RADAR SYSTEM FOR MOTOR VEHICLES

Abstract

A radar system for motor vehicles, with a plurality of transmit/receive units arranged on separate installation supports for installation at various locations in the motor vehicle, an evaluation system for evaluating the radar signals received on a plurality of channels in a plurality of processing steps, a first processing step delivering a digital time signal for each channel, which digital time signal represents the received radar signal, and a final processing step delivering as the result location data for individual radar objects and at least the final processing step being implemented for the plurality of transmit/receive units in a central evaluation unit with which the transmit/receive units in each case communicate via a raw data interface. The each of raw data interfaces has a serializer, which is configured to transfer raw data from the plurality of channels of the transmit/receive unit in question serially to the central evaluation unit.

Claims

1. A radar system for a motor vehicle, comprising: a plurality of transmit/receive units arranged on separate installation supports for installation at various locations in the motor vehicle; an evaluation system configured to evaluate radar signals received on a plurality of channels in a plurality of processing steps, a first processing step delivering a digital time signal for each channel, which digital time signal represents the received radar signals, and a final processing step delivering as a result location data for individual radar objects and at least the final processing step being implemented for the plurality of transmit/receive units in a central evaluation unit with which each respective transmit/receive unit of the transmit/receive units communicates via a respective raw data interface; wherein each of the respective raw data interfaces has a serializer, which is configured to transfer raw data from the plurality of channels of the respective transmit/receive unit serially to the central evaluation unit.

2. The radar system as recited in claim 1, wherein at least one of the transmit/receive units has a plurality of semiconductor modules, which each evaluate signals from a number of receive antennas, and in which each of the semiconductor modules is provided with its own serializer.

3. The radar system as recited in claim 1, wherein the central evaluation unit has a deserializer for each of the serializers in the transmit/receive units, the deserializer configured to convert the serially received signals back into parallel signal sequences for further processing in a processor.

4. The radar system as recited in claim 1, wherein the central evaluation unit and each of the transmit/receive units have a control unit configured for controlling functions of the radar system, and the control units of the transmit/receive units are connected to the control unit of the evaluation unit via communication channels.

5. The radar system as recited in claim 4, wherein the communication channels for the control units are separated from the communication channels for the raw data.

6. The radar system as recited in claim 4, wherein the control units of the transmit/receive units are synchronized with one another and with the control unit of the central evaluation unit and the central evaluation unit is configured for coherent evaluation of signals of the transmit/receive units.

7. The radar system as recited in claim 6, wherein the central evaluation unit and each of the transmit/receive units have a local real-time clock for synchronizing the control units.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a top view of a motor vehicle with a radar system according to an example embodiment of the present invention.

[0027] FIG. 2 is a block diagram of the radar system of FIG. 1, in accordance with an example embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0028] FIG. 1 is a schematic representation of a radar system of a motor vehicle 10. The radar system comprises a plurality of (ten in the example shown) transmit/receive units 12, which are installed separate from one another, in each case on their own installation support (printed circuit board or package), at different locations in the motor vehicle.

[0029] Each transmit/receive unit 12 has as signal output a raw data interface 14, which is connected via a physical serializer 16 and a cable 18 to a central evaluation unit 20, which evaluates the raw data of all the transmit/receive units 12.

[0030] FIG. 2 shows the central evaluation unit 20 and two of the transmit/receive units 12 as separate blocks. Virtually the entire functionality of an individual transmit/receive unit 12 is implemented in one or more semiconductor modules 22, for example MMICs (Monolithic Microwave Integrated Circuits) or an SoC (system on chip). Antenna arrays of the transmit/receive unit 12 are represented only symbolically in the drawings and, in the example shown, comprise separate transmit antennas Tx and receive antennas Rx, which are arranged offset relative to one another in the horizontal direction in such a way as to achieve an angular resolution in azimuth.

[0031] It may be assumed, by way of example, that the radar system shown here operates according to the FMCW principle. The transmit antennas of each transmit/receive unit 12 transmit a succession of radar signals frequency modulated in ramped manner in each measuring cycle. The signals reflected at the located objects are received by the receive antennas and mixed with a component of the signal transmitted at the receive time, such that a low-frequency beat signal is obtained for each antenna element, the frequency and phase of which obtains the distance and relative speed information about the located object. These beat signals are evaluated for each receive antenna in a separate receive channel of the semiconductor module 22. In this case, the complex amplitudes of the beat signals are sampled and digitized at a high cycle rate over the duration of the measuring cycle. The digitized data form raw data, which are transferred to the central evaluation unit 20 via the raw data interface 14.

[0032] In the example shown, the central evaluation unit 20 is formed by a control device, which also controls the functions of the transmit/receive units and in which the time signals of all the transmit/receive units 12 are jointly evaluated in a fast processor 24 with associated working memory 26. In the course of evaluation, the time signal is converted in each receive channel by fast Fourier transform into a spectrum in which each located object is distinguished as a peak at a specific frequency. By aligning the data obtained at various frequency ramps, the distance information is separated in conventional manner from the relative speed information, such that the distance and the relative speed of each located object can be determined. Furthermore, by comparing the amplitudes and phases of the signals received in different receive channels, the azimuth angle of each located object is determined. The information obtained in this way about the located object is output via a vehicle interface 28, for example a fast Ethernet interface or a CAN bus, to other electronic components in the vehicle, for example to a driver assistance system. A memory 30 (for example a flash memory or hard disk) enables the storage or at least buffering of evaluation results in the central evaluation unit 20.

[0033] In the example shown, each transmit/receive unit 12 has a plurality of semiconductor modules 22, and each semiconductor module has its own raw data interface 14 with associated serializer 16. By way of example, it may be assumed that each semiconductor module 22 pre-evaluates and digitizes the receive signal from forty receive antennas Rx on parallel receive channels. In the serializer 16, the time signals arriving in parallel in the forty channels are serialized and transferred one after the other to the central evaluation unit 20 as a serial signal on a single core of the cable 18. The cable 18 therefore does not need forty cores for each semiconductor module 22, but rather just one single core.

[0034] The central evaluation unit 20 has a deserializer 32 for each transmit/receive unit 12, with which the arriving signals are deserialized and then routed onward in parallel to the processor 24.

[0035] In the example shown, in addition to the transmit/receive units 12 of the radar system, a video camera V is also provided, the data from which are likewise transferred to the processor 24 and further processed therein.

[0036] For control and synchronization functions, the central evaluation unit 20 contains a control unit 34, which receives a time signal from a local real-time clock 36.

[0037] Each transmit/receive unit 12 also contains a control unit 38, which receives a time signal from a local real-time clock 40 and drives the semiconductor modules 22.

[0038] The control unit 34 of the evaluation unit 20 and the control unit 38 of each transmit/receive unit 12 communicate with one another via one or more cores of the cable 18, which connects these components. In the example shown, each control unit is associated with a serializer/deserializer 42, with which in each case the transmitted signals are serialized and the received signals are deserialized. Since, however, the data exchange which takes place between the control units 34, 38 is on a significantly smaller scale than transfer of the raw data of the semiconductor modules 22, other communication channels and protocols can also be provided for control unit communication.

[0039] The local real-time clocks 36, 40 are adjusted relative to one another by occasional exchange of reference signals, such that the transmit/receive units 12 may optionally be synchronized with one another and their data coherently evaluated.

[0040] For instance, the processor 24 can also evaluate signals which were transmitted by one of the transmit/receive units and received by the other. Due to the large distance between the transmit/receive units, the two antenna arrays then form an overall array with a very large aperture, which enables high-resolution angle measurement.