METHOD AND APPARATUS FOR ESTABLISHING THE DISTANCE BETWEEN A VEHICLE AND AN INFRASTRUCTURE DEVICE

Abstract

A method and an apparatus establish a distance as well as to a vehicle. In the method for establishing a distance between a vehicle and an infrastructure device, at least two vehicle-mounted reception devices receive a signal transmitted by the infrastructure device. Each of the vehicle-mounted reception devices contains at least two antenna elements. For each reception device, a reception device-specific distance between the vehicle and the infrastructure device is established in accordance with the antenna signals generated by the antenna elements, and the shortest of all the reception device-specific distances is established as the distance.

Claims

1. A method for determining a distance between a vehicle and an infrastructure device, which comprises the steps of: receiving, by at least two vehicle-mounted receiving devices, a signal sent by the infrastructure device, each of the vehicle-mounted receiving devices having at least two antenna elements; determining for each of the vehicle-mounted receiving devices, a receiving device-specific distance between the vehicle and the infrastructure device in dependence on antenna signals generated by the antenna elements, the distance between the vehicle and the infrastructure device being determined as the receiving device-specific distance that is a shortest receiving device-specific distance of all the determined receiving device-specific distances; and generating, via a vehicle-mounted transmitting device, a calibration signal, wherein at least one of the vehicle-mounted receiving devices receives the calibration signal, wherein as a function of at least one signal characteristic of the calibration signal received by the antenna elements of the at least one vehicle-mounted receiving device at least one signal correction factor is determined for at least one antenna element of the at least one vehicle-mounted receiving device, wherein an antenna signal or a digitized antenna signal is corrected depending on the at least one signal correction factor.

2. The method according to claim 1, which further comprises: digitizing the antenna signals of the vehicle-mounted receiving devices with a first sampling rate, at least temporarily; determining a signal start section for each digitized antenna signal; and determining a receive direction of the signal in dependence on signal start sections.

3. The method according to claim 2, which further comprises reducing the first sampling rate when a predetermined time interval after a beginning of sampling with the first sampling rate has passed and/or when the signal start section contains at least a predetermined number of sample values.

4. The method according to claim 2, which further comprises determining a receiving device-specific line-of-sight signal from the antenna signals of a vehicle-mounted receiving device depending on a receiving direction, each device-specific line-of-sight signal being the signal transmitted along a shortest connecting line between a respective specific receiving device and the infrastructure device.

5. The method according to claim 4, which further comprises determining the receiving device-specific distance in dependence on the receiving device-specific line-of-sight signal.

6. The method according to claim 5, which further comprises extracting a data symbol from the receiving device-specific line-of-sight signal, wherein the receiving device-specific distance is determined depending on the data symbol.

7. The method according to claim 8, wherein the data symbol for different phase positions of a reference symbol is correlated with the reference symbol, wherein a phase offset is determined between the data symbol and a maximally correlating reference symbol, the distance being determined in dependence on the phase offset.

8. The method according to claim 4, which further comprises determining a vehicle speed in dependence on at least two distances determined one after another.

9. The method according to claim 8, which further comprises determining the vehicle speed in dependence on the receiving direction.

10. The method according to claim 1, which further comprises transmitting the antenna signals or digitized antenna signals via an ultra high data rate signal transmission line.

11. The method according to claim 1, wherein for each of the antenna elements of the vehicle-mounted receiving devices the antenna signals are digitized before a transmission to a vehicle-mounted evaluation device.

12. The method according to claim 1, which further comprises: interrupting a transmission of the signal for a predetermined period of time by the infrastructure device; detecting an interruption by a vehicle-mounted evaluation device; and carrying out a determination of the distance after a detection of the interruption.

13. The method according to claim 1, which further comprises carrying out the determination of the distance if signal energy of the antenna signals is greater than a predetermined threshold.

14. The method according to claim 1, wherein for at least two of the vehicle-mounted receiving devices, a receiving device-specific signal propagation time is determined for the distance between the vehicle and the infrastructure device in dependence on the antenna signals generated by the antenna elements, wherein the receiving device-specific signals of a plurality of the vehicle-mounted receiving devices are transformed into a common time system in dependence on signal propagation times.

