JP6690881B2 - Time synchronization device, positioning device, method and program - Google Patents

Description

  The present invention is a technique for realizing highly accurate time synchronization, and particularly highly accurate time synchronization even in an environment in which a navigation satellite signal of the Global Navigation Satellite System (GNSS) cannot always be received as a visible satellite signal. And technology for realizing positioning.

  GNSS such as GPS (Global Positioning System) is a means for realizing highly accurate time (phase) synchronization between base stations, which is required in a mobile communication system of Time Division Duplex (TDD) system. The use of is expanding. The GNSS satellite (navigation satellite) is equipped with a highly accurate atomic clock that is synchronized with Coordinated Universal Time (UTC), and transmits a navigation satellite signal synchronized with it by radio waves, but at any point on the earth. By receiving the signal of this navigation satellite, it becomes possible to time-synchronize with UTC.

  However, since the navigation satellite signal transmitted from the navigation satellite causes a propagation delay until it reaches the receiving point, the signals of at least four navigation satellites are received at the same time to correct the delay time, and the receiving position of the signal is received. It is necessary to specify the four parameters of the three-dimensional coordinate information (x, y, z) and the reception time information (t). In the case of GPS, at present, more than 24 navigation satellites are operated by orbiting the earth in 6 quasi-synchronous orbits at a cycle of about 12 hours. It is necessary to select an environment that can always capture at least four navigation satellites.

  When using GNSS for the purpose of highly accurate time synchronization, the line-of-sight space of navigation satellite signals around an antenna (hereinafter, navigation satellite signal antenna) that receives navigation satellite signals due to buildings or trees may be blocked. This may cause a limitation on the number of visible satellite signals that can be received as direct waves. Generally, base stations of mobile communication systems tend to be installed at higher densities in urban areas where traffic demand is high. According to a report (see Non-Patent Document 1) in which the reception state of navigation satellite signals is estimated by simulation. In the urban area (Shinjuku subcenter area), the area where 4 or more navigation satellite signals can be captured as direct waves at all times is limited to 13.5% in area ratio (excluding the rooftop of buildings). Therefore, it is a challenge to realize highly accurate and stable time synchronization even in an environment where it is difficult to constantly capture the required number of navigation satellite signals as direct waves and the reception state of the navigation satellite signals is not good. Has become.

  When positioning using navigation satellite signals or performing time synchronization with navigation satellite signals, it is important to select a receiving environment with an open space that can receive more visible satellite signals that can be received as direct waves. It is effective in improving. Furthermore, positioning and time accuracy will be further improved if the visible satellites are evenly distributed over the sky. An index called DOP (Dilution Of Precision) is often used as an index representing the accuracy deterioration due to the bias of the satellite arrangement in the sky.

  Other factors that affect accuracy in positioning and time synchronization by the navigation satellite signal are reflected waves and diffracted waves (reflected waves and diffracted waves generated when the navigation satellite signal is reflected and diffracted by structures around the navigation satellite signal antenna and the ground. A case where a so-called multipath signal) is received can be mentioned.

  FIG. 17 shows a schematic diagram for explaining the situation of generation of multipath signals. As shown in FIG. 17, the multipath signal is classified into a case involving a direct wave (a multipath signal of a visible satellite signal) and a case not involving a direct wave (a multipath signal of an invisible satellite signal). Regarding the former, in the normal case where the reception strength of the direct wave is larger than the reception strength of the multipath signal, an algorithm that effectively reduces the effect of the multipath signal by correlation signal processing in the navigation satellite signal reception circuit has been studied so far. (See Non-Patent Document 2). On the other hand, with regard to the latter multipath signal that does not involve direct waves, it is difficult to fundamentally remove the effect unless the navigation satellite signal in question is used for positioning or time synchronization. Has a great influence on.

  FIG. 18 shows an example of the reception status of multipath signals. As a result of installing the GPS satellite signal antenna in an environment surrounded by buildings and receiving the GPS satellite signal, as shown in the upper part of FIG. 18, a visible satellite located in an open space on the sky image at the GPS antenna installation position. In addition to the signals (# 6, # 9 in the example of FIG. 18), many of the invisible satellite signals shielded by the structures (# 2, # 3, # 5, # 7, # 12 in the example of FIG. 18). It was confirmed that # 17, # 19, # 23, and # 25) were received as a multipath signal. Also, as shown in the lower part of FIG. 18, the reception characteristics of GPS satellite signals with time are assumed to be open sky rather than the number of visible satellites obtained by simulation from an open space considering the structure around the GPS antenna. The number of navigation satellite signals received was close to the number of satellites. Here, the “open sky” means an open environment in the sky with no shield around.

  Since the multipath signal has a longer propagation path length than the direct wave and reaches the navigation satellite signal antenna with a delay, the time generated by receiving the multipath signal of the invisible satellite without the direct wave is the visible satellite. There is a relative delay compared to the time generated by receiving the signal. In addition, the larger the distance from the navigation satellite signal antenna to the reflection point, the larger the propagation delay time difference of the reflected wave with respect to the direct wave, and the larger the generated time difference becomes.

  In order to measure the difference (time error) between the time obtained by receiving the navigation satellite signal in the environment where the multipath signal of FIG. 18 is generated and the time obtained by receiving the navigation satellite signal in the open sky environment in FIG. The configuration of the experimental system used is shown below. The GPS satellite signal received in each environment is input to each of two GPS receivers of the same model, and the phase error of the 1PPS (Pulse Per Second) signal which is the timing output signal of the generated time information is measured as a time error. It measured with the instrument over time. As a result, as shown in FIG. 20, the time generated from the navigation satellite signal received in the environment where the multipath signal is generated is 250 ns or more at the maximum with respect to the time generated from the navigation satellite signal received in the open sky environment. , Confirmed that it would be delayed.

  Conventionally, various methods for reducing the influence of such a multipath signal have been considered. One of the methods for reducing the influence of multipath signals will be described. The multipath signal is attenuated when the navigation satellite signal is reflected and diffracted by the building. Further, when reflected by a building or the like, the turning direction of the circular polarization characteristic of the navigation satellite signal is reversed. By utilizing the inversion of the circularly polarized wave characteristic associated with this reflection, the navigation satellite signal antenna can be provided with an isolation characteristic that depends on the circularly polarized wave characteristic to attenuate the signal strength of the reflected wave reflected an odd number of times. . Further, the signal strength of the reflected wave from the ground or a low elevation angle can be attenuated by the vertical directivity of the navigation satellite signal antenna. The above is one of the methods for reducing the influence of multipath signals by the navigation satellite signal antenna.

  As a method of reducing the influence of other multipath signals, which is realized in the navigation satellite signal receiving device, positioning and time can be determined by the reception intensity of the received navigation satellite signal and the signal-to-noise ratio (SNR). A navigation satellite signal used for positioning or time synchronization by performing relative weighting processing on the navigation satellite signal used for synchronization, or by the reception intensity of the received navigation satellite signal or the threshold of the signal-to-noise ratio (SNR). There is a method of selecting. FIG. 20 shows the result of measuring the deterioration accuracy of the time accuracy when the navigation satellite signal is selected by the threshold value of the signal to noise ratio (SNR). As shown in FIG. 20, when a navigation satellite signal with a signal-to-noise ratio (SNR) of 35 dB or more is selected from the navigation satellite signals received in the measurement of FIG. 19 to generate the time, the time difference is significantly improved to 100 ns or less. It was confirmed to do.

