Radar system with switchable angular resolution

The invention relates to a radar system with a Radar sensor which a transmitting module, a receiving module and a having driver circuit, wherein the transmitter module, a first having plurality of sub antennas and the receiver module having a second plurality of sub antennas, and wherein the driver circuit in a first operating mode in each case at least one part of the antenna of the transmitter module together with at least one part of the antenna of the receiver module operates, in order to achieve a first, small angular resolution and wherein the driver circuit in a second operating mode each group of partial antennas that transmit module and a group of partial antennas of the receiving module together operates to obtain a second, high angular resolution.

Furthermore, the invention relates to a method for operating of such a radar system.

Such a radar system and such a method are known from EP 1324068 A2.

Radar sensors in motor vehicles in general for Monitoring the vehicle environment used, wherein Applications such as parking assistance, blind spot monitoring, accident anticipation (Pre-crash sensing), start / stop operation or Driving with distance monitoring and / or regulation (Cruise Control Support) come into question. there differ, the requirements for the angular resolution from application to application.

For Nahfeldüberwachung blind spot (Blind Spot Detection) is a broad radiation field required. A good angular resolution, however, is less important. To the For it is when maneuvering a motor vehicle important to know if there is anything in the blind spot, because then must be stopped immediately. It is against less important to know where the object precisely is because in any case has to be stopped.

On the other hand it is an error monitoring important along a lane that distance information not disturbed by vehicles in adjacent lanes be what a higher angular resolution requires. Around different angular resolution requirements with a to cover single radar sensor, it is desirable change the angular resolution or to change course.

For this purpose, according to EP 1324068 A2 comblike interlocking partial antennas of a transmitter module and a receiving module either as single pairs of transmit sub antenna and receiving part Antenna or as groups (Sets) of adjacent partial antennas operated. make this in the two different modes of operation two different azimuthal angle resolutions a. In which Subject of EP 1324068 A2 is any part of the antenna on its own, separate switch with a Driver circuit. The large number of switches and the associated drive paths is the land use such an arrangement is comparatively large. this applies especially if it is limited to the number the operating modes, the only azimuthal between a high Resolution and low resolution azimuthal differ, is in relationship.

Against this background, the object of the invention in the indication of a radar system with switchable Angular resolution, with a variety of operating modes minimal space consumption and circuit complexity allows.

This object is with a radar system of the mentioned type characterized in that the driver circuit in at least one further operating mode in each case at least a part of the antenna of the transmitter module together with a group of sub-antennas of the receiving module, or a group of Partial antennas of the transmitter module together with at least one Part antenna of the receiver module operates.

Furthermore, this object is in a process of type stated by the fact that, in at least a further operating mode, at least a part of the antenna the transmitter module together with a group of partial antennas the receiving module, or group of antennas of the part Transmission module together with at least a part of the antenna Receiving module is operated.

By these combinations different Angle ranges in which the radar sensor is reflecting Objects detected by a clever combination of Partial antennas of the transmitter module and the receiver module with minimal amount of circuitry realized. It is exploits the fact that the said angular range in both a radiation angle of the transmit sub-antenna (s) as also in a reception angle range of the receiving-part antenna (s) must be located.

By ümschaltbare with little effort combinations narrow or wide Abstrahlwinkelbereichen with narrow or wide reception angle ranges are already apparent at only two different widths by the Combinations wide / wide; wide narrow; narrow / wide and narrow / narrow up to four different angular ranges, between which one or two switching processes can be selected. As a result, compared to the cited prior art only a significantly lower Number of high frequency switches and associated Ansteuerpfaden requires what the land use and the circuit complexity in the preparation of Transmitter modules and receiver modules significantly reduced. Thus, the object of the invention is completely achieved.

It is preferable that the driving circuit in the first Operating mode exactly one partial antenna of the transmitter module along with precisely partial antenna of the receiver module operates.

Since individual partial antennas in comparison with a plurality synchronously operated partial antennas a wide own emission and reception characteristics, results in this mode a small Angular resolution. The low angular resolution, however, with a broad detection range in the vicinity of the connected radar sensor so that this mode of operation particularly well suited for monitoring of closer Vehicle environment is suitable, with the objects, for example in blind spots (blind spots) a field of view of a driver can be detected.

It is also preferred that the group of partial antennas each also comprising at least one partial antenna, the is operated in the first operating mode.

By this measure, the circuit scale is further reduced since a switching off of a part of antenna deleted. The change is by connecting the remaining Part antennas on an existing connection with realized minimal effort.

It is further preferred that the group of partial antennas all partial antennas of the transmitter module or the Receiving module includes.

