Reference signal generating device and reference signal generating method

Abstract

The purpose of the present invention is to provide a technology capable of using time pulse signals extracted by a GNSS reception unit to operate a high-precision positioning calculation unit and a V2X transceiver unit that use signals with different frequencies. In the present invention, a signal generation unit synchronizes a time pulse signal used by a high-precision positioning calculation unit of a vehicle with a synchronization reset signal and divides the frequency of the time pulse signal, to thereby generate a frequency-divided signal usable in a V2X transceiver unit of the vehicle, or multiplies the frequency of a time pulse signal usable in the V2X transceiver unit, to thereby generate a frequency-multiplied signal usable in the high-precision positioning calculation unit.

Description

[Technical Field]

[0001] The present disclosure relates to a reference signal generating device and a reference signal generating method. [Background technology]

[0002] A V2X (Vehicle to Everything) transceiver is required to use a 1 Hz, i.e., 1 PSS, signal so that it can communicate with the other device in time synchronization, and to synchronize with UTC (Coordinated Universal Time), which serves as the time standard. Conventional GNSS (Global Navigation Satellite System) receivers output highly accurate 1 PPS time pulse signals, and inputting these time pulse signals into a V2X transceiver makes it possible to normalize the communication operation of the V2X transceiver. Patent Document 1 describes that a GPS (Global Positioning System) receiver generates a 1 PPS signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-173326 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, locators (hereinafter referred to as "HDL") with higher accuracy than ordinary locators have been proposed. In order for HDL to generate highly accurate position information, time pulse signals with frequencies higher than 1PPS, such as 5PPS and 10PPS, are required, and accordingly, GNSS receivers that output time pulse signals such as 5PPS and 10PPS have also been proposed.

[0005] However, if the GNSS receiver outputs a time pulse signal other than 1PPS, the time pulse signal cannot be used by the V2X transceiver. Conversely, if the GNSS receiver outputs a 1PPS time pulse signal, the time pulse signal cannot be used by the HDL.

[0006] Therefore, the present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that enables a high-precision positioning calculation unit and a V2X transceiver unit that use signals with different frequencies to operate using a time pulse signal extracted by a GNSS receiver. [Means for solving the problem]

[0007] The reference signal generating device according to the present disclosure includes an acquisition unit that acquires a time pulse signal extracted by a GNSS receiving unit of a vehicle, and a signal generating unit that generates a divided signal that can be used by a V2X transceiver unit of the vehicle by synchronizing the time pulse signal acquired by the acquisition unit and used by a high-precision positioning calculation unit of the vehicle with a synchronous reset signal and dividing the frequency of the time pulse signal, or generates a multiplied signal that can be used by the high-precision positioning calculation unit by multiplying the time pulse signal acquired by the acquisition unit and used by the V2X transceiver unit. [Effects of the Invention]

[0008] According to the present disclosure, a time pulse signal used in a high-precision positioning calculation unit of a vehicle is synchronized with a synchronous reset signal and frequency-divided to generate a frequency-divided signal that can be used in a V2X transceiver unit of the vehicle, or a time pulse signal that can be used in the V2X transceiver unit is multiplied to generate a frequency-multiplied signal that can be used in the high-precision positioning calculation unit. With this configuration, the high-precision positioning calculation unit and the V2X transceiver unit, which use signals with different frequencies, can be operated by the time pulse signal extracted by the GNSS receiver.

