JP6953860B2 - Electronic clock, date and time information acquisition method and program - Google Patents

Description

The present invention relates to an electronic clock, a date and time information acquisition method and a program.

Conventionally, there is a technique for receiving radio waves from a positioning satellite in an electronic clock to acquire date and time information. Radio waves from the positioning satellite can be received regardless of the location on the earth if the positioning satellite is visible. As such radio waves, those transmitted from positioning satellites (GPS satellites) related to GPS (Global Positioning System) in the United States are widely used.

On the other hand, there is a problem that the power consumption related to the reception of radio waves from the positioning satellite and the decoding of the date and time is significantly larger than the operation related to the counting and display of the normal date and time, and the load on the battery of the electronic clock is large. On the other hand, conventionally, there is a technique of receiving only the information necessary for acquiring an accurate date and time in a short time in combination with the information of the date and time counted by the electronic clock. In addition, there is a technique of generating a code string that is expected to be received based on the counting date and time in the electronic clock, and acquiring the date and time according to the matching status between the assumed code string and the actually received code string (patented). Document 1).

JP-A-2017-9333

However, if only the signal (navigation message) transmitted by the radio wave from one positioning satellite is used, the accuracy will be sufficient when the radio wave reception strength is low or when it is necessary to distinguish between similar code strings. There is a problem that it becomes difficult to distinguish and it is not possible to efficiently and surely obtain an accurate date and time.

An object of the present invention is to provide an electronic clock, a date and time information acquisition method, and a program capable of acquiring an accurate date and time more efficiently and reliably.

In order to achieve the above object, the present invention
A receiver that receives radio waves from positioning satellites,
A timekeeping section that counts the current date and time,
Control unit and
With
The receiving unit includes a transmission radio wave including a signal from the first positioning satellite and a transmission radio wave including a signal from a second positioning satellite in which information is transmitted in a format different from the signal from the first positioning satellite. And can be received,
The first cycle related to the transmission of date and time information in the signal from the first positioning satellite is shorter than the second cycle related to the transmission of date and time information in the signal from the second positioning satellite.
When the maximum estimated deviation amount of the date and time counted by the time measuring unit deviates from the reference width corresponding to the first cycle, the control unit is expected to receive from the first positioning satellite. A assumed code string of 1 and a second assumed code string expected to be received from the second positioning satellite are generated, and at least a part of each of the first assumed code string and the second assumed code string is It is an electronic clock characterized by identifying the current date and time based on the received timing.

According to the present invention, there is an effect that an accurate date and time can be acquired more efficiently and reliably in an electronic clock.

It is a block diagram which shows the functional structure of the electronic clock of this embodiment. It is a figure explaining the format of the signal (navigation message) transmitted by the radio wave from the GPS satellite. It is a figure which shows the format of the signal (navigation message) transmitted by the radio wave from the GLONASS satellite. It is a flowchart which shows the control procedure of the date and time correction control processing executed by the electronic clock of this embodiment. It is a flowchart which shows the control procedure of the satellite radio wave reception control processing executed in the satellite radio wave reception processing unit. It is a flowchart which shows the control procedure of the code matching process called in the satellite radio wave reception control process. It is a flowchart which shows another example of the control procedure of a code collation process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a functional configuration of the electronic clock 1 of the present embodiment.

The electronic clock 1 includes a microcomputer 40, a satellite radio wave reception processing unit 50, an antenna A1, an operation reception unit 61, a display unit 62, a measurement unit 63, a ROM 64 (Read Only Memory), a power supply unit 70, and the like. Be prepared.

The microcomputer 40 controls the overall operation of the electronic clock 1. The microcomputer 40 includes a CPU 41 (Central Processing Unit), a RAM 43 (Random Access Memory), an oscillation circuit 46, a frequency dividing circuit 47, a timekeeping circuit 48 (timekeeping unit), and the like.

The CPU 41 performs various arithmetic processes to perform a control operation. As the control operation, in addition to various control operations related to normal date and time display operation, acquisition of current date and time information, and correction of the date and time counted by the timekeeping circuit 48, operations according to various functions of the electronic clock 1, for example, alarm notification. Functions, timer functions, stopwatch functions, etc. may be included.

The RAM 43 provides the CPU 41 with a working memory space and stores temporary data. The RAM 43 displays the current date and time (local time) in the set world region such as the current position, and the local time setting 432 including the time zone setting and daylight saving time setting when using it, that is, the time difference information from the UTC date and time and Information related to the location (city) is stored. The local time setting 432 includes information on the presence / absence and type of standard radio waves that can be received at the position (city).
The host control unit 401 is configured by the CPU 41 and the RAM 43.

Further, the RAM 43 stores and holds the date and time information acquisition history information 431. The date and time information acquisition history information 431 includes information on the acquisition destination of the current date and time information acquired from the outside in the past and the acquisition date and time. The information on the acquisition destination and the acquisition date and time stored in the date and time information acquisition history information 431 is stored at least once, but may be stored a plurality of times. Further, the date / time information acquisition history information 431 may include information when an attempt to acquire the information fails.

The oscillation circuit 46 generates and outputs a signal (clock signal) having a predetermined frequency, here, for example, 32.768 kHz. For example, a crystal oscillator or the like is used to generate a clock signal. This crystal oscillator may be externally attached to the microcomputer 40. The frequency of the clock signal output from the oscillation circuit 46 changes depending on the external environment, mainly the temperature.