15. An apparatus for determining a distance between a vehicle and an infrastructure device, the apparatus comprising: at least two vehicle-mounted receiving devices for receiving a signal of the infrastructure device, each of said vehicle-mounted receiving devices having at least two antenna elements; at least one evaluation device configured to determine a receiving device-specific distance between the vehicle and the infrastructure device for each of said vehicle-mounted receiving devices depending on antenna signals generated by said antenna elements, and to determine the distance between the vehicle and the infrastructure device as the receiving device-specific distance that is a shortest receiving device-specific distance of all said determined receiving device-specific distances; and wherein at least one of the vehicle-mounted receiving devices is further configured to receive a calibration signal which is generated via a vehicle-mounted transmitting device, wherein as a function of at least one signal characteristic of the calibration signal received by the antenna elements of the at least one vehicle-mounted receiving device at least one signal correction factor is determined for at least one antenna element of the at least one vehicle-mounted receiving device, wherein an antenna signal or a digitized antenna signal is corrected depending on the at least one signal correction factor.

16. The apparatus according to claim 15, wherein said antenna elements of at least one of said vehicle-mounted receiving devices are in a circular or linear configuration.

17. The device according to claim 15, wherein said vehicle-mounted receiving devices each have at least one A/D converter device for digitization of the antenna signals generated by said antenna elements.

18. The apparatus according to claim 15, further comprising at least one ultra high date rate (UHDR) signal transmission line, wherein at least one of said vehicle mounted receiving devices and said evaluation device are connected via said UHDR signal transmission line for signal communication.

19. The apparatus according to claim 15, further comprising at least one vehicle-mounted transmitting device for a calibration signal.

20. A vehicle, comprising: an apparatus for determining a distance between the vehicle and an infrastructure device, said apparatus containing: at least two vehicle-mounted receiving devices for receiving a signal of the infrastructure device, each of said vehicle-mounted receiving devices having at least two antenna elements; at least one evaluation device configured to determine a receiving device-specific distance between the vehicle and the infrastructure device for each of said vehicle-mounted receiving devices depending on antenna signals generated by said antenna elements, and to determine the distance between the vehicle and the infrastructure device as the receiving device-specific distance that is a shortest receiving device-specific distance of all said determined receiving device-specific distances; and wherein at least one of the vehicle-mounted receiving devices is further configured to receive a calibration signal which is generated via a vehicle-mounted transmitting device, wherein as a function of at least one signal characteristic of the calibration signal received by the antenna elements of the at least one vehicle-mounted receiving device at least one signal correction factor is determined for at least one antenna element of the at least one vehicle-mounted receiving device, wherein an antenna signal or a digitized antenna signal is corrected depending on the at least one signal correction factor.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0114] The invention will now be described in further detail based on exemplary embodiments. The figures show:

[0115] FIG. 1 a schematic block wiring diagram of an apparatus according to the invention,

[0116] FIG. 2 a schematic arrangement of an infrastructure device and a plurality of receiving devices in a vehicle,

[0117] FIG. 3 a schematic plan view of a vehicle,

[0118] FIG. 4 a schematic block wiring diagram of an apparatus according to the invention in a second embodiment,

[0119] FIG. 5 a schematic functional block wiring diagram of components in a vehicle,

[0120] FIG. 6 a schematic flow diagram of a method according to the invention,

[0121] FIG. 7 a schematic time waveform of a transmission signal of an infrastructure device,

[0122] FIG. 8 a schematic functional block wiring diagram,

[0123] FIG. 9 a schematic illustration of a UCA receiving device,

[0124] FIG. 10 a schematic plan view of a dedicated traffic situation of an intersection,

[0125] FIG. 11 a schematic block wiring diagram of an apparatus according to the invention in a further embodiment and

[0126] FIG. 12 a schematic illustration of a UCA receiving device with a vehicle-mounted transmitting device.

DESCRIPTION OF THE INVENTION

[0127] In the following, identical reference numerals denote elements with identical or similar technical features.

[0128] FIG. 1 shows a block wiring diagram of an apparatus 1 according to the invention for determining a distance between a vehicle 2 (see e.g. FIG. 2) and an infrastructure device 3. The infrastructure device 3 can be, for example, a transmitting and receiving device for OFDM signals, in particular LTE signals. For example, the infrastructure device 3 can be a transmitter mast or a part thereof.

[0129] The apparatus comprises a plurality of receiving devices 4a, 4b, . . . , 4x and a vehicle-mounted evaluation device 5. The receiving devices 4a, 4b, . . . , 4x are connected to the evaluation device 5 for signal communication. Both the receiving devices 4a, 4b, . . . , 4x and the evaluation device 5 are arranged on board the vehicle.