[0009] The objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a configuration of a locator system according to a first embodiment. [Figure 2] 5 is a diagram for explaining an operation to be compared with the operation of the frequency divider according to the first embodiment. FIG. [Figure 3] 5 is a diagram for explaining the operation of a frequency divider according to the first embodiment. FIG. [Figure 4] 4 is a diagram for explaining the operation of a control unit according to the first embodiment. FIG. [Figure 5] 5 is a flowchart showing the operation of a control unit according to the first embodiment. [Figure 6] 5 is a flowchart showing the operation of a control unit according to the first embodiment. [Figure 7] 5 is a flowchart showing the operation of a control unit according to the first embodiment. [Figure 8] 5 is a flowchart showing the operation of a control unit according to the first embodiment. [Figure 9] FIG. 10 is a block diagram showing the configuration of a locator system according to a second embodiment. [Figure 10] FIG. 10 is a block diagram showing a hardware configuration of a reference signal generating device according to another modified example. [Figure 11] FIG. 10 is a block diagram showing a hardware configuration of a reference signal generating device according to another modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] <First Embodiment> Fig. 1 is a block diagram showing the configuration of a locator system according to Embodiment 1. The locator system in Fig. 1 includes a GNSS (Global Navigation Satellite System) receiving unit 1, an acquiring unit 2, a high-precision positioning calculation unit 3, a control unit 4, a frequency dividing unit 5, a temperature monitoring unit 6, a backup power supply unit 7, an RTC (Real-Time Clock) 8, a comparing unit 9, a storage unit 10, a switching unit 11, and a V2X (Vehicle to Everything) transceiver unit 12.

[0012] 1 includes a reference signal generating device according to the first embodiment, which includes an acquisition unit 2, a control unit 4, and a frequency divider unit 5 serving as a signal generating unit. However, the reference signal generating device is not limited to this, and may not include the control unit 4, or may include at least one of a GNSS receiving unit 1, a high-precision positioning calculation unit 3, an RTC 8, a comparison unit 9, a storage unit 10, a switching unit 11, and a V2X transceiver unit 12. In this specification, for example, "at least one of A, B, C, ..., and Z" means any one of all combinations of one or more elements extracted from the group of A, B, C, ..., and Z.

[0013] The locator system of Fig. 1 is communicatively connected to a vehicle control unit 21, a sensor 22, and an imaging unit 23. The vehicle control unit 21 controls the vehicle based on the vehicle speed and the like. The sensor 22 is, for example, a six-axis sensor that detects the acceleration of the vehicle on three axes (front-rear, left-right, and up-down) and the angular velocity around the three axes. The imaging unit 23 captures images of the outside of the vehicle. For example, a drive recorder capable of capturing images of the inside and outside of the vehicle is used as the imaging unit 23.

[0014] 1, vehicle control unit 21, sensor 22, and photographing unit 23 are provided outside the locator system, but at least one of them may be provided in the locator system. Furthermore, in the first embodiment, the locator system, vehicle control unit 21, sensor 22, and photographing unit 23 are described as being provided in the vehicle, but as will be described later, some of these may be provided outside the vehicle.

[0015] Next, each component of the locator system in FIG. 1 will be described.

[0016] The GNSS receiver 1 extracts GNSS measurement data, such as a CN (carrier-to-noise ratio) value and a navigation message, and a time pulse signal based on radio waves from GNSS satellites. In the first embodiment, the time pulse signal extracted by the GNSS receiver 1 is described as a 10 Hz, i.e., 10 PPS, time pulse signal, but is not limited to this. The time pulse signal extracted by the GNSS receiver 1 may be any time pulse signal with a frequency higher than 1 Hz, i.e., 1 PPS, and may be, for example, a 5 Hz, i.e., 5 PPS, time pulse signal.

[0017] The acquisition unit 2 acquires the GNSS measurement data and time pulse signals extracted by the GNSS receiver 1. In the example of Fig. 1, the acquisition unit 2 is an interface to the GNSS receiver 1, but it may be the GNSS receiver 1 itself. The acquisition unit 2 outputs the GNSS measurement data to the high-precision positioning calculation unit 3, and outputs the time pulse signals to the high-precision positioning calculation unit 3 and the frequency divider 5.

[0018] The high-precision positioning calculation unit 3 is, for example, a High-Definition Locator (HDL). The high-precision positioning calculation unit 3 calculates the position of the vehicle based on the GNSS measurement data from the acquisition unit 2 and a 10 PPS time pulse signal having a higher frequency than 1 PPS from the acquisition unit 2. Note that, when the vehicle speed of the vehicle control unit 21 and the detection result of the sensor 22 are synchronized, the high-precision positioning calculation unit 3 may appropriately correct the vehicle position using them.

