Receiver, abnormality detection method, and abnormality detection program

Abstract

[Problem] To propose a receiving device, an abnormality detecting method, and an abnormality detecting program capable of detecting an abnormality relating to a reference signal that has been output. [Solution] This receiving device comprises an output unit, an input unit, and a detecting unit. The output unit outputs a first signal, which is a periodic reference signal generated on the basis of a positioning signal, to a first transmission line connected to an external device. The input unit accepts input of a second signal, which is a signal resulting from the first signal on the first transmission line being returned from the external device side via a second transmission line. The detecting unit detects an abnormality relating to the reference signal on the basis of the signal characteristics of the second signal.

Description

[Technical Field]

[0001] The present disclosure relates to a receiving device, an abnormality detection method, and an abnormality detection program. [Background technology]

[0002] Conventionally, there is known a receiving device that generates a reference signal with an accurate frequency and timing based on a positioning signal received from a GNSS (Global Navigation Satellite System) satellite or the like. The receiving device outputs the generated reference signal to a wireless communication facility such as a mobile phone base station or a terrestrial digital broadcasting transmitter. The wireless communication facility generates radio waves with an accurate transmission timing and frequency based on the acquired reference signal.

[0003] In addition, a technology has been proposed in which the reference signal generation path is duplicated, and if an abnormality occurs in one generation path, the path is switched to the other generation path, thereby maintaining normal output of the reference signal (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4719100 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional technology only ensures that the reference signal is output normally, but does not ensure that the reference signal reaches an external device such as a wireless communication device normally after being output. Therefore, in order to ensure that the output reference signal reaches an external device normally, it is preferable to detect whether an abnormality occurs in the reference signal after being output.

[0006] Therefore, the present disclosure proposes a receiving device, an abnormality detection method, and an abnormality detection program that can detect an abnormality in a reference signal after it has been output. [Means for solving the problem]

[0007] In order to solve the above problems, a receiving device according to the present disclosure includes an output unit, an input unit, and a detection unit. The output unit outputs a first signal, which is a periodic reference signal generated based on a positioning signal, to a first transmission line connected to an external device. The input unit inputs a second signal, which is a signal that is the first signal on the first transmission line returning from the external device side via a second transmission line. The detection unit detects an abnormality related to the reference signal based on the signal characteristics of the second signal.

[0008] This allows the receiving device to detect an abnormality in the reference signal (second signal) after it has been output.

[0009] The receiving device according to the present disclosure also includes a comparison unit that compares signal characteristics of the first signal and the second signal, and the detection unit detects the abnormality based on a comparison result of the comparison unit.

[0010] This allows the receiving device to detect an abnormality in the reference signal (first signal) before it is output, for example, and can further improve the accuracy of detecting an abnormality in the reference signal (second signal) after it is output.

[0011] The input unit receives the second signal from the second transmission line connected to the first transmission line at the end on the external device side.

[0012] This allows the receiving device to detect whether the reference signal has been normally input to the external device.

[0013] The input unit also receives the second signal from the external device connected to the second transmission line.

[0014] This allows the receiving device to detect an abnormality occurring across the entire first transmission line.

[0015] The comparator compares the phases of the first signal and the second signal, and the detector detects the abnormality when the phase difference between the first signal and the second signal is not within a predetermined threshold range.

[0016] This allows the receiving device to perform abnormality detection while eliminating the influence of path delays that occur from when the second signal is output until it is re-input.

[0017] Furthermore, the detection unit determines that the abnormality is a disruption of the second signal when the phase of the second signal is ahead of the phase of the first signal and the phase difference increases over time.

[0018] This allows the receiving device to detect the disruption of the second signal (the reference signal after being output).

[0019] Furthermore, when the phase of the second signal lags behind the phase of the first signal and the phase difference increases over time, the detection unit determines that the abnormality is a disruption of the first signal.

[0020] This allows the receiving device to detect the disruption of the first signal (the reference signal before being output).

[0021] The receiving device according to the present disclosure further includes an estimation unit configured to estimate a characteristic delay value of the second signal relative to the first signal based on the phase difference, and the detection unit configured to set the threshold range to include the characteristic delay value.

[0022] This allows the receiving device to set a threshold range that offsets the inherent delay value caused by the length of the transmission line, thereby improving the accuracy of detecting abnormalities.

[0023] In addition, the detection unit executes the abnormality detection process at an upstream timing corresponding to the upstream boundary of the threshold range, and if the phase difference at that upstream timing is less than a predetermined threshold, identifies the abnormality as noise being mixed into the second signal.

[0024] This allows the receiving device to detect the presence of noise in the second signal.

[0025] In addition, the detection unit executes the abnormality detection process at a downstream timing corresponding to the downstream boundary of the threshold range, and if the phase difference at that downstream timing does not fall within the threshold range, it identifies the abnormality as a disruption of the second signal.

[0026] This allows the receiving device to detect the disruption of the second signal.

[0027] The detection unit executes the abnormality detection process at three or more timings set at predetermined intervals within one period of the reference signal.

[0028] This allows the receiving device to detect an abnormality early.

[0029] In addition, the abnormality detection method disclosed herein outputs a first signal, which is a periodic reference signal generated based on a positioning signal, to a first transmission line connected to an external device, inputs a second signal, which is a signal that the first signal of the first transmission line returns from the external device side via a second transmission line, and detects an abnormality related to the reference signal based on the signal characteristics of the second signal.

[0030] This makes it possible for the abnormality detection method to detect an abnormality in the reference signal (second signal) after it has been output.

[0031] In addition, the abnormality detection program according to the present disclosure causes a computer to execute a process of outputting a first signal, which is a periodic reference signal generated based on a positioning signal, to a first transmission line connected to an external device, inputting a second signal, which is a signal that the first signal on the first transmission line returns from the external device side via a second transmission line, and detecting an abnormality related to the reference signal based on the signal characteristics of the second signal.