[0130] Each receiving device 4a, 4b, . . . , 4x comprises n antenna elements 6a, 6b, . . . , 6n, where n is greater than 1. A transmission signal, which is sent by the infrastructure device 3, is received by the antenna elements 6a, 6b, . . . , 6n of the receiving devices 4a, 4b, . . . , 4x. In this case it is possible that only some or all of the antenna elements 6a, 6b, . . . , 6n of some or all of the receiving devices 4a, 4b, . . . , 4x receive the transmission signal. For example, some or all of the antenna elements 6a, 6b, . . . , 6n of one receiving device 4a, 4b, . . . , 4x or a plurality of receiving devices 4a, 4b, . . . , 4x may be hidden, so that the transmission signal is either not received or only with an unwanted time delay.

[0131] The antenna signals generated by the antenna elements 6a, 6b, . . . , 6n upon receipt of the transmission signal are transmitted to the evaluation device 5 by the receiving devices 4a, 4b, . . . , 4x. To do this, the antenna signals can be digitized. This will be explained in more detail below.

[0132] Using the evaluation device 5, in accordance with the antenna signals a receiving device-specific distance d can be determined for each of the receiving devices 4a, 4b, . . . , 4x which transmits antenna signals to the evaluation device 5.

[0133] For this purpose, the evaluation device 5 can execute the method illustrated in FIG. 6, for example.

[0134] In addition, the evaluation device determines the minimum possible distance of all the receiving device-specific distances as the distance between the vehicle 2 and the infrastructure device 3. For example, it is possible that the receiving device-specific distance between the vehicle and the infrastructure device is determined as a function of a distance between a reference point of the infrastructure device 3 and a reference point of the respective receiving device 4a, 4b, . . . , 4x. The reference point of a receiving device 4a, 4b, . . . , 4x can be, for example, a geometric midpoint of the antenna elements 6a, 6b, . . . , 6n. A spatial position of the reference point of the receiving device 4a, 4b, . . . , 4x in a vehicle coordinate system of the vehicle 2 can also be known in advance. If this is the case, a distance between the reference point of the infrastructure device 3 and a reference point of the vehicle 2 can also be determined as the distance. If a position of the reference point of the infrastructure device 3 in a global reference coordinate system is known, then the position 2 of the vehicle in this global reference coordinate system can also be determined.

[0135] The antenna elements 6a, 6b, . . . , 6n are preferably designed as so-called patch antennas or strip antennas.

[0136] FIG. 2 shows a schematic arrangement of an infrastructure device 3 and a vehicle 2 with a plurality of receiving devices 4a, 4b, 4c, 4d, 4e, 4f, 4h.

[0137] In this case, the antenna elements 6 of the individual receiving devices are shown schematically, wherein for the sake of clarity only one antenna element 6 of each receiving device 4a, . . . , 4h is labeled with a reference numeral.

[0138] The vehicle 2 in this example comprises the receiving devices 4a, . . . , 4h. Antenna elements 6 of the receiving devices 4a, . . . , 4h are preferably, but not necessarily, arranged in non-metallic parts or elements of the vehicle 2, for example, in a front fender, rear fender, an element of a door trim, in a B-pillar or in a vehicle roof or in a front windshield.

[0139] Various designs of the receiving devices 4a, . . . , 4h are also illustrated. The antenna elements 6 of a first set of receiving devices 4a, 4d are arranged in a circle and thus form a so-called UCA antenna structure. In this case antenna elements 6 are arranged along a circumference of a circle at a predetermined distance apart from each other. The predetermined distance along the circle can be, for example, in a range of lambda/2 (=half a wavelength of the high-frequency signal used).

[0140] The antenna elements 6 of the further set of remaining receiving devices 4b, 4c, 4e, 4f, 4g, 4h are arranged linearly, i.e. along a straight line. The antenna elements 6 of these receiving devices 4b, 4c, 4e, 4f, 4g, 4h thus form so-called ULA-antenna structures.

[0141] It is shown that the antenna elements 6 of individual receiving devices 4b, 4e, 4g, 4h of the further set form horizontal ULA-antenna structures, wherein the antenna elements are arranged along a line running parallel to a plane, wherein the plane is oriented perpendicular to a vehicle vertical axis z (yaw axis). The antenna elements 6 of the remaining receiving devices 4c, 4f of the further set each form a so-called vertical ULA-antenna structure, wherein the antenna elements 6 are arranged along a line oriented parallel to the vehicle vertical axis z.