  Further, a method of reducing the influence of other multipath signals realized in the navigation satellite signal receiving apparatus will be described. As shown in FIG. 21, the generation status of the multipath signal differs depending on the elevation angle of the navigation satellite signal. Since the height of the building around the navigation satellite signal antenna that causes reflection and diffraction is finite, if the distance between the building and the installation position of the navigation satellite signal antenna is large, the reflection of the navigation satellite signal with a large elevation angle is reflected. Regarding the signal, since the reflection angle on the vertical wall of the building is small, the reflected signal propagates toward the ground and does not reach the navigation satellite signal antenna. On the other hand, since the navigation satellite signal with a low elevation angle has a large reflection angle on the vertical wall of the building, the reflected wave that causes a large propagation delay time difference compared to the direct wave is likely to reach the navigation satellite signal antenna. For this reason, there has been conventionally performed a coping method for reducing the influence of the multipath signal by filtering the navigation satellite signal by the threshold value of the elevation angle and selecting the navigation satellite signal used for positioning and time synchronization.

Tomohiro Hakada, Yusuke Konishi, Yutetsu Xu, Ryosuke Shibasaki, "Improvement of GNSS utility evaluation simulation system using 3D map", [online], [January 18, 2015 search], Internet <URL: http: //gi-studentjp.org/s_forum/pdf/2003/35_hakamada.pdf> Nobuaki Kubo, "Reduction of multipath error in GPS positioning and possibility of high precision positioning", PhD thesis, Tokyo University of Marine Science and Technology, 2005

  The following points are problems in the conventional method for reducing the deterioration of accuracy that occurs when an invisible satellite signal is received as a multipath signal that does not accompany a direct wave during positioning by a navigation satellite signal or time synchronization.

(1) Method of selecting the navigation satellite signal itself in the navigation satellite signal receiving device (1-1) Method using elevation angle mask Navigation used for positioning and time synchronization by setting a threshold value for the elevation angle of the navigation satellite signal This is a method of selecting satellite signals. With this method, there is a possibility that visible satellite signals that can be received as direct waves, which originally contributes to improvement of time synchronization accuracy, may be eliminated. Therefore, an appropriate satellite signal may not be selected for use in time synchronization.

(1-2) Method Using SNR Mask This is a method in which a threshold value is set to the received signal strength of the received navigation satellite signal, signal-to-noise ratio, etc., and the satellite signal used for positioning and time synchronization is selected. In this method, the optimum value for setting the threshold depends on the reception characteristics of the navigation satellite signal antenna, the installation environment of the navigation satellite signal antenna, the sensitivity of the navigation satellite receiver, and the like. In addition, when the set threshold value is strict (when the threshold of received signal strength, signal-to-noise ratio, etc. is large), the four required for positioning and time synchronization are set in a time zone when the number of receivable visible satellite signals is small. There is a concern that the navigation satellite signal cannot be secured. On the other hand, when the threshold value is set loosely (when the threshold value of received signal strength or signal-to-noise ratio is small), invisible satellite signals received as multipath signals without direct waves cannot be sufficiently eliminated. there is a possibility. For this reason, it may not be possible to correctly select a satellite signal suitable for use in time synchronization and an inappropriate satellite signal.

(2) Method of performing correction processing after receiving the navigation satellite signal in the navigation satellite signal receiving device (2-1) Method of weighting based on SNR Depending on the received signal strength of the received navigation satellite signal, signal-to-noise ratio, etc. In this method, satellite signals used for positioning and time synchronization are weighted during signal processing. In this method, when the number of invisible satellite signals received as multipath signals without direct waves is larger than the number of visible satellite signals that can be received as direct waves, the contribution of invisible satellite signals is relatively large. As a result, deterioration of the time synchronization accuracy due to the selection of an unsuitable satellite signal for time synchronization may not be avoided.

(3) Method of attenuating navigation satellite signals inappropriate for use in time synchronization (antenna processing)
(3-1) Method using polarization isolation A navigation satellite that is reflected an odd number of times by a navigation satellite signal antenna that has an isolation characteristic that depends on circular polarization by utilizing the fact that the rotation direction of the circular polarization of the reflected signal is inverted. This is a method of attenuating the signal strength of the signal. According to this method, it is possible to attenuate the reception intensity of the signal to some extent, but a signal having a reception sensitivity higher than that of the navigation satellite signal reception circuit can be received. In other words, this is a method in which the influence of the multipath signal may not be eliminated, and for the signal reflected twice, the rotation direction is further inverted and returned to the original state, so that attenuation cannot be obtained. Therefore, a signal that is not suitable for use in time synchronization may be selected.

(3-2) Method of using directional antenna This is a method of attenuating the reflected wave from the ground or low elevation angle by the directivity of the navigation satellite signal antenna in the vertical direction. Although this method can attenuate the received signal strength of the reflected wave to some extent as in the above, due to the influence of the multipath signal, a signal that is not suitable for use in time synchronization may be selected.

  As described above, in the related arts (1) to (3), it may not be possible to correctly select a satellite signal suitable for use in time synchronization and an inappropriate satellite signal.

  The present invention has been made in view of the above problems, and highly accurate even in an environment in which the reception characteristics of navigation satellite signals are not good, in which many invisible satellite signals that are multipath signals without direct waves are received. A time synchronization device and a positioning device capable of realizing time synchronization or positioning, a method thereof, and a program are provided.

  In order to achieve the above-mentioned object, the present invention compares the time information generated by the combination of the received navigation satellite signals and selects the navigation satellite signal suitable for the time synchronization and positioning by the navigation satellite. . Here, in the navigation satellite signal selection processing, a plurality of navigation satellite signals related to a combination having earlier time information within the time of the allowable error value determined based on the reception state of the navigation satellite signal is selected.

  That is, the present invention is a time synchronization device that receives a navigation satellite signal from a navigation satellite and generates time information synchronized with a predetermined standard time based on the time information included in the navigation satellite signal. A navigation satellite signal receiving unit that generates time information synchronized with the navigation satellite based on the navigation satellite signals received simultaneously from the above navigation satellites, and a predetermined standard time based on the time information generated by the navigation satellite signal receiving unit. For each combination of a time information generation unit that generates synchronized time information and a navigation satellite signal from four or more navigation satellites that can be simultaneously received, the time information generated using the navigation satellite signal reception unit is acquired. , The plurality of acquired time information is compared to extract a plurality of navigation satellite signals related to the combination with the earliest time information, and the time information is extracted using the navigation satellite signal receiving unit based on the extracted navigation satellite signals. And a control unit for controlling to generate and output time information synchronized with a predetermined standard time by using the time information generation unit based on the obtained time information, and the control unit is the navigation satellite. The present invention is characterized in that a plurality of navigation satellite signals related to a combination in which time information is early are extracted within a time of an allowable error value determined based on a signal reception state.

