JP2011226933A - Time display device and time display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption when moving back to an original area or moving to the same area more than once, by capturing a position information satellite efficiently in a short time through utilization of a past reception result, even if the area has a time difference.SOLUTION: Area satellite information for capturing a position information satellite is recorded in an area page different for each area in such a manner that area information, day and month, time, the satellite and frequency deviation are related to each other, and a more valid area page is selected according to an area setting from outside.

Description

  The present invention relates to a clock that corrects and displays the time of an internal clock based on time information included in radio waves from a satellite such as a position information satellite.

  The main purpose of the position information satellite is to obtain the position of the reception point from the position of a plurality of position information satellites and the delay time of radio waves from those position information satellites. However, position information satellites are equipped with extremely accurate clocks such as atomic clocks, and there are many clocks that display accurate time by correcting the time of the internal clock based on the time information from the position information satellite. It is disclosed. (For example, see Patent Document 1)

  In Patent Document 1, the positioning satellite that has been successfully received in each time zone and the frequency deviation due to the Doppler effect are stored for each time zone, and the positioning satellite and frequency that have been successfully received in the past in a predetermined time zone. A method of acquiring a position information satellite in a short time from the deviation is disclosed.

  Furthermore, in Patent Document 1, the received data to be stored is associated with the date, and the received data is effectively utilized even if the date changes by advancing the time by 4 minutes per day at the time of storage and reading. A method is also disclosed.

  An example of a conventional “capture satellite table” for this purpose is shown in FIG. Here, the time count corresponds to the time when 360 is defined as one day. That is, one day is 0 to 359 every 4 minutes, and one day is corrected as one time count. This correction is because the time when the position information satellite comes to the same position when viewed from the earth is advanced by 4 minutes per day. Therefore, the “acquisition satellite table” specifies the time count corresponding to the reference date and time.

  For each time count, the hygiene number of the position information satellite captured in the past and the frequency deviation are recorded. By using the satellite number and the frequency deviation stored in the time count corresponding to the date and time received by this “capture satellite table”, the position information satellite can be quickly captured.

  However, the invention disclosed in Patent Document 1 is based on the premise that the clock is fixed at a specific place, and when moving to an area with a time difference, the problem is that the stored data cannot be used. was there.

  Therefore, Patent Document 2 discloses a method of using “capable GPS satellite data” indicating satellites that can be captured in each time zone as shown in FIG. However, since information about latitude is not included, the “capable GPS satellite data” cannot be associated with a frequency deviation. Therefore, there is a problem that a longer time and a larger amount of electric power are consumed for capturing.

Japanese Patent Laid-Open No. 10-82875 JP 2008-39567 A

  Therefore, in the present invention, even when moving to an area with a time difference, when returning to the original area or moving to the same area multiple times, the position information satellite can be efficiently used in a short time by utilizing past reception results. It is intended to reduce power consumption by capturing.

  In order to solve the above-described problem, a time display device according to the present invention includes a standard time receiving unit that receives a radio wave from a satellite to obtain a standard time, and generates an internal time by counting a reference clock that is generated internally, and the standard time. RTC means for correcting the internal time, time display means for displaying the time according to the internal time, reception information for receiving the reception result of the standard time receiving means, the date and time, the satellite, and the frequency deviation are stored in association with each other. Storage means, expected time calculation means for calculating an expected time when the frequency deviation is expected to be close to the reception result stored in the reception storage means, control means for managing the overall status and sequence, and operation It consists of a regional input means that performs a user interface with a person.

  In addition, the time display method according to the present invention includes a region setting step for setting region information, a standard time receiving step for obtaining standard time by receiving radio waves from a satellite, and a region information and a month for receiving a reception result in the standard time receiving step. A reception storage step for recording the date, time, satellite, and frequency deviation in association with each other, a reference clock generation step for generating a reference clock from which internal time is generated, and generating an internal time by counting the reference clock RTC process for correcting the internal time according to the standard time, a time display process for displaying the time according to the internal time, and an expected time at which the frequency deviation can be expected to be received from the reception result stored in the reception storage process. It was made to operate according to the expected time calculation process.

