JP6186008B2 - Location information transmitter maintenance method and position information transmitter used therefor - Google Patents

Description

  The present invention relates to a maintenance method for a position information transmitter.

  A system that performs positioning using radio signals transmitted from artificial satellites such as GPS (Global Positioning System) satellites (hereinafter referred to as “satellite positioning signals”) cannot receive satellite positioning signals indoors and underground shopping areas. If a communication terminal such as a GPS receiver enters the area, the positioning accuracy is lowered or positioning becomes impossible.

  As a solution for this, for example, in Japanese Patent Application Laid-Open No. 2012-177629 (Patent Document 1), position information, which is information indicating a position, is used in GPS in an area where a satellite positioning signal cannot be received, such as indoors and underground shopping areas Frequency (for example, center frequency 1.57542 GHz), modulation scheme (specifically, BPSK (Binary Phase-Shift Keying)), multiple access scheme (specifically, direct spread spectrum CDMA (Code Division Multiple Access)), etc. (hereinafter referred to as “location information signal”), a location information transmitter (indoor transmitter) is installed and received by a communication terminal such as a mobile phone A technique for acquiring the current position of the user from the position information signal is disclosed.

  In addition, the quasi-zenith satellite system user interface specification (IS-QZSS) version 1.5 appendix Ground Complementary Signal (IMES) (Non-Patent Document 1) describes the signal specifications of the location information transmitter that transmits this location information. Therefore, a very high accuracy is required such that the frequency accuracy of the signal is within ± 0.2 ppm.

  Therefore, if a clock that satisfies frequency accuracy, for example, OCXO (constant temperature chamber type crystal oscillator) is mounted on the position information transmitter, the cost increases, so voltage controlled temperature compensation that requires high-precision frequency stability at a low price. In many cases, a voltage controlled, temperature compensated crystal oscillator (VCTCXO) is mounted. However, even with a VCTCXO having the required frequency accuracy, frequency fluctuations occur due to deterioration over time. Therefore, in order to use the position information transmitter stably for a long period of time, the frequency due to deterioration over time of the clock of the transmitter It is necessary to correct the deviation.

JP 2012-177629 A

Quasi-Zenith Satellite System User Interface Specification (IS-QZSS) Version 1.5 Appendix Ground Supplementary Signal (IMES) Quasi-Zenith Satellite System Navigation Service. Interface Specification for QZSS (IS-QZSS) V1.5 ANNEX Indoor Messaging System (IMES)

  A location information transmitter installed as an infrastructure must always transmit a signal at a stable frequency in order not to stop the service of the mobile terminal. Therefore, since a position information transmitter that has been operating continuously for a long time may break down or shift in frequency due to deterioration over time, maintenance work is required to perform an inspection survey several times a year. However, when performing maintenance work, a high-accuracy detection device that detects an error in frequency due to deterioration over time is required, and the cost of the device and the cost of the worker are large.

In order to solve the above problems, for example, the configuration described in the claims is adopted. Application has included a plurality of means for solving the above problems, if the one example, the reference frequency of the received frequency and said mobile terminal when the mobile terminal receives a signal from the positional information transmitter The frequency correction value of the position information transmitter is calculated using a plurality of Doppler frequencies collected from a plurality of mobile terminals , and the center frequency of the position information transmitter is adjusted based on the frequency correction value. .

  Since the frequency shift due to the aging deterioration of the position information transmitter can be acquired via the network, the work of checking the position information transmitter can be made unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram of a system configuration for explaining a maintenance method for a position information transmitter according to a first embodiment. It is a detailed block diagram explaining the maintenance system of the positional information transmitter of Example 1. FIG. It is a data structural example of the transmission information table of the positional infomation transmitter of Example 1. FIG. It is a data structural example of the reception information table of the mobile terminal of Example 1. 6 is a data configuration example of a correction value table of the data analysis unit of the first embodiment. It is explanatory drawing of the method of calculating the frequency correction value of Example 1. FIG. It is explanatory drawing of the method of detecting the abnormality of the positional infomation transmitter of Example 2. FIG. It is explanatory drawing of the method of detecting the positional information setting abnormality of the positional information transmitter of Example 3. FIG.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a conceptual diagram of a system configuration for explaining a maintenance method of a position information transmitter according to the present embodiment. In FIG. 1, a position information transmitter 200 is a transmitter that transmits its own position information, and is installed indoors and has a function of transmitting position information continuously at a specific frequency. The mobile terminal 220 receives a signal from the position information transmitter 200 in order to grasp its own position, and specifies its own position. In such a system, it is necessary that the signal from the position information transmitter is transmitted correctly, and means for detecting an abnormality of the position information transmitter is required. As a means for detecting the abnormality, a data analysis unit 250 is provided. The data analysis unit 250 detects an abnormality such as a frequency change or a failure due to aged deterioration of the position information transmitter in the analysis processing unit 16 from the reception information 15 obtained from a plurality of mobile terminals, and detects the frequency correction value 17 and the abnormality detection. Information 18 is generated and maintenance of the location information transmitter having an abnormality is performed.