  Further, the present invention is a time synchronization device that receives a navigation satellite signal from a navigation satellite and generates time information synchronized with a predetermined standard time based on the time information included in the navigation satellite signal. Or, a navigation satellite signal receiving unit that generates time information synchronized with the navigation satellite based on the navigation satellite signals received individually or simultaneously from a plurality of navigation satellites and the position information of a predetermined receiving position, and the navigation satellite signal receiving unit. A time information generation unit that generates time information that is synchronized with a predetermined standard time based on the time information, and a navigation satellite signal reception unit for each of the navigation satellite signals from multiple navigation satellites that can be received simultaneously. The navigation satellite signal receiving unit acquires the time information generated by using the acquired navigation information, compares the acquired time information, and extracts a plurality of navigation satellite signals with fast time information, and based on the extracted navigation satellite signals. Generating time information using, and a control unit for controlling to generate and output time information synchronized with a predetermined standard time using the time information generation unit based on the obtained time information, and the control unit A plurality of navigation satellite signals whose time information is early are extracted within the time of the allowable error value determined based on the reception state of the navigation satellite signals.

  Further, the present invention is a positioning device that receives a navigation satellite signal from a navigation satellite and generates reception position information based on time information and satellite position information included in the navigation satellite signal. For each combination of the navigation satellite signal receiving unit that generates time information and reception position information synchronized with the navigation satellite based on the navigation satellite signals received simultaneously from the navigation satellite signal and the navigation satellite signals from four or more navigation satellites that can be simultaneously received. Then, the time information generated using the navigation satellite signal reception unit is acquired, the acquired time information is compared, and the plurality of navigation satellite signals related to the combination with the earlier time information are extracted, and the extracted navigation satellite signals are added. A navigation satellite signal receiving section for generating reception position information based on the navigation satellite signal receiving section, and controlling the obtained reception position information to be output. Characterized in that the time within time information tolerance value determined based on the reception state of extracting a plurality of navigation satellite signals according to the earlier combination.

  According to the present invention, it is possible to correctly select a navigation satellite signal that is suitable for use in time synchronization or positioning and an unsuitable navigation satellite signal. For this reason, the open space for receiving the navigation satellite signals is limited, and highly accurate time synchronization is achieved even in an environment where the reception condition of the navigation satellite signals is poor, which receives invisible satellite signals as multipath signals without direct waves. The effect of realizing positioning and positioning is expected.

  The following effects can be expected in a mode in which positioning and time synchronization are performed simultaneously using four or more navigation satellite signals.

  (A) When the number of visible satellite signals is 3 or less, the invisible is selected by selecting the combination of the signals of the satellites with the earliest generated time from the combination of four satellite signals including the invisible satellite at each time. Improves time synchronization accuracy and positioning accuracy by eliminating navigation satellite signals that are received as reflected and diffracted waves with a large propagation delay time that are likely to significantly deteriorate time synchronization accuracy and positioning accuracy can do.

  (B) When the number of visible satellite signals is 4, the visible satellite signal is selected by selecting the combination of the satellite signals having the earliest generated time from the combination of four satellite signals at each time. By eliminating the invisible satellite signal, it is possible to improve time synchronization accuracy and positioning accuracy.

  (C) When the number of visible satellite signals is 5 or more, time synchronization accuracy and positioning accuracy can be improved by generating time information using visible satellite signals that can be received at each time.

  In addition, the following effects can be expected in a mode in which the coordinates of the navigation satellite signal antenna are set and time synchronization is performed using one or more navigation satellite signals.

  (D) When the number of visible satellite signals is 0, the time synchronization accuracy of the invisible satellite signals can be greatly deteriorated by selecting the combination of the signals of the earliest invisible satellites at each time. It is possible to improve the time synchronization accuracy by eliminating the navigation satellite signals that are received as reflected waves and diffracted waves that have a high property and have a large propagation delay time difference.

  (E) When the number of visible satellite signals is 1 or more, the time synchronization accuracy can be improved by using the visible satellite signals that can be received at each time to generate the time information.

  Furthermore, the following effects can be expected in both forms.

  (F) It is expected that the influence of multipath signals can be effectively eliminated without depending on the reception characteristics of the navigation satellite signal antenna and the performance of the navigation satellite reception circuit.

  (G) By properly setting the parameter value, it is possible to correctly select the visible satellite signal and effectively reduce the influence on the time accuracy and positioning accuracy of the invisible satellite.

  (H) In the present invention, a satellite signal used for time synchronization and positioning is selected based on time information obtained by combining satellite signals. Therefore, thresholds are set for the received signal strength of the received navigation satellite signal and the signal-to-noise ratio. However, there is no risk that the required number of navigation satellites cannot be secured, which has been a problem in the conventional method of selecting satellite signals used for positioning and time synchronization.

  (I) In the present invention, it is not necessary to mount the circularly polarized wave isolation characteristic or the directivity in the vertical direction in the navigation satellite signal antenna, so that the cost of the navigation satellite signal antenna can be reduced as a side effect. Becomes

Configuration diagram showing an example of an embodiment of a time synchronization device of the present invention Graph showing the relationship between tolerance value and accuracy Measurement result of time accuracy against tolerance value in open sky reception environment (1) Measurement result of time accuracy against tolerance value in open sky reception environment (2) Measurement result of time accuracy against allowable error value in multipath reception environment (1) Measurement result of time accuracy against allowable error value in multipath reception environment (2) Measurement result of time accuracy against allowable error value in multipath reception environment (3) Diagram explaining the reception status in the open sky reception environment Diagram illustrating the reception status in a multipath reception environment The figure explaining the relationship between the satellite signal number which exceeds a CNR threshold value, and an allowable error value. Diagram illustrating multipath reception environment (1) The figure which shows the evaluation result of the time synchronization accuracy in a multipath reception environment (1). The figure which shows the evaluation result of two-dimensional positioning accuracy in a multipath reception environment (1). Diagram illustrating the multipath reception environment (2) The figure which shows the evaluation result of the time synchronization accuracy in a multipath reception environment (2). The figure which shows the evaluation result of two-dimensional positioning accuracy in a multipath reception environment (2). Schematic diagram explaining the occurrence of multipath signals Multipath signal generation status Configuration diagram showing the measurement system for deterioration of time accuracy in a multipath environment Measurement result of deterioration of time accuracy in multipath environment Schematic diagram showing the relationship between the elevation angle of the navigation satellite and the reflected wave

  FIG. 1 shows the configuration of the entire system including an example of an embodiment of the time synchronization device of the present invention. This system includes a navigation satellite signal antenna 1, a navigation satellite signal receiving unit 2, a time information generating unit 3, a control unit 4, and a setting unit 5.

