JP5200636B2 - Electronic clock and time correction method of electronic clock - Google Patents

Description

  The present invention relates to an electronic timepiece that receives a satellite signal transmitted from a position information satellite such as a GPS satellite and obtains the current date and time, and a time correction method for the electronic timepiece.

  In a GPS (Global Positioning System) system, which is a system for positioning its own position, a GPS satellite having an orbit around the earth is used, and this GPS satellite is provided with an atomic clock. For this reason, the GPS satellite has extremely accurate time information (GPS time, satellite time information).

By the way, the current standard time in the world is Coordinated Universal Time (UTC). This UTC is based on the International Atomic Time (TAI) using an atomic clock, but since there is a slight difference between this TAI and the time based on the rotation of the earth (Universal Time, UT), it is in units of 1 second relative to the TAI. The difference with universal time is adjusted to less than 1 second.
On the other hand, since the GPS time is not adjusted as described above, an error in the accumulated value of the adjustment time occurs between UTC and GPS time. For this reason, the satellite signal transmitted from the GPS satellite includes information indicating leap second information (UTC offset) indicating the difference between the GPS time and UTC.

This leap second information is currently +14 seconds. In the future, when the leap second is adjusted in UTC, it is necessary to update the leap second information of the satellite signal. For this reason, the satellite signal includes the scheduled date (usually the last day of December or June) on which the leap second will be adjusted, and the adjusted leap second (UTC offset amount).
An electronic timepiece is known in which time and leap second information is acquired from a GPS satellite, and when the UTC leap second is adjusted, the correct UTC can be obtained at that time (Patent Literature). 1).

JP-A-8-297178

However, in Patent Document 1, leap second information (UTC offset related information) is received every time a GPS satellite signal is received in order to check whether the leap second has been updated.
Here, since the leap second information is transmitted only once every 12.5 minutes, in order to receive the leap second information when performing a satellite signal reception operation, the maximum is 12.5. Reception must continue for a minute. For this reason, there is a problem that it cannot be used in a device with a small amount of power such as a wristwatch.

  An object of the present invention is to provide an electronic timepiece and a time correction method for an electronic timepiece that can receive leap second information and reduce power consumption at the time of reception.

The electronic timepiece of the present invention is an electronic timepiece including a receiving unit that receives a satellite signal transmitted from a position information satellite, and a control unit that controls the operation of the receiving unit, wherein the control unit includes the receiving unit. Time information acquisition means for acquiring time information by driving and determining whether leap second information can be acquired within a certain time from that time when the time information acquisition means acquires time information When it is determined that it is possible to drive the receiving unit to acquire leap second information, and when it is determined that acquisition is not possible, the leap second information acquisition unit that stops driving the receiving unit , the acquired time information and Time correction means for correcting the display time based on leap second information.

In the present invention, when the time information is acquired by the time information acquisition means, the leap second information acquisition means determines whether the leap second information can be acquired within a predetermined time, and acquires the leap second information within the predetermined time. When possible, the reception is continued and leap second information is acquired. For this reason, since the leap second information can be acquired and the reception process can be completed within the predetermined time, the reception process time for acquiring the leap second information can be shortened, and the power consumption can be reduced.
In addition, since leap second information is acquired, even when leap seconds are implemented, the time adjustment means can calculate and display an accurate time.

In the present invention, the time information acquisition means is capable of acquiring date information in addition to the time information, and the leap second information acquisition means is a leap second update in which the date information acquired by the time information acquisition means is preset. Only when it is included in the time, it is determined whether the leap second information can be acquired within the predetermined time, and when it is determined that the leap second information can be acquired , the receiver is driven to acquire the leap second information , It is preferable to stop driving the receiving unit when it is determined that the signal cannot be acquired .
Here, the leap second update time means, for example, from a predetermined period before the date when the leap second may be updated to the date when the leap second may be updated. Normally, in UTC, the last day of June or the last day of December is a date when leap seconds may be updated. Therefore, the leap second update time is set a predetermined period before that date (for example, one month before). That's fine.

In the present invention, the leap second information reception process is performed when the reception processing date falls within the leap second update time, and the leap second information reception process is not performed at times other than the leap second update time. , Power consumption can be reduced.
In addition, since leap second information is received at leap second update time, even if leap second is actually updated on the date when leap second may be updated, the leap second update date is in advance And can display the exact time from when the leap second was updated.

  In the present invention, the satellite signal is composed of a plurality of pages, the leap second information is included in a predetermined page, and the leap second information acquisition means acquires the time information by the time information acquisition means. In this case, it is possible to detect the page being received, calculate the time until the page including the leap second information is transmitted from the page being received, and determine whether the leap second information can be acquired within the predetermined time. It is preferable to judge.

In the present invention, since it is possible to grasp the time until leap second information can be acquired based on the received data of the satellite signal, it is possible to accurately determine whether leap second information can be acquired within a certain time.
For example, when a GPS satellite is used as the position information satellite, the navigation message of the satellite signal transmitted from the GPS satellite is composed of 25 pages, and each page is composed of 5 subframes. The leap second information is stored in subframe 4 of page 18. Since transmission of each page takes 30 seconds, if the page at the time of receiving the time information is known, the time until the page 18 can be received is also known, and it can be accurately determined whether leap second information can be acquired within a certain time. .