[0142] The antenna elements of the receiving devices 4b, 4c, 4e, 4f, 4g, 4h can be arranged along the line a predetermined distance of lambda/2 apart.

[0143] Also shown is an infrastructure device 3, which emits the schematically illustrated signals LOS, bLOS. Also shown is the fact that a blocked signal bLOS is blocked by an object 7, for example another vehicle, and therefore cannot be received by any of the antenna elements 6 of the receiving devices 4a, . . . , 4h. An unblocked transmission signal LOS is not blocked and can be received, for example, by the antenna elements 6 of the receiving device 4a but also by antenna elements 6 of other receiving devices 4b, 4h. This illustrates that the signal LOS is a so-called line-of-sight signal. This means that the received signal can propagate along a straight line connecting line between the receiving device 4a and the infrastructure device 3.

[0144] Depending on the arrangement of the antenna elements 6 of the receiving devices 6 in the vehicle, a receiving direction of the unblocked transmission signal LOS can be determined as a function of the antenna signals. The receiving direction can be determined in a receiving device-fixed or -specific coordinate system, for example, in the coordinate system of a UCA antenna structure or a ULA antenna structure. If the position and orientation of the antenna structures of the receiving devices 4a, . . . , 4h in the vehicle coordinate system are known, then a receiving direction can be determined in the vehicle coordinate system also.

[0145] In particular, the receiving direction can be determined in the form of an azimuth angle az and elevation angle el (see FIG. 9). In FIG. 9 this is shown with respect to a coordinate system of a UCA antenna structure. Of course, these angles can also be determined in the vehicle coordinate system, however.

[0146] In this case enable the vertical ULA antenna structures shown in FIG. 2 advantageously enable a determination of an elevation angle el and the horizontal ULA antenna structures enable the determination of an azimuth angle az. The ULA antenna structure enables the determination of both angles el, az. In the vehicle coordinate system the azimuth angle az can be determined, for example, in a plane defined by the vehicle longitudinal axis and the vehicle transverse axis. The elevation angle can be determined as an angle between the receiving direction and the vertical axis z of the vehicle.

[0147] FIG. 3 shows a schematic plan view of a vehicle 2. The vehicle 2 comprises a plurality of receiving devices 4a, 4b, 4c, 4d, 4e, 4f and an evaluation device 5. The evaluation device 5 can comprise a microcontroller or can be designed as such. Also, the evaluation device 5 can comprise an FPGA, or can be designed as such. This shows that the receiving devices 4a, . . . , 4f are connected to each other and to the evaluation device 5 for signal communication via a UHDR-signal transmission line 8. The UHDR-signal transmission line allows signal transmission at up to 20 Gbit/s. Such a transmission capacity can be necessary, in particular when the antenna signals are digitized with a high sampling rate. This may be necessary, in particular, for determining a signal start section, which will be explained further below.

[0148] FIG. 4 shows a schematic block wiring diagram of an apparatus according to the invention in a further embodiment. The apparatus 1 in turn comprises a plurality of receiving devices 4a, 4b, 4c, 4d, each with a plurality of antenna elements 6a, 6b. The receiving devices 4a, 4b, 4c, 4d also comprise an A/D converter device 9 in each case. The A/D converter devices 9 are designed here as so-called GSa/s A/D converter devices and enable a digitization of the analog received signals with a sampling rate of up to 2-4 G-samples per second. In the case shown, the antenna signals of all antenna elements 6a, 6b of a receiving device 4a, . . . , 4d are digitized by an A/D converter device. Of course, it is also possible that the antenna signals of the antenna elements are each digitized by a separate A/D converter device.

[0149] It is also possible, by means of the receiving devices 4a, in particular by means of the A/D converter devices 9, to generate a digitized received signal in the form of an in-phase component I and a quadrature component Q. These components I, Q are then transmitted by the UHDR-signal transmission line 8 shown in FIG. 3 to an evaluation device 5. This comprises interfaces 10 for the UHDR-signal transmission lines 8. Also shown is a processing unit 11 of the evaluation device 5, which performs the signal processing of the transmitted components I, Q, in other words of the transmitted digitized received signal. This data processing can comprise a data modulation, demodulation and data encoding. Furthermore, the distance can be determined by the data processing.