[0019] The high-precision positioning calculation unit 3 also calculates UTC (Coordinated Universal Time) based on the GNSS measurement data and outputs it to the control unit 4. Furthermore, the high-precision positioning calculation unit 3 performs arithmetic processing such as correction on the time pulse signal and synchronizes with UTC to generate a 1PPS second signal that is a generated signal that can be used by the V2X transceiver unit 12. The second signal generated by the high-precision positioning calculation unit 3 is output to the comparison unit 9 and the switching unit 11.

[0020] The control unit 4 outputs a synchronization reset signal to the frequency dividing unit 5 based on the UTC calculated by the high-precision positioning calculation unit 3. For example, when UTC is at a predetermined time (X hours, Y minutes, Z seconds), the control unit 4 outputs a synchronization reset signal to the frequency dividing unit 5. The control unit 4 also performs operations other than those described above, which will be described later.

[0021] The frequency divider 5 generates a first signal of 1 PPS, which is a frequency-divided signal that can be used by the V2X transceiver 12, by synchronizing with a synchronous reset signal and dividing the frequency of the time pulse signal acquired by the acquirer 2 and used by the high-precision positioning calculation unit 3. Since the first signal to be generated is a 1 PPS signal, if the time pulse signal used by the high-precision positioning calculation unit 3 is an n PPS signal, the frequency divider 5 divides the frequency of the time pulse signal by n.

[0022] FIG. 2 shows the results when a 10 PPS time pulse signal is divided by 10. The example in FIG. 2 indicates that the rising edges of pulses marked with "0" in the time pulse signal should be synchronized with UTC times such as X:Y:00, X:Y:01, etc. However, simply dividing the 10 PPS time pulse signal by 10 often results in the resulting signal not being synchronized with UTC times such as X:Y:00, X:Y:01, etc., as shown in FIG. 2. Therefore, the frequency divider 5 divides and synchronizes the time pulse signal with a synchronous reset signal.

[0023] 3 shows the results when a 10 PPS time pulse signal is synchronized with a synchronous reset signal and divided by 10. As shown in FIG. 3, the frequency divider 5 synchronizes the rising edge of the pulse following the falling edge of the synchronous reset signal, among the multiple pulses of the 10 PPS time pulse signal, with UTC, and generates a 1 PSS signal based on that pulse to generate a first signal. Note that the deviation between the rising edge of the pulse to be synchronized with UTC and the falling edge of the synchronous reset signal in the time pulse signal can be allowed to be less than the interval between the rising edges of adjacent pulses in the time pulse signal (100 msec in the example of FIG. 3).

[0024] Unless there is some reason such as a failure of the frequency dividing unit 5, the first signal generated by the frequency dividing unit 5 is not out of sync with the time pulse signal. The first signal generated by the frequency dividing unit 5 is output to the comparing unit 9 and the switching unit 11.

[0025] The temperature monitoring unit 6 in Figure 1 monitors the ambient temperature used to correct the RTC signal generated by the RTC 8. The backup power supply unit 7 supplies power to the RTC 8 when, for example, the vehicle's ACC power supply is off. This allows the RTC 8 to operate even when, for example, the vehicle's ACC power supply is off.

[0026] The RTC 8 generates a 1PPS RTC signal that can be used by the V2X transceiver 12. In the first embodiment, the RTC 8 is configured to be able to appropriately correct the RTC signal based on the ambient temperature monitored by the temperature monitoring unit 6 and a correction signal from the control unit 4, which will be described later. The RTC signal generated by the RTC 8 is output to the comparison unit 9 and the switching unit 11.

[0027] The comparison unit 9 compares either the first signal or the second signal with the RTC signal, and stores the comparison results, such as the difference in rising timing, in the storage unit 10. The storage unit 10 stores the comparison results of the comparison unit 9 and correction values ​​corresponding to the comparison results. Note that the storage unit 10 may also store GNSS measurement data previously extracted by the GNSS receiver 1.