The frequency dividing circuit 47 outputs a frequency dividing signal obtained by dividing the clock signal input from the oscillation circuit 46 by a set frequency dividing ratio. The frequency division ratio setting may be changed by the CPU 41.
The timekeeping circuit 48 counts and holds the current date and time (time and date) by counting a signal having a predetermined frequency (which may be the same frequency as the clock signal) input from the frequency dividing circuit 47. The date and time counting accuracy by the timekeeping circuit 48 depends on the accuracy of the clock signal from the oscillation circuit 46 described above, that is, the date and time counted by the timekeeping circuit 48 depends on the time counting time (that is, the number of times the input signal is counted). The deviation from the exact date and time may change accordingly. The CPU 41 can correct the counted date and time based on the current date and time acquired by the satellite radio wave reception processing unit 50. Since the amount of deviation in the counting date and time by the timekeeping circuit 48 is almost constant under certain conditions (mainly temperature), the size expected as the maximum value (maximum estimated deviation amount) is obtained here with the exact date and time last time. As it is proportional to the elapsed time since then, it is determined in the form of, for example, 0.5 seconds × the number of elapsed days. The actual deviation amount is one of the range of the maximum estimated deviation amount (here, within the range of ± maximum estimated deviation amount) according to the temperature transition of the time measuring circuit 48 and the like.

The satellite radio wave reception processing unit 50 can receive transmission radio waves from positioning satellites related to satellite positioning systems (GNSS; Global Navigation Satellite System) such as GPS (Global Positioning System) in the United States and GLONASS (Global Navigation Satellite System) in Russia. Yes, a reception operation for processing these received radio waves is performed to acquire information on the current date and time and the current position, and the information requested by the CPU 41 is output to the CPU 41 in a predetermined format. The satellite radio wave reception processing unit 50 includes a reception unit 51, a module control unit 52, a storage unit 53, and the like.

The receiving unit 51 receives and detects the transmitted radio wave from the positioning satellite to be received, performs acquisition processing for identifying the positioning satellite and identifying the phase of the transmitted signal, and is based on the captured identification information and phase of the positioning satellite. The transmission signal (navigation message) is continuously demodulated and acquired by tracking the transmission radio wave from the positioning satellite.

The module control unit 52 includes a CPU and the like, and performs various controls related to the operation of the satellite radio wave reception processing unit 50. The module control unit 52 causes the receiving unit 51 to receive radio waves from the positioning satellite at an appropriate timing according to the instruction from the microcomputer 40, performs processing related to the acquisition of the current date and time, acquires necessary information, and obtains the necessary information. Identify and calculate the current position (that is, positioning). The module control unit 52 may have a dedicated hardware circuit as a configuration for collating the assumed code string with the received code string and performing an operation related to the collation result when performing the predicted reception acquisition described later.

The storage unit 53 stores reception control information 531 such as various setting data and reception information, and a program related to control executed by the module control unit 52 in the satellite radio wave reception processing unit 50. The setting data includes, for example, format data of the navigation message of each positioning satellite, reference data for determining the reception level, and the like. Further, the received information includes, for example, the acquired predicted orbit information (Almanac) of each positioning satellite. In addition, in the setting data, in order to correct the deviation related to leap seconds between the date and time transmitted from the GPS positioning satellite (referred to as GPS satellite; the first positioning satellite) and the UTC date and time (Agreement World Time). The value of, the cycle number of WN, the leap year cycle number of the positioning satellite related to GLONASS (referred to as GLONASS satellite; the second positioning satellite), and the like are included. The GPS satellites referred to here include complementary satellites such as Michibiki, which transmit navigation messages in substantially the same format at the same transmission frequency as GPS. Further, when complementary satellites that transmit navigation messages in substantially the same format as the GLONASS satellite become available, these complementary satellites are included in the GLONASS satellite.

The operation reception unit 61 receives an external input operation such as a user operation. The operation reception unit 61 includes a push button switch crown and the like, and outputs an operation signal corresponding to each operation of pressing the push button switch and pulling out, rotating, and pushing back the crown to the CPU 41. Alternatively, the operation reception unit 61 may have a touch sensor or the like.

The display unit 62 displays various information based on the control of the CPU 41 (microcomputer 40). The display unit 62 includes a display driver 622, a display screen 621, and the like. The display screen 621 performs digital display by, for example, a segment system, a dot matrix system, or a liquid crystal display screen (LCD) based on a combination thereof. Alternatively, the display unit 62 may have a configuration capable of displaying by a pointer and a stepping motor that rotates the pointer instead of the digital display by the display screen 621. The display driver 622 outputs a drive signal for displaying on the display screen 621 to the display screen 621 based on the control signal from the CPU 41.

The measurement unit 63 measures the physical quantity to be measured and outputs the physical quantity or the comparison result between the physical quantity and the reference value to the CPU 41. The measuring unit 63 includes a light amount sensor 631.

The light amount sensor 631 is provided, for example, in parallel with the display screen of the display unit 62, and measures the amount of light emitted from the outside. As the light amount sensor 631, for example, a photodiode is used. The light amount sensor 631 outputs an electric signal (voltage signal or current signal) according to the amount of incident light, and this electric signal is digitally sampled by an ADC (analog / digital converter) (not shown) and input to the CPU 41.

The ROM 64 stores a program 641 for the CPU 41 to execute a control operation, initial setting data, and the like. The ROM 64 may have a non-volatile memory such as a flash memory capable of rewriting and updating data in addition to or in place of the mask ROM. Program 641 includes a control program for acquiring the current date and time.

Of the above, the host control unit 401 (CPU 41, RAM 43) and the module control unit 52 form a control unit (computer) in the electronic clock 1 of the present embodiment.

Next, a case where the current date and time is acquired by the operation of the satellite radio wave reception processing unit 50 will be described in more detail.