  FIG. 2 is a detailed configuration diagram illustrating a maintenance method of the position information transmitter. In FIG. 2, the position information transmitter 200 is installed indoors where satellite positioning signals cannot be received, and a large number of position information transmitters 200 are installed at intervals according to the required positioning accuracy.

  The VCTCXO 214 is a TCXO (temperature compensated crystal oscillator) having the ability to control the vibration frequency with an analog voltage. The VCTCXO 214 functions as a clock oscillator that oscillates a clock signal to the CPU 210 and controls the vibration frequency from the CPU 210. A voltage is input. The CPU 210 and the storage unit 211 are connected by a serial interface or a bus. The CPU 210 reads the transmission information table 212 and the correction value table 213 stored in the storage unit 211, generates a position information message to be transmitted, A position information signal compatible with the satellite positioning signal is transmitted from the wireless transmission unit 215.

  A position information signal transmitted from the position information transmitter is spectrum-spread by a code pattern of a PRN (Pseudo Random Noise) number, modulated to a carrier wave in a predetermined frequency band, and transmitted.

  The mobile terminal 220 is a terminal held by a person such as a mobile phone. The wireless reception unit 230 receives a signal from the location information transmitter 200, decodes the message by the CPU 231, and stores the reception information table 234 in the storage unit 233. Remember. Further, the CPU 231 sets the difference between the center frequency (reception frequency) when the signal from the position information transmitter 200 is received and the reference frequency of the mobile terminal in the reception information table 234 as a Doppler frequency.

  The network unit 240 is connected to the plurality of mobile terminals 220 via the wireless communication unit 235 and is connected to the data analysis unit 250.

  The data analysis unit 250 receives the reception information table 234 from a plurality of mobile terminals, stores the received information table 234 in the storage unit 260, and then calculates a frequency correction value and an abnormality detection in the analysis process 261. The calculated frequency correction value and abnormality detection information are stored in the correction value table 262 and the abnormality detection table 263, respectively. The correction value table 262 is transmitted to the position information transmitter 200, and the correction value table 213 of the position information transmitter 200 is updated via the communication unit 216. That is, the position information transmitter has a function of adjusting the center frequency by software, and can adjust the center frequency by inputting a frequency correction value via the network.

  FIG. 3 is a data configuration example of the transmission information table 212 of the position information transmitter 200. As shown in FIG. 3, position information 30, PRN 31, reference frequency 32, and transmission output 33 are registered in the transmission information table 212. In the position information 30, the latitude, longitude, and floor values constituting the position data transmitted by the position information transmitter 200 are set. A PRN number assigned to the wireless transmission unit 215 is set in the PRN 31. For example, in IMES (Indoor Messaging System) described in Non-Patent Document 1, ten numbers (channels) 173 to 182 can be used. In the reference frequency 32, a frequency serving as a reference of a signal transmitted from the position information transmitter 200 is set. In IMES (Indoor Messaging System) described in Non-Patent Document 1, 15754.282 [MHZ] or 15754118 is available. In the transmission output 33, an output level of a signal transmitted from the position information transmitter 200 is set.

  FIG. 4 is a data configuration example of the reception information table 234 of the mobile terminal 220. As shown in FIG. 4, in the reception information table 234, model name 40, reception time 41, position information 42, PRN 43, Doppler frequency 44, and reception intensity 45 are registered. In the model name 40, an ID indicating the type of mobile terminal is set. In the reception time 41, a time at which a signal from the position information transmitter 200 is received is set. In the position information 42, position data when a signal from the position information transmitter 200 is received is set. In the PRN 43, a PRN number assigned to a signal from the position information transmitter 200 is set. In the Doppler frequency 44, a frequency deviation from 1575.42 [MHZ] which is a reference frequency of the satellite positioning signal is set. The reception intensity 45 is set to the signal intensity when a signal from the position information transmitter 200 is received.