[0032] This allows the abnormality detection program to detect an abnormality in the reference signal (second signal) after it has been output. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is a diagram illustrating an overview of an abnormality detection method according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram illustrating a configuration example of a receiving device according to an embodiment. [Figure 3] FIG. 10 is a diagram illustrating an example (part 1) of an abnormality detection process performed by a detection unit. [Figure 4] FIG. 10 is a diagram illustrating an example (part 2) of an abnormality detection process performed by the detection unit. [Figure 5] FIG. 10 is a diagram illustrating an example (part 3) of an abnormality detection process performed by the detection unit. [Figure 6] 10A and 10B are diagrams illustrating an example of a process of estimating a specific delay value by an estimation unit. [Figure 7] 10A and 10B are diagrams illustrating an example of a threshold range setting process performed by a detection unit. [Figure 8] 10A and 10B are diagrams illustrating timings of an abnormality detection process performed by a detection unit. [Figure 9] 10A and 10B are diagrams illustrating an example of a process performed by a detection unit to identify noise contamination in a second signal. [Figure 10] 10A and 10B are diagrams illustrating an example in which the detection unit performs an abnormality detection process at three timings. [Figure 11] 10 is a flowchart illustrating a procedure for an abnormality detection process executed by a receiving device according to an embodiment. [Figure 12]10 is a flowchart showing the procedure of an abnormality identification process (part 1) executed by the receiving device according to the embodiment. [Figure 13] 10 is a flowchart showing the procedure of a second abnormality identification process executed by the receiving device according to the embodiment. [Figure 14] FIG. 10 is a diagram illustrating an example of the configuration of a receiving system according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same components are designated by the same reference numerals, and redundant description will be omitted.

[0035] First, an overview of an anomaly detection method according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an overview of an anomaly detection method according to an embodiment. The anomaly detection method according to an embodiment is executed by a receiving device 1 shown in Fig. 1. Note that Fig. 1 also shows an example configuration of a receiving system S including the receiving device 1.

[0036] 1, a receiving system S according to the embodiment includes a receiving device 1 and an external device 100. In the receiving system S, the receiving device 1 and the external device 100 are wired connected by a first transmission line 41. The receiving device 1 is also connected to a second transmission line 42, which is connected to the first transmission line 41 by a connection unit 50.

[0037] The receiving device 1 is, for example, a Global Navigation Satellite System (GNSS) receiving device. The receiving device 1 receives a GNSS signal, which is a positioning signal, and generates a reference signal (a first signal, which will be described later) synchronized with a reference time indicated by the GNSS signal. Note that the reference time is, for example, a Global Positioning System (GPS) time or a Coordinated Universal Time (UTC) time.

[0038] The external device 100 is a device that uses the reference signal generated by the receiving device 1. The external device 100 is, for example, a device that functions as a mobile phone base station, a device that functions as a terrestrial digital broadcasting transmitting station, a device involved in vehicle-to-vehicle communication, a device involved in road-to-vehicle communication, etc. Note that the external device 100 is not limited to the above-mentioned devices, and may be any device that uses a reference signal.

[0039] Here, we will explain the conventional technology related to receiving devices. In the conventional technology, there is a technology that duplicates the generation path of the reference signal, and if an abnormality occurs in one generation path, switches to the other generation path, thereby maintaining normal output of the reference signal.

[0040] However, the conventional technology only ensures that the reference signal is output normally, but does not ensure that the output reference signal reaches an external device such as a wireless communication device normally. Therefore, to ensure that the output reference signal reaches an external device normally, it is preferable to detect whether an abnormality occurs in the reference signal after it is output. Note that abnormalities in the reference signal after it is output include, for example, noise contamination from other signals by a third party or interruption of the reference signal due to a break in the transmission line.

[0041] Therefore, in the abnormality detection method of the embodiment, the reference signal after being output to the outside by the receiving device 1 is re-input to the receiving device 1, and the receiving device 1 detects an abnormality in the reference signal after being output by analyzing the signal characteristics of the re-input reference signal.

[0042] Specifically, in the anomaly detection method according to the embodiment, the receiving device 1 first generates a first signal, which is a periodic reference signal, based on the positioning signal received by the receiving unit 2 (step S1). The periodic reference signal is a periodic signal synchronized with a reference time indicated by the positioning signal, and is, for example, a 1 PPS (Pulse Per Second) signal. Note that the periodic reference signal is not limited to 1 PPS, and may be a pulse signal with a frequency exceeding 1 Hz or a frequency less than 1 Hz.

[0043] Next, in the abnormality detection method according to the embodiment, the receiving device 1 outputs a first signal to the first transmission line 41 connected to the external device 100 (step S2). As a result, the reference signal is input to the external device 100 via the first transmission line 41.

[0044] Next, in the abnormality detection method according to the embodiment, the receiving device 1 inputs a second signal, which is a signal that is the first signal on the first transmission line 41 returning from the external device 100 side via the second transmission line 42, to the input unit 4 (step S3). In the example shown in Fig. 1, the receiving device 1 inputs the second signal from the second transmission line 42 that is connected to the first transmission line 41 at the end on the external device 100 side.

[0045] Next, in the anomaly detection method according to the embodiment, the receiving device 1 detects an anomaly related to the reference signal based on the signal characteristics of the input second signal (step S4). Here, the signal characteristics include, for example, the phase, period, frequency, duty ratio, and number of pulses in a predetermined period.

[0046] Specifically, in the anomaly detection method according to the embodiment, the receiving device 1 detects an anomaly related to the second signal, i.e., an anomaly related to the output reference signal, when the signal characteristics of the second signal do not satisfy a predetermined standard. For example, the receiving device 1 detects an anomaly when the phase of the second signal lags or leads the reference phase by a threshold value or more.

[0047] In this way, in the abnormality detection method of the embodiment, the receiving device 1 can detect an abnormality in the reference signal after it has been output by re-inputting the reference signal (second signal) after it has been output to the outside into the receiving device 1 and analyzing the signal characteristics.

[0048] Furthermore, since the receiving device 1 inputs the second signal via the first transmission line 41 and the second transmission line 42, if no abnormality is detected in the second signal, it can be assumed that the reference signal has been input normally to the external device 100.

[0049] In the abnormality detection method according to the embodiment, the signal characteristics of the reference signal (first signal) before output and the reference signal (second signal) after output are compared, and an abnormality related to the reference signal can be detected based on the comparison results; details of this point will be described later.

[0050] Next, a configuration example of the receiving device 1 according to the embodiment will be described with reference to Fig. 2. Fig. 2 is a functional block diagram showing a configuration example of the receiving device 1 according to the embodiment. Note that in the block diagram of Fig. 2, only components necessary for explaining the features of this embodiment are shown in functional blocks, and descriptions of general components are omitted.

[0051] In other words, each component shown in the block diagram of Figure 2 is a functional concept and does not necessarily have to be physically configured as shown. For example, the specific form of distribution and integration of each functional block is not limited to that shown, and all or part of it can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0052] As shown in FIG. 2, the receiving device 1 includes a receiving unit 2, an output unit 3, an input unit 4, a control unit 10, and a storage unit 30.

[0053] The receiver 2 is an antenna that receives a positioning signal. For example, the receiver 2 receives the positioning signal, which is a GNSS signal, from a GNSS satellite. The GNSS satellite may be a GPS satellite, a QZSS (Quasi-Zenith Satellite System) satellite, a GLONASS (Global Navigation Satellite System) satellite, a GALILEO satellite, or the like.