FIG. 2 is a diagram illustrating a format of a signal (navigation message) transmitted by radio waves from GPS satellites.
In GPS, a total of 25 pages of frame data in units of 30 seconds are transmitted from each GPS satellite, and all the data is output at a cycle of 12.5 minutes. In GPS, a C / A code unique to each GPS satellite is used, and this C / A code is repeated at a cycle of 1 msec with 1023 codes (chips) arranged at 1.023 MHz. Since the head of this chip is synchronized with the internal clock of the GPS satellite, by detecting this phase shift for each GPS satellite, the propagation time, that is, the phase shift according to the distance from the GPS satellite to the current position (Pseudo distance) is detected.

Each frame data is composed of 5 subframes (6 seconds each; first cycle). Further, each subframe is composed of 10 words (code blocks, 0.6 seconds each, in order WORD1 to WORD10). Each word is 30 bits long (ie, consists of 30 binary codes).
The data formats of WORD1 and WORD2 are the same for all subframes. That is, the contents of WORD1 and WORD2 can be acquired every 6 seconds in all subframes. In WORD1, a telemetry word (TLM Word) is transmitted. The telemetry word contains an 8-bit fixed code string, the preamble, followed by a 14-bit telemetry message (TLM Message), followed by a 1-bit Integrity Status Flag and a 1-bit spare bit. , A 6-bit parity code string (parity check code) is arranged. In WORD2, a handover word (HOW) is transmitted. In HOW, following the 17-bit TOW-Count (also referred to as Z count) indicating the elapsed time within the week, the Alert Flag and the Anti-Spoof Flag are indicated by 1 bit each. Then, a subframe ID (Subframe-ID) indicating a subframe number (cycle number) is indicated by 3 bits, and a 6-bit parity code string is arranged with 2 bits for matching the parity code string sandwiched between them.

The data after WORD3 differs depending on the subframe. WORD3 of subframe 1 includes a 10-bit WN (week number) at the beginning. Subframes 2 and 3 mainly include ephemeris (precision orbit information), and a part of subframe 4 and subframe 5 transmit ephemeris (predicted orbit information). That is, this information can be acquired once every 30 seconds within the frame. The leap second correction value described above is transmitted once every 12.5 minutes only in frame 4 on the 18th page.

Normally, in order to decipher a navigation message, it is necessary to identify the fixed code string (preamble) included at the beginning of each subframe. Of these, the date and time indicated by TOW-Count in each subframe is the date and time at the beginning of the next subframe.

The information required for the satellite radio wave reception processing unit 50 to obtain the current date and time depends on the magnitude of the deviation that can be included in the date and time counted by the timekeeping circuit 48. If the date and time counted by the timekeeping circuit 48 does not deviate so much that the date or week is different, only TOW-Count is acquired from any of the subframes (the required time is about 2 to 6 seconds), and the timekeeping circuit 48 counts. Accurate date and time can be obtained by combining with the date and time (partial reception acquisition). Even in the case of partial reception acquisition, here, by receiving up to WORD3 of one subframe, WN included in WORD3 of subframe 1 may also be received depending on the reception timing. If there may be a large difference in the date and time counted by the timekeeping circuit 48, the WN of the subframe 1 is also received, that is, by acquiring all the data related to the date and time from the navigation message (about 3 to 30 seconds). , The date and time is acquired from the information acquired from the GPS satellite without considering the counting date and time of the timekeeping circuit 48 (full reception acquisition). The "all data related to the date and time" here does not include the correction information related to the correction value of the leap second.

If the difference between the date and time counted by the clock circuit 48 is sufficiently small (± 3 seconds or less with respect to the exact date and time; reference width), the content of the received navigation message, that is, fixed at 8 bits at the beginning of each subframe. A code string (preamble), a 17-bit TOW-Count of the HOW, and a 3-bit subframe ID) can be assumed in advance. In addition, the code of each 1 bit that is not in the set state in the normal transmission state, such as the spare bit included in the telemetry word and HOW, Integrity Status Flag, Alert Flag, and Anti-Spoof Flag, is assumed to be in the reset state. Is also good. In addition, if the positioning satellites Ephemeris and Ephemeris are acquired and held, it is assumed that the same orbit information will be received within the valid period.

Therefore, the date and time indicated by the assumed code string (first assumed code string) generated by the code assumed in advance based on the counting date and time and the estimated deviation amount, and the code string (received code string) that matches the assumed code string. ) Is received (a part of the date and time information; match detection timing) to identify and acquire the current date and time. In this predicted reception, it is not necessary to decode (decode) the code string again at the time of reception, and only the match / mismatch with the assumed code string needs to be determined. Since the navigation message transmitted from the GPS satellite may be code-inverted for each word (30 bits), the inverted code strings may be combined and generated to determine the match / mismatch. The assumed code string may be detected by treating the code string that exactly matches the code string and the code string that completely does not match the assumed code string in the same manner. For example, of the number of codes (collation number) that have been compared and collated, the larger of the number of matches and the number of mismatches is set as the number of matches (≧ number of collations / 2), and the matching timing at which the number of matches satisfies a predetermined probability condition. Can be determined as a match timing. The predetermined probability condition can be, for example, that the identification probability of the code string having the largest number of matches is smaller than the identification probability of the code string having the second largest number of matches.

FIG. 3 is a diagram showing the format of a signal (navigation message) transmitted by radio waves from the GLONASS satellite.
In GLONASS, a total of five frame data are transmitted from each GLONASS satellite in units of 30 seconds (second cycle), and a super frame including all data having a 2.5-minute cycle is configured. The radio wave from the GLONASS satellite is modulated and transmitted at a cycle of 1 msec by a pseudo-random range code transmitted at 500 kbps.