[0028] The control unit 4 outputs a correction signal to the RTC 8 for correcting the RTC signal generated by the RTC 8 based on the comparison result and the correction value stored in the storage unit 10. In other words, the control unit 4 corrects the RTC signal based on the comparison result between the RTC signal and either the first signal or the second signal.

[0029] FIG. 4 is a diagram illustrating the correction of the RTC signal based on the comparison result between the first signal and the RTC signal. When the reception conditions of the GNSS receiver 1 are good and the 1 PPS accuracy of the first signal is high, the storage unit 10 stores a counter value indicating the difference between the first signal and the RTC signal. The number of comparisons to obtain the difference is arbitrary, and the control unit 4 outputs a correction signal to the RTC 8 to adjust the rising edge of the RTC signal based on the counter value. This allows the RTC 8 to align the rising edge of the RTC signal with the rising edge of the first signal.

[0030] 4, the correction of the RTC signal based on the comparison result between the first signal and the RTC signal has been described, but the correction of the RTC signal based on the comparison result between the second signal and the RTC signal is similar to the above.Which of the first signal or the second signal is used for the comparison of the RTC signal is determined by the control unit 4, as will be described later.

[0031] As described above, if the RTC signal generated by the RTC 8 is not appropriately corrected, the deviation from the time pulse signal will be larger than that of the first and second signals, but if it is appropriately corrected, the deviation will be about the same as that of the first and second signals. Furthermore, if the GNSS receiver 1 cannot receive radio waves from GNSS satellites, such as when the vehicle is located inside a tunnel, the accuracy of the first and second signals will decrease, but the accuracy of the RTC signal will not decrease.

[0032] 1 selects one of the first signal, the second signal, and the RTC signal based on at least one of the external conditions of the vehicle and the presence or absence of a failure in the frequency divider unit 5, and outputs a switching control signal indicating the result of the selection to the switching unit 11. The switching unit 11 switches the signal to be output to the V2X transceiver unit 12, among the first signal, the second signal, and the RTC signal, so that the signal indicated by the switching control signal from the control unit 4 is output to the V2X transceiver unit 12. The V2X transceiver unit 12 uses the input signal, i.e., the 1 PPS signal synchronized with UTC, to communicate (i.e., transmit and receive) with a counterpart device such as the V2X transceiver unit 12 of another vehicle.

[0033] According to the above configuration, the control unit 4 selects one of the first signal, the second signal, and the RTC signal as the signal to be used by the V2X transceiver unit 12, based on at least one of the external situation of the vehicle and the presence or absence of a failure in the frequency divider unit 5. In the first embodiment, the external situation of the vehicle includes the positioning result of the high-accuracy positioning calculation unit 3, the vehicle speed of the vehicle control unit 21, the detection result of the sensor 22, and the imaging result of the imaging unit 23.

[0034] An example of the selection made by the control unit 4 according to the first embodiment will be described below. Based on the external conditions of the vehicle, the control unit 4 determines whether the vehicle position is a location where the reception conditions of the GNSS receiver 1 may deteriorate or a location where the reception conditions of the GNSS receiver 1 may improve. For example, the control unit 4 calculates the sum of a score previously associated with the positioning result of the high-precision positioning calculation unit 3 and a score previously associated with the vehicle speed of the vehicle control unit 21 for each of the current vehicle position and the future vehicle position. If the sum of the scores for the future vehicle position is higher than the sum of the scores for the current vehicle position, the control unit 4 determines that the location is a location where the reception conditions of the GNSS receiver 1 may improve. If the sum of the scores for the future vehicle position is lower than the sum of the scores for the current vehicle position, the control unit 4 determines that the location is a location where the reception conditions of the GNSS receiver 1 may deteriorate. The pre-associated scores may be set by default or may be changed as appropriate based on GNSS measurement data previously extracted by the GNSS receiver 1.