[0054] The output unit 3 has an output terminal that outputs a first signal, which is a reference signal generated by the control unit 10 of the receiving device 1. As shown in Fig. 2, the output unit 3 outputs the first signal to a first transmission line 41 connected to the external device 100. As a result, the reference signal is output to the external device 100 via the first transmission line 41.

[0055] The input unit 4 has an input terminal to which a second signal, which is a signal that returns from the external device 100 side via the second transmission line 42 as the first signal on the first transmission line 41, is input. As shown in Fig. 2, the input unit 4 inputs the second signal, which is input to the input terminal from the second transmission line 42 connected to the first transmission line 41 at the end on the external device 100 side, to the receiving device 1. Note that the end on the external device 100 side may be located closer to the external device 100, and more specifically, may be located closer to the external device 100 than the output unit 3.

[0056] The first transmission line 41 and the second transmission line 42 are cable members that transmit signals, and are, for example, coaxial cables.

[0057] The connection unit 50 is a connection member that connects the first transmission line 41 and the second transmission line 42. The connection unit 50 is, for example, a distributor that distributes a signal transmitted in the first transmission line 41 to the second transmission line 42.

[0058] The connection unit 50 is preferably disposed at the terminal end of the first transmission line 41 on the external device 100 side. This ensures a relatively long distance over which the second signal is transmitted through the first transmission line 41, allowing the downstream detection unit 19 to detect with high accuracy any abnormality in the reference signal (second signal) occurring in the first transmission line 41.

[0059] The control unit 10 includes a TCXO 11, a synthesizer 12, a downconverter unit 13, a baseband processing unit 14, a positioning calculation unit 15, a generation unit 16, a comparison unit 17, an estimation unit 18, a detection unit 19, and a notification unit 20.

[0060] Here, the receiving device 1 includes, for example, a computer having a central processing unit (CPU), read only memory (ROM), random access memory (RAM), a hard disk drive, input / output ports, and various other circuits.

[0061] The computer's CPU functions as the TCXO 11, synthesizer 12, downconverter unit 13, baseband processing unit 14, positioning calculation unit 15, generation unit 16, comparison unit 17, estimation unit 18, detection unit 19 and notification unit 20 of the control unit 10, for example, by reading and executing an abnormality detection program stored in the ROM.

[0062] In addition, at least some or all of the TCXO 11, synthesizer 12, downconverter unit 13, baseband processing unit 14, positioning calculation unit 15, generation unit 16, comparison unit 17, estimation unit 18, detection unit 19 and notification unit 20 of the control unit 10 can be configured using hardware such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

[0063] The storage unit 30 is configured with a storage device such as a semiconductor element memory, a hard disk drive, etc. The storage unit 30 stores various programs and various information required for processing by the control unit 10.

[0064] The TCXO 11 is an oscillator that uses a quartz crystal as a resonator. The TCXO 11 generates a signal of a preset frequency and outputs it to the synthesizer 12.

[0065] The synthesizer 12 generates a demodulation signal from the signal generated by the TCXO 11 and outputs the demodulation signal to the downconverter unit 13. The synthesizer 12 also converts the signal generated by the TCXO 11 into a clock signal and outputs the clock signal to the baseband processing unit 14 and the generation unit 16.

[0066] The downconverter unit 13 receives the positioning signal from the receiver 2 and the demodulation signal from the synthesizer 12. The downconverter unit 13 downconverts the positioning signal, which is an RF (Radio Frequency) signal, using the demodulation signal to convert it from an RF signal to an IF (Intermediate Frequency) signal. The downconverter unit 13 outputs the IF signal to the baseband processor 14.

[0067] The baseband processing unit 14 demodulates the IF signal using the clock signal output by the synthesizer 12 as a sampling frequency to convert it into a baseband signal. The baseband processing unit 14 outputs the baseband signal to the positioning calculation unit 15.

[0068] The positioning calculation unit 15 calculates the position and reference time of the receiving device 1 by performing positioning calculations based on the baseband signal input from the baseband processing unit 14. Specifically, the positioning calculation unit 15 reads the navigation message indicated by the baseband signal and acquires the satellite orbit, thereby calculating the position of the receiving device 1 and calculating the time error between the clock on the receiving device 1 side and the clock installed on the GNSS satellite.

[0069] The positioning calculation unit 15 corrects the time of the clock on the receiving device 1 side based on the time error, thereby obtaining an accurate reference time synchronized with the high-precision clock installed on the GNSS satellite. Furthermore, the positioning calculation unit 15 calculates the clock offset and clock drift of the clock signal by performing positioning calculations. The positioning calculation unit 15 outputs the clock offset and clock drift to the generation unit 16.

[0070] The generator 16 corrects the phase and frequency of the clock signal based on the clock offset and clock drift input from the positioning calculation unit 15. Specifically, the generator 16 corrects the timing of the rising edge of the clock signal based on the clock offset. The generator 16 also corrects the frequency of the clock signal based on the clock drift. The generator 16 also functions as a frequency divider, and generates a reference signal, for example, 1 PPS, synchronized with a reference time by dividing the clock signal whose phase and frequency have been corrected.

[0071] In addition, when the generation unit 16 is in a holdover state where reception of the positioning signal has been interrupted due to external noise such as interference waves or a malfunction of the receiving unit 2, the generation unit 16 may generate a new reference signal using a past reference signal generated before the holdover state.

[0072] The comparison unit 17 compares the signal characteristics of the first signal input from the generation unit 16 and the second signal input from the input unit 4. The comparison unit 17 is, for example, a phase comparator, and compares the phases of the first signal and the second signal as the signal characteristics. Specifically, the comparison unit 17 compares the phases of the latest first signal and the latest second signal. Then, the comparison unit 17 calculates the phase difference between the first signal and the second signal as the comparison result.

[0073] When either the first signal or the second signal is interrupted and is no longer input to the comparison unit 17, the comparison unit 17 calculates the phase difference using the signal immediately before the interruption. This point will be described in detail later.

[0074] Furthermore, the comparison section 17 is not limited to a phase comparator, and may have a function of comparing signal characteristics such as the period, frequency, duty ratio, and number of pulses in a predetermined period of the first and second signals.

[0075] Furthermore, the comparison section 17 may compare any one of the signal characteristics of phase, period, frequency, duty ratio, and number of pulses in a predetermined period, or may compare two or more of the signal characteristics.

[0076] The estimation unit 18 estimates an inherent delay value of the second signal relative to the first signal based on the phase difference that is the comparison result of the comparison unit 17. The inherent delay value is an inherent delay time that occurs depending on the lengths of the first transmission line 41 and the second transmission line 42. The inherent delay value may be expressed in terms of time or a phase angle (degrees or radians).