In the present invention, when the leap second information acquisition unit determines that leap second information cannot be acquired within the predetermined time, the driving of the receiving unit is stopped, and when the leap second information can be acquired, It is preferable to drive the receiving unit to acquire leap second information.

  In the present invention, when it is determined that leap second information cannot be acquired within a certain time, the reception operation is temporarily stopped, so unnecessary reception processing can be eliminated and power consumption can be reduced. Further, since it is time to acquire leap second information, the receiving unit is driven, so that leap second information can be acquired with certainty.

In the present invention, when it is determined that the leap second information acquisition unit cannot acquire leap second information within the predetermined time, the driving of the reception unit may be stopped and the reception process may be terminated.

  In the present invention, when it is determined that the leap second information cannot be acquired within the predetermined time, since the reception process is terminated by stopping the operation of the reception unit, unnecessary reception processing can be eliminated, and consumption Electric power can be reduced. In this reception operation, leap second information cannot be acquired, but for example, it is possible to acquire leap second information within a certain period of time by repeating reception, such as receiving regularly every day. By repeating the above for a certain number of times, leap second information can be acquired. Therefore, for example, if reception is repeated every day before a predetermined period (for example, one month) before the leap second update date, the leap second information can be sufficiently acquired during the one month.

In the present invention, it is preferable that reception result display means for displaying a reception result is provided, and the reception result display means is configured to be able to display whether or not time information has been received and acquired.
In the present invention, since the reception result display means is provided, the user can easily grasp the reception result.

  In the present invention, the reception result display means includes a case where the time information is not received, a case where at least the time information is received and a leap second information and positioning information are not received, and at least the time information and leap second information. It is preferable to be configured to be able to distinguish and display the case in which positioning information is received and the case in which at least time information, leap second information, and positioning information are received.

  Since the reception result display means of the present invention can display the reception result in at least four stages, the user can grasp the reception result in detail, and can perform a forced reception operation as necessary, which is convenient. It can be improved.

In the present invention, it is preferable that the reception result display means moves a pointer and displays each reception result according to the indicated position.
In the present invention, since the reception result can be displayed using a guideline for indicating the time, the number of parts can be reduced as compared with the case where a dedicated display device for displaying the reception result is provided.

The time adjustment method for an electronic timepiece according to the present invention is a time adjustment method for an electronic timepiece including a receiving unit that receives a satellite signal transmitted from a position information satellite, and is a time for driving the receiving unit to acquire time information. When the time information is acquired in the information acquisition step and the time information acquisition step, it is determined whether leap second information can be acquired within a predetermined time from that time, and the reception is performed when it is determined that the acquisition is possible The leap second information is acquired by driving the unit, and if it is determined that the leap second information is not obtained , the leap second information acquisition step that stops the driving of the receiving unit, and the display time is corrected based on the acquired time information and leap second information And a time correction step.
Also in the present invention, the same operational effects as the electronic timepiece can be obtained.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
The embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

[First Embodiment]
FIG. 1 is a schematic diagram showing a wristwatch 1 with a GPS satellite signal receiving device (hereinafter referred to as “GPS wristwatch 1”) which is an electronic timepiece according to the present invention, and FIG. 2 is a main hardware configuration of the GPS wristwatch 1 FIG.
As shown in FIG. 1, the GPS wristwatch 1 includes an analog display device including a dial 2 and hands 3. A small clock 4 is provided on a part of the dial 2.

The pointer 3 includes a second hand, a minute hand, an hour hand, and the like, and is driven by a step motor through a gear.
The small clock 4 includes a minute hand and an hour hand, and is driven by a step motor for a small clock through a gear. The small clock 4 is used, for example, for displaying a time in a time zone different from the time indicated by the hands 3.

The GPS wristwatch 1 acquires satellite time information and positioning information by receiving satellite signals from a plurality of GPS satellites 5 orbiting the earth in a predetermined orbit, and corrects the internal time information to the current time. It is configured to be able to.
The GPS satellite 5 is an example of the position information satellite in the present invention, and a plurality of GPS satellites 5 exist above the earth. Currently, about 30 GPS satellites 5 orbit.
Further, the GPS wristwatch 1 is provided with a button 6 and a crown 7 as an input device (external operation member).

[Circuit configuration of GPS wristwatch]
Next, the circuit configuration of the GPS wristwatch 1 will be described.
As shown in FIG. 2, the GPS wristwatch 1 includes a GPS device (GPS module) 10, a control unit (CPU) 20, a storage device 30, a time display device 40, and a solar cell 50. The storage device 30 includes a RAM 31 and a ROM 32. Each of these devices communicates data via the data bus 60.