[0035] When the vehicle is located in a location where the reception conditions of the GNSS receiver 1 may deteriorate (for example, at the entrance to a tunnel), the control unit 4 generally selects the RTC signal as the signal to be used by the V2X transceiver 12. When the vehicle is located in a location where the reception conditions of the GNSS receiver 1 may improve (for example, at the exit of a tunnel), the control unit 4 generally selects the first signal or the second signal as the signal to be used by the V2X transceiver 12. When there is no failure in the frequency divider 5, the control unit 4 generally selects the first signal as the signal to be used by the V2X transceiver 12. When there is a failure in the frequency divider 5, the control unit 4 generally selects the second signal or the RTC signal as the signal to be used by the V2X transceiver 12.

[0036] <Operation> Hereinafter, a specific example of the selection by the control unit 4 according to the first embodiment will be described with reference to the flowcharts of Figs. 5 to 8. Fig. 5 is a flowchart showing the overall operation of the selection by the control unit 4. The processing of Fig. 5 is repeated as appropriate. In the following description, the use of a signal refers to the use of a signal by the V2X transceiver unit 12.

[0037] In step S1, the control unit 4 determines whether or not the RTC signal is being used. If it is determined that the RTC signal is being used, the process proceeds to step S5, and if it is determined that the RTC signal is not being used, the process proceeds to step S2.

[0038] In step S2, the control unit 4 determines whether the vehicle is located in a location where there is a possibility of deterioration in the reception conditions of the GNSS receiving unit 1. If it is determined that the vehicle is located in this location, the process proceeds to step S4, and if it is determined that the vehicle is not located in this location, the process proceeds to step S3.

[0039] In step S3, the normal mode in which the first signal or the second signal can be used is executed, and then the process of FIG.

[0040] In step S4, switching mode A, which allows the use of the RTC signal, is executed, after which the processing in FIG. 5 ends.

[0041] In step S5, switching mode B, which allows the use of the first signal, is executed, after which the processing in FIG. 5 ends.

[0042] FIG. 6 is a flowchart showing the operation in the normal mode in step S3 of FIG.

[0043] In step S11, the control unit 4 determines whether the reception condition of the GNSS reception unit 1 is good based on the CN value extracted by the GNSS reception unit 1, etc. If it is determined that the reception condition of the GNSS reception unit 1 is good, the process proceeds to step S12, but if it is determined that the reception condition of the GNSS reception unit 1 is not good, no switching is performed and the operation in Fig. 6 ends.

[0044] Note that, since it is assumed here that the RTC signal has not been corrected, such as when the locator system is started up, the operation in Fig. 6 ends when it is determined that the reception conditions of the GNSS receiver 1 are poor. If the RTC signal has already been corrected within a certain period of time before the determination in step S11, the RTC signal may be used when it is determined in step S11 that the reception conditions of the GNSS receiver 1 are poor.

[0045] In step S12, the control unit 4 determines whether the accuracy of the first signal is worse than the accuracy of the second signal. For example, if the difference between the rising edges of the first signal and the second signal is equal to or less than a threshold, the control unit 4 determines that the accuracy of the first signal is worse than the accuracy of the second signal; otherwise, the control unit 4 determines that the accuracy of the first signal is not worse than the accuracy of the second signal. If it is determined that the accuracy of the first signal is worse than the accuracy of the second signal, the process proceeds to step S13, and if it is determined that the accuracy of the first signal is not worse than the accuracy of the second signal, the process proceeds to step S16.

[0046] In step S13, the control unit 4 determines whether or not there is a malfunction in the frequency dividing unit 5. If it is determined that there is a malfunction in the frequency dividing unit 5, the process proceeds to step S14, and if it is determined that there is no malfunction in the frequency dividing unit 5, the operation in FIG. 6 ends without switching.

[0047] In step S14, the control unit 4 switches the switching unit 11 so that the second signal is used. In step S15, the control unit 4 corrects the RTC signal based on the comparison result between the second signal and the RTC signal. Thereafter, the operation in FIG. 6 ends.

[0048] In step S16, the control unit 4 switches the switching unit 11 so that the first signal is used. In step S17, the control unit 4 corrects the RTC signal based on the comparison result between the first signal and the RTC signal. Thereafter, the operation in FIG. 6 ends.