[0077] The inherent delay value is used when setting a threshold range in the subsequent detection unit 19, and the method for setting the threshold range and the method for estimating the inherent delay value will be described in detail below with reference to FIGS.

[0078] The detection unit 19 detects an abnormality in the reference signal based on the signal characteristics of the second signal. In the example shown in Fig. 2, the detection unit 19 detects an abnormality in the reference signal based on the comparison result of the comparison unit 17. Details of the abnormality detection process by the detection unit 19 will be described later.

[0079] The notification unit 20 notifies anomaly information relating to the anomaly to the outside when an anomaly is detected by the detection unit 19. The anomaly information may include, for example, information on whether or not an anomaly exists, the type of the identified anomaly (disruption or noise contamination), the time of the anomaly occurrence, etc.

[0080] For example, the notification unit 20 notifies (transmits) the abnormality information in text format to the external device 100 or a terminal device of an administrator who manages the external device 100. Alternatively, if the receiving device 1 is equipped with a display unit (not shown), the notification unit 20 displays the abnormality information on the display unit.

[0081] Furthermore, in the case where the receiving device 1 includes a light source unit (not shown), the notification unit 20 may notify the abnormality information indicating the presence or absence of an abnormality by turning on the light source unit.

[0082] Here, the detection process of the detection unit 19 will be described in more detail with reference to Figs. 3 to 5. Figs. 3 to 5 are diagrams showing examples (parts 1 to 3) of the abnormality detection process by the detection unit 19. Fig. 3 shows a case where the first signal and the second signal are normal. Fig. 4 shows a case where the second signal is abnormal (disrupted), and Fig. 5 shows a case where the first signal is abnormal (disrupted).

[0083] 3 to 5, a first signal output at time n is referred to as a "first signal FSn," and a second signal corresponding to the first signal FSn is referred to as a "second signal SSn." When the first signal and the second signal are not distinguished by time, they are collectively referred to as a "first signal FS" and a "second signal SS."

[0084] 3, the second signal SSn is input again after being output to the outside, and is therefore input to the input unit 4 with a delay relative to the first signal FSn. Similarly, the second signal SSn+1 is input to the input unit 4 with a delay relative to the first signal FSn+1. The delay time of the second signal SS relative to the first signal FS is approximately constant because it is due to hardware such as the first transmission line 41 and the second transmission line 42.

[0085] In other words, if the first signal FS and the second signal SS are normal, the second signal SS will always lag in phase with respect to the first signal FS, and the phase difference will always fall within a certain range.

[0086] Therefore, the detecting unit 19 detects the presence or absence of an abnormality in the reference signal (first signal FS or second signal SS) depending on whether the phase difference, which is the comparison result of the comparing unit 17, falls within a predetermined threshold range α. Note that in FIGS. 3 to 5, the threshold range α is set to be the range from the rising time of the first signal FS to the time of the threshold TH. Also, in FIGS. 3 to 5, the detecting unit 19 reads out the phase difference from the comparing unit 17 only once per period of the first signal FS.

[0087] As shown in FIG. 3, if the phase difference t1 read out by the comparator 17 at time T1 falls within the threshold range α, the detector 19 detects that the reference signals (first signal FSn and second signal SSn) at time n are normal.

[0088] Similarly, if the phase difference t2 read by the comparison unit 17 at time T2 falls within the threshold range α, the detection unit 19 detects that the reference signals (first signal FSn+1 and second signal SSn+1) at time n+1 are normal.

[0089] On the other hand, the detecting unit 19 detects an abnormality in the reference signal (first signal FS or second signal SS) when the phase difference read from the comparing unit 17 does not fall within the threshold range α. This point will be described with reference to FIGS. 4 and 5.

[0090] First, FIG. 4 shows an abnormality related to the second signal SS, in which the second signal SSn+1 at time n+1 is externally interrupted.

[0091] If the phase difference read from the comparison unit 17 does not fall within the threshold range α and the phase of the second signal SS leads the phase of the first signal FS, the detection unit 19 detects an abnormality in the second signal SS.

[0092] 4, the phase difference t12 read at time T12 is larger than the threshold range α because the phases of the latest first signal FSn+1 and the second signal SSn immediately before the interruption are compared. That is, the phase difference t12 does not fall within the threshold range α.

[0093] 4, when the first signal FSn and the second signal SSn are normal, the phase difference t11 is a phase difference in which the second signal SSn lags behind the first signal FSn. On the other hand, when the second signal SSn+1 is interrupted, the phase difference t12 is a phase difference in which the second signal SSn is mathematically advanced relative to the first signal FSn+1. In other words, the phase of the second signal SS leads the phase of the first signal FS.

[0094] More specifically, when the phase difference is calculated by subtracting the phase of the second signal SS from the phase of the first signal FS, the phase difference t11 is a negative value and the phase difference t12 is a positive value. In other words, the sign of the phase difference will be different depending on whether the second signal SS is normal or abnormal. Note that when the phase difference is calculated by subtracting the phase of the first signal FS from the phase of the second signal SS, the signs will be opposite.

[0095] In this way, the detecting section 19 can detect an abnormality in the reference signal (second signal SS) after it is output, by using the phase difference that is the comparison result of the comparing section 17.

[0096] Furthermore, when the detection unit 19 detects an abnormality in the second signal SS, if the phase difference increases with the passage of time, it determines that the detected abnormality is a disruption of the second signal SS. This is because the phase difference gradually increases with the passage of time when the phase comparison is between the second signal SSn immediately before the disruption and the latest first signal FS (first signal FSn+2 or later).

[0097] More specifically, when the phase difference is calculated by subtracting the phase of the second signal SS from the phase of the first signal FS, the phase difference takes on a larger positive value with each passing period.

[0098] That is, when the detector 19 detects an abnormality, if the phase of the second signal SS is ahead of the phase of the first signal FS and the phase difference increases over time, the detector 19 determines that the abnormality is an interruption of the second signal SS, thereby making it possible to detect an interruption of the reference signal after it has been output.

[0099] If the phase difference does not increase over time and returns to fall within the threshold range α, the detection unit 19 may determine that the second signal SS has been temporarily interrupted (instantaneous interruption).

[0100] Next, Fig. 5 shows an abnormality in the first signal FS, in which the first signal FSn+1 is interrupted at time n+1. That is, Fig. 5 shows a case in which only the second signal SSn+1 is input to the comparator 17.

[0101] If the phase difference read from the comparison unit 17 does not fall within the threshold range α and the phase of the second signal SS lags behind the phase of the first signal FS, the detection unit 19 detects an abnormality in the first signal FS.

[0102] 5, the phase difference t22 read at time T22 is large because the phase of the first signal FSn immediately before the interruption and the phase of the latest second signal SSn+1 are compared, and the phase difference t22 does not fall within the threshold range α.