  FIG. 5 is a data configuration example of the correction value table 262 of the data analysis unit 250. As shown in FIG. 5, position information 50, PRN 51, frequency correction value 52, transmission output correction value 53, and position information correction value 54 are registered in the correction value table 262. In the position information 50, position data when received by the mobile terminal 220 is set. In the PRN 51, the PRN number when received by the mobile terminal 220 is set. In the frequency correction value 52, the correction value of the frequency of the mobile terminal 220 calculated in the analysis processing 261 is set. Similarly, the transmission output correction value 53 and the position information correction value 54 are set with the correction value of the frequency of the mobile terminal 220 calculated in the analysis processing 261. By associating the position information 50 with the PRN 51, the position information transmitter 200 to be corrected is specified.

FIG. 6 is an explanatory diagram of a method for calculating the frequency correction value 52 in the analysis process 261. That is, in order to obtain the transmission clock error 601 of the location information transmitter 200, a number of Doppler frequencies 602 obtained from a number of mobile terminals 220, that is, the center frequency (reception frequency when receiving signals from the location information transmitter). ) And the difference between the reference frequency of the mobile terminal and the frequency correction value 52 is calculated. For example, the actual transmission frequency of the position information transmitter is estimated from an average value of a large number of Doppler frequencies 1, 2,... N obtained from a large number of mobile terminals 220 shown in FIG. It can be obtained by subtracting from the set frequency. See formula (1) below.
Frequency correction value = Setting frequency of position information transmitter-AVERAGE (Doppler frequency 1, Doppler frequency 2, ..., Doppler frequency N) (1)
Note that, as an actual transmission frequency estimation method, estimation may be performed by statistical processing such that an optimal value is selected on the assumption that the distribution of many Doppler frequencies 1, 2,... N is a normal distribution.

As described above, according to this embodiment, the mobile terminal a plurality of mobile Doppler frequency which is the difference between the reference frequency of the received frequency and said mobile terminal when receiving a signal from the positional information transmitter A frequency correction value of the position information transmitter is calculated using a plurality of Doppler frequencies collected from the terminal , and a center frequency of the position information transmitter is adjusted based on the frequency correction value. In addition, the acquisition time and the position information received from the position information transmitters of the plurality of mobile terminals are collected, and the position information is obtained using the plurality of acquisition times, the plurality of position information, and the plurality of Doppler frequencies. Adjust the center frequency of the transmitter. That is, the frequency correction value is obtained by estimating the aging degradation error of the clock mounted on the position information transmitter by statistical processing using the position information collected from a plurality of mobile terminals , the time, and the Doppler frequency. The frequency of the location information transmitter can be corrected via the network.

  Therefore, since the frequency shift due to the aging deterioration of the position information transmitter can be acquired via the network, the work of checking the position information transmitter becomes unnecessary. In addition, by monitoring the location information, time, and Doppler frequency from the transmitter over the network, it is possible to reduce the number of device failures and maintenance.

Further, the position information transmitter includes a clock oscillator that can be variably controlled, and a wireless transmitter that transmits a radio signal including position information at a predetermined frequency by the clock oscillator, and the mobile terminal transmits the radio signal. Receives a frequency correction value of the location information transmitter calculated using a plurality of Doppler frequencies collected from a plurality of mobile terminals , a Doppler frequency that is a difference between the reception frequency at the time of reception and the reference frequency of the mobile terminal In addition, the center frequency of the position information transmitter can be adjusted by controlling the frequency of the clock oscillator based on the frequency correction value. In addition, the acquisition time and position information of the plurality of mobile terminals that have received the radio signals are received, and the frequency of the clock oscillator is controlled based on the plurality of acquisition times, the plurality of position information, and the frequency correction value. The center frequency of the position information transmitter can be adjusted.

  In the present embodiment, an example in which an abnormality of the position information transmitter associated with the elapsed time is determined will be described.