Each frame data is composed of 15 strings (2 seconds each). Each string consists of an array of 85 binary codes transmitted at 50 bps (1.7 sec) and a time mark transmitted at 100 Hz (0.3 sec).

Of the 15 strings, the first 4 strings contain ephemeris data (Immediate Information) and the remaining 11 strings contain almanac data (Non-immediate Information). At the beginning of the 15th string, the fixed code "0" is transmitted, and then the string number m (string No.) is transmitted in 4 bits. Then, after 72-bit information is transmitted, an 8-bit Hamming code is transmitted, and finally a 30-bit time mark is transmitted.

When receiving radio waves from the GLONASS satellite, if the deviation of the timekeeping circuit 48 is assumed to be shorter (± 15 seconds or less) than the frame length (30 seconds), the content of the navigation message of the received frame. Can be partially assumed. In addition to the above-mentioned fixed code "0" and string number m, as shown in the table of FIG. Information determined according to the source GLONASS satellite can be used as the assumed code string (second assumed code string).

Information related to the current date and time includes time tk, day number NT from January 1 of the leap year, day number NA related to almanac data, and cycle number N4 having a 4-year cycle from 1996. The information whose transmission contents are defined in the format includes the number of satellites of Almanac transmitted in each frame P3 (5 satellites in 1-4 frames and 4 satellites in 5 frames) and orbit information satellites transmitted in Almanac. There is a number nA (set in order every two strings) and the like. The information determined according to the received GLONASS satellite includes the slot number n of the GLONASS satellite (a number determined according to the arrangement position in the satellite orbit).

Further, the time mark may be included in the assumed code string. When identifying the time mark, since this code string is transmitted at 100 Hz and has a frequency twice that of the other codes as described above, when identifying the code related to the navigation message from the GLONASS satellite, for example, From the beginning, all the codes may be identified at 100 Hz (in units of 10 msec), and it may be assumed that the same code continues two times for the 50 Hz portion.

For the parity code string of the GPS satellite and the Hamming code of the GRONASS satellite, each bit is received and identified by using the actual received data (received code string) and assuming the position of the received code string in the navigation message. It can be calculated for each and added to the assumed code string. However, if the identification of the received code string itself is inaccurate, the parity code string and Hamming code value will naturally be inaccurate, so the code of each parity value and Hamming code will be calculated and added to the assumed code string. Is limited to the case of the reception intensity (C / N ratio) at which the probability of misidentification of the reception code is sufficiently low.

In this way, since the conceivable code part exists intermittently, as the generated data of the assumed code string, the code indicating the possibility of assumption (assumability determination flag) and the assumption of the possible part are assumed for each bit position. Two bits of the resulting binary code are used. Then, only the conceivable part is collated with the corresponding position of the received code string.

Every time the received code is identified, the received code string is compared and collated with respect to the assumed code string by each relative positional relationship (topological), and the correlation value is obtained at the relative position where both code strings match (described above). Identification probability, etc.) shows the maximum value. Further, for the navigation message acquired from the GPS satellite, the value of TOW-Count shifts by one in the cycle of 6 seconds according to the subframe length, so that the peak of the correlation value occurs in the cycle of 6 seconds. That is, by comparing the maximum correlation value acquired for the relative positional relationship of the width equal to or larger than the subframe length with the second largest correlation value, it is possible to determine with sufficient accuracy which is the correct matching timing. Easy to disappear.

On the other hand, for the navigation message acquired from the GLONASS satellite, the time tk value is similarly deviated by one in a 30-second cycle according to the frame length, and a peak of the correlation value occurs in a 30-second cycle. Therefore, similarly, it is not possible to discriminate between the maximum correlation value acquired and the second largest correlation value with respect to the relative positional relationship having a width equal to or larger than the frame length with sufficient accuracy.

As described above, each positioning satellite alone may not satisfy the probabilistic condition and the normal date and time may not be determined. In addition to the 6-second cycle, for example, when the received code string may contain a misidentified code (when the reception intensity is slightly low), it is sufficient that similar code strings exist at different locations in the subframe. Similarly, it is difficult to determine the correct matching timing when the determination cannot be made with accuracy or when the date and time counted by the timekeeping circuit 48 deviates more than expected and the assumed subframe period is incorrect. In the electronic clock 1 of the present embodiment, in such a case, the assumed reception related to the navigation message of the GPS satellite and the assumed reception related to the navigation message of the GLONASS satellite, which have different cycles of the assumed code strings and the format (style) of the navigation message, By combining, the overall correlation value of the matching timing with a slightly higher correlation value (that is, when it is not the exact matching timing) is greatly reduced, and the exact matching timing is identified.

As a method of integrating the result of the detection of the matching timing between the received code string and the assumed code string from the GPS satellite and the detection of the matching timing between the received code string and the assumed code string from the GRONASS satellite, here, the matching is performed. A method is used in which the number of codes is added and based on the ratio of the number of matching codes to the total number of matching codes, it is collectively determined whether or not the matching timing is common to both the GPS satellite and the GLONASS satellite.

FIG. 4 is a flowchart showing a control procedure by the host control unit 401 (CPU 41) of the date and time correction control process executed by the electronic clock 1 of the present embodiment.
This date / time correction control process is periodically activated under a predetermined condition (for example, when the light amount sensor 631 detects incident light having a predetermined intensity or higher) at intervals of once a day or more, or is operated by the user. It is activated based on the detection of a predetermined input operation to the reception unit 61.

When the date / time correction control process is started, the host control unit 401 (CPU 41) acquires the latest correction date / time by referring to the date / time information acquisition history information 431 (step S401). The host control unit 401 estimates the maximum amount of deviation of the date and time counted by the timekeeping circuit 48 based on the elapsed time from the latest correction date and time to the current date and time counted by the timekeeping circuit 48 (step S402).