The time display device 40 includes the pointer 3 and the small clock 4 that display time and positioning information.
The solar cell 50 functions as a power source for the GPS wristwatch 1. The power source is not limited to the solar battery 50 but may be a primary battery or a rechargeable secondary battery other than the solar battery.

[Configuration of GPS device]
The GPS device 10 includes a GPS antenna 11 and processes satellite signals received via the GPS antenna 11 to acquire time information and position information.
The GPS antenna 11 is a patch antenna that receives satellite signals from a plurality of GPS satellites 5 orbiting the earth over a predetermined orbit. The GPS antenna 11 is disposed on the back side of the dial 2 and is configured to receive radio waves that have passed through the surface glass of the GPS wristwatch 1 and the dial 2.
For this reason, the dial 2 and the surface glass are made of a material that transmits radio waves that are satellite signals transmitted from the GPS satellite 5. For example, the dial 2 is made of plastic.

  Although not shown, the GPS device 10 receives a satellite signal transmitted from the GPS satellite 5 and converts it into a digital signal, as in the case of a normal GPS device, and a correlation between the received signals. A BB unit (baseband unit) that performs determination and synchronizes, and an information acquisition unit that acquires time information and positioning information from a navigation message (satellite signal) demodulated by the BB unit.

The RF unit includes a band pass filter, a PLL circuit, an IF filter, a VCO (Voltage Controlled Oscillator), an ADC (A / D converter), a mixer, an LNA (Low Noise Amplifier), an IF amplifier, and the like.
The satellite signal extracted by the band-pass filter is amplified by the LNA, mixed with the VCO signal by the mixer, and down-converted to IF (Intermediate Frequency). The IF mixed by the mixer passes through an IF amplifier and IF filter, and is converted into a digital signal by an ADC (A / D converter).

The BB unit includes a local code generation unit that generates a local code composed of the same C / A code as that used at the time of transmission by the GPS satellite 5, and a correlation value between the local code and a reception signal output from the RF unit. And a correlation unit for calculating.
If the correlation value calculated by the correlator is equal to or greater than a predetermined threshold, the C / A code used for the received satellite signal matches the generated local code, and the satellite signal is captured. (Synchronized). Therefore, the navigation message can be demodulated by correlating the received satellite signal with the local code.

[Navigation message]
The information acquisition unit acquires time information and position information from the navigation message demodulated by the BB unit. Here, the navigation message transmitted from the GPS satellite 5 is configured as shown in FIG. That is, the navigation message is composed of 25 pages from Page1 to Page25. The GPS satellite 5 repeatedly transmits a navigation message composed of these 25 pages (Full-Page).
Each page is also called a frame and has a data amount of 1500 bits. Since the data rate of the navigation message is 50 bps, it takes 30 seconds to transmit one page (frame). To transmit 25 pages (Full-Page), 30 seconds × 25 = 750 seconds = 112. It takes 5 minutes.

Each page (frame) includes five subframes (SF1 to SF5). Each subframe is composed of 10 words. Each word has a data length of 30 bits, and has a data portion of 24 bits and a parity bit of 6 bits. Therefore, each subframe has 300 bits of data and takes 6 seconds to transmit.
In each subframe, the first words 1 and 2 are set to TLM (telemetry word) and HOW (hand over word) used for synchronization during reception processing. The HOW includes time information TOW (Time of Week, also referred to as “Z count”) of GPS signals.

Subframes 1 to 3 transmit the same type of data in each page.
In addition to TLM and HOW, subframe 1 includes week number data, satellite health data indicating the status of the satellite itself, and data such as a clock correction coefficient.
In subframes 2 and 3, detailed orbit information (ephemeris) of each GPS satellite 5 is stored in addition to TLM and HOW.

On the other hand, subframes 4 and 5 store information related to all satellites such as almanac (general orbit information of all GPS satellites 5). Since these pieces of information have a large amount of data, the subframes 4 and 5 transmit different types of data for each page.
For example, leap second information is in subframe 4 of page 18, as shown in FIG. In subframe 4 of page 18, in addition to TLM and HOW, ionosphere correction coefficients ˜α _{0 to} α ₃ , β _{0 to} β _3, etc. are stored in words 3 to 5, and UTC parameter A ₁ is stored in words 6 and 7. , A ₂ are stored.
In addition, leap second information is stored in the words 8 to 10. Specifically, the epoch time information is stored in t _0t and WN _t of word 8, the current leap second is stored in Δt _LS , the update week of leap seconds is stored in WN _LSF , and DN is stored in DN. The leap second update date is stored, and the updated leap second is stored in Δt _LSF .

Therefore, the information acquisition unit extracts a predetermined data portion from the received navigation message, and acquires time information and position information. For this reason, in this embodiment, the receiving unit is configured by the GPS device 10.
Further, if subframe 4 of page 16 transmitted at 12.5 minute intervals is received, leap second information can be acquired.