[0150] FIG. 5 shows a schematic functional block wiring diagram. A receiving device 4 receives transmission signals of an infrastructure device 3 (see, for example, FIG. 1). The antenna signals of the antenna elements 6a, 6b of the receiving device 4 are digitized, in particular in each case using an A/D converter device 9.

[0151] In a further process step 12 a receiver-specific distance is determined between the receiving device 4 and the infrastructure device 3, not shown in FIG. 5. This can be carried out by the evaluation device 5 shown in FIG. 1. In a further process step 13 a process known as framing is carried out, which involves the generation of data flows in a desired format. In a further process step 14, user data can be extracted from the data stream generated in process step 13. In a further process step 15, these user data can be used for a desired application, such as the control of a vehicle assistance system. Also shown is the fact that the data stream or parts thereof generated in process step 13, in particular also extracted user signals, can in turn be sent from the vehicle 2 to external devices, for example, including the infrastructure device 3. For this purpose, in a further process step 16 a data modulation can be carried out, and in a following process step 17 a so-called FDMA-modulation process. In addition, for example by means of the A/D converter device 9 already described, which can also be used as a D/A-converter, a digital signal can be converted into an analog signal and emitted via an antenna element 6. Thus the hardware is used for both localization as well as data transmission. For example, the distance from the vehicle 2, determined according to the invention, can also be transmitted to the infrastructure device 3.

[0152] From the functional block wiring diagram shown in FIG. 5, it can be seen that the transmission signal can be used both to determine the distance and to transmit user data. This means that the transmission signal enables, on the one hand, the determination of the distance between vehicle 2 and infrastructure device 3, but at the same time can be used for the transmission of user signals emitted by the vehicle 2, for example to control a vehicle assistance system.

[0153] FIG. 6 shows a schematic flow diagram of a method according to the invention for determining a distance between a vehicle 2 and an infrastructure device 3 (see, for example, FIG. 2).

[0154] In a first step S1 a start time of the method, i.e. the method for distance determination with angle estimation and spatial filtering, is specified or detected. The transmission of the transmission signal from the infrastructure device 3 can be interrupted, in particular periodically, for a predetermined time interval. The receiving devices 4a, 4b, . . . , 4x (see, for example, FIG. 1) can, however, be used to receive signals continuously. If an interruption or a re-occurring signal transmission after the interruption of the transmit signal is detected, i.e., a pause in transmission, then the start time can be defined as the time at which the re-occurring signal transmission is detected following a pause. An interruption can be detected, for example, if a signal power is less than a predetermined threshold. A re-occurring signal transmission after the interruption can be detected, for example, if the signal power, for example in the form of a signal level, increases above a predetermined threshold. Also, the detection time can be the time at which a rising edge of the signal level is detected.

[0155] Of course, however, there are also other possible ways of determining or defining a start time for the distance determination.

[0156] To perform the angle estimation and spatial filtering for the extraction of the line-of-sight signal in the receiver, in a second step S2 after the detection of the transmission pause or after the start time of the method, the antenna signals received by the antenna elements 6a, 6b of a receiving device 4 are digitized with a predetermined first sampling rate, which is in the range of 2 to 4 giga-samples/second. Furthermore, a signal start section of each digitized antenna signal is determined. The signal start section in this case comprises the samples that were generated during a predetermined time interval after the start time. Alternatively or cumulatively, the signal start section can comprise a predetermined maximum number of sampling values. The signal start section in this case is referred to as a so-called snapshot of the digitized antenna signals.

[0157] It is possible, but not mandatory, that after the determination or generation of the signal start section the sampling rate is reduced from the first sample rate to a further, lower sampling rate, which can be dependent on the signal bandwidth. This is described in the LTE standard, for example.

[0158] Therefore, a signal starting section does not comprise all the samples of a digitized antenna signal.

[0159] In a third step S3, the signal start sections are used as a basis for determining a receiving direction of the transmission signal. For this purpose, the signal starting sections that were generated by the antenna elements 6 of a receiving device 4 or by the antenna elements 6 of a plurality of devices 4 can be used. For example, to determine the receiving direction the signal starting sections, which were generated by antenna elements 6 of a UCA antenna structure, can be evaluated. This advantageously enables the determination of both an azimuth angle az and an elevation angle el (see FIG. 9). The signal starting sections of all antenna elements 6 of a ULA-antenna structure can also be evaluated to determine either an azimuth angle az or an elevation angle el.