  The navigation satellite signal antenna 1 is an antenna for receiving a navigation satellite signal. The navigation satellite signal reception unit 2 is a functional unit that receives a plurality of navigation satellite signals, calculates time information at the reception position, and outputs the time information to the time information generation unit 3. The time information generation unit 3 is a functional unit that generates time information and outputs it to the outside. The control unit 4 is a functional unit for controlling the navigation satellite signal reception unit and the time information generation unit. The setting unit 5 is a functional unit for setting various parameters of the system. The configuration and operation of each functional unit will be described in detail below.

  The navigation satellite signal antenna 1 is connected to the navigation satellite signal receiving unit 2 by a coaxial cable or the like, and transmits the received navigation satellite signal to the navigation satellite signal receiving unit 2.

  The navigation satellite signal receiver 2 has two operation modes, a fixed position estimation mode and a position fixed mode. In the fixed position estimation mode, the navigation satellite signal receiving unit 2 receives the signals of at least four navigation satellites at the same time, so that the three-dimensional coordinate information (x, y, z) of the signal reception position and the reception time information ( The four parameters of t) are specified by calculation, and the time information received from the navigation satellite is corrected based on the propagation delay time from the position of the navigation satellite to the receiving point.

  In the fixed position mode, the navigation satellite signal receiving unit 2 receives the signal of at least one navigation satellite based on the preset three-dimensional coordinate information (x, y, z) of the receiving position to thereby obtain the reception time information. (T) is specified by calculation, and the time information received from the navigation satellite is corrected based on the propagation delay time from the position of the navigation satellite to the reception point.

  Further, in any operation mode, the navigation satellite signal receiving unit 2 corrects the transmission delay time of the transmission path such as the coaxial cable between the navigation satellite signal antenna 1 and the navigation satellite signal receiving unit 2 to obtain the navigation satellite signal antenna. The time information at the installation position of 1 is generated.

  The navigation satellite signal receiving unit 2 outputs the time information synchronized in this way to the navigation satellite and the information regarding the navigation satellite used to the time information generating unit 3 and the control unit 4. As an example of the time information, for notifying a timing signal in a signal format such as 1PPS (Pulse Per Second) synchronized with a navigation satellite signal and information (ToD: Time of the Day) regarding absolute time such as time / second, Time code data in a format such as NMEA (National Marine Electronics Association) 0183 is used. Further, as the information regarding the navigation satellite, the navigation satellite system type, satellite number, etc. are used. On the other hand, the navigation satellite signal receiving unit 2 selects a navigation satellite signal to be used for positioning and time synchronization based on an instruction from the control unit 4.

  The navigation satellite signal receiving unit 2 may be installed inside the device, or may be a navigation satellite signal receiving device placed outside the device. In the fixed position estimation mode, the navigation satellite signal receiving section 2 can store the reception position information calculated by the positioning by the navigation satellite signal. In that case, if the position of the navigation satellite signal antenna 1 is not moved, then time synchronization can be performed if at least one navigation satellite signal is received in the fixed position mode thereafter.

  The time information generation unit 3 is a functional unit responsible for generating time synchronized with the navigation satellite signal, and based on the time information supplied from the navigation satellite signal reception unit 2, a predetermined standard time, here the UTC described above. Generates a time signal synchronized with. Specifically, the time information generation unit 3 has an oscillator and a phase locked loop (PLL: Phase Locked Loop) installed therein, and controls the timing depending on the 1PPS signal supplied from the navigation satellite signal reception unit 2. At the same time as the synchronization, the time information matched with the absolute time is generated by the ToD information supplied from the navigation satellite signal receiving unit 2. When the signal from the navigation satellite signal receiving unit 2 is interrupted, the time information generation unit 3 can maintain and continue generation of time information by self-propelling (holdover).

  The time information generation unit 3 also has a role of supplying time information to a device (time-synchronized device) outside the device that performs time synchronization. As the time information used at this time, in addition to the above 1PPS / ToD, a PTP (Precision Time Protocol) protocol defined by IEEE1588 version 2 is used and a packet communication interface such as Ethernet (registered trademark) is used. A case in which time information is supplied is also assumed.

  The control unit 4 controls the navigation satellite signal reception unit 2 and the time information generation unit 3 in order to realize an algorithm for generating time information described later based on the parameter information input to the setting unit 5, and receives the navigation satellite signal. Processing such as comparison of time information output from the unit 2 and extraction of navigation satellites is performed.

  The setting unit 5 externally sets various parameters necessary for system operation. The parameters to be set include a fixed position estimation mode and a fixed position mode as operation modes of the navigation satellite signal receiving unit 2, set position coordinate values in the fixed position mode, the navigation satellite signal antenna 1 and the navigation mode. To realize an algorithm for generating a correction value of a transmission delay time generated in a transmission path such as a coaxial cable connecting the satellite signal receiving section 2, a navigation satellite signal type to be used, a time zone of a navigation satellite signal receiving position, and time information described later. It includes the above parameter settings. As an example of the method for setting the position coordinate value, setting the latitude, longitude, and altitude above sea level of the navigation satellite signal antenna installation position can be considered.

  The present invention provides time synchronization for generating highly accurate time information with a small error from the time of a navigation satellite system when an invisible satellite signal is received as a multipath signal (reflected wave, diffracted wave) without direct waves. The present invention relates to a device, a positioning device, a method thereof, and a program. The operation algorithm will be described below.

  First, as a precondition, a visible satellite signal (a direct wave signal or a multipath signal accompanied by a direct wave), an invisible satellite signal (in the environment where there is a structure that blocks the propagation of the navigation satellite signal around the navigation satellite signal antenna 1) Regardless of (multipath signal without direct wave), four or more navigation satellite signals can be received in the fixed position estimation mode and one or more navigation satellite signals in the position fixed mode. Further, it is unknown whether the received navigation satellite signal is a visible satellite signal or an invisible satellite signal.

  Under the above preconditions, the navigation satellites used for positioning and time synchronization are selected from the received navigation satellite signals and the time accuracy is improved by the following procedure. Here, improving the time accuracy means reducing the difference (delay) from the time generated by the visible satellite signal received in the open sky environment at the receiving position of the navigation satellite signal by the navigation satellite signal antenna 1. The control unit 4 controls the navigation satellite signal receiving unit 2 and the time information generating unit 3 based on the set values of the parameters set by the setting unit 5 to generate the time information according to the procedure.

(1) Case of Fixed Position Estimation Mode In the fixed position estimation mode, time information is generated by either of the following procedure (A) or (B). Which one is to be mounted / used is arbitrary, and both may be mounted and one may be arbitrarily used.

  The following procedures (A) and (B) acquire time information generated using the navigation satellite signal receiving unit 2 for each combination of navigation satellite signals from four or more navigation satellites that can be simultaneously received, By comparing a plurality of acquired time information, a plurality of navigation satellite signals relating to a combination having earlier time information is extracted, and positioning / time synchronization is performed based on the extracted navigation satellite signals. In the extraction process, a plurality of navigation satellite signals associated with a combination having earlier time information within the time of the allowable error value dT are extracted. Hereinafter, each procedure will be described in detail.