[0049] FIG. 7 is a flowchart showing the operation of the switching mode A in step S4 of FIG.

[0050] In step S21, the control unit 4 determines whether or not the RTC signal has already been corrected. If it is determined that the RTC signal has already been corrected, the process proceeds to step S22. If it is determined that the RTC signal has not been corrected, the operation in FIG. 7 ends without switching.

[0051] In step S22, the control unit 4 switches the switching unit 11 so that the RTC signal is used, and then the operation in FIG.

[0052] FIG. 8 is a flowchart showing the operation of the switching mode B in step S5 of FIG.

[0053] In step S31, the control unit 4 determines whether the vehicle is located in a location where there is a possibility of improving the reception conditions of the GNSS receiving unit 1. If it is determined that the vehicle is located in the location, the process proceeds to step S32, and if it is determined that the vehicle is not located in the location, the operation in Fig. 8 ends without switching.

[0054] In step S32, the control unit 4 determines whether the reception conditions of the GNSS receiver 1 are good based on the CN value extracted by the GNSS receiver 1, etc. If it is determined that the reception conditions of the GNSS receiver 1 are good, the process proceeds to step S33, but if it is determined that the reception conditions of the GNSS receiver 1 are not good, the operation in Fig. 10 ends without switching. Note that if the RTC signal has already been corrected within a certain period before the determination in step S32, the RTC signal may be used when it is determined in step S32 that the reception conditions of the GNSS receiver 1 are not good.

[0055] In step S33, the control unit 4 switches the switching unit 11 so that the first signal is used, and then the operation of FIG.

[0056] <Summary of the First Embodiment> According to the reference signal generation device of the first embodiment as described above, the time pulse signal acquired by the acquisition unit 2 and used by the high-precision positioning calculation unit 3 is synchronized with a synchronous reset signal and frequency-divided, thereby generating a first signal that can be used by the V2X transceiver unit 12. According to this configuration, the time pulse signal extracted by the GNSS receiver unit 1 can operate the high-precision positioning calculation unit 3 and the V2X transceiver unit 12, which use signals with different frequencies.

[0057] Furthermore, according to the first embodiment, one of the first signal, the second signal, and the RTC signal is selected as the signal to be used by the V2X transceiver 12 based on at least one of the external conditions of the vehicle and the presence or absence of a failure in the frequency divider 5. With this configuration, even if the accuracy of the first signal is poor or if the frequency divider 5 has failed, the V2X transceiver 12 can use an appropriate 1PPS signal.

[0058] Furthermore, according to the first embodiment, the RTC signal is corrected based on the result of comparing the RTC signal with either the first signal or the second signal. With this configuration, the deviation of the RTC signal from the time pulse signal can be made to be approximately the same as the deviation of the first signal or the second signal from the time pulse signal.

[0059] <Embodiment 2> 9 is a block diagram showing the configuration of a locator system according to Embodiment 2. In the following, among the components according to Embodiment 2, components that are the same as or similar to the components described above are given the same or similar reference numerals, and different components will be mainly described.

[0060] The GNSS receiver 1 extracts GNSS measurement data and a time pulse signal based on radio waves from GNSS satellites. However, in the second embodiment, the time pulse signal extracted by the GNSS receiver 1 is a 1PPS time pulse signal.

[0061] The acquisition unit 2 acquires the GNSS measurement data and time pulse signals extracted by the GNSS reception unit 1 , outputs the GNSS measurement data to the high-precision positioning calculation unit 3 , and outputs the time pulse signals to the comparison unit 9 and the switching unit 11 .

[0062] The comparison unit 9 stores the comparison result between the time pulse signal and the RTC signal in the storage unit 10. The control unit 4 corrects the RTC signal based on the comparison result stored in the storage unit 10, i.e., the comparison result between the time pulse signal and the RTC signal.

[0063] The control unit 4 selects either the time pulse signal or the RTC signal based on the external situation of the vehicle, and outputs a switching control signal indicating the result of the selection to the switching unit 11. The switching unit 11 switches the signal to be output to the V2X transceiver 12, either the time pulse signal or the RTC signal, so that the signal indicated by the switching control signal from the control unit 4 is output to the V2X transceiver 12 and the multiplier unit 16.