The host control unit 401 determines whether or not the estimated amount of deviation is within ± 15 seconds (if the direction of deviation can be specified, within 30 seconds in the direction of deviation; the same applies hereinafter) (step S403). ). If it is determined that the time is within ± 15 seconds (“YES” in step S403), the host control unit 401 outputs an execution command for predictive reception acquisition to the satellite radio wave reception processing unit 50 (step S404). .. Then, the process of the host control unit 401 shifts to step S406.

If it is determined that the estimated deviation amount is not within ± 15 seconds (“NO” in step S403), the host control unit 401 outputs a partial reception acquisition execution command to the satellite radio wave reception processing unit 50. (Step S405). Then, the process of the host control unit 401 shifts to step S406.
If there is no history data in the date / time information acquisition history information 431, such as when the system is started for the first time or when the battery is restarted after the battery runs out, or when the date and time have been corrected by the user's manual operation most recently, the host control unit In step S405, in step S405, full reception acquisition is selected instead of partial reception acquisition, and an execution command is output to the satellite radio wave reception processing unit 50.

When the process proceeds to step S406, the host control unit 401 listens for the result input from the satellite radio wave reception processing unit 50 and determines whether or not the date and time acquisition is successful (step S406). If it is determined to be successful (“YES” in step S406), the host control unit 401 corrects the counting date and time of the timekeeping circuit 48 (step S407). Then, the process of the host control unit 401 shifts to step S408. If it is determined that the date and time acquisition was not successful (“NO” in step S406), the process of the host control unit 401 proceeds to step S408.

When the process shifts to the process of step S408, the host control unit 401 updates the date / time information acquisition history information 431 (step S408). Then, the host control unit 401 ends the date / time correction control process.

FIG. 5 is a flowchart showing a control procedure by the module control unit 52 of the satellite radio wave reception control processing executed by the satellite radio wave reception processing unit 50 of the electronic clock 1 of the present embodiment.

In this satellite radio wave reception control process, which is an embodiment of the date / time identification step (date / time identification means) of the date / time information acquisition method of the present invention, a command for predictive reception acquisition is input from the host control unit 401 in the above date / time correction control process. Will be started if The host control unit 401 transmits the date and time counted by the timekeeping circuit 48 to the module control unit 52 together with this command.

When the satellite radio wave reception control process is started, the module control unit 52 acquires the amount of deviation of the counting date and time of the timekeeping circuit 48 from the host control unit 401 (step S101). Alternatively, the module control unit 52 estimates the amount of deviation in the counting date and time based on the acquisition history information of the date and time information acquired from the host control unit 401 or held by itself, that is, the elapsed time from the previous date and time acquisition. Calculate the value.

The module control unit 52 determines whether or not the deviation amount is within ± 3 seconds (step S102). If it is determined that the time is within 3 seconds (“YES” in step S102), the module control unit 52 considers a deviation of ± 3 seconds from the assumed code string assumed to be received from the GPS satellite. (Step S113). The module control unit 52 starts the reception operation by the reception unit 51 and performs the radio wave capture operation from the GPS satellite (step S114). Then, the process of the module control unit 52 shifts to step S105.

If it is determined that the deviation amount is not within ± 3 seconds (“NO” in step S102), the module control unit 52 sets the assumed code sequence that is assumed to be received from the GPS satellite and the GLONASS satellite, respectively. It is generated with a length considering a deviation of 15 seconds (step S103). The module control unit 52 starts a reception operation by the reception unit 51 and performs a radio wave capture operation from GPS satellites and GLONASS satellites (step S104). Then, the process of the module control unit 52 shifts to step S105.

When the process proceeds to step S105, the module control unit 52 tracks the radio signal of the captured positioning satellite and identifies the reception code of the demodulated navigation message (step S105). Each time the 1-bit code is identified, the module control unit 52 sequentially stores the identified reception code up to the maximum code length predetermined for each positioning satellite by FIFA (First-In First-Out), and the positioning is performed. A code matching process for collating with the assumed code string generated for the satellite is performed (step S106).

The module control unit 52 determines whether or not the timing of the received code string that matches the assumed code string with the reference accuracy or higher is identified (step S107). If it is determined that it has not been identified (“NO” in step S107), the module control unit 52 determines whether or not a timeout time has elapsed from the start of radio wave reception (step S108). If it is determined that the elapse has not occurred (“NO” in step S108), the module control unit 52 updates the assumed code string (step S109), and then returns the process to step S105. If it is not necessary to update the assumed code string in 1-bit units because the parity code string or the Hamming code is not added to the assumed code string, the assumed code string may be updated only when necessary.

If it is determined that the timeout time has elapsed (“YES” in step S108), the process of the module control unit 52 proceeds to step S122.

When it is determined that the timing of the received code string that matches the assumed code string has been identified in the determination process of step S107 (“YES” in step S107), the module control unit 52 sets the assumed code string and the match timing. Based on this, the current date and time is determined (step S121). Then, the process of the module control unit 52 shifts to step S122.

When the process proceeds to step S122, the module control unit 52 ends the reception operation by the reception unit 51 (step S122). The module control unit 52 outputs the result (information on the current date and time or notification that the acquisition of the current date and time was unsuccessful) to the host control unit 401 at an appropriate timing (step S123). Then, the module control unit 52 ends the satellite radio wave reception control process.

FIG. 6 is a flowchart showing a control procedure by the module control unit 52 of the code matching process called in the satellite radio wave reception control process.