Procedure (A)
(A) Positioning / time synchronization is performed for each of the _n C ₄ combinations of the _four satellite signals extracted from the received n navigation satellite signals.
(A) A combination of satellite signals from which the earliest time T ₀ is obtained is extracted from the obtained _n C ₄ time values.
(C) Next, the reference time of T ₀ + dT ₁ is set by the allowable error value dT ₁ set in the setting unit 5 in advance.
(D) From the _n C ₄ time values obtained in (a) above, all combinations of satellite signals whose values are earlier than T ₀ + dT ₁ are extracted.
(E) Hereinafter, among the received n navigation satellite signals, 5, 6, 7, 8, ..., Each combination of _n satellite signals ( _n C ₅ , _n C ₆ , _n C ₇ , _n C ₈ ..., _n C _n combinations), similarly, as a result of positioning and time synchronization, all combinations of navigation satellite signals whose times obtained are earlier than T ₀ + dT ₁ are extracted.
(F) Positioning and time synchronization are performed using the satellite signals extracted in (d) and (e), and the obtained time information is used as the time information generated by the received navigation satellite signal.

That is, the procedure (A) acquires time information generated using the navigation satellite signal receiving unit 2 for each combination of navigation satellite signals from four or more navigation satellites that can be simultaneously received, and acquires the plurality of acquired time information. A plurality of navigation satellite signals associated with combinations that generate time information earlier than the time obtained by adding a predetermined allowable error value dT ₁ to the reference time with the earliest time among the time information Positioning and time synchronization are performed based on signals.

Procedure (B)
(A) Positioning / time synchronization is performed for each of the _n C ₄ combinations of the _four satellite signals extracted from the received n navigation satellite signals.
(A) A combination of satellite signals from which the earliest time T ₀ is obtained is extracted from the obtained _n C ₄ time values.
(C) Next, the T ₀ + dT ₂ reference time is set by the allowable error value dT ₂ set in advance in the setting unit 5.
(D) All combinations of received satellite signals whose values are later than T ₀ + dT ₂ out of the _n C ₄ time values obtained in (a) above are extracted.
(E) Among the satellite combinations obtained in (d) above, the navigation satellite signals other than the satellites in (a) above are excluded from the satellite signals used for positioning and time synchronization, and positioning and time synchronization are performed. The obtained time information is used as the time information generated by the received navigation satellite signal.

That is, the procedure (B) acquires time information generated using the navigation satellite signal receiving unit 2 for each combination of navigation satellite signals from four or more navigation satellites that can be simultaneously received, and acquires the plurality of acquired time information. Of a plurality of navigation satellite signals associated with a combination that generates time information later than a time obtained by adding a predetermined allowable error value dT ₂ to the reference time, with the earliest time among the time information of Among the signals, those excluding the navigation satellite signal from which the reference time was generated are excluded as navigation satellite signals, and those excluding the exclusion navigation satellite signal from each simultaneously receivable navigation satellite signal are extracted, and the extracted navigation satellite Positioning and time synchronization are performed based on signals.

(2) Case of fixed position mode Procedure (C) acquires time information generated by using the navigation satellite signal receiving unit 2 for each of navigation satellite signals from a plurality of navigation satellites that can be simultaneously received, It compares a plurality of acquired time information, extracts a plurality of navigation satellite signals having earlier time information, and performs positioning and time synchronization based on the extracted navigation satellite signals. In the extraction process, a plurality of navigation satellite signals whose time information is early within the time of the allowable error value dT are extracted. Hereinafter, the procedure (C) will be described in detail.

Procedure (C)
(A) Time synchronization is performed using each of the received n navigation satellite signals.
(A) From the obtained n number of time values, the satellite from which the earliest time T ₀ is obtained is extracted.
(C) Next, the reference time of T ₀ + dT ₃ is set by the allowable error value dT ₃ set in advance in the setting unit 5.
(D) A satellite whose time value is earlier than T ₀ + dT ₃ is extracted.
(E) Positioning and time synchronization are performed using the satellite signal extracted in (d) above, and the obtained time information is used as the time information generated by the received navigation satellite signal.

That is, the procedure (C) acquires time information generated using the navigation satellite signal receiving unit 2 for each of navigation satellite signals from a plurality of navigation satellites that can be simultaneously received, and acquires the plurality of acquired time information. Of the plurality of navigation satellite signals that generate time information earlier than the time obtained by adding the predetermined allowable error value dT ₃ to the reference time, using the earliest time as the reference time, the positioning / time is calculated based on the extracted navigation satellite signals. It is for synchronization.

The above tolerance value dT _{(dT 1} steps _{(A), dT 2} steps _(B), dT ₃ steps (C)) is a parameter set by the setting unit 5. Note that 0 may be set as the allowable error value dT in some cases. A method of determining the allowable error value dT will be described later.

  The reason why the time synchronization accuracy is improved in each case of the number of visible satellite signals received in each procedure will be described below.

Procedure (A)
When the number of visible satellite signals is 3 or less, the combination of the signals of the satellites with the earliest time to be generated is selected from the combination of the four satellite signals including the invisible satellites at each time by (a). By properly setting dT ₁ , among the invisible satellite signals due to (d) and (e), there is a high possibility that the time synchronization accuracy will be greatly deteriorated, and the navigation received as a reflected wave or a diffracted wave with a large propagation delay time The satellite signal can be eliminated, and the time synchronization accuracy can be improved.

When the number of visible satellite signals is four, the combination of the signals of the satellites with the earliest generated time is selected from among the combinations of the four satellite signals at each time by (a). Expected to choose. This is because the invisible satellite signal is received as a reflected wave or a diffracted wave having a larger propagation delay than the visible satellite signal. Then, by properly setting dT ₁ , invisible satellite signals can be eliminated by (d) and (e), and the time synchronization accuracy can be improved.

When the number of visible satellite signals is 5 or more, the combination of satellite signals having the earliest generation time is selected from among the combinations of four satellite signals at each time by (a). Is expected to choose. By appropriately setting dT ₁ , invisible satellite signals can be eliminated by (d) and (e), and time synchronization accuracy can be improved by selecting more visible satellite signals of 5 or more. it can.

Procedure (B)
When the number of visible satellite signals is 3 or less, the combination of the signals of the satellites with the earliest time to be generated is selected from the combination of the four satellite signals including the invisible satellites at each time by (a). By setting dT ₂ appropriately, among the invisible satellite signals due to (d) and (e), there is a high possibility that the time synchronization accuracy will be greatly deteriorated, and the navigation received as a reflected wave or diffracted wave with a large propagation delay time The satellite signal can be eliminated, and the time synchronization accuracy can be improved.

When the number of visible satellite signals is four, the combination of the signals of the satellites with the earliest generated time is selected from among the combinations of the four satellite signals at each time by (a). Expected to choose. By properly setting dT ₂ , invisible satellite signals can be eliminated by (d) and (e), and the time synchronization accuracy can be improved.