[0160] The determination of the receiving direction, in particular the determination of an azimuth angle az and an elevation angle el, as a function of the signal starting sections is described using the example of a UCA antenna structure in section III.A. of the paper by A. El Assaad et al., “Distance and vehicle speed estimation in OFDM multipath channels”, 2016 21st International Conference on microwave, radar and wireless communications (MIKON) (2016), 1-5.

[0161] Between the second step S2 and the third step S3 a signal correction of the analogue or digital antenna signal can be determined in accordance with at least one signal correction factor. This can be determined, as is explained in more detail below, in accordance with a calibration signal, which is emitted by a vehicle-mounted transmitting device 27 (see, for example, FIG. 11).

[0162] It is also described in the same section that from a digitized antenna signal, thus no longer exclusively from the signal start section, of a receiving device 4, in a fourth step S4 a receiving device-specific line-of-sight signal can be determined based on the already determined receiving direction. In the fourth step S4 therefore, a signal is determined by computation, which was transmitted along a straight connecting line, i.e. the line-of-sight, from the infrastructure device 3 to the respective receiving device 4. This can also be referred to as spatial filtering of the antenna signals.

[0163] In a fifth step S5, the receiving device-specific distance is determined in accordance with the receiving device-specific line-of-sight signal determined in the fourth step S4.

[0164] In the fifth step S5, in particular a data symbol can be extracted from the receiving device-specific line-of-sight signal. In addition, this extracted data symbol can be correlated with a reference symbol for different phase angles of this reference symbol. The reference symbol designates a defined symbol, known in advance, which is transmitted by the infrastructure device 3 via or in the transmission signal. The reference symbol used can have a defined, previously known phase angle. In addition, the phase angle is determined for which the correlation between the reference symbol and the data symbol is a maximum. In addition, the propagation time of the receiving device-specific line-of-sight signal is determined as a function of the corresponding phase offset. Further, from this propagation time the distance between the infrastructure device 3 and the receiving device 4 can be determined.

[0165] Then, in the fifth step S5 a vehicle speed, in particular a receiving device-specific vehicle speed, can also be determined. This vehicle speed may be determined in particular as a function of at least two, in particular receiving device-specific, distances determined consecutively.

[0166] The determination of both the receiving device-specific distance and the receiving device-specific vehicle speed is described e.g. in section III.B of the above-mentioned paper by A. El Assaad et al., “Distance and vehicle speed estimation in OFDM multipath channels”, 2016 21st International Conference on microwave, radar and wireless communications (MIKON) (2016), 1-5.

[0167] Further, in the fifth step S5 the shortest possible distance of all the receiving device-specific distances can be determined as the resulting distance. It is also conceivable in this case to determine a vehicle speed from two consecutively determined resulting distances.

[0168] In a sixth step S6, the transmitted signal or the digitized received signal can be used to extract user data, such as video data, audio data or data for other applications in the vehicle 2.

[0169] FIG. 7 shows a schematic time waveform of a transmission signal which can be emitted by an infrastructure device 3. This shows that the transmission of the signal is periodically interrupted, wherein an interruption lasts for a predetermined period T. The period T can be, for example, 10 μs. The interruption can be implemented, for example, by a transmitting device of the infrastructure device 3 being deactivated or modulated for the predetermined time interval periodically with a frequency of greater than 5 Hz.

[0170] It is also shown that the signal power during the interruption is small, in particular close to 0. During an actual signal transmission, the signal power is greater than a predetermined threshold.

[0171] In this case it is possible that the vehicle-mounted evaluation device 5 detects an interruption, and in particular the re-occurring signal transmission following an interruption, wherein the detection time can be used as the start time (trigger time) for the distance determination method according to the invention.

[0172] FIG. 8 shows a schematic functional wiring diagram of the teaching according to the invention.

[0173] A plurality of receiving devices 4a, 4b, . . . , 4x is shown, each with a plurality of antenna elements 6a, 6b, . . . , 6n. In a process step 18, the received signals which are generated by the antenna elements 6a, 6b, . . . , 6n are at least temporarily digitized with the first sampling rate and transmitted to an evaluation device 5 via a UHDR-signal transmission line 8 (see FIG. 4). In a further process step 19 the evaluation device 5 determines a receiving device-specific receiving direction and a receiving device-specific line-of-sight signal. In a further process step 20, for each receiving device 4a, . . . , 4x a receiving device-specific propagation time of the receiving device-specific line-of-sight signal is determined. In a further process step 21, a temporal synchronization of the receiving device-specific line-of-sight signals can be carried out based on the receiving device-specific signal propagation times of the receiving device-specific line-of-sight signals. In particular, all the receiving device-specific line-of-sight signals can be transformed into a common time system, for example a time system of the infrastructure device 3.