When the code matching process is called, the module control unit 52 relatives each code of the identification code number N identified for the GPS satellite and the identification code number M identified for the GRONASS satellite to the assumed code string and the assumed error range, respectively. An operation of collating while shifting the position r (while changing the relative positional relationship) is performed (step S601). When the acquisition timing is different between the GPS satellite and the GLONASS satellite, the identification signature number M and the identification code signature N may be different.

The module control unit 52 sets the collation number Ncp in which the reception code string of the GPS satellite and the assumed code string are collated for all the relative positions r within the assumed error range, and the reception code string and the assumed code string of the GRONASS satellite. It is determined whether or not the total number of collations (Ncp + Mcp) including the collation number Mcp collated in step 2 is equal to or greater than the predetermined lower limit number NM0 (step S602). That is, the module control unit 52 determines whether or not the number of codes that are actually collated with the probable codes that exist in a discrete manner is equal to or greater than the lower limit number NM0 with respect to the identification codes N and M to be collated. Determine.

When it is determined that the lower limit number is not NM0 or more (“NO” in step S602), the module control unit 52 ends the code matching process and returns the process to the satellite radio wave reception control process. When it is determined that the lower limit number is NM0 or more (“YES” in step S602), the module control unit 52 has the total number of matches F (total number of match codes) for each collated relative position. The relative position r1 from which the largest maximum number of matches F1, the second largest number of runner-up matches F2, and the maximum number of matches F1 have been acquired is specified (step S603).

The module control unit 52 acquires (calculates here) the probabilities that the maximum number of matches F1 and the number of runner-up matches F2 can be detected as appearance probabilities P1 and P2, respectively (step S604). In the calculation of the appearance probabilities P1 and P2, the probability of matching with the assumed code string and the probability of not matching (misidentification probability) may be halved, or the misidentification probability based on the received radio wave intensity, C / N ratio, or the like. May be set.

The module control unit 52 determines whether or not the ratio P1 / P2 of the appearance probability is less than the reference ratio Pth (step S605). If it is determined that the ratio is not less than Pth (“NO” in step S605), the module control unit 52 ends the code matching process and returns the process to the satellite radio wave reception control process. When it is determined that the reference ratio is less than Pth (“YES” in step S605), the module control unit 52 identifies the relative position r1 of the maximum number of matches F1 as the match timing (step S606) and processes it. Return to satellite radio reception control processing.

FIG. 7 is a flowchart showing another example of the control procedure by the module control unit 52 of the code matching process.
In the code matching process of the above embodiment, the number of code matches, the appearance probability and the matched relative position acquired from the GPS satellite are added to the number of code matches, the appearance probability and the matched relative position acquired from the GLONASS satellite. However, in the code matching processing of other examples, each is handled separately.

When the codes of the identification code numbers N and M are collated with the code of the assumed code string at each relative position r in the process of step S601, the module control unit 52 performs each relative position in the received code string from the GPS satellite. It is determined whether or not the collation number Ncp in r is the lower limit number N0 or more, and the collation number Mcp in each relative position r of the received code strings from the GRONASS satellite is the lower limit number M0 or more (step). S602a). The lower limit numbers N0 and M0 can be set to be equal to the above-mentioned lower limit numbers NM0, respectively.

When it is determined that either of the collation numbers Ncp and Mcp is not equal to or more than the lower limit number (“NO” in step S602a), the module control unit 52 ends the code collation process and performs the process by satellite radio wave reception control. Return to processing. When it is determined that all the numbers are equal to or greater than the lower limit (“YES” in step S602a), the module control unit 52 has the maximum number of matches obtained by matching at each relative position r related to the code string received from the GPS satellite. The maximum number of matches F1M among the number of matches F1N (the number of first match codes), its appearance relative position r1N and the number of runner-up matches F2N, and the number of matches by matching at each relative position r related to the code sequence received from the GRONASS satellite. (Second number of matching codes), the relative appearance position r1M and the number of runner-up matching numbers F2M are specified (step S603a).

The module control unit 52 determines whether or not the relative position r1N and the relative position r1M are equal, that is, whether or not the reception is at the same timing (step S611). Depending on the difference in the relative distance between the current position and the positioning satellite, the reception timing may deviate by about one code (50 msec), so a deviation of ± 1 code may be allowed. If it is determined that the timings are not the same (“NO” in step S611), the module control unit 52 ends the code matching process and returns the process to the satellite radio wave reception control process.

When it is determined that the timings are the same (“YES” in step S611), the module control unit 52 determines the appearance probabilities P1N, P1M, P2N of the maximum matching numbers F1N, F1M and the runner-up matching numbers F2N, F2M. Each P2M is acquired (calculated) (step S604a). In the module control unit 52, the ratio P1N / P2N of the appearance probability for the reception code string of the GPS satellite is less than the reference ratio Pth, and the ratio P1M / P2M of the appearance probability for the reception code string of the GLONASS satellite is less than the reference ratio Pth. (Step S605a).

When it is determined that the ratio of at least one of the appearance probabilities is not less than the reference ratio Pth (“NO” in step S605a), the module control unit 52 ends the code matching process and performs the process by satellite radio wave reception control. Return to processing. When it is determined that the ratio of the appearance probabilities is less than the reference ratio Pth (“YES” in step S605a), the module control unit 52 sets the appearance relative positions r1N (r1M) of the maximum matching numbers F1N and F1M. It is identified as a coincidence timing (step S606a). When a deviation such as ± 1 code is allowed between the relative position r1N and the relative position r1M as described above, one of them, for example, the relative position r1N related to the reception code string from the GPS satellite, the number of collations Ncp, and Mcp. Criteria for determining which one to prioritize, such as the relative position related to the larger one, may be set in advance. Then, the module control unit 52 ends the code matching process and returns the process to the satellite radio wave reception control process.