  In the time display device and the time display method according to the present invention, even when moving to an area with a time difference, when returning to the original area or moving to the same area multiple times, it is desired to use the past reception result. By efficiently capturing the position information satellite in a short time with a frequency deviation expected to be high, power consumption can be reduced.

1 is a block diagram showing a preferred embodiment of a time display device according to the present invention. Process flow diagram of time display method according to the present invention Flow chart of regional setting process according to the present invention Conceptual diagram of regional satellite information according to the present invention Conceptual diagram of expected time according to the present invention The conceptual diagram which shows operation | movement of the regional page creation process which concerns on this invention External view of time display means according to the present invention The figure which shows an example of the acquisition satellite table of the conventional time display apparatus The figure which shows another example of the acquisition satellite table of the conventional time display apparatus.

  In order to solve the above-described problem, a time display device according to the present invention includes a standard time receiving unit that receives a radio wave from a satellite to obtain a standard time, and generates an internal time by counting a reference clock that is generated internally, and the standard time. RTC means for correcting the internal time, time display means for displaying the time according to the internal time, reception information for receiving the reception result of the standard time receiving means, the date and time, the satellite, and the frequency deviation are stored in association with each other. Storage means, expected time calculation means for calculating an expected time when the frequency deviation is expected to be close to the reception result stored in the reception storage means, control means for managing the overall status and sequence, and operation It consists of a regional input means that performs a user interface with a person.

  In addition, the time display method according to the present invention includes a region setting step for setting region information, a standard time receiving step for obtaining standard time by receiving radio waves from a satellite, and a region information and a month for receiving a reception result in the standard time receiving step. A reception storage step for recording the date, time, satellite, and frequency deviation in association with each other, a reference clock generation step for generating a reference clock from which internal time is generated, and generating an internal time by counting the reference clock RTC process for correcting the internal time according to the standard time, a time display process for displaying the time according to the internal time, and an expected time at which the frequency deviation can be expected to be received from the reception result stored in the reception storage process. It was made to operate according to the expected time calculation process.

  The time display device according to the present invention will be described in detail with reference to the drawings. In the following description of the present embodiment, <> is used as a large heading, [] is used as a small heading, and () is used as a small heading.

<Time display device / time display method>
FIG. 1 shows a block configuration of a preferred embodiment of a time display device 101 according to the present invention. FIG. 2 is a process flow diagram showing an example of the operation of the time display method according to the present invention.

[Region input means / region setting process]
In order to operate the time display device 101 according to the present invention, it is first necessary to set a region to be used in the region setting step 201. In addition, when the area information is set from the outside of the time display device, the area used in the area setting step 201 is set. FIG. 3 shows an example of the process flow of the region setting process 201.

(Regional input process)
In the region input step 301, the region information is set using the region input means 108 by an input from the outside of the time display device. The area input means 108 is a user interface for inputting area information to the time display device 101 and is realized by using a general-purpose CPU input / output port, but may be realized by a dedicated circuit. The region information may be a region name, but in this embodiment, the region is represented by a time difference. Since the time difference does not include information on latitude, the frequency deviation due to the Doppler effect when moving in a region is generally not determined. However, people who frequently move to different areas often move to the same area repeatedly, such as moving to an overseas branch or moving between their home country and their current address, and relatively rarely move to different longitudes of the same latitude. Focusing on this, I expressed the area by time difference. When returning to the same area, setting the time difference makes it possible to know not only the time that can be supplemented from the past reception results but also the frequency deviation.

(Regional page creation process)
FIG. 4 shows an example of the regional satellite information 401. The regional satellite information 401 stores information related to the supplement of the location information satellite for each region, and includes one or more regional pages 402 corresponding to the region.

  In the region page creation step 303, when the set region is the first region, a new region page 402 of the reception result is secured, and initial values are written for the newly set time difference and the standard time of the final reception information.

  The standard time field of the last received information of the new region page 402 is blank when the time display device is used for the first time. However, when changing the region from another region, in order to be able to calculate the expected time with a high probability of being received, the value is calculated and written according to Equation 2 from the standard time of the last received information in the other region. .