  FIG. 7 is an explanatory diagram of a method for detecting an abnormality of the position information transmitter 200 in the analysis process 261. A specific position information transmitter with a lapse of time at a location where a large number of mobile terminals 220 continuously receive signals from the position information transmitter 200 in the order of arrangement, from the position information transmitters 200 arranged continuously. It is detected that the signal from 200 has not been received continuously, and an abnormality in the position information transmitter 200 is detected. That is, in FIG. 7, when the mobile terminals 3... N have not received a signal from the location information transmitter 2 from a certain point in time, the location information transmitter 2 determines that an abnormality has occurred with the elapsed time. .

  As described above, according to this embodiment, it is possible to detect an abnormality of the position information transmitter from the relationship between a plurality of acquisition times and a plurality of position information. That is, by monitoring the location information and time from the transmitter over the network, it is possible to reduce the number of equipment failures and maintenance.

  In this embodiment, an example of detecting a location information setting abnormality of a location information transmitter will be described.

  FIG. 8 is an explanatory diagram of a method for detecting a location information setting abnormality of the location information transmitter 200 in the analysis process 261. In a location where a large number of mobile terminals 220 continuously receive signals from the location information transmitter 200 in the order of arrangement, signals from the location information transmitter 200 arranged in succession are received from a specific location information transmitter 200. It is detected that the position information to be transmitted is transmitting different coordinates, and a position information setting abnormality of the position information transmitter 200 is detected. That is, in FIG. 8, when the mobile terminals 1... N receive different position information at a specific reception time, a signal from the position information transmitter 2 is detected as a position information setting abnormality of the position information transmitter.

  As described above, according to the present embodiment, it is possible to adjust the set value of the position information transmitted from the position information transmitter based on the relationship with the plurality of acquired position information for a plurality of acquisition times. That is, by monitoring the location information and time from the transmitter over the network, it is possible to reduce the number of equipment failures and maintenance.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

200 Position Information Transmitter 212 Transmission Information Table 213 Correction Value Table 214 VCTCXO
220 Mobile terminal 234 Reception information table 240 Network unit 250 Data analysis unit 261 Analysis processing 262 Correction value table 263 Abnormality detection table 601 Transmission clock error 602 Doppler frequency

Claims (7)

A maintenance method for a location information transmitter,
Using a plurality of Doppler frequencies collected from a plurality of mobile terminals , a Doppler frequency that is a difference between a reception frequency when the mobile terminal receives a signal from the location information transmitter and a reference frequency of the mobile terminal Calculate the frequency correction value of the position information transmitter,
A position information transmitter maintenance method, comprising adjusting a center frequency of the position information transmitter based on the frequency correction value. A location information transmitter maintenance method according to claim 1,
Further, the acquisition time and position information received from the position information transmitter of the plurality of mobile terminals are collected, and using the plurality of acquisition times, the plurality of position information, and the plurality of Doppler frequencies, A maintenance method for a position information transmitter, comprising adjusting a center frequency of the position information transmitter. A location information transmitter maintenance method according to claim 2,
A maintenance method for a location information transmitter, wherein an abnormality of the location information transmitter is detected from the relationship between the plurality of acquisition times and the plurality of location information. A location information transmitter maintenance method according to claim 2,
A position information transmitter maintenance method comprising adjusting a set value of position information transmitted from a position information transmitter from a relationship with a plurality of acquired position information for the plurality of acquisition times. A location information transmitter for transmitting location information,
A clock oscillator that can be variably controlled, and a radio transmitter that transmits a radio signal including position information at a predetermined frequency by the clock oscillator;
The location information calculated using a plurality of Doppler frequencies collected from a plurality of mobile terminals , a Doppler frequency that is a difference between a reception frequency when the mobile terminal receives the radio signal and a reference frequency of the mobile terminal Receive the frequency correction value of the transmitter,
A position information transmitter, wherein the center frequency of the position information transmitter is adjusted by controlling the frequency of the clock oscillator based on the frequency correction value. The position information transmitter according to claim 5,
Further, the acquisition time and position information of the plurality of mobile terminals that have received the radio signals are received, and the frequency of the clock oscillator is controlled based on the plurality of acquisition times, the plurality of position information, and the frequency correction value. And adjusting a center frequency of the position information transmitter. The position information transmitter according to claim 6,
A position information transmitter that adjusts a set value of position information transmitted from the position information transmitter based on a relationship with a plurality of acquired position information for the plurality of acquisition times.

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