order for synchronization in the radar system 200 to take place, the transmitted measurement data from the first control unit 60 must, for example, be timestamped for each Chirp or cycle are added so that the central control device 120 can make good use of the transmitted data from the Radarsensorkopf 100 measurement data.

The transmission antenna 10 of the radar sensor head 100 has an oscillator 30 for generating a carrier frequency, wherein the oscillator 30 is adjustable by the second control unit 160 of the central control device 120. By implementing the first control unit 60 in the radar sensor head 100, which interacts functionally with the second control unit 160, control of the components of the radar sensor head 100 by the central control device 120 can advantageously be realized. Thus, the oscillator or oscillators of the Radarsensorkopfes 100 can be controlled or regulated directly or indirectly.

Oscillators of a radar system 200 with at least two radar sensor heads 100 (not shown) can be synchronized with one another by the central control device 120. In a vehicle, a plurality of mutually objected radar sensor heads 100 can be installed and connected in a data-conducting manner to one or more central control devices 120 via data connections. By implementing control units 60 in the different radar sensor heads 100, when multiple radar sensor heads 100 are used, the respective oscillators of the transmit antennas 10 can be synchronized with each other. In this way, the accuracy of the measurement results can be advantageously increased. As a result, the driver assistance functions or the automated driving functions of the vehicle can be optimized. In addition, the number of radar sensor heads 100 used without negative

Influences of performance can be increased as desired.

The central control device 120 has at least one processor for processing received data and at least one memory 130 for at least temporary storage of data. As a result, the central control device 120 can at least temporarily store the measured data transmitted by the data line 110 from the radar sensor head 100 and in accordance with FIG

Process, forward or issue the request of the respective application. The central controller 120 may be swapped as needed by a more powerful controller. Since microprocessor technology is preferably used, sophisticated algorithms can be used to process the Measurement data used and thus more accurate calculation results can be achieved.

It is also conceivable that several (for example three) radar sensor heads 100 are connected via corresponding data lines 110 to a central control device 120 (not shown). The central control device 120 outputs control commands via the data lines 110 to the control units 60 of the respective radar sensor heads 100, whereby the different

Radar sensor heads 100 and in particular the respective oscillators 30 are optimally matched and synchronized.

3 shows a basic sequence of a method for producing a radar sensor head.

In a step 300, provision is made of at least one transmitting antenna 10 for generating and at least one receiving antenna 20 for receiving radar waves.

In step 310, provision is made of a preprocessing unit 50 for defined preprocessing of received data.

In step 320, an interface 80 for connecting the radar sensor head 100 to a data line 110 is provided.

In a step 330, a provision of a calibration data device 50, 70 for at least partial calibration of the transmitting antenna 10 and / or the receiving antenna 20 is carried out, wherein calibration data for the transmitting antenna 10 and the receiving antenna 20 can be stored by means of the calibration data device 50, 70.

Claims

claims

A radar sensor head (100) for a radar system, comprising:

at least one transmitting antenna (10) for generating and at least one receiving antenna (20) for receiving radar waves;

a preprocessing unit (50) for defined preprocessing of received data;

an interface (80) for connecting the Radarsensorkopfs (100) to a data line (1 10); and

a calibration data device (50, 70) for at least partially calibrating the transmitting antenna (10) and / or the receiving antenna (20), wherein calibration data for the transmitting antenna (10) and the receiving antenna (20) can be stored by means of the calibration data device (50, 70) are.

2. radar sensor head (100) according to claim 1, characterized in that by means of the calibration data (50, 70) a full calibration is feasible bar.

3. radar sensor head (100) according to claim 1 or 2, characterized in that during calibration to defined channels of the transmitting antenna (10) and / or the receiving antenna (20) is a calibration matrix applicable.

4. radar sensor head (100) according to any one of the preceding claims, characterized in that during the calibration process, a frequency correction is feasible.

5. radar sensor head (100) according to any one of the preceding claims, characterized in that the calibration data are at least one of the following: typical noise level, antenna properties, amplitude / phase deviations, position of the antenna elements, temperature characteristics, temperature responses.

6. radar sensor head (100) according to any one of the preceding claims, characterized in that by means of the preprocessing unit (50) is a Fourier transformation executable.

7. radar sensor head (100) according to any one of the preceding claims, characterized in that the at least one receiving antenna (20) received radar waves by an analog-to-digital converter (40) convertible into digital measurement data and markable with at least one time information (Z) are.

8. radar system (200) comprising:

at least one radar sensor head (100) according to one of claims 1 to 7; at least one central controller (120) for transmitting data and processing received data; and

a data line (1 10) between the at least one central

Control device (120) and the at least one radar sensor head (100).

9. radar system (200) according to claim 8, wherein the at least one central

Control device (120) has at least one transformation unit (140) for processing received data and at least one memory (130) for at least temporary storage of data.

10. Radar system (200) according to claim 8 or 9, wherein digital measurement data from

Radarsensorkopf (100) via the at least one data line (110) to the at least one central control device (120) are transferable and in the at least one central control device (120) by at least one time information (Z) are synchronized.

1 1. A method for producing a Radarsensorkopfs (100), comprising the

Steps:

Providing at least one transmitting antenna (10) for generating and at least one receiving antenna (20) for receiving

Radar waves;

Providing a preprocessing unit (50) for the defined

Preprocessing of received data; Providing an interface (80) for connecting the

Radar sensor head (100) to a data line (110); and

Providing a calibration data device (50, 70) for the at least partial calibration of the transmitting antenna (10) and / or the

Receiving antenna (20), wherein by means of the calibration data device (50,

70) calibration data for the transmitting antenna (10) and the receiving antenna (20) can be stored.