When the number of visible satellite signals is 5 or more, the combination of satellite signals having the earliest generation time is selected from among the combinations of four satellite signals at each time by (a). Is expected to choose. By properly setting dT ₂ , invisible satellite signals can be eliminated by (d) and (e), and time synchronization accuracy can be improved by selecting more visible satellite signals of 5 or more. it can.

Procedure (C)
When the number of visible satellite signals is 0, among the invisible satellites at each time, the signal of the satellite with the earliest generated time is selected by (a). By properly setting dT ₃ , (d) eliminates navigation satellite signals that are received as reflected or diffracted waves with a large propagation delay time that are likely to significantly deteriorate time synchronization accuracy among invisible satellite signals. The time synchronization accuracy can be improved.

When the number of visible satellite signals is 1, the satellite with the earliest time generated at each time is selected by (a), and this is expected to select the visible satellite signal. By setting dT ₃ appropriately, the invisible satellite signal can be eliminated by (d) and (e), and the time synchronization accuracy can be improved.

When the number of visible satellite signals is 2 or more, the satellite with the earliest time generated at each time is selected by (a), and this is expected to select the visible satellite signal. By appropriately setting dT ₃ , it is possible to eliminate invisible satellite signals by (d) and (e), and further improve the time synchronization accuracy by selecting more than two visible satellite signals. it can.

Next, will be described in detail a method of determining the tolerance value dT (Step _{(dT 1} of _{A), dT 2} steps _(B), dT ₃ steps (C)).

The optimum value of the set value of the allowable error value dT varies depending on the satellite signal reception state. In the open sky reception environment, many visible satellite signals are received. In that case, it is effective to receive as many satellite signals as possible that are evenly distributed in the sky to reduce the DOP value and improve accuracy. Is. Therefore, it is necessary to set a relatively large value as the allowable error value dT and select as many visible satellite signals as possible. Since the time obtained from the combination of visible satellite signals has a small delay from the reference time T _0, all visible satellite signals can be selected by setting the allowable error value dT to about 20 ns. On the other hand, when the allowable error value dT is 0 or 20 ns or less, all visible satellite signals may not be selected.

  On the other hand, in a multipath reception environment in which the number of visible satellite signals is 4 or less, when the allowable error value dT is 0, it is expected to select the satellite signal including the visible satellite signal and realizing the highest accuracy. However, as the allowable error value dT increases, there is a concern that the accuracy may deteriorate as a result of selecting many invisible satellite signals. That is, it is desirable that the allowable error value dT be small.

  FIG. 2 is a diagram showing the relationship between the set value of the allowable error value dT and the accuracy. In the open sky reception environment, the larger the setting value of the allowable error value dT, the smaller the time error. However, in the multipath receiving environment, the larger the setting value of the allowable error value dT, the larger the time error. In FIG. 2, the case where the number of visible satellites is 8 or more is the "open sky reception environment", and the case where the number of visible satellites is 4 or less is the "multipath reception environment".

  An evaluation result when the allowable error value dT is fixed by using the time synchronization device according to the above embodiment is shown. 3 and 4 show the evaluation results in the open sky environment. The evaluation index is the time error measurement time. FIG. 3 is an evaluation result in the case where the satellite signal is selected with the value of the allowable error value dT set to 0 ns in the open sky environment, and the above procedures (A) to (C) are not adopted as a comparison target and all satellite signals are The evaluation result when using is also described. FIG. 4 shows a measurement of the time error when the satellite signal is selected with the allowable error value dT set to 10 ns in the open sky environment. As shown in FIGS. 3 and 4, when the value of the allowable error value dT is set to 0 ns, the time error is increased by about 30 ns as compared with the case where all satellite signals are received. It was confirmed that when the value was set to 10 ns, the increase in time error was reduced to about several ns.

  5, 6, and 7 show the evaluation results in the multipath environment. The evaluation index is the time error measurement time. FIGS. 5, 6 and 7 show time errors when satellite signals are selected with the allowable error value dt set to 0 ns, 5 ns and 10 ns in a multipath environment. As shown in FIGS. 5, 6 and 7, it was not confirmed that the time error was reduced by increasing the allowable error value dt.

  From the above, it is preferable to determine the allowable error value dT according to the reception environment of satellite signals. Specifically, it is preferable to increase the allowable error value dT as the receiving environment is closer to the open sky environment, and to decrease the allowable error value dT as it is closer to the multipath environment. In other words, it is preferable that the larger the number of visible satellites, the larger the allowable error value dT, and the smaller the number of visible satellites, the smaller the allowable error value dT.

  As for the actual reception environment of satellite signals, various reception environments are assumed, from the state of so-called open full sky where no structure exists around the antenna to the reception environment of 0 visible satellite signals. As a method of optimizing the setting value of the error tolerance dT according to the reception environment, it is considered that a method of referring to the reception state (reception intensity or signal-to-noise ratio (SNR)) of the received navigation satellite signal is effective. . That is, based on the reception intensity or SNR, if there are many satellite signals with large reception intensity or SNR, it is estimated that the reception environment is closer to the open sky, in other words, it is estimated that the number of visible satellites is large, and error tolerance The value dT is set to a large value. On the contrary, when the number of these satellite signals is small, it is estimated that the reception environment is closer to the multipath environment, in other words, the number of visible satellites is small, and the error allowable value dT is set to 0 or a small value. To do.

  Specifically, it is conceivable that a threshold value of the reception strength or the SNR is set in advance and the value of the error allowable value dT is determined based on the number of satellite signals exceeding this. It is highly probable that the satellite associated with the satellite signal whose reception intensity or SNR threshold exceeds a predetermined threshold is a visible satellite, and therefore the number of satellite signals is estimated to be the number of visible satellites. A carrier-to-noise ratio (CNR) can be used as one of the SNR indexes. If this CNR is received at 40 dB-Hz or higher, the satellite signal is likely to be a visible satellite signal. Therefore, when using CNR, it is preferable to use a value of 40 dB-Hz as the CNR threshold value.

  A specific example of presetting the CNR threshold and setting the value of the error allowable value dT based on the number of satellite signals exceeding the CNR threshold will be described with reference to FIGS. 8, 9, and 10.

  8 and 9 are screen copies of software for observing the reception state of satellite signals with respect to the reception environment. FIG. 8 shows GPS in the case of observation in the open sky reception environment, and FIG. 9 in the case of observation in the multipath reception environment. An example of a signal reception situation is shown. When the CNR threshold is set to 40 dB-Hz in FIGS. 8 and 9, the number of satellite signals exceeding the CNR threshold is 11 in FIG. 8 and 4 in FIG.