A program executed by the control unit 20 is stored in the ROM 32 of the storage device 30.
On the other hand, the RAM 31 of the storage device 30 has a data storage area for storing time information, position information, and leap second information acquired by reception, and a time difference storage area for storing position information and a time difference with respect to UTC at that location. Is provided. Note that when the position information (latitude and longitude) is acquired, the control unit 20 acquires a time difference (+9 hours in Japan) corresponding to the position information from the time difference storage area, and the time information ( The time of the present location can be calculated by adding UTC offset (+14 seconds as of February 2008) to GPS time to obtain UTC, and further adding the time difference. Therefore, by correcting the hands 3 at the calculated time of the current value, the time of the current location can be accurately displayed even when moving across the time zone.

  The control unit (CPU) 20 performs various controls according to programs stored in the ROM 32. Therefore, the control unit 20 includes a time information acquisition unit 21, a leap second information acquisition unit 22, and a time correction unit 23 as shown in FIG.

The time information acquisition unit 21 controls the driving of the GPS device 10 to receive satellite signals when a preset reception time is reached or when a reception operation is performed by an input device such as the button 6 or the crown 7. The process is executed, time information is acquired, and stored in the RAM 31.
The leap second information acquisition unit 22 drives and controls the GPS device 10 to acquire leap second information and stores it in the RAM 31.
The time correction unit 23 calculates time based on the time information and leap second information acquired by the time information acquisition unit 21 and leap second information acquisition unit 22, and displays the time of the time display device 40 such as the hands 3 and the small clock 4. Is corrected to the calculated time.

[Time information reception processing]
Next, the reception process of the GPS wristwatch 1 will be described with reference to the flowchart of FIG.
The reception process shown in FIG. 6 also performs leap second reception at a predetermined time when time information is periodically received and time adjustment is performed. In addition, the update time of leap seconds in UTC is determined by the central office of the International Earth Rotation Observation Project, and is usually implemented on the last day of June or December. Therefore, in the present embodiment, it is attempted to acquire leap second information from a predetermined period (for example, one month before) on which the leap second may be updated (June 30 and December 31). Yes. However, since leap second information is transmitted every 12.5 minutes as described above, power consumption increases if reception is continued until leap second information can be acquired by one reception. For this reason, one reception time is limited to a fixed time (for example, 1 minute), and control is performed so as to acquire leap second information while repeating reception within the predetermined period.

That is, when the reception process of FIG. 6 is started, the time information acquisition means 21 of the control unit 20 drives the GPS device 10, starts reception, and starts a time information acquisition process (S11).
Next, when the start of reception is instructed, the GPS device 10 performs a satellite search process (S12). Specifically, the GPS device 10 generates a C / A code pattern of the GPS satellite 5 and searches for a correlation value of the received satellite signal.

Next, the time information acquisition unit 21 determines whether the search processing for all satellites is completed (S13).
If it is determined as “Yes” in S13 and all the satellites have been searched, there is no satellite that can receive the satellite signal. Therefore, the time information acquisition unit 21 stops the driving of the GPS device 10 and performs reception processing. Exit.

  On the other hand, when it is determined “No” in S13, the time information acquisition unit 21 determines whether or not the GPS satellite 5 has been captured (S14). Specifically, the time information acquisition means 21 determines whether or not the GPS satellite 5 has been captured based on the correlation value between each C / A code and the received satellite signal.

If "No" is determined in S14, the time information acquisition unit 21 returns to the process of S12 and continues the satellite search process. For example, when searching No. 1 to 30 GPS satellites 5 in order, the GPS device 10 first generates a C / A code of the No. 1 GPS satellite 5 and obtains a correlation value with the received satellite signal. . Here, it can be seen that if the correlation value is high, the No. 1 GPS satellite 5 is captured, and if the correlation value is low, it is not captured. If it is determined in S14 that it has not been captured and the process returns to S12, the GPS device 10 generates a C / A code for the next No. 2 GPS satellite 5 and obtains a correlation value with the received satellite signal.
The time information acquisition unit 21 repeats the above processing until it is determined that the GPS satellite 5 has been captured in S14.

  When it is determined in S14 that the GPS satellite 5 has been captured, the time information acquisition unit 21 determines whether or not the reception time has timed out (S15). That is, the time information acquisition unit 21 detects the signal level of the received signal and determines that a time-out occurs when a state in which the reception state is poor and correct data cannot be received continues for a preset time. Note that the time for determining the timeout may be any time as long as it is possible to detect whether the satellite signal can be received by detecting the signal level of the satellite signal, and may be set as appropriate in implementation.

If the time information acquisition unit 21 determines that the time-out has occurred in S15, the time information acquisition unit 21 returns to S12 and continues the process from the search for another GPS satellite 5.
On the other hand, when it is determined that the time-out is not timed out in S15, the time information acquisition unit 21 determines whether or not the Z count has been acquired (S16).

If the time information acquisition unit 21 determines in S16 that the Z count cannot be acquired, the process returns to S14 and continues the processing.
On the other hand, when it is determined that the Z count has been acquired in S16, the time information acquisition unit 21 determines whether GPS Week (week number data) has been acquired (S17).