As described above, the electronic clock 1 of the present embodiment includes a receiving unit 51 that receives radio waves from a positioning satellite, a timekeeping circuit 48 that counts the current date and time, a host control unit 401, and a module control unit 52 (collectively). Control unit) and. The receiving unit 51 is a GRONASS satellite (second positioning satellite) in which information is transmitted in a format (format) different from the transmission radio wave including the signal from the GPS satellite (first positioning satellite) and the signal from the GPS satellite. It is possible to receive the transmitted radio wave including the signal from the GPS satellite, and the control unit receives from the first assumed code string and the GRONASS satellite, which are expected to be received from the GPS satellite, based on the date and time counted by the timing circuit 48. A second assumed code string that is expected to be received is generated, and the current date and time is identified based on the timing at which at least a part of each of the first assumed code string and the second assumed code string is received.
In this way, for navigation messages from two satellites whose dates and times are transmitted in different formats, by generating an assumed code string and collating it with the received code string, the reception strength is insufficient for one code string or a similar code. Sufficient accuracy and accuracy when a column exists and sufficient accuracy cannot be obtained, or when the actual deviation amount is larger than the maximum estimated deviation amount and there is a possibility of misidentifying one of the code strings. It is possible to identify whether or not the matching position of the code sequence has been obtained for both positioning satellites. Therefore, with this electronic clock 1, it is possible to acquire an accurate date and time more efficiently and reliably. In particular, as compared with the case where the received code strings from a plurality of positioning satellites related to the same positioning system are compared with the assumed code strings, the accuracy can be improved and the misidentification can be discriminated efficiently.

Further, the control unit generates a first assumed code string and a second assumed code string having a code length corresponding to the maximum estimated deviation amount of the date and time counted by the time counting circuit 48, and the control unit generates the first assumed code string and the second assumed code string with respect to the received code string by the receiving unit 51. The relative positional relationship between the first assumed code string and the second assumed code string is changed and collated within the range of the maximum estimated deviation amount, and the first assumed code string and the second assumed code string are collated, respectively. Identify when at least part of it was received.
In this way, by generating the assumed code strings within the range of the estimated deviation amount that is normally assumed, it is possible to obtain a plurality of types of code strings without increasing the amount of memory and the amount of collation processing more than necessary. By performing each collation, the possibility of misidentification can be sufficiently reduced. That is, the date and time identification accuracy can be efficiently improved.

Further, the transmission cycle of the date and time information is different between the signal from the GPS satellite to be received and the signal from the GLONASS satellite.
In this way, by combining and collating the received code strings acquired from the positioning satellites whose date and time information is transmitted in different cycles, the possibility of misidentification due to the cycle shift is reduced, and the accuracy within the accurate cycle is reduced. It is possible to identify the correct timing more reliably. As a result, it is possible to improve the efficiency of the processing related to the generation and collation of the assumed code string and the accuracy of the date and time information at the same time.

Further, the first cycle (subframe cycle 6 seconds) related to the transmission of the date and time information in the signal from the GPS satellite is from the second cycle (frame cycle 15 seconds) related to the transmission of the date and time information in the signal from the GLONASS satellite. When the maximum estimated deviation amount of the date and time counted by the time counting circuit 48 deviates from the reference width corresponding to the first cycle, the control unit determines the first assumed code string and the second assumed code string. Is generated, and the transmitted radio wave including the signal from the first positioning satellite and the transmitted radio wave including the signal from the second positioning satellite are received to identify the current date and time.
In this way, when it is assumed that the accuracy of the date and time counted by the timekeeping circuit 48 is sufficiently higher than the subframe period of the navigation message received from the GPS satellite, the reception and assumption of the radio wave from the GLONASS satellite The collation with the code string can be omitted to reduce the memory usage and the load related to the collation. On the other hand, when the accuracy of the date and time counted by the timekeeping circuit 48 is not sufficient, radio waves from both GPS satellites and GLONASS satellites are received as described above to identify the received code string, and each is compared with the assumed code string. By doing so, the possibility that the matching timing is not detected and time is wasted can be sufficiently reduced, and the date and time can be identified efficiently with sufficient accuracy.

In addition, the maximum estimated deviation amount is obtained based on the elapsed time since the previous date and time information was acquired. Since the amount of deviation of the crystal oscillator often used in the electronic clock 1 largely depends on the elapsed time, the maximum amount of deviation can be easily and almost certainly estimated by determining the amount of deviation in proportion to the elapsed time in this way. Can be done. As a result, the possibility that the current date and time cannot be identified because the assumed code string and the received code string do not match can be easily sufficiently reduced.

Further, the control unit collates the received code string from the GPS satellite with the first assumed code string in each relative positional relationship, and obtains the first matching code number and the received code string from the GRONASS satellite. The number of second matching codes obtained by collating the second assumed code string with each relative positional relationship is added up for each relative positional relationship, and the total number of matching codes for each relative positional relationship is added up. Based on the total number of matching codes obtained, the timing at which the first assumed code string and the second assumed code string are received is detected.
In this way, by simply adding the matching results for the code strings of different formats to identify the optimum code string, it is possible to easily and surely avoid misidentification and identify the exact current date and time.

Further, the control unit generates a part of the first assumed code string and the second assumed code string based on the code received and identified by the receiving unit 51. That is, the code string calculated from the code string transmitted in a shorter period than the transmission cycle of the date and time information such as the parity value and the Hamming code, the output code string, the orbit information of the positioning satellite, etc. are received once. If so, for a code string in which the same code string is continuously transmitted repeatedly during the valid period, the assumed code string is received after the code string required for calculating the parity value is received and after the code string within the valid period is received. Can be used as. By increasing the number of codes of the assumed code string in this way, it is possible to identify the matching timing more efficiently and in a short time and obtain the accurate current date and time.