  An example of setting the allowable error value dT based on the CNR of the received satellite signal will be described with reference to FIG. In the specific example of the present embodiment, the function is set such that the larger the number of satellite signals that exceeds the CNR threshold, the larger the allowable error value dT. FIG. 10 is a diagram showing a function for obtaining the allowable error value dT set for the number of satellite signals exceeding the CNR threshold. In the example of FIG. 10, the allowable error value dT is set to 0 ns when the number of satellite signals exceeding the CNR threshold is 4 or less, and the allowable error value dT is 20 ns when the number of satellite signals exceeding the CNR threshold is 10 or more. And the allowable error value dT is linearly increased from 0 ns to 20 ns in the section where the number of satellite signals exceeds the CNR threshold value from 4 to 10. It should be noted that the setting example according to FIGS. 8 to 10 is not limited to this, and the CNR threshold, the value of the allowable error value dT based on the CNR of the reception satellite signal, and the signal exceeding the CNR threshold in the function of FIG. The constants (4 and 10) about the number and the function for obtaining the allowable error value dT set for the number of satellite signals exceeding the CNR threshold value are preset with appropriate values and appropriate functional formulas based on experiments and the like. be able to. As an index used to estimate the receiving environment, that is, an index used to estimate the number of visible satellites, in addition to CNR, which is one of the SNR indices, the SNR itself and the reception status of satellite signals such as the reception intensity are used. Other indicators can be used.

  The role of each functional unit in performing the above procedure is as follows.

  The navigation satellite signal receiving unit 2 performs positioning and time synchronization using a designated navigation satellite signal among the received navigation satellite signals based on an instruction from the control unit 4, and obtains time information and a navigation satellite obtained as a result. The signal information is output to the time information generation unit 3 and the control unit 4. The time information generation unit 3 generates and outputs time information based on the time information and the navigation satellite signal information output from the navigation satellite signal reception unit 2 and the parameter value input from the control unit 4. The control unit 4 creates a table of combinations of navigation satellite signals based on the received navigation satellite signal information output from the navigation satellite signal reception unit 2 and the parameter setting information input to the setting unit 5, and the navigation satellite signal combination table is created. The satellite signal receiving unit 2 is instructed to perform positioning and time synchronization. For each combination of navigation satellite signals, the time information obtained from the navigation satellite signal receiving unit 2 is compared, the navigation satellite is extracted, and finally the navigation satellite signal receiving unit 2 is designated to generate the time information. Positioning and time synchronization for obtaining time information output to the unit 3 are instructed. In this extraction processing, the allowable error value dT calculated from the reception intensity or SNR of the navigation satellite signal received by the navigation satellite signal receiving unit 2 and the setting information such as the threshold value input to the setting unit 5 is used. Further, the control unit 4 outputs the parameter setting information input to the setting unit 5 to the navigation satellite signal receiving unit 2 and the time information generating unit 3.

  According to the present invention, the influence of the multipath signal can be effectively eliminated without depending on the reception characteristics of the navigation satellite signal antenna and the performance of the navigation satellite reception circuit, and the effect of improving the time synchronization accuracy can be expected.

  Further, by setting the parameter values appropriately, it is possible to effectively reduce the influence on the time accuracy of the invisible satellite signal and improve the time synchronization accuracy. Performance evaluation of the time synchronization device according to the present embodiment in a multipath reception environment was performed. 11 is a diagram illustrating a multipath receiving environment surrounded by buildings, FIG. 12 is a diagram showing an evaluation result of time synchronization accuracy in the environment, and FIG. 13 is an evaluation result of two-dimensional positioning accuracy in the environment. FIG. The positioning result in FIG. 13 is obtained by the positioning in step (f) of procedure (A) or step (e) of procedure (B) described above. As shown in FIGS. 12 and 13, it was confirmed that the time error and the two-dimensional positioning accuracy were significantly improved by enabling the statistical satellite selection, which is a feature of the present invention. FIG. 14 is a diagram illustrating a multipath reception environment in which a GPS antenna is installed near a window, FIG. 15 is a diagram showing an evaluation result of time synchronization accuracy in the environment, and FIG. 16 is a diagram showing an evaluation result of two-dimensional positioning accuracy in the environment. It is a figure. The positioning result in FIG. 16 is obtained by the positioning in step (f) of procedure (A) or step (e) of procedure (B) described above. Even when more than half of the open space is closed, as shown in FIGS. 15 and 16, by enabling the statistical satellite selection, which is a feature of the present invention, time error and two-dimensional positioning accuracy are achieved. Was confirmed to be significantly improved.

  In the present invention, since the satellite signal used for time synchronization is selected according to the time obtained by combining the satellite signals, it is not necessary to implement circular polarization isolation or vertical isolation in the navigation satellite signal antenna. It is possible to reduce the cost of the signal antenna.

  As described above, according to the present invention, highly accurate time information synchronized with a navigation satellite signal can be generated even in an environment where the required number of visible satellite signals cannot be temporarily captured and the reception environment is not good. It will be possible.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this. For example, the time synchronization device according to the above-described embodiment has both a position fixing mode that can be used when the position information of the reception position is known in advance and a fixed position estimation mode that does not require the position information of the reception position. However, only one of them may be mounted depending on the usage form. Alternatively, the operation may be started in the fixed position estimation mode, and then may be shifted to the position fixed mode based on the derived position.

  Further, in the above-described embodiment, all the received n navigation satellite signals are processed (step (A) of procedure (A), step (A) of procedure (B), and procedure (C)). In order to reduce the calculation processing, the present invention may be applied after the navigation satellite signals are selected into a predetermined number by masking processing such as an elevation angle mask or an SNR mask.

  Further, although the position of the navigation satellite signal antenna is fixed in the above-mentioned embodiment, the present invention can be applied to the case where the navigation satellite signal antenna is moved. In this case, the update frequency of the output in the fixed position estimation mode is improved as necessary.

  Further, although one navigation satellite system is used in the above-described embodiment, the present invention can be applied to a so-called multi-GNSS usage mode in which a plurality of navigation satellite systems are used in combination. In this case, since the number of visible satellite signals is increased, improvement in accuracy is expected. The combination target can use not only the global navigation satellite system but also the regional navigation satellite system. Global navigation satellite systems include GPS, GLONASS, Galileo, etc., and regional navigation satellite systems include Beidou, QZSS, etc.

  Further, although the time synchronization device has been described in the above embodiment, the present invention can be applied to the positioning device to improve the positioning accuracy. That is, the navigation satellite signal selection algorithm used to generate time information in the time synchronization device can be applied to generation of reception position information. In this case, the positioning device may have the processing function (procedure (A) or (B)) of the fixed position estimation mode in the time synchronization device described above. Then, the reception position information obtained as a result of the positioning in step (f) of procedure (A) or step (e) of procedure (B) described above may be output. That is, this positioning device includes the navigation satellite signal antenna 1, the navigation satellite signal receiving unit 2, the control unit 4, and the setting unit 5 in the configuration of the above-described synchronization device, and the positioning device of the above procedure (A) is used. It suffices to output the reception position information obtained by positioning by the navigation satellite signal receiving unit 2 in step (f) or step (e) of the procedure (B). A reception position information output unit may be further provided in order to output the reception position information output by the navigation satellite signal reception unit 2 in a predetermined format and timing.