If the time information acquisition unit 21 determines in step S17 that the GPS Week has not been acquired, the time information acquisition unit 21 returns to step S14 and continues the process.
On the other hand, when the time information acquisition unit 21 determines that the GPS Week has been acquired in S17, a leap second information acquisition step by the leap second information acquisition unit 22 is performed.
That is, the leap second information acquisition unit 22 determines whether the acquired date information corresponds to the leap second update time (S18).
Here, as described above, the leap second update time is updated from a predetermined period (for example, one month before) on which the leap second may be updated (June 30 and December 31). Means the time until the day when there is a possibility of being done. In this embodiment, the period from June 1 to June 30 and the period from December 1 to December 31 are set as leap second update times. Therefore, the leap second information acquisition means 22 refers to the date information based on the received GPS Week (week number) and determines whether it is the leap second update time.

If the leap second information acquisition unit 22 determines in S18 that it is the leap second update time, it determines whether leap second information can be acquired within a predetermined time (S19).
As described above, leap second information is included in subframe 4 of page 18. If the Z count can be received, it can be determined which page of data is currently being received. If the page number of the currently received satellite signal is known, the time until the subframe 4 of page 18 is transmitted can be determined, and whether leap second information can be acquired within a fixed time can also be determined.

  If the leap second information acquisition unit 22 determines “Yes” in S19, it performs leap second information acquisition processing (S20). That is, the GPS device 10 continues the reception process until the leap second is acquired. At this time, since the GPS Week is stored in the subframe 1 and the leap second information is stored in the subframe 4, the subframes 2 and 3 in the meantime, that is, the ephemeris of the GPS satellite 5 is also acquired. Therefore, if the ephemeris can be acquired from at least three GPS satellites 5, the current location positioning process can be performed simultaneously.

The leap second information acquisition unit 22 ends the reception when the leap second is acquired (S21). The acquired leap second information is stored in the RAM 31. If position information is also acquired, the position information is also stored in the RAM 31.
If the time information acquisition means 21 determines that it is not the leap second update time in S18 and if it is determined that the leap second information cannot be acquired within a certain time in S19, the time information acquisition means 21 does not acquire the leap second information. Reception ends (S21).

And the time correction means 23 calculates | requires the present | current time based on the acquired information, and corrects the instruction | indication of the pointer | guide 3 (S22).
That is, when the GPS Week is acquired in S17, the time information acquisition unit 21 stores the time information based on the acquired Z count and the date information based on the GPS Week in the RAM 31.
Therefore, in S22, the time correction means 23 calculates the GPS time from the Z count and GPS Week stored in the RAM 31, and adds the UTC offset acquired from the leap second information to the GPS time to obtain the UTC. In addition, when new leap second information cannot be acquired, the time correction means 23 calculates | requires UTC using the leap second information (UTC offset) previously acquired and memorize | stored in RAM31.
Furthermore, the time correction means 23 adds the time difference memorize | stored in RAM31 to UTC, and calculates the time of the present location. When the position information is acquired in this reception process, the time difference corresponding to the position information is read from the time difference storage area of the RAM 31 and the time difference stored in the RAM 31 is updated. Thereby, the time of the present location can be calculated using the time difference corresponding to the latest position information.
Thus, the reception process ends. And in this embodiment, a time information acquisition process is comprised by each process of S11-S17 implemented by the time information acquisition means 21, and a leap second information acquisition process is implemented by the leap second information acquisition means 22 S18. The time adjustment process is configured by the process of S22 performed by the time correction means 23.

  The fixed time in S19 may be set based on the timing at the time of reception processing. That is, pages 1 to 25 of the navigation message are transmitted every 750 seconds (12.5 minutes). Since 1 day = 86400 seconds / 750 seconds = 15.2, when 1 day elapses, 750 seconds × 0.2 = 150 seconds, that is, 5 pages shifted. That is, when the reception process is executed at the same time every day, the pages transmitted at that timing are shifted by 5 pages every day. Therefore, if the page 18 is received at the same time every day for 150 seconds, the page 18 including leap second information can be received within five days. For this reason, the predetermined time may be set to 2.5 minutes, for example.

[Effect of the first embodiment]
According to this embodiment, there are the following effects.
(1) When periodic reception processing is performed, only when it is determined that leap second information can be acquired within a certain period of time, reception is continued and acquisition of leap second information is performed, so the reception processing time can be shortened. Power consumption can be reduced. That is, since leap second information is transmitted every 12.5 minutes, if it is attempted to acquire leap second information without making any judgment, reception processing must be continued for a maximum of 12.5 minutes.
On the other hand, in this embodiment, in S19, it is determined whether or not leap second information can be acquired within a certain time, for example, within 2.5 minutes, and leap second information is received only in that case. The reception time can be suppressed to 2.5 minutes at the maximum. For this reason, compared with the case where reception must be continued for a maximum of 12.5 minutes, the power consumption can be greatly reduced, and it can be applied to a wristwatch with a small battery capacity.