This configuration is an emission or a receiving characteristic with a minimum generates angular width. A minimum angular width is very good for a monitor more distant areas suitable. It is, for example of a Distance control system important that information about the Distance to a preceding vehicle in the same lane Car not on by vehicles adjacent lanes be disturbed. It is therefore desirable to provide a single Lane at a distance of typically 30 to 100 To resolve meters.

A further preferred embodiment is characterized out that the sub-antennas, which in the first operating mode be used together, separately to the driver circuit are connected.

This embodiment of the circuitry minimizing expense. Since the partial antennas for the first Mode are also active in the other modes, can independently of an operating-switching be connected to the driver circuit.

is also preferred that the remaining portion of antennas of a Group by a single switch with the Driver circuit are connected.

This refinement also contributes to a minimization of Switch number and the number of drive paths with what the Land use of the radar sensor is reduced.

It is also preferable that the partial antennas respectively of several slot-coupled patch antennas to assemble.

From such a planar antenna primitives can be by periodic arrangement of the antenna primitives build phased array, their dimensioning and geometric arrangement of the radiation, so the Field distribution in front of the antenna is determined. By appropriate phased excitation of periodically arranged Antenna primitives can be a scan different spatial directions without changing the achieve geometric alignment of the radar sensor (Principle of phased array radar).

An advantage over the planar antenna structures conventional antennas is that they in themselves manufacture expensive and more compact lightweight construction blank and that it is easy to Microstrip line circuits for wide Frequency ranges (100 MHz to 100 GHz) integrated can be. The thinness of the metal of Radiating surfaces and the fact that in the electrically conductive surfaces of the patches not very good electrical conductivity is required, leaves many various production methods.

A further preferred embodiment is characterized from that the transmission module spatially separated from the Receiving module is arranged on the radar sensor.

This refinement also contributes to a lower Land use in as a result of the spatial Summary of the transmit sub antennas and the receiving part Antenna in the sum of driver paths shorter and can be realized for drive paths associated switches.

It is also preferred that the number of partial antennas of The transmitting module of the number of antennas of the part Receiving module is different.

This asymmetry is achieved in particular that the combinations narrow / wide and narrow width differ. Thereby, for example, at the top mentioned embodiment effectively four different Angular resolution provided with minimal effort.

Furthermore, it is preferable that each antenna portion at least two having along a line disposed radiation fins.

Through these embodiments can already the partial antennas even a structurally predetermined directivity were obtained, the respective radiation field an increasing number of radiating surfaces narrower and thus is accurate angle.

is also preferred that the radar sensor in at least an operating mode is operated in pulsed mode.

The advantages of patch antenna is a disadvantage a comparatively low frequency bandwidth over. A large bandwidth is desirable, however, since the spatial resolution reflective objects, so the smallest possible distance at which two objects as separate are recognized separately, with increasing bandwidth improved. Pulsed operation increases the limited bandwidth, since the time duration of a delta_t Signal and the area occupied by him spectrum requirements, ie the bandwidth is inversely proportional to each other.

Further advantages result from the description and the accompanying figures.

It is understood that the aforementioned features and the still to be explained not only in the particularly given combination, but also in other usable combinations or alone, without departing from the scope of the present invention.

drawings

Embodiments of the invention are in the drawings are displayed and in the description below explained in more detail. The drawings show in schematic form:<dl tsize="6"><dt>Fig. 1</dt><dd>an overall view of the radar sensor;</dd><dt>FIG. 2</dt><dd>a partial section of the radar sensor from FIG. 1; </dd><dt>Fig. 3</dt><dd>different driving pattern of part of antennas Radar sensor according to the Fig. 1;</dd><dt>Fig. 4</dt><dd>different angular resolutions that when A result of the control pattern of FIG. 3 set to;</dd><dt>Fig. 5</dt><dd>a first embodiment of a circuit to control different groups of Partial antennas; and</dd><dt>Fig. 6</dt><dd>a second embodiment of a circuit to control different groups of Partial antennas.</dd></dl>

The numeral 10 in the figure 1 indicates the schematic Overall view of a radar sensor having a housing 12, is closed by a lid fourteenth The with the numeral 16 designated arrow indicates the direction of the longitudinal axis of a Motor vehicle on. The arrangement of the radar sensor 10 relative to the direction 16 corresponds to a typical Mounting position for monitoring the apron of a Motor vehicle. but the invention is of course not limited to such relative orientation of the radar sensor 10 to the direction 16 of the longitudinal axis of the motor vehicle limited.