[0103] 5, both the phase difference t21 and the phase difference t22 are phase differences in which the second signal SS lags behind the first signal FS in phase, i.e., the phase of the second signal SS lags behind the phase of the first signal FS.

[0104] More specifically, when the phase difference is calculated by subtracting the phase of the second signal SS from the phase of the first signal FS, both the phase difference t21 and the phase difference t22 are negative values, meaning that the sign of the phase difference does not change whether the first signal FS is normal or abnormal.

[0105] In this way, the detecting unit 19 can detect an abnormality in the reference signal (first signal FS) before it is output by using the phase difference that is the comparison result of the comparing unit 17. More specifically, the detecting unit 19 can detect an abnormality in the input of the first signal FS from the generating unit 16 to the comparing unit 17.

[0106] Furthermore, when the detection unit 19 detects an abnormality related to the first signal FS, if the phase difference increases with the passage of time, it determines that the detected abnormality is a disruption of the first signal FS (disruption of input to the comparison unit 17). This is because the phase difference gradually increases with the passage of time due to a phase comparison between the first signal FSn immediately before the disruption and the latest second signal SS (second signal SSn+2 or later).

[0107] More specifically, when the phase difference is calculated by subtracting the phase of the second signal SS from the phase of the first signal FS, the phase difference becomes increasingly negative with each passing period.

[0108] In other words, when the detection unit 19 detects an abnormality, if the phase of the second signal SS lags behind the phase of the first signal FS and the phase difference increases over time, it determines that the abnormality is a disruption of the first signal FS.

[0109] This allows the detection unit 19 to detect the interruption of the reference signal before it is output. More specifically, the detection unit 19 can detect that the input of the first signal FS from the generation unit 16 to the comparison unit 17 has been interrupted.

[0110] If the phase difference does not increase over time and returns to fall within the threshold range α, the detection unit 19 may determine that the first signal FS has been temporarily interrupted (instantaneous interruption).

[0111] As described in Figures 3 to 5, the detection unit 19 detects abnormalities based on the comparison results of the comparison unit 17, and can therefore detect abnormalities in both the reference signal before output (first signal FS) and the reference signal after output (second signal SS).

[0112] Furthermore, the detection unit 19 can detect an abnormality when an external signal other than the reference signal is input as the second signal SS by comparing it with the first signal FS.

[0113] In other words, by detecting an abnormality based on the comparison result of the comparison unit 17, the detection unit 19 is able to detect an abnormality in the reference signal (first signal FS) before output, and can further improve the detection accuracy for an abnormality in the reference signal (second signal SS) after output.

[0114] Furthermore, the detection unit 19 detects an abnormality based on whether the phase difference between the first signal FS and the second signal SS falls within the threshold range α, thereby enabling abnormality detection that eliminates the influence of path delays that occur until the second signal SS is re-input after being output.

[0115] Next, the process of setting the threshold range α described above will be described with reference to Fig. 6 and Fig. 7. For example, the threshold range α is set based on the inherent delay value described above. Fig. 6 is a diagram showing an example of the process of estimating the inherent delay value by the estimation unit 18. Fig. 7 is a diagram showing an example of the process of setting the threshold range α by the detection unit 19.

[0116] First, the process of estimating the inherent delay value will be described with reference to Fig. 6. As described above, the second signal SS is output and then re-input via the first transmission line 41 and the second transmission line 42, and therefore its phase is delayed by the inherent delay value relative to the first signal FS.

[0117] In other words, the inherent delay value is a value (time or phase angle) according to the lengths of the first transmission line 41 and the second transmission line 42. In other words, since the inherent delay value is a delay caused by hardware, it is always approximately constant. Taking Fig. 6 as an example, the inherent delay value of the second signal SSn relative to the first signal FSn and the inherent delay value of the second signal SSn+1 relative to the first signal FSn+1 are approximately the same value.

[0118] Therefore, the estimation unit 18 estimates the inherent delay value based on the phase difference between the first signal FS and the second signal SS. For example, the estimation unit 18 estimates the average value of phase differences obtained multiple times over a predetermined period as the inherent delay value. In the example shown in Fig. 6, the estimation unit 18 estimates the average value of the phase difference between the first signal FSn and the second signal SSn and the phase difference between the first signal FSn+1 and the second signal SSn+1 as the inherent delay value.

[0119] The estimation unit 18 may estimate, as the characteristic delay value, not only the average value but also the mode or median of multiple phase differences obtained over a predetermined period. Alternatively, the estimation unit 18 may estimate, as the characteristic delay value, a phase difference obtained at a certain timing.

[0120] Next, the process of setting the threshold range α by the detection unit 19 will be described with reference to Fig. 7. Note that Fig. 7 shows the inherent delay value D estimated by the estimation unit 18. The detection unit 19 sets, for example, a first threshold value THa on the upstream side and a second threshold value THb on the downstream side with respect to the inherent delay value D. Note that the "upstream side" refers to the side in which the phase advances with respect to the inherent delay value D, and the "downstream side" refers to the side in which the phase lags with respect to the inherent delay value D. Then, the detection unit 19 sets the range between the first threshold value THa and the second threshold value THb as the threshold range α.

[0121] 7 shows a threshold range α in which the intermediate value between the first threshold value THa and the second threshold value THb is the inherent delay value D. That is, the detection unit 19 sets the threshold range α so as to include the inherent delay value estimated by the estimation unit 18. This makes it possible to set the threshold range α in which the inherent delay value D caused by the lengths of the first transmission line 41 and the second transmission line 42 is offset, thereby improving the accuracy of detecting an abnormality.

[0122] In addition, the detection unit 19 can tolerate a slight deviation in the phase difference in the abnormality detection process by setting the threshold range α to the range between the first threshold THa on the upstream side and the second threshold THb on the downstream side with respect to the inherent delay value D.

[0123] It is preferable that the timings at which the phase difference is read out, that is, times T1, T2, T11, T12, T21, and T22 (see FIGS. 3 to 5), i.e., the timings at which the abnormality detection process is performed, are downstream of the inherent delay value D. It is also more preferable that the timing at which the abnormality detection process is performed is downstream of the second threshold value THb. This allows the detector 19 to accurately avoid reading out the phase difference when the second signal SS is not input.

[0124] On the other hand, by setting the timing of performing the abnormality detection process upstream of the first threshold value THa, the detection unit 19 can detect that noise has been mixed into the second signal SS before the latest second signal SS is input. This point will be described with reference to FIGS. 8 and 9.

[0125] Fig. 8 is a diagram showing the timing of the abnormality detection process by the detector 19. Fig. 9 is a diagram showing an example of the process by the detector 19 to identify noise contamination in the second signal SS.