(2) Also, it is determined whether it is the leap second update time, and the leap second information reception process is performed only in the leap second update time, so it is necessary to perform leap second information acquisition processing at other times The power consumption can be reduced accordingly.
In other words, leap seconds are frequently performed once every several years, and the time is also set to the end of June or the end of December. For this reason, if leap second information reception processing is performed only immediately before, for example, one month in June or one month in December, the leap second may be updated on the last day of June or December. When the leap second is implemented, the UTC offset amount is changed and stored in the RAM 31, so that the correct time can be calculated and displayed thereafter. Therefore, it is not necessary to perform leap second reception processing itself at a time other than the leap second update time, for example, January to May or July to November, and power consumption can be reduced by that amount.

(3) Furthermore, since the leap second information includes the leap second update date and the updated leap second (UTC offset), if leap second information is obtained, leap second was implemented in UTC. At this time, the UTC offset stored in the RAM 31 can also be reliably updated. Thereby, the UTC calculated by adding the UTC offset to the GPS time can also be set to the correct time, and an accurate time display can be performed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG. In the following embodiments, the same or similar configurations as those of the other embodiments described above are denoted by the same reference numerals, and description thereof is omitted or simplified.
In the second embodiment, leap second information is forcibly acquired by a user's reception operation. For example, immediately after the GPS wristwatch 1 is turned on, the current time, date information, and the like cannot be completely acquired. Therefore, it can be used when the time information is completely acquired.
The forced reception process is performed by, for example, pressing one button 6 for a predetermined time or longer (for example, 3 seconds or longer).

  As shown in FIG. 7, the processes from S11 to S17 are the same as those in the first embodiment. That is, when the reception process of FIG. 7 is started by a manual reception operation or the like, the time information acquisition unit 21 performs the reception start process of S11 and the satellite search process of S12 as in the first embodiment, and S13 It is determined whether or not the search processing for all satellites has been completed. If the search has been completed, the reception processing is terminated.

If the search has not been completed, the time information acquisition means 21 performs a process for determining whether the satellite has been acquired in S14 and a process for determining a reception time timeout in S15. When the satellite has not been captured in S14 and in the case of timeout in S15, the time information acquisition unit 21 returns to the satellite search in S12 and continues the process.
On the other hand, if the time-out is not timed out in S15, the time information acquisition unit 21 performs the Z count acquisition determination in S16 and the GPS Week acquisition determination in S17.

If the time information acquisition unit 21 determines “No” in S16 and S17, the time information acquisition unit 21 returns to S12 and continues the process from the search for other GPS satellites 5.
On the other hand, when it is determined that the time information acquisition unit 21 has acquired GPS Week in S17, the leap second information acquisition unit 22 determines whether leap second information can be acquired within a predetermined time (S19). This fixed time may be set in consideration of, for example, power consumption due to continued reception, and is set to 1 minute, for example.

  When the leap second information acquisition unit 22 determines in S19 that leap second information can be received within a certain time, the leap second information acquisition unit 22 performs the leap second information acquisition process in S20 and the reception end process in S21 as in the first embodiment. The correction means 23 performs the time correction process of S22.

On the other hand, if the leap second information acquisition unit 22 determines “No” in S19, the reception is temporarily interrupted (S31). And the leap second information acquisition means 22 makes the GPS apparatus 10 sleep (S32).
Since the leap second information acquisition unit 22 knows the time until the leap second information can be acquired in S19, the leap second information acquisition means 22 refers to the internal time and determines whether or not the time at which the leap second information can be acquired is reached (S33). ).

The leap second information acquisition unit 22 maintains the sleep state of S32 until the time at which leap second information can be acquired in S33.
If the leap second information acquisition unit 22 determines in S33 that the leap second information can be acquired, the reception start process in S11 is performed. That is, the leap second information acquisition unit 22 operates the GPS device 10 in the sleep state and resumes reception.
For example, in S19, if the currently received page is “6”, (18−6) × 30 seconds = 360 seconds (6 minutes) is required up to page 18 including leap second information, and the above-mentioned constant If it is determined that leap second information cannot be acquired within a time (for example, 1 minute), the sleep state may be maintained for 5 minutes from that point, for example, and reception of S11 may be started after 5 minutes.

  When S11 to S19 are executed, it is determined as “Yes” in S19. Therefore, the leap second information acquisition unit 22 performs the leap second information acquisition process in S20 and the reception end process in S21. , S22 time correction processing is performed.

[Effects of Second Embodiment]
According to such 2nd Embodiment, there can exist the same effect as the said 1st Embodiment, and also there exist the following effects.
(2-1) In this embodiment, if leap second information cannot be acquired within a certain time, the reception is temporarily suspended and the GPS device 10 is put into a sleep state, and reception is resumed when it is time to acquire leap second information. Therefore, the time for operating the GPS device 10 to receive leap second information can be minimized, and the power consumption can be further reduced.
For example, if it is determined in S19 that leap second information can be received after 6 minutes, for example, the GPS device 10 can be put to sleep for 5 minutes, and then the operation of the GPS device 10 can be resumed to receive leap second information. In this case, since the GPS device 10 has only to be operated for about 1 minute to receive leap second information, the power consumption can be further reduced as compared with the first embodiment.