On an end surface 18 of the radar sensor 10 is a flat transmitter module 20 is arranged, which by a flat Receiving module 22 are separated by an imaginary line 24 becomes. The radar sensor 10 shown in FIG. 1, So a spatial separation of transmitter module 20 and Receiving module 22. In the example of FIG. 1, the Transmitter module 20 includes five sub-antennas 26, 28, 30, 32 and 34, from the five radiation surfaces (patches) 36, 38, 40, 42, and 44 are made. Analog, the receiver module in the example of FIG. 1, three sub-antennas 46, 48, 50, consisting of five radiating surfaces 52, 54, 56, 58 and 60 consist.

It will be appreciated that the transmitting module 20 in place of five Partial antennas generally k partial antennas with 1 Radiating surfaces and the receiver module 22 in place of three partial antennas also part m antennas, each with n may have radiation surfaces. In this case, the number of Sub-antennas of the transmitter module of the number of part antennas the receiver module differ. Each of the partial antennas sets of several patch antennas or radiating surfaces together, arranged linear manner. The patch antennas can be excited slot coupled. Numeral 62 refers to a connection element via which the radar sensor 10, for example a supply voltage is supplied and / or from the radar sensor 10 signals to Control units of a motor vehicle output.

Figure 2 shows the radar sensor 10 according to Figure 1 in the Part-section, the inner illustrated in FIG 2 Construction of the radar sensor 10 per se is known. In the figure, 2, numeral 64 is a feed network connected to said Connecting element 62 is on and from Figure 1 in conjunction a first side 66 of a high frequency substrate 68 is arranged. A metallic ground plane 70 is on a second side 72 of the high frequency substrate 68 arranged.

A radiating surface 36 is an aperture 74 in the metallic ground plane 70 and a between the Ground plane 70 and the radiating surface 36 arranged Dielectric of the feed network 64 for radiating electromagnetic waves are excited. A recess 76 in a reinforcing structure 78 defines an air volume 80 between the radiation surface 36 and the ground plane 70th The volume of air 80 forms the dielectric between the Ground plane 70 and the radiating surface 36 is. The radiating surface 36 is connected to the housing 12 and preferably arranged externally on the housing 12th The Radiation surface 36 acts as a resonator of the Feed network 64 by capacitive coupling to radiation electromagnetic wave is excited. The aperture 74 is usually performed as an elongated slot.

In FIG. 3, four different driving pattern shown, with which the feed network 64, the five Partial antennas 26 to 34 of the transmission module 20 and the three Partial antennas 46 to 50 of the receiver module 22 in four various operating modes operates.

Corresponds to the constellation of FIG. 3, wherein the respective part antenna 30 of the transmission module 20 together operated with a partial antenna 48 of the receiver module 22 is, the above combination of wide / wide. In the Fig. 4, the vehicle 82 on a center lane 84 a three-lane road 86 with a right-hand lane 88 and a left lane 90 shows results of these Operating mode to a wide field of view 92 of the Radar sensor 10, the good one for a monitoring blind spot in front of the driver immediately before Vehicle 82 is.

The constellation of FIG. 3a shows a so Radar system in which the feed network 64 first in a Operating mode exactly one partial antenna 30 of the transmission module 20 along with precisely part antenna 48 of the receiver module 22 operates.

In the control pattern of FIG. 3b is Feeding only a single part of the antenna 30 of the transmitter module 20 produces a broad radiation spectrum and with a narrower angular resolution of the receiver module 22 combined. The narrower angular resolution of Receiving module 22 is driving a group of generates sub-antennas 46, 48, 50 of the receiving module 22nd In the sum resulting from this combination a narrower Field of view 94, as shown in FIG. 4.

Here, the group of sub-antennas 46 comprises, 48, 50 preferably also the at least one part of the antenna 48, which in first mode of operation according to FIG. 3a is operated. More preferably, but not necessarily, includes the group of partial antennas all partial antennas 46, 48, 50 of The receiving module 22, as shown in FIG. 3b.

An even narrower field of view with the drive pattern FIG. 3c generated. There is first a very narrow Emission of the transmission module 20 by driving a group of sub-antennas 26, 28, 30, 32, 34 of the Transmission module 20 generates. This very narrow Radiation is a broad or coarse Angular resolution of the receiving module 22 combined by Enabling a single patch antenna 48 of the receiver module 30 is generated. In sum, results from this Combining the designated in FIG. 4 by the numeral 96 Field of view that is narrower in relation to the field of view 94th

Preferably, the group of the activated partial antennas 26, 28, 30, 32, 34 of the transmission module 20 and the least a patch antenna 30, which in the first operating mode according to the . 3a is operated Fig. More preferably, but not necessarily, includes the group of partial antennas all Sub-antennas 26, 28, 30, 32, 34 of the transmission module 20, as is shown in Fig. 3c.