[0064] The multiplier 16 generates a multiplied signal that can be used by the high-precision positioning calculation unit 3 by multiplying the time pulse signal that is acquired by the acquisition unit 2 and can be used by the V2X transceiver 12. Since the time pulse signal is a 1PPS signal, if the signal used by the high-precision positioning calculation unit 3 is an mPPS signal, the multiplier 16 multiplies the time pulse signal by m. In the following description, the multiplied signal will be described as a 10PPS signal, but any signal with a frequency higher than 1PPS may be used, such as a 5PPS signal.

[0065] The high-precision positioning calculation unit 3 calculates the position of the vehicle based on the GNSS measurement data from the acquisition unit 2 and the 10 PPS time pulse signal from the multiplication unit 16, which has a frequency higher than 1 PPS.

[0066] <Summary of the second embodiment> According to the reference signal generation device of the second embodiment as described above, the time pulse signal acquired by the acquisition unit 2 and usable by the V2X transceiver unit 12 is multiplied to generate a multiplied signal usable by the high-precision positioning calculation unit 3. According to this configuration, the time pulse signal extracted by the GNSS receiver unit 1 can operate the high-precision positioning calculation unit 3 and the V2X transceiver unit 12, which use signals with different frequencies.

[0067] Furthermore, according to the second embodiment, based on the external conditions of the vehicle, either the time pulse signal or the RTC signal is selected as the signal to be used by the V2X transceiver unit 12. With this configuration, even if the accuracy of the time pulse signal is poor, the V2X transceiver unit 12 can use an appropriate 1PPS signal.

[0068] Furthermore, according to the second embodiment, the RTC signal is corrected based on the result of comparing the time pulse signal with the RTC signal. With this configuration, the RTC signal can be made to be approximately the same as the time pulse signal.

[0069] <Other variations> The above-described acquisition unit 2 in FIGS. 1 and 2 and the signal generation unit, which is a generic concept of the above-described frequency divider 5 in FIG. 1 and the frequency multiplier 16 in FIG. 9, are hereinafter referred to as the "acquisition unit 2, etc." The acquisition unit 2, etc. are realized by a processing circuit 81 shown in FIG. 10. That is, the processing circuit 81 includes an acquisition unit that acquires a time pulse signal extracted by a GNSS receiver in the vehicle, and a signal generation unit that generates a frequency-divided signal usable in a V2X transceiver in the vehicle by synchronizing with a synchronous reset signal and frequency-dividing the time pulse signal acquired by the acquisition unit and used in a high-precision positioning calculation unit in the vehicle, or that generates a multiplied signal usable in the high-precision positioning calculation unit by multiplying the time pulse signal acquired by the acquisition unit and usable in the V2X transceiver. The processing circuit 81 may be implemented by dedicated hardware, or may be implemented by a processor that executes a program stored in a memory. Examples of the processor include a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, and a DSP (Digital Signal Processor).

[0070] When the processing circuit 81 is dedicated hardware, the processing circuit 81 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The functions of each unit such as the acquisition unit 2 may be realized by a circuit in which processing circuits are distributed, or the functions of each unit may be realized together by a single processing circuit.

[0071] When the processing circuit 81 is a processor, the functions of the acquisition unit 2 and the like are realized in combination with software and the like. The software and the like includes, for example, software, firmware, or software and firmware. The software and the like is written as a program and stored in a memory. As shown in FIG. 11 , the processor 82 applied to the processing circuit 81 realizes the functions of each unit by reading and executing a program stored in a memory 83. That is, the reference signal generation device includes a memory 83 for storing a program that, when executed by the processing circuit 81, results in the following steps: acquiring a time pulse signal extracted by a GNSS receiver of the vehicle; and synchronizing the time pulse signal used in the high-precision positioning calculation unit of the vehicle with a synchronous reset signal and dividing the frequency of the time pulse signal with a synchronous reset signal to generate a divided signal usable in the V2X transceiver unit of the vehicle, or multiplying the time pulse signal usable in the V2X transceiver unit to generate a multiplied signal usable in the high-precision positioning calculation unit. In other words, this program can be said to cause a computer to execute the procedures and methods of the acquisition unit 2 and the like. Here, the memory 83 may be, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), an HDD (Hard Disk Drive), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, a DVD (Digital Versatile Disc), a drive device for any of these, or any storage medium to be used in the future.