(2-2) Furthermore, since leap second information is received after the GPS device 10 is put to sleep, leap second information can be reliably received during one reception operation. For this reason, if the forced reception process of the present embodiment is performed manually from a state where the current time, date information, or the like cannot be acquired, accurate time display that reflects leap second information can be performed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIGS. In the third embodiment, a function for displaying a reception result is added to each of the above embodiments.
That is, the control unit 20 according to the third embodiment includes a reception result display unit 24 in addition to the time information acquisition unit 21, the leap second information acquisition unit 22, and the time correction unit 23, as shown in FIG.
The reception result display means 24 displays the reception result using the minute hand 41 of the small clock 4.

In the third embodiment, when a predetermined operation (for example, an operation of pressing one button 6) is performed, the reception result display mode is set.
In the reception result display mode, the reception result display unit 24 displays the reception result by moving the minute hand 41 of the small clock 4 based on the contents of the reception processing result. The reception result is stored in the RAM 31 when reception processing is performed, and the reception result display means 24 moves and displays the minute hand 41 based on the reception result stored in the RAM 31.

  That is, in the present embodiment, the reception result stored in the RAM 31 is divided into five levels from level 0 to level 4. Level 0 is a state of not receiving time information. Level 1 is when only time information (Z count) is received, or when time information (Z count) and date information (GPS Week) are received. Level 2 is a case where time information (Z count) and leap second information are received. Level 3 is when time information (Z count), leap second information, and date information (GPS Week) are received. Level 4 is the case where time information (Z count), leap second information, date information (GPS Week), and positioning information are received.

If the reception result stored in the RAM 31 is level 0, the reception result display means 24 moves the minute hand 41 of the small clock 4 to the 0 minute position and stops as shown in FIG. 9A.
If the reception result is level 1, the reception result display means 24 moves and stops the minute hand 41 of the small clock 4 to the 10-minute position as shown in FIG. As shown in FIG. 9C, the minute hand 41 of the small clock 4 is moved to the 20-minute position and stopped.
Furthermore, if the reception result is level 3, the reception result display means 24 moves and stops the minute hand 41 of the small clock 4 to the 40-minute position as shown in FIG. As shown in FIG. 9 (E), the minute hand 41 of the small clock 4 is moved to the 50 minute position and stopped.

  At this time, it may be instructed by the second hand 331 of the pointer 3 whether or not the reception is successful. That is, since the unreceived level 0 has not been successfully received, the second hand 331 may be moved to the 20-second position (position for instructing reception failure) and stopped as shown in FIG. . Further, in levels 1 to 4 at least receiving time information (Z count), as shown in FIGS. 9B to 9E, the second hand 331 is moved to the 10-second position (position instructing successful reception). Then you may stop.

[Effect of the third embodiment]
According to such 3rd Embodiment, there can exist the same effect as said each embodiment, and there exist the following effects.
(3-1) Since the reception result display means 24 is provided, the user can easily grasp whether or not the reception is successful and what information has been received. Therefore, for example, it is possible to grasp whether leap second information is received in automatic reception that is performed periodically. For this reason, when the leap second information cannot be received, the user can be prompted to perform the forced reception operation of the second embodiment to receive the leap second information. As a result, the GPS wristwatch 1 can receive leap second information and perform accurate time display.

(3-2) Further, in the present embodiment, since five levels of reception results can be displayed from level 0 to level 4, detailed reception results can be displayed to the user. Therefore, the user can easily grasp not only whether leap second information has been acquired, but also whether date information and positioning information have been received, and can perform a receiving operation as necessary. For example, in the reception process after moving across a time zone by an airplane or the like, if the positioning information has not been received, the time difference of the current location cannot be acquired, so the time of the current location cannot be displayed. In this case, if the user displays the reception result and the level is 0 to 3, the user knows that the positioning information has not been acquired, and performs a necessary response, for example, a receiving process for acquiring the positioning information, or a time difference setting. Can be processed manually.

[Modification]
The present invention is not limited to the above embodiments.
For example, the GPS wristwatch 1 may have the functions of the first and second embodiments, execute the process of the first embodiment at the time of automatic reception, and execute the process of the second embodiment at the time of manual reception.
Further, the leap second information may be surely acquired by performing the processing of the second embodiment even during automatic reception.

  In the first embodiment, if it is determined in S19 that the leap second information cannot be acquired within a certain time and the reception process is terminated, the next time based on the page information when the time information is acquired in the reception process. The periodic reception time may be adjusted, and at the next reception, reception may be started at a time at which leap second information can be acquired within a certain time.

  Further, in the first to third embodiments, the multi-hand timepiece having the small clock 4 in addition to the normal hand 3 has been exemplified, but the present invention is not limited to the small clock 4 but may be a liquid crystal display or electronic paper. The present invention may be applied to a combination timepiece having the display device described above or a digital timepiece without a pointer. In particular, when a display device is provided, the reception result may be displayed on the display device.