[0126] 8, the detection unit 19 performs the detection process at timings Ta and Tb corresponding to both boundaries of the threshold range α. Specifically, the detection unit 19 performs the detection process at upstream timing Ta corresponding to the upstream boundary (first threshold THa) of the threshold range α and downstream timing Tb corresponding to the downstream boundary (second threshold THb).

[0127] 8 shows an example in which the timing overlapping with the first threshold THa is set as the upstream timing Ta, but the upstream timing Ta may be slightly upstream or slightly downstream of the first threshold THa. Also, in FIG. 8, an example in which the timing overlapping with the second threshold THb is set as the downstream timing Tb, but the downstream timing Tb may be slightly upstream or slightly downstream of the second threshold THb. In other words, the upstream timing Ta and the downstream timing Tb can be any timing before or after the second signal SS is input.

[0128] 9 shows an example in which an abnormality in the second signal SS due to noise contamination is detected using the upstream timing Ta and the downstream timing Tb. Note that FIG. 9 shows an example in which noise N is detected between the second signal SSn and the second signal SSn+1.

[0129] In such a case, the detection unit 19 first performs a detection process at the upstream timing Ta, and if the phase difference ta at the upstream timing Ta is less than a predetermined threshold, it determines that the abnormality is noise mixed into the second signal SS.

[0130] If the second signal SS is not contaminated with noise N, the phase difference ta (indicated by the dashed arrow) at the upstream timing Ta is the phase difference between the first signal FSn+1 and the second signal SSn, because the upstream timing Ta is the timing before the second signal SSn+1 is input.

[0131] On the other hand, when noise N is mixed into the second signal SS, the phase difference ta (solid arrow) at the upstream timing Ta becomes the phase difference between the first signal FSn+1 and the noise N. In other words, the phase difference ta when noise N is mixed is smaller than the phase difference ta when noise N is not mixed.

[0132] That is, the phase difference ta when noise N is mixed in is less than the threshold value (the phase difference ta when noise N is not mixed in). This allows the detection unit 19 to detect the mixing of noise N into the second signal SS.

[0133] Next, the detector 19 performs a detection process at downstream timing Tb, and if the phase difference tb at downstream timing Tb falls within the threshold range α, detects that the second signal SSn+1 has been normally input.

[0134] If the second signal SSn+1 in FIG. 9 is interrupted, the phase difference tb at the downstream timing Tb becomes the phase difference ta at the upstream timing Ta (solid arrow or dashed arrow), and does not fall within the threshold range α.

[0135] That is, when the phase difference tb at the downstream timing Tb does not fall within the threshold range α, the detector 19 determines that the abnormality is a disruption of the second signal SS, thereby enabling the detector 19 to detect the disruption of the second signal SS.

[0136] Although the above describes an example in which the estimated inherent delay value is used in the process of setting the threshold range α, the inherent delay value may also be used to adjust the output timing of the first signal FS. For example, assuming that the connection unit 50 is located at the end on the external device 100 side, the receiving device 1 outputs the first signal FS with its phase advanced by half the inherent delay value. This allows the receiving device 1 to output the first signal FS with the delay due to the first transmission line 41 from the output unit 3 to the external device 100 offset, thereby enabling the external device 100 to obtain timing closer to the reference time when using the reference signal.

[0137] In FIG. 9, the detection unit 19 performs the detection process at two timings (upstream timing Ta and downstream timing Tb) corresponding to both boundaries of the threshold range α, but the timing for performing the detection process is not limited to this.

[0138] For example, the detection unit 19 may execute the detection process at three or more predetermined timings within one cycle of the reference signal (for example, the period from time n to time n+1) regardless of the threshold range α. This point will be described with reference to FIG.

[0139] Fig. 10 is a diagram showing an example in which the detecting unit 19 performs the anomaly detection process at three timings. As shown in Fig. 10, the detecting unit 19 performs the anomaly detection process at three timings T31, T32, and T33 during the period from time n to time n+1, which is one cycle of the reference signal. In other words, the detecting unit 19 reads out the phase difference from the comparing unit 17 at three timings T31, T32, and T33.

[0140] In the example shown in FIG. 10, the phase difference read at timing T31 is the phase difference between the first signal FSn and noise N1. If noise N1 were not present, the phase difference read at timing T31 would be the phase difference between the first signal FSn and the second signal SS from one cycle earlier. Therefore, the detector 19 detects the presence of noise N1 when the phase difference read at timing T31 is a value different from the phase difference between the first signal FSn and the second signal SS from one cycle earlier. In other words, the detector 19 can detect the presence of noise N1 early, at timing T31.

[0141] 10, the phase difference read out at timing T33 is the phase difference between the first signal FSn and the noise N2. If the noise N2 were not present, the phase difference read out at timing T33 would be the phase difference between the first signal FSn and the second signal SSn (the same phase difference as the phase difference at timing T32). Therefore, the detector 19 detects the presence of the noise N2 when the phase difference read out at timing T33, which is the timing after the second signal SSn is input, is a value different from the phase difference between the first signal FSn and the second signal SSn. In other words, the detector 19 can detect the presence of the noise N2 early at timing T33.

[0142] This allows the detector 19 to detect abnormalities such as noise contamination earlier than when the detection process is performed at the two timings (the upstream timing Ta and the downstream timing Tb).

[0143] Although FIG. 10 shows an example in which the detection process is performed at three timings T31, T32, and T33, the detection unit 19 may perform the detection process at four or more timings, such as every 10 msec.

[0144] In addition, in the above description, the detection unit 19 detects an abnormality in the reference signal by comparing the signal characteristics of the first signal FS and the second signal SS. However, for example, the detection unit 19 may detect an abnormality in the reference signal based only on the signal characteristics of the second signal SS without using the first signal FS.

[0145] For example, when the period of the second signal SS is temporarily disrupted due to the inclusion of noise, the detection unit 19 detects an abnormality in the output reference signal (second signal SS). Also, when the input of the second signal SS is interrupted, the detection unit 19 detects an abnormality in the output reference signal. That is, the detection unit 19 detects an abnormality in the reference signal based on the signal characteristics of the second signal SS.

[0146] Next, the procedure of the process executed by the receiving device 1 according to the embodiment will be described with reference to Figs. 11 to 13. Fig. 11 is a flowchart showing the procedure of the abnormality detection process executed by the receiving device 1 according to the embodiment. Fig. 12 is a flowchart showing the procedure of the abnormality identification process (part 1) executed by the receiving device 1 according to the embodiment. Fig. 13 is a flowchart showing the procedure of the abnormality identification process (part 2) executed by the receiving device 1 according to the embodiment.

[0147] First, the procedure of the abnormality detection process will be described with reference to FIG.