1 ... Navigation satellite signal antenna, 2 ... Navigation satellite signal receiving unit, 3 ... Time information generating unit, 4 ... Control unit, 5 ... Setting unit

Claims (12)

A time synchronization device that receives a navigation satellite signal from a navigation satellite and generates time information synchronized with a predetermined standard time based on the time information included in the navigation satellite signal,
A navigation satellite signal receiving unit that generates time information synchronized with the navigation satellites based on the navigation satellite signals received simultaneously from four or more navigation satellites;
A time information generation unit that generates time information synchronized with a predetermined standard time based on the time information generated by the navigation satellite signal reception unit,
For each combination of navigation satellite signals from four or more navigation satellites that can be received simultaneously, the time information generated using the navigation satellite signal reception unit is acquired, and the acquired time information is compared to obtain time information. , Multiple navigation satellite signals related to the fast combination are extracted, time information is generated using the navigation satellite signal receiving unit based on the extracted navigation satellite signals, and predetermined using the time information generating unit based on the obtained time information. And a control unit that controls to generate and output time information synchronized with the standard time of
The time synchronization device, wherein the control unit extracts a plurality of navigation satellite signals related to a combination having earlier time information within a time of an allowable error value determined based on a reception state of the navigation satellite signals. A time synchronization device that receives a navigation satellite signal from a navigation satellite and generates time information synchronized with a predetermined standard time based on the time information included in the navigation satellite signal,
A navigation satellite signal receiving unit that generates time information synchronized with the navigation satellite based on navigation satellite signals received independently or simultaneously from one or more navigation satellites and position information of a predetermined reception position,
A time information generation unit that generates time information synchronized with a predetermined standard time based on the time information generated by the navigation satellite signal reception unit,
For each of the navigation satellite signals from multiple navigation satellites that can be received at the same time, the time information generated using the navigation satellite signal receiving unit is acquired, and the acquired time information is compared. The navigation satellite signal is extracted, the time information is generated using the navigation satellite signal receiving unit based on the extracted navigation satellite signal, and the time information generating unit is used to generate the predetermined standard time based on the obtained time information. And a control unit for controlling to generate and output synchronized time information,
The time synchronization device, wherein the control unit extracts a plurality of navigation satellite signals whose time information is early within a time of a permissible error value determined based on a reception state of the navigation satellite signals. The time synchronization device according to claim 1 or 2, wherein the allowable error value is determined based on the number of navigation satellite signals that exceed a predetermined signal-to-noise ratio threshold value. The time synchronization device according to claim 1 or 2, wherein the allowable error value is determined based on the number of navigation satellite signals that exceed a predetermined threshold of reception intensity. A time information generating method in a time synchronizing device that receives a navigation satellite signal from a navigation satellite and generates time information synchronized with a predetermined standard time based on time information included in the navigation satellite signal,
The time synchronizer is based on the navigation satellite signal receiving unit that generates time information synchronized with the navigation satellite based on the navigation satellite signals simultaneously received from four or more navigation satellites, and the time information generated by the navigation satellite signal receiving unit. A time information generation unit that generates time information synchronized with a predetermined standard time, and a control unit that controls the navigation satellite signal reception unit and the time information generation unit,
The time information generation method is
Controlling to obtain time information generated using a navigation satellite signal receiving unit for each combination of navigation satellite signals from four or more navigation satellites that can be simultaneously received,
A step of controlling to extract a plurality of navigation satellite signals related to a combination in which the time information is early within the time of the allowable error value determined based on the reception state of the navigation satellite signal by comparing the acquired time information;
Based on the extracted navigation satellite signal, the navigation satellite signal reception unit is used to generate time information, and based on the obtained time information, the time information generation unit is used to generate and output time information synchronized with a predetermined standard time. A time information generating method in a time synchronizing device, comprising: A time information generating method in a time synchronizing device that receives a navigation satellite signal from a navigation satellite and generates time information synchronized with a predetermined standard time based on time information included in the navigation satellite signal,
The time synchronization device includes a navigation satellite signal receiving unit that generates time information synchronized with the navigation satellite based on navigation satellite signals received individually or simultaneously from one or a plurality of navigation satellites and position information of a predetermined reception position; A time information generation unit that generates time information synchronized with a predetermined standard time based on the time information generated by the satellite signal reception unit, and a control unit that controls the navigation satellite signal reception unit and the time information generation unit ,
The time information generation method is
For each of the navigation satellite signals from a plurality of navigation satellites that can be received simultaneously, a step of controlling to obtain time information generated using the navigation satellite signal receiving unit,
A step of controlling the plurality of navigation satellite signals whose time information is early within the time of the allowable error value determined based on the reception state of the navigation satellite signals by comparing the obtained plurality of time information,
Based on the extracted navigation satellite signal, the navigation satellite signal reception unit is used to generate time information, and based on the obtained time information, the time information generation unit is used to generate and output time information synchronized with a predetermined standard time. A time information generating method in a time synchronizing device, comprising:   A time information generation program that causes a computer to function as each unit of the time synchronization device according to claim 1. A positioning device that receives a navigation satellite signal from a navigation satellite and generates reception position information based on time information and satellite position information included in the navigation satellite signal,
A navigation satellite signal receiving unit that generates time information and reception position information synchronized with the navigation satellite based on the navigation satellite signals received from four or more navigation satellites at the same time,
For each combination of navigation satellite signals from four or more navigation satellites that can be received simultaneously, the time information generated using the navigation satellite signal reception unit is acquired, and the acquired time information is compared to obtain time information. Control to extract multiple navigation satellite signals related to a fast combination, generate reception position information using the navigation satellite signal receiving unit based on the extracted navigation satellite signals, and output the obtained reception position information. Section and
The positioning device is characterized in that the control unit extracts a plurality of navigation satellite signals associated with a combination having earlier time information within a time of an allowable error value determined based on a reception state of the navigation satellite signals. The positioning device according to claim 8, wherein the allowable error value is determined based on the number of navigation satellite signals that exceed a predetermined signal-to-noise ratio threshold value. The positioning device according to claim 8, wherein the allowable error value is determined based on the number of navigation satellite signals that exceed a predetermined threshold value of reception intensity. A positioning method in a positioning device which receives a navigation satellite signal from a navigation satellite and generates reception position information based on time information and satellite position information included in the navigation satellite signal,
The positioning device includes a navigation satellite signal receiving unit that generates time information and reception position information synchronized with the navigation satellite based on navigation satellite signals that are simultaneously received from four or more navigation satellites, and a control unit that controls the navigation satellite signal receiving unit. With and
As for the positioning method, the control unit
For each of the navigation satellite signals from a plurality of navigation satellites that can be received simultaneously, a step of controlling to obtain time information generated using the navigation satellite signal receiving unit,
A step of controlling to extract a plurality of navigation satellite signals related to a combination in which the time information is early within the time of the allowable error value determined based on the reception state of the navigation satellite signal by comparing the acquired time information;
A positioning method in a positioning device, comprising the step of generating reception position information using a navigation satellite signal receiving unit based on the extracted navigation satellite signal, and controlling to output the obtained reception position information. .   A positioning program that causes a computer to function as each unit of the positioning device according to claim 8.