2) (New final reception standard time) = (Final reception standard time in other areas) + (New time difference-Time difference in other areas)

  This is because, as shown in FIG. 6, satellites tend to approach closer to an earlier standard time in a region with a smaller time difference. Incidentally, FIG. 6 shows the relationship between the standard time of a certain day and the longitudes of the three satellites. The horizontal axis is standard time of a certain day, and the vertical axis is longitude. In the figure, diagonal straight lines, dotted lines, and alternate long and short dash lines represent different satellites. Since the actual orbit of the satellite has an inclination angle with respect to the equator plane, the relationship between time and longitude is not a straight line, but in the present embodiment, it is simplified and linearly approximated.

  The frequency deviation and signal strength fields remain blank because they have not been received.

(Regional page selection process)
In the region page selection step 304, the region page 402 corresponding to the region input in the region input step 301 is selected and validated. When the time display device is used for the first time, the region page 402 that has not been stored except for the time difference is selected. For the validated regional page, the reception result is written by the reception storage means in the reception storage step, and is read out in the expectation time calculation step.

  When the region page 402 is selected, an expected time calculation step to be performed later is executed to obtain an expected time.

[Standard time receiving means / standard time receiving process]
In the standard time receiving means 103 or the standard time receiving step 202, when the region information is set in the region setting step 201 or when the current time and the expected time coincide with each other in the adjustment time determination 208, the time included in the radio wave from the position information satellite is related. Navigation message data is received, and Greenwich Mean Time is calculated from the received navigation message data.

  However, if the position information satellite that can be captured, such as the initial stage, or the frequency deviation is unknown, the position information satellite is not a geostationary satellite and is not always in a position where radio waves can be received. Further, there is a frequency deviation of about 5,000 Hz due to the Doppler effect accompanying the movement of the position information satellite. For this reason, the position information satellite is captured by measuring the radio field intensity for the combination of the assumed position information satellite and frequency deviation, and then the navigation message data relating to the time is received and the standard time is calculated from the received navigation message data. To do.

  In addition, when moving to the first area, it is captured at an expected time with a high possibility of capture, but the frequency is unknown and capture is performed while changing the frequency.

  If the area has not been changed, it is captured in a short time at a frequency with a proven track record at the expected time.

[Reception storage means / reception storage process]
In the reception storage means 104 or the reception storage step 203, when the position information satellite is captured by the standard time reception means 103 or the standard time reception step 202 and the navigation message data relating to the time is successfully received, the reception result is stored in the local satellite information 401. Store in the region page 402 corresponding to the received region. However, if the signal strength is weaker than the stored value, the regional page may not be updated.

  An example of the regional satellite information 401 for storing the reception result is shown in FIG. As shown in FIG. 4, the reception result is stored in a different region page 402 for each region of the regional satellite information 401. In each area page 402, area information, reception date, reception time, frequency deviation, and signal intensity are stored in association with each other. Since the reception result is configured to be stored for each satellite, the frequency deviation and the signal intensity are not stored for the unreceived satellite.

  The reception storage means is realized by a general-purpose CPU and a general-purpose memory, but may be realized by a dedicated logic circuit or a register.

[RTC means / reference clock generation process / RTC process]
The RTC means 105 generates a reference clock internally in the reference clock generation step 204. In the RTC step 205, the reference clock generated in the reference clock generation step 204 is counted to generate an internal time so as to coincide with Greenwich Mean Time, and the internal time is corrected based on the standard time from the standard time receiving means 103.

[Expected time calculation means / expected time calculation process]
In the expected time calculation means 106 or the expected time calculation step 207, reception is expected with the same frequency deviation from the reception result stored in the regional page 402 that is enabled corresponding to the current region of the regional satellite information 401. The expected time is calculated by equation (1).

(Equation 1) Expected time = last reception time−24 hours · (expectation date−last reception date) /365.24

  Equation 1 corresponds to the period of the position information satellite and is corrected so that the elapsed time from the last reception time is 24 hours earlier per year. However, when the calculation result of Equation 1 is after 24:00, 24 hours are subtracted, and when it is minus, 24 hours are added.

  FIG. 5 shows, as an example, the calculation result of the expected time corresponding to the currently valid regional page 402 at the top of the regional satellite information 401 in FIG. As described above, the calculation of the expected time is performed for all the position information satellites in which the reception results are stored.

  The expectation time calculation means 106 is calculated by a general-purpose CPU, but may be calculated by a dedicated logic circuit.