[0148] 11, first, the receiver 2 receives a positioning signal (step S101), and then the downconverter 13 and the baseband processor 14 demodulate the positioning signal (step S102).

[0149] Next, the positioning calculation unit 15 calculates the reference time by performing positioning calculation based on the demodulated baseband signal (step S103). Next, the generation unit 16 generates a reference signal based on the calculated reference time (step S104).

[0150] Next, the output unit 3 outputs the first signal FS, which is the generated reference signal, to the first transmission line 41 connected to the external device 100 (step S105). Next, the input unit 4 inputs a second signal SS, which is a signal returned from the external device 100 side via the second transmission line 42 as the first signal FS of the first transmission line 41 (step S106).

[0151] Next, the comparison unit 17 compares the phases of the first signal FS and the second signal SS (step S107). Next, the detection unit 19 determines whether the phase difference, which is the comparison result of the comparison unit 17, falls within a predetermined threshold range α (step S108).

[0152] If the phase difference falls within the threshold range α (step S108: Yes), the detection unit 19 determines that there is no abnormality in the reference signal (step S109), and ends the process.

[0153] On the other hand, if the phase difference is not within the threshold range α (step S108: No), the detection unit 19 determines that there is an abnormality in the reference signal (step S110). Next, if the detection unit 19 detects an abnormality, the notification unit 20 notifies the outside (external device 100) of abnormality information regarding the abnormality (step S111), and ends the process.

[0154] Next, the procedure of the abnormality identification process (part 1) will be described with reference to Fig. 12. The abnormality identification process shown in Fig. 12 is performed after step S110 in the abnormality detection process shown in Fig. 11.

[0155] As shown in FIG. 12, when detecting an abnormality, the detector 19 determines whether the phase of the second signal SS is ahead of the phase of the first signal FS (step S201).

[0156] If the phase of the second signal SS is ahead of the phase of the first signal FS (step S201: Yes), the detection unit 19 determines whether the phase difference of the phase lead (towards the upstream side) increases over time (step S202).

[0157] If the phase difference of the phase lead increases with the passage of time (step S202: Yes), the detection unit 19 determines that the second signal SS has been interrupted (step S203), and ends the process.

[0158] On the other hand, if the phase difference of the phase lead does not increase with the passage of time (step S202: No), the detection unit 19 determines that the abnormality of the second signal SS is other than a disruption (step S204) and ends the process. The abnormality of the second signal SS other than a disruption is, for example, noise contamination, temporary disruption, etc.

[0159] Also, in step S201, if the phase of the second signal SS lags behind the phase of the first signal FS (step S201: No), the detection unit 19 determines whether the phase difference of the phase lag (towards the downstream side) increases over time (step S205).

[0160] If the phase difference of the phase delay increases with the passage of time (step S205: Yes), the detection unit 19 determines that the first signal FS has been interrupted (step S206), and ends the process.

[0161] On the other hand, if the phase difference of the phase delay does not increase with the passage of time (step S205: No), the detection unit 19 determines that the abnormality is in the first signal FS other than the interruption (step S207), and ends the process. The abnormality in the first signal FS other than the interruption is, for example, noise contamination, temporary interruption, etc.

[0162] Next, the procedure of the abnormality identification process (part 2) will be described with reference to Fig. 13. The abnormality identification process shown in Fig. 13 is performed instead of or in parallel with the processes from step S107 onwards in the abnormality detection process shown in Fig. 11.

[0163] 13, the detecting unit 19 reads out the phase difference, which is the comparison result of the comparing unit 17, at the upstream timing Ta (step S301). Then, the detecting unit 19 determines whether the read phase difference is less than a predetermined threshold value (step S302).

[0164] If the phase difference is less than the threshold value (step S302: Yes), the detection unit 19 determines that noise has been mixed into the second signal SS (step S303). On the other hand, if the phase difference is equal to or greater than the threshold value (step S302: No), the detection unit 19 determines that noise has not been mixed into the second signal SS (step S304).

[0165] Next, the detecting unit 19 reads out the phase difference, which is the comparison result of the comparing unit 17, at the downstream timing Tb (step S305). Next, the detecting unit 19 determines whether the read out phase difference falls within a predetermined threshold range α (step S306).

[0166] If the phase difference falls within the threshold range α (step S306: Yes), the detector 19 determines that the input of the second signal SS to the comparator 17 is normal (step S307), and ends the process.

[0167] On the other hand, if the phase difference is not within the threshold range α (step S306: No), the detection unit 19 determines that the input of the second signal SS to the comparison unit 17 is abnormal (disrupted) (step S308), and ends the process.

[0168] As described above, according to one embodiment of the present disclosure, the receiving device 1 includes an output unit 3, an input unit 4, and a detection unit 19. The output unit 3 outputs a first signal FS, which is a periodic reference signal generated based on a positioning signal, to a first transmission line 41 connected to the external device 100. The input unit 4 inputs a second signal SS, which is a signal that is the first signal on the first transmission line 41 returning from the external device 100 via a second transmission line 42. The detection unit 19 detects an abnormality related to the reference signal based on the signal characteristics of the second signal SS. This allows the receiving device 1 to detect an abnormality related to the reference signal (second signal SS) after it has been output.

[0169] In the above-described embodiment, the input unit 4 is configured to receive the second signal SS from the second transmission line 42 connected to the first transmission line 41 at the end on the external device 100 side. In addition to this configuration, the input unit 4 may be configured as shown in Fig. 14, for example, as long as it receives the second signal SS that is returned from the external device 100 side via the second transmission line 42 as the first signal FS of the first transmission line 41.

[0170] Here, another configuration example of the receiving system S will be described with reference to Fig. 14. Fig. 14 is a diagram showing a configuration example of the receiving system S according to a modified example. In Fig. 14, the input unit 4 inputs a second signal from the external device 100 connected to the second transmission line 42. Specifically, as shown in Fig. 14, the first transmission line 41 is connected to the output unit 3 of the receiving device 1 and the input terminal 100a of the external device 100. Furthermore, the second transmission line 42 is connected to the input unit 4 of the receiving device 1 and the output terminal 100b of the external device 100. In other words, the first transmission line 41 and the second transmission line 42 connect the receiving device 1 and the external device 100 independently of each other.

[0171] In this configuration, the output unit 3 of the receiving device 1 outputs the first signal FS to the first transmission line 41. As a result, a reference signal is input to the external device 100 via the input terminal 100a. The external device 100 also outputs the first signal FS, which is the reference signal input to the input terminal 100a, from the output terminal 100b to the second transmission line 42. As a result, the second signal SS, which is the first signal FS output from the external device 100, is input to the input unit 4 of the receiving device 1 from the second transmission line 42.