[0072] The above describes a configuration in which each function of the acquisition unit 2, etc. is realized either by hardware or software, etc. However, this is not limited to this, and a configuration in which part of the acquisition unit 2, etc. is realized by dedicated hardware and another part is realized by software, etc. For example, the function of the acquisition unit 2 can be realized by a processing circuit 81 as dedicated hardware, and the other functions can be realized by the processing circuit 81 as a processor 82 reading and executing a program stored in a memory 83.

[0073] As described above, the processing circuitry 81 can realize the above-mentioned functions by hardware, software, or a combination of these.

[0074] The reference signal generation device and locator system described above can also be applied to a reference signal generation system constructed as a system by appropriately combining a vehicle device, a communication terminal, the functions of an application installed on at least one of the vehicle device and the communication terminal, and a server. Examples of communication terminals include mobile phones, smartphones, and tablets. The functions or components of the reference signal generation device described above may be distributed among the devices that make up the system, or may be centralized in one of the devices. For example, a memory unit equivalent to memory unit 10 may be provided in a server, and multiple vehicles may share the information stored in the memory unit, thereby improving the accuracy of RTC signal correction by control unit 4 and selection of V2X transceiver unit 12.

[0075] It should be noted that the embodiments and modifications may be freely combined, and the embodiments and modifications may be modified or omitted as appropriate.

[0076] The above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned. [Explanation of symbols]

[0077] 1 GNSS receiver, 2 acquisition unit, 3 high-precision positioning calculation unit, 4 control unit, 5 frequency divider, 8 RTC, 16 multiplier unit.

Claims

1. an acquisition unit that acquires a time pulse signal extracted by a GNSS receiving unit of the vehicle; a signal generation unit that generates a frequency-divided signal that can be used in a V2X transceiver unit of the vehicle by synchronizing with a synchronous reset signal and dividing the frequency of the time pulse signal acquired by the acquisition unit and used in a high-precision positioning calculation unit of the vehicle, or that generates a multiplied signal that can be used in the high-precision positioning calculation unit by multiplying the time pulse signal acquired by the acquisition unit and used in the V2X transceiver unit; A reference signal generating device comprising:

2. 2. The reference signal generating device according to claim 1, the signal generating unit generates the frequency-divided signal; a control unit that selects one of the frequency-divided signal, the signal generated by the high-precision positioning calculation unit, and an RTC signal as the signal to be used by the V2X transceiver unit, based on at least one of an external situation of the vehicle and whether or not the signal generation unit has a failure.

3. 3. The reference signal generating device according to claim 2, The control unit corrects the RTC signal based on a comparison result between the RTC signal and either the frequency-divided signal or the generated signal.

4. 2. The reference signal generating device according to claim 1, the signal generating unit generates the multiplied signal; A reference signal generating device further comprising a control unit that selects either the time pulse signal or the RTC signal as the signal to be used by the V2X transceiver unit based on an external situation of the vehicle.

5. 5. The reference signal generating device according to claim 4, The control unit corrects the RTC signal based on a comparison result between the time pulse signal and the RTC signal.

6. Acquire the extracted time pulse signal by the GNSS receiver of the vehicle; A reference signal generation method comprising: generating a frequency-divided signal that can be used in a V2X transceiver unit of the vehicle by synchronizing the time pulse signal used in the high-precision positioning calculation unit of the vehicle with a synchronous reset signal and dividing the frequency of the time pulse signal; or generating a multiplied signal that can be used in the high-precision positioning calculation unit by multiplying the time pulse signal that can be used in the V2X transceiver unit.

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