  Further, the reception result display means 24 of the third embodiment displays the reception results in five stages of levels 0 to 4. However, as the reception result display means, at least time information has been received and acquired. Can be displayed, and the number of reception result display stages may be set as appropriate in the implementation.

The electronic timepiece of the present invention is not limited to a wristwatch, and may be a pocket watch, and can be widely used for various electronic timepieces that are carried and used.
Furthermore, the electronic timepiece may be various electronic devices having other functions in addition to the clock function. For example, it can be widely used for various electronic devices such as a mobile phone having a GPS function and a clock function, and a navigation device.

  Moreover, although each above-mentioned embodiment demonstrated the GPS satellite, this invention is not only a GPS satellite but other global navigation satellite systems, such as Galileo (EU), GLONASS (Russia), Hokuto (China). (GNSS), a geostationary satellite such as SBAS, or a position information satellite that transmits a satellite signal including time information, such as a quasi-zenith satellite.

It is the schematic which shows the wristwatch with GPS which concerns on this invention. It is the schematic which shows the circuit structure of the wristwatch with GPS. It is a figure explaining the structure of a satellite signal. It is a figure explaining the structure of the page containing the leap second information of a satellite signal. It is a block diagram which shows the structure of the control part of 1st Embodiment. It is a flowchart which shows the reception process of 1st Embodiment. It is a flowchart which shows the reception process of 2nd Embodiment. It is a block diagram which shows the structure of the control part of 3rd Embodiment. It is a figure which shows an example of the reception result display state of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... GPS wristwatch, 3 ... Hand, 4 ... Small clock, 5 ... GPS satellite, 10 ... GPS device, 20 ... Control part, 21 ... Time information acquisition means, 22 ... Leap second information acquisition means, 23 ... Time correction means 24 ... Reception result display means, 30 ... Storage device, 40 ... Time display device.

Claims (9)

A receiving unit for receiving a satellite signal transmitted from the position information satellite;
An electronic timepiece comprising a control unit for controlling the operation of the receiving unit,
The controller is
Time information acquisition means for driving the receiver to acquire time information;
When the time information is acquired by the time information acquisition means, it is determined whether leap second information can be acquired within a certain time from that point, and the reception unit is driven when it is determined that acquisition is possible Leap second information acquisition means for acquiring leap second information and stopping driving of the receiving unit when it is determined that acquisition is not possible ;
Time correction means for correcting the display time based on the acquired time information and leap second information;
An electronic timepiece characterized by comprising: The electronic timepiece according to claim 1,
The time information acquisition means can acquire date information in addition to time information,
The leap second information acquisition means includes
Only when the date information acquired by the time information acquisition means is included in a preset leap second update time, it is determined whether leap second information can be acquired within the predetermined time, and can be acquired. An electronic timepiece characterized in that when it is determined, the receiving unit is driven to acquire leap second information, and when it is determined that acquisition is not possible, the driving of the receiving unit is stopped . The electronic timepiece according to claim 1 or 2,
The satellite signal is composed of a plurality of pages, and the leap second information is included in a predetermined page,
The leap second information acquisition unit detects a page being received when the time information is acquired by the time information acquisition unit, and a time until a page including the leap second information is transmitted from the received page To determine whether leap second information can be acquired within the predetermined time. The electronic timepiece according to any one of claims 1 to 3,
If the leap second information acquisition means determines that leap second information cannot be acquired within the predetermined time, it stops driving the reception unit and drives the reception unit when the leap second information can be acquired. An electronic timepiece characterized by acquiring leap second information. The electronic timepiece according to any one of claims 1 to 3,
When the leap second information acquisition unit determines that leap second information cannot be acquired within the predetermined time, the leap second information acquisition unit stops driving the reception unit and ends the reception process. The electronic timepiece according to any one of claims 1 to 5,
A reception result display means for displaying the reception result;
The reception result display means includes
An electronic timepiece configured to be able to display whether or not time information has been received and acquired. The electronic timepiece according to claim 6,
The reception result display means includes
When time information is not received,
When at least time information is received and leap second information and positioning information are not received,
When at least time information and leap second information are received and positioning information is not received,
When receiving at least time information, leap second information, positioning information,
An electronic timepiece characterized in that it can be displayed separately. The electronic timepiece according to claim 7,
The reception result display means includes
An electronic timepiece that moves a pointer and displays each reception result according to the indicated position. A time correction method for an electronic timepiece comprising a receiver for receiving a satellite signal transmitted from a position information satellite,
A time information acquisition step of acquiring time information by driving the receiving unit;
When the time information is acquired in the time information acquisition step, it is determined whether leap second information can be acquired within a certain time from that time, and the reception unit is driven when it is determined that acquisition is possible. Leap second information acquisition step of acquiring leap second information and stopping the driving of the receiving unit when it is determined that acquisition is not possible ;
A time correction step of correcting the display time based on the acquired time information and leap second information;
A time correction method for an electronic timepiece, comprising:

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