[0174] In a subsequent process step 22, a receiving device-specific distance and a receiving device-specific vehicle speed can then be determined for each receiving device 4a, 4b, . . . , 4x.

[0175] In a subsequent process step 23 the resulting distance can be determined as the minimum receiving device-specific distance, and the resultant vehicle speed can be determined as the vehicle speed determined by the receiving device 4 that also produces the shortest possible receiving device-specific distance. Then, in the subsequent process step 23, the resulting distance can be used to determine the position of the vehicle in a global reference coordinate system, in particular in which a position of the infrastructure device 3 in the global reference system is known. Information about this position can be transmitted, for example, by the infrastructure device 3 via transmission signals to the vehicle 2, wherein this information can be extracted from the transmission signal as user signals. In addition to the information, further user signals can of course also be extracted from the transmission signal.

[0176] If the receiving device and the distance are known, then the vehicle position can be determined from the position of the infrastructure device 3 in the global reference coordinate system as well as in the reference coordinate system. Thus, in a further process step 24 the vehicle position in the global reference coordinate system can be determined. This information can then be transmitted to the infrastructure device 3. The information on the vehicle position in the global reference coordinate system can then be transmitted via the infrastructure device 3 to a central control device, which can control a flow of traffic or generate appropriate control signals based on this information and transmit them to vehicles and/or signaling systems. Of course, information about the vehicle speed can also be transmitted to the infrastructure device 3 and from there to a central control device. In a further process step 25, further user signals can be extracted from the transmission signal and used for in-vehicle applications, for example for controlling a vehicle assistance system.

[0177] This therefore enables a simultaneous distance determination and communication.

[0178] FIG. 9 shows a schematic diagram of a UCA antenna structure with antenna elements 6a, . . . , 6b, 6c, 6d, 6e, 6f, 6g, 6h. It is also shown that the antenna elements 6a, 6h are arranged along a circular line. Also illustrated is an antenna structure-specific coordinate system with spatial axes x, y, z and an azimuth angle az and an elevation angle el. Also shown is a line-of-sight signal LOS, wherein the azimuth angle az designates an angle between the longitudinal axis x of the coordinate system and a line of the line-of-sight signal LOS which is projected into a plane defined by the longitudinal axis x and the transverse axis y. An elevation angle el designates the angle between the vertical spatial axis z and the line-of-sight signal LOS.

[0179] It is of course possible to transform the angles az, el determined in the antenna structure-specific coordinate system, which can also be designated as a receiving device-specific coordinate system, into a vehicle coordinate system if the position and orientation of the antenna structure-specific coordinate system in the vehicle coordinate system is known in advance.

[0180] FIG. 10 shows a schematic plan view of a first side of a traffic node in the form of an intersection 26. The intersection consists of four approach roads R1, R2, R3, R4, each with two carriageways B, wherein each carriageway B has two lanes S. Each carriageway B has a width W1. Each lane S has a width W2. It is also evident that the approach roads R1, . . . , R4 each have lengths L. Also shown is a vehicle 2, which is driving on a right-hand lane S of a carriageway B of the first approach road R1.

[0181] A vehicle coordinate system is shown, in particular the vehicle longitudinal axis x.sub.v and the vehicle transverse axis y.sub.v. A vehicle vertical axis z.sub.v (see also FIG. 2) here is oriented perpendicular to the remaining axes x.sub.v, y.sub.v and points towards the observer.

[0182] Also shown is a global reference coordinate system with a longitudinal axis x.sub.w and a transverse axis y.sub.w. A vertical axis, not shown, of the global reference coordinate system is in this case also oriented perpendicular to the two remaining axes x.sub.w, y.sub.w and oriented towards the observer. Also shown is an infrastructure device 3, which can be arranged, for example, at the origin of the global reference coordinate system. The global coordinate system can be a fixed coordinate system relative to a transport node.

[0183] The vehicle 2 can comprise an apparatus 1 for distance determination. Using the apparatus 1, as previously explained, a distance can be determined between the vehicle 2 and the infrastructure device 3. In this method, if a receiving direction of a line-of-sight signal LOS is determined, then a position 2 of the vehicle in the global reference coordinate system can then be determined. This position and possibly a vehicle speed can then be used, in particular by a central control device which is not shown, to control a traffic flow of vehicles in the region of the transport node 26. For this purpose, appropriate control signals can be generated by the central control device and transmitted to the respective vehicle 2, for example via the infrastructure device 3.