The difference between the fields of view 94 and 96 in the Fig. 4 results from the fact that the generation of the Field of view 96 a total of six sub-antennas 26, 28, 30, 32, 34 and 48 involved, while the field of view 94 by four sub-antennas 30 and 46, 48, 50 produced.

Fig. 3d finally shows a control pattern, the one to maximum fine angular resolution leads. For this purpose a narrow emission with a narrow Reception angle of a narrow angle of resolution Receiving module 22 combined. For the narrow Radiation are all part of antennas 26, 28, 30, 32, 34 of the transmission module 20 and sub-antennas 46, 48, 50 of the receiver module 22 operate together. The resulting narrow field of view 98 of the radar sensor 10 is also shown in Fig. 4. As shown in FIG. 4 be seen, the field of view 98 is best suited for an error monitoring, since it is also at a greater distance front of the radar sensor 10 and the vehicle 82 no Overlap with the adjacent lanes 88 and 90 having. However, it has the disadvantage of a large blind spot immediately before the vehicle 82nd

By a suitable control is cyclically or depending on demand between the different modes of Fig. 3 is switched. One possible criterion for the needs of represents the driving speed. At high Speed ​​narrow fields of view, as a rule be useful and are at low speeds wide fields of view be more useful.

A combination of 1 to 4 discloses thus an Radar system with a radar sensor 10, the transmitting module 20, a receiving module 22 and a feed network 64 Having the transmitting module 20, a first plurality of Sub-antennas 26, 28, 30, 32, 34 and comprises the Reception module 22 a second plurality of sub-antennas 46, 48, 50, and wherein the feed network 64 in a first operating mode (Fig. 3a) in each case at least one Part antenna 30 of the transmission module 20 together with at least a part of the antenna 48 of the receiver module 22 operates to a first, small angular resolution with a wide Field of view to achieve 92 and wherein the feed network 64 in a second operating mode (Fig. 3d) each is a group of sub-antennas 26, 28, 30, 32, 34 of the transmission module 20 and a group of sub-antennas 46, 48, 50 of the receiving module 22 operates together to create a second, high angular resolution to achieve with a narrow field of view 98th additionally operates the feed network 64 in at least one other Operating mode (Fig. 3b) each have at least a part of antenna 30 of the transmission module 20, together with a group of Sub-antennas 46, 48, 50 of the receiving module 22, or (Fig. 3c) a group of partial antennas 26, 28, 30, 32, 34 of Transmission module 20 together with at least a part of the antenna 48 the receiver module 22nd

Fig. 5 shows the arrangement of the sub-antennas 26, 28, 30, 32, 34 and 46, 48, 50 along with a first embodiment the feed network 64. This embodiment is characterized firstly by the fact that the sub-antennas 30, 48, which in first operating mode are operated together, each separately with an excitation subcircuit 100 of Feed network 64 connected. It carried the Connecting the antenna part 30 via a path 102 and the Connecting the antenna portion 48 is via a path 104th Next, the configuration is distinguished by the FIG. 5 by the fact that the rest of antennas of a group each by a common switch 106, 108 with the Exciting subcircuit 100 connected. In the Embodiment of FIG. 5, the switch via the 106 connected group by all other partial antennas 26, 28, 32, 34 of the transmission module 20 is defined. analogously the switched via switch 108 by group all rest of antennas 46, 50 of the receiver module 22 defined.

The switches 106 and 108 are controlled by a controller 110 actuated via paths 112 and 114th The controller 110 may in Be the radar sensor 10 integrated or as an external Control be implemented, with the feed network 64 communicates via the connection element 62nd As external Controls are in particular an engine control unit and / or a brake control unit and / or an airbag control unit of the vehicle 82 in question.

The controller 110 controls method for operating the Radar sensor 10 and particularly controls the switching between different modes of operation as an example have been explained with reference to FIGS 3 and 4. FIG. In this case, the radar sensor 10 in at least one mode of operation be operated pulsed to the angular resolution further improve.

Fig. 6 shows an arrangement of the sub-antennas 26, 28, 30, 32, 34 and 46, 48, 50 together with a second Design of the feed network 64. The second Embodiment according to Fig. 6 differs from the first embodiment of FIG. 5 in that a Single switch 106 is replaced by two switches 116, 118 and that as a single switch 108 by two switches was 120, 122, replaced. As a result, the paths 102 and 104 fail shorter than in the subject in FIG. 5.