[Time display means / time difference conversion process / time display process]
The time display means 107 converts the standard time internal time to the local time in the time difference conversion step 209, and displays the local time in the time display step 210. The time display means displays the digital time as shown in FIG. 7a. However, the time may be displayed by a long hand and a short hand as shown in FIG. 7b.

[Control means]
The control means 109 manages the overall status and process. The control means 109 is realized using a CPU, but it goes without saying that a sequencer or the like may be used.

  The description of the operation of the control unit 109 is included in the description of each unit and each process described above, but the operation that has not been described will be described below.

(Calculation time judgment)
In the calculation time determination 206, the expected time calculation step 207 is executed when the internal time is 0:00 AM and 0 seconds, and the process moves to the adjustment time determination 208 for other times. In this embodiment, the expected time calculation step 207 is executed once a day, but this is not a limitation.

(Adjustment time judgment)
In the adjustment time determination 208, the expected time calculated by the expected time calculation means 106 in the expected time calculation step 207 is collated with the internal time from the RTC means 105, and if they match, the standard time reception step 103 is executed. If so, the process proceeds to the time difference conversion step 209. When the standard time reception step 202 is executed, the satellite reception is started from a proven frequency deviation or a nearby frequency with respect to the satellite whose internal time matches the expected time.

  However, from the viewpoint of reducing power consumption, even when the expected time and the internal time match, if the predetermined time has not elapsed since the last reception, the accuracy of the internal time is sufficiently high, so the standard time reception step 202 is executed. Instead, the process shifts to the time difference conversion step 209.

  In addition, when reception is not possible at the expected time, the standard time reception process 202 is executed at another time. Furthermore, when there are many unreceived columns of regional satellite information, the standard time reception process 202 is periodically executed even when the expected time does not match the internal time.

(Continuous operation)
Note that the reference clock generation step 204, the RTC step 205, the time difference conversion step 209, the time display step 210, the calculation time determination 206, and the adjustment time determination 208 themselves are continuously operated.

<Other implementation methods>
The example in the case where the internal time is converted to the local time and displayed so as to be close to the Greenwich Mean Time has been described above, but the time difference is corrected as appropriate even if another time such as the local clock is generated, for example. Just do it. Other times may be used similarly for the standard reception time of local satellite information and the expected time.

Moreover, although the last reception standard time was made to correspond to each satellite by the regional satellite information as described above, a satellite that can be received for each time zone may be made to correspond. The same applies to the expected time.

101 Time display device 103 Standard time reception means 104 Reception storage means 105 RTC means 106 Expectation time calculation means 107 Time display means 108 Regional input means 109 Control means 201 Regional setting process 202 Standard time reception process 203 Reception storage process 204 Reference clock generation process 205 RTC Step 207 Expected time calculation step 210 Time display step 401 Regional satellite information 402 Regional page

Claims (2)

In the time display device that corrects the time based on the time information of radio waves coming from the satellite,
A standard time receiving means for obtaining standard time by receiving radio waves from a satellite;
RTC means for generating an internal time by counting a reference clock generated internally and correcting the internal time according to the standard time;
Time display means for displaying the time according to the internal time;
Receiving storage means for storing the area information, the date, the time, the satellite, and the frequency deviation received from the reception result of the standard time receiving means;
Expected time calculation means for calculating an expected time at which the frequency deviation is expected to be close to the reception result stored in the reception storage means;
Control means for managing the overall status and sequence;
A time display device having a regional input means for performing a user interface with an operator. In the time display method that corrects the time based on the time information of radio waves coming from the satellite,
Region setting process for setting region information;
A standard time reception process for obtaining standard time by receiving radio waves from a satellite;
A reception storage step of recording the area information, the date, the time, the satellite, and the frequency deviation associated with the reception result in the standard time reception step;
A reference clock generation process for generating a reference clock from which internal time is generated;
An RTC process for generating an internal time by counting a reference clock and correcting the internal time according to the standard time;
A time display process for displaying the time according to the internal time;
An expected time calculation step of calculating an expected time at which a frequency deviation can be expected to be received from the reception result stored in the reception storage step, and
A time display method, wherein the standard time receiving step determines a satellite and a time to be received based on the expected time.

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