[0184] Simulations have shown that using the proposed method a mean error in the distance of less than 50 cm and an azimuth angle error of less than 1 degree can be obtained, regardless of the vehicle speed.

[0185] FIG. 11 shows a schematic block wiring diagram of an apparatus 1 according to the invention in a further embodiment. In contrast to the embodiment shown in FIG. 1, the apparatus 1 in this case comprises one vehicle-mounted transmitting device 27 per vehicle-mounted receiving device 4a, 4b, . . . , 4x in order to generate a calibration signal. FIG. 11 shows that these vehicle-mounted transmitting devices 27 are each part of the receiving devices 4a, 4b, . . . 4x. This is not mandatory, however. It is also not necessarily the case that the apparatus 1 comprises one vehicle-mounted transmitting device 27 per vehicle-mounted receiving device 4a, 4b, . . . , 4x in order to generate a calibration signal. Also, the apparatus 1 can comprise only a single vehicle-mounted transmitting device 27 or else only one vehicle-mounted transmitting device 27 each for selected, but not all, vehicle-mounted receiving devices 4a, 4b, . . . , 4x. The vehicle-mounted transmitting devices 27 in this case can be arranged at a previously known spatial location relative to the antenna elements 6 of the vehicle-mounted receiving devices 4a, 4b, . . . , 4x.

[0186] FIG. 12 shows a schematic diagram of a UCA antenna device with antenna elements 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h and with a vehicle-mounted transmitting device 27. In contrast to the embodiment shown in FIG. 9 a vehicle-mounted transmitting device 27 for a calibration signal is shown, which is arranged at the center point of the circle on the circumference of which the antenna elements 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h are arranged.

[0187] The vehicle-mounted transmitting devices 27 shown in FIG. 11 and FIG. 12 enable the generation of a calibration signal, which can then be received by the antenna elements 6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h of the vehicle-mounted receiving devices 4a, 4b, . . . , 4x.

[0188] In addition, depending on at least one signal property of the calibration signal received by the antenna elements 6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, at least one signal correction factor, e.g. a phase drift and an amplitude drift correction factor, can be determined for each antenna element 6, 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h of a receiving device 4a, 4b, . . . , 4x. This signal correction factor can be determined in particular on the basis of the previously known spatial position of the vehicle-mounted transmitting device and/or of known (transmission) properties of the calibration signal.

[0189] Also, an antenna signal or a digitized antenna signal, which is generated when a transmission signal of the infrastructure device 3 is received, can then be corrected in accordance with the at least one signal correction factor.

LIST OF REFERENCE NUMERALS

[0190] 1 apparatus

[0191] 2 vehicle

[0192] 3 infrastructure device

[0193] 4, 4a, 4b, . . . , 4x receiving device

[0194] 5 evaluation device

[0195] 6, 6a, 6b, . . . , 6n antenna element

[0196] 7 object

[0197] 8 UHDR signal transmission line

[0198] 9 A/D converter device

[0199] 10 interface

[0200] 11 data processing unit

[0201] 12 process step

[0202] 13 process step

[0203] 14 process step

[0204] 15 process step

[0205] 16 process step

[0206] 17 process step

[0207] 18 process step

[0208] 19 process step

[0209] 20 process step

[0210] 21 process step

[0211] 22 process step

[0212] 23 process step

[0213] 24 process step

[0214] 25 process step

[0215] 26 intersection

[0216] 27 vehicle-mounted transmitting device

[0217] S1 first step

[0218] S2 second step

[0219] S3 third step

[0220] S4 fourth step

[0221] S5 fifth step

[0222] S6 sixth step

[0223] R1, R2, R3, R4 approach road

[0224] B road surface

[0225] S driving lane

[0226] W1 width of a carriageway

[0227] W2 width of a driving lane

[0228] L length

[0229] x longitudinal axis

[0230] y transverse axis

[0231] z vertical axis

[0232] x.sub.v vehicle longitudinal axis

[0233] y.sub.v vehicle transverse axis

[0234] z.sub.v vehicle vertical axis

[0235] x.sub.w longitudinal axis of the global reference coordinate system

[0236] y.sub.w transverse axis of the global reference coordinate system

[0237] LOS line-of-sight signal