[0172] In this way, according to the receiving device 1 of the modified example, the first signal FS that is once input to the external device 100 via the first transmission line 41 is input as the second signal SS, so that abnormalities occurring throughout the first transmission line 41 can be detected.

[0173] Furthermore, in the above-described embodiment, the receiving device 1 has been described as having a configuration that includes the comparison unit 17, the estimation unit 18, the detection unit 19, and the notification unit 20 internally. However, for example, at least one of the comparison unit 17, the estimation unit 18, the detection unit 19, and the notification unit 20 may be connected externally to the receiving device 1. For example, the reference signal generating device may have a configuration in which at least one of the comparison unit 17, the estimation unit 18, the detection unit 19, and the notification unit 20 is connected externally to the receiving device 1.

[0174] Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically using a known method. In addition, the information including the processing procedures, specific names, various data, and parameters shown in the above documents and drawings can be changed as desired unless otherwise specified. For example, the various information shown in each drawing is not limited to the information shown in the drawings.

[0175] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0176] Furthermore, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. For example, the technical scope of the present invention also includes configurations obtained by appropriately combining the above-described embodiments in an area where the processing content is not contradictory. Furthermore, the order of each step shown in the flowcharts and sequence diagrams of the above-described embodiments can be changed as appropriate. [Explanation of symbols]

[0177] 1. Receiving device 2. Receiving section 3 Output section 4 Input section 10 Control Unit 11 TCXO 12 Synthesizer 13 Down converter section 14 Baseband processing section 15 Positioning calculation unit 16 Generation part 17 Comparison section 18 Estimation part 19 Detector 20 Notification Department 30 Storage section 41 First Transmission Line 42 Second Transmission Line 50 Connection 100 External device S receiving system α threshold range

Claims

1. an output unit that outputs a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; an input section for inputting a second signal, which is a signal that the first signal of the first transmission line returns via a second transmission line branched from the first transmission line; a detection unit that detects an abnormality related to the reference signal based on a signal characteristic of the second signal; A receiving device comprising:

2. a comparison unit that compares signal characteristics of the first signal and the second signal; The detection unit detecting the abnormality based on the comparison result of the comparison unit; 2. The receiving device according to claim 1.

3. The input unit the second signal is input from the second transmission line connected to the first transmission line at the end on the external device side; 3. The receiving device according to claim 1 or 2.

4. The input unit inputting the second signal from the external device connected to the second transmission line; 3. The receiving device according to claim 1 or 2.

5. The comparison unit comparing the phases of the first and second signals; The detection unit detecting the abnormality when a phase difference between the first signal and the second signal does not fall within a predetermined threshold range; 3. The receiving device according to claim 2.

6. The detection unit If the phase of the second signal leads the phase of the first signal and the phase difference increases over time, the abnormality is identified as a disruption of the second signal.

6. The receiving device according to claim 5.

7. The detection unit If the phase of the second signal lags behind the phase of the first signal and the phase difference increases over time, the abnormality is identified as a disruption of the first signal.

6. The receiving device according to claim 5.

8. an estimation unit that estimates a characteristic delay value of the second signal relative to the first signal based on the phase difference; The detection unit setting the threshold range to include the characteristic delay value; 8. The receiving device according to claim 5, wherein the receiving device is a digital signal processing device.

9. The detection unit executing the abnormality detection process at an upstream timing corresponding to an upstream boundary of the threshold range, and identifying the abnormality as noise contamination in the second signal when the phase difference at the upstream timing is less than a predetermined threshold; 9. The receiving device according to claim 5, wherein the receiving device is a digital signal processing device.

10. The detection unit performing a detection process for the abnormality at a downstream timing corresponding to a downstream boundary of the threshold range, and identifying the abnormality as a disruption of the second signal when the phase difference at the downstream timing does not fall within the threshold range; 10. The receiving device according to claim 5, wherein the receiving device is a digital signal processing device.

11. The detection unit The abnormality detection process is executed at three or more timings set at predetermined intervals within one cycle of the reference signal.

9. The receiving device according to claim 5, wherein the receiving device is a digital signal processing device.

12. outputting a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; a second signal is input, the second signal being a signal that returns via a second transmission line branched from the first transmission line; detecting an anomaly with respect to the reference signal based on a signal characteristic of the second signal; Anomaly detection methods.

13. outputting a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; a second signal is input, the second signal being a signal that returns via a second transmission line branched from the first transmission line; detecting an anomaly with respect to the reference signal based on a signal characteristic of the second signal; An anomaly detection program that causes a computer to execute a process.

14. An output unit that outputs a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; an input unit that inputs a second signal, which is a signal that is the first signal on the first transmission line and returns from the external device side via a second transmission line; a comparison unit that compares the phases of the first signal and the second signal; a detection unit that detects an abnormality related to the reference signal based on a comparison result of the comparison unit; Equipped with The detection unit If the phase of the second signal is ahead of the phase of the first signal and the phase difference increases over time, the abnormality is identified as a disruption of the second signal. Receiving device.

15. An output unit that outputs a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; an input unit that inputs a second signal, which is a signal that is the first signal on the first transmission line and returns from the external device side via a second transmission line; a comparison unit that compares the phases of the first signal and the second signal; a detection unit that detects an abnormality related to the reference signal based on a comparison result of the comparison unit; Equipped with The detection unit If the phase of the second signal lags behind the phase of the first signal and the phase difference increases over time, the abnormality is identified as a disruption of the first signal. Receiving device.

16. An output unit that outputs a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; an input unit that inputs a second signal, which is a signal that is the first signal on the first transmission line and returns from the external device side via a second transmission line; a comparison unit that compares the phases of the first signal and the second signal; a detection unit that detects an abnormality related to the reference signal when a phase difference between the first signal and the second signal does not fall within a predetermined threshold range; Equipped with The detection unit executing the abnormality detection process at an upstream timing corresponding to an upstream boundary of the threshold range, and identifying the abnormality as noise contamination in the second signal when the phase difference at the upstream timing is less than a predetermined threshold; Receiving device.

17. An output unit that outputs a first signal, which is a periodic reference signal generated based on the positioning signal, to a first transmission line connected to an external device; an input unit that inputs a second signal, which is a signal that is the first signal on the first transmission line and returns from the external device side via a second transmission line; a comparison unit that compares the phases of the first signal and the second signal; a detection unit that detects an abnormality related to the reference signal when a phase difference between the first signal and the second signal does not fall within a predetermined threshold range; Equipped with The detection unit performing a detection process for the abnormality at a downstream timing corresponding to a downstream boundary of the threshold range, and identifying the abnormality as a disruption of the second signal when the phase difference at the downstream timing does not fall within the threshold range; Receiving device.

Images