Further, in the date and time information acquisition method of the present embodiment, the first assumed code string that is expected to be received from the GPS satellite and the second assumed code string that is expected to be received from the GRONASS satellite are assumed based on the date and time counted by the time counting circuit 48. Includes a date and time identification step that generates the assumed code string of the above and identifies the current date and time based on the timing at which at least a part of each of the first assumed code string and the second assumed code string is received.
In such a date and time information acquisition method, the radio wave reception strength and reception from one positioning satellite are received by identifying whether or not the matching position of the code string is obtained for both positioning satellites with sufficient accuracy. It is possible to sufficiently reduce the occurrence of situations such as misidentification and difficulty in identification that may occur due to a code string, etc., and to efficiently and surely acquire an accurate date and time. In particular, as compared with the case where the received code strings from a plurality of positioning satellites related to the same positioning system are compared with the assumed code strings, the accuracy can be improved and the misidentification can be discriminated efficiently.

Further, in the program 641 (satellite radio wave reception control processing) of the present embodiment, the first assumed code string that is expected to be received from the GPS satellite based on the date and time counted by the time counting circuit 48 in the computer (control unit). And generate a second assumed code string that is expected to be received from the GLONASS satellite, and identify the current date and time based on the timing when at least a part of each of the first assumed code string and the second assumed code string is received. It functions as a means for identifying the date and time.
By installing such a program and letting the CPU execute it, it is possible to easily and surely reduce the occurrence of misidentification and difficult-to-identify situations, and efficiently and accurately acquire the current date and time.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, in the above embodiment, it is determined whether or not the radio wave of the GLONASS satellite is received and collated with the assumed code string depending on whether or not the maximum deviation amount estimated at the counting date and time is ± 3 seconds or more. Regardless of whether it is 3 seconds or more, the radio wave of the GLONASS satellite may be received and collated with the assumed code string.

Further, the length of the assumed code string to be generated is not limited to the length corresponding to the deviation amount of ± 3 seconds or ± 15 seconds, and is based on the estimated maximum deviation amount and the head position of the assumed code string. It can be variably determined according to the length or the like in which the number of collable codes required for the stochastic calculation is surely included.

Further, in the above embodiment, the configuration in which the date and time can be acquired is described as only the satellite radio wave reception processing unit 50, but another configuration, for example, a radio wave (time code) including the date and time information in a long wavelength band is transmitted. You may also use standard radio waves or proximity wireless communication, for example, acquisition of an accurate date and time by receiving Bluetooth (registered trademark). In this case, the estimated value of the maximum deviation amount of the date and time may be obtained based on the elapsed time since the exact date and time was acquired by any of these methods and the date and time counted by the timekeeping circuit 48 was corrected. ..

Further, in the above embodiment, the case where the radio wave reception from the GPS satellite and the radio wave reception from the GLONASS satellite are combined has been described as an example, but the combination of navigation messages in different formats is limited to this. I can't. The signals from the two types of positioning satellites may have the same transmission cycle of date and time information.

Further, in the above description, a ROM 64 composed of a non-volatile memory such as a flash memory or a mask ROM is used as an example of a computer-readable medium for storing the program 641 related to the satellite radio wave reception control of the present invention at the time of acquiring the current date and time information. However, it is not limited to these. As another computer-readable medium, a portable recording medium such as an HDD (Hard Disk Drive), a CD-ROM, or a DVD disc can be applied. A carrier wave is also applied to the present invention as a medium for providing data of a program according to the present invention via a communication line.
In addition, specific details such as the configuration, control procedure, and display example shown in the above embodiment can be appropriately changed without departing from the spirit of the present invention.

Although some embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and the equivalent scope thereof.
The inventions described in the claims originally attached to the application of this application are added below. The claims in the appendix are as specified in the claims originally attached to the application for this application.

[Additional Notes]
<Claim 1>
A receiver that receives radio waves from positioning satellites,
A timekeeping section that counts the current date and time,
Control unit and
With
The receiving unit includes a transmission radio wave including a signal from the first positioning satellite and a transmission radio wave including a signal from a second positioning satellite in which information is transmitted in a format different from the signal from the first positioning satellite. And can be received,
The control unit is expected to receive from the first assumed code sequence and the second positioning satellite based on the date and time counted by the timing unit. An electronic clock comprising generating 2 assumed code strings and identifying the current date and time based on the timing at which at least a part of each of the first assumed code string and the second assumed code string is received.
<Claim 2>
The control unit
The first assumed code string and the second assumed code string of the code length corresponding to the maximum estimated deviation amount of the date and time counted by the timekeeping unit are generated.
The first assumed code string and the second assumed code string are collated while being changed within the range of the maximum estimated deviation amount with respect to the received code string received by the receiving unit. The electronic clock according to claim 1, wherein at least a part of each of the assumed code string and the second assumed code string is specified.
<Claim 3>
The electronic clock according to claim 1 or 2, wherein the signal from the first positioning satellite and the signal from the second positioning satellite have different transmission cycles of date and time information.
<Claim 4>
The first cycle related to the transmission of date and time information in the signal from the first positioning satellite is shorter than the second cycle related to the transmission of date and time information in the signal from the second positioning satellite.
When the maximum estimated deviation amount of the date and time counted by the timekeeping unit deviates from the reference width corresponding to the first cycle, the control unit has the first assumed code string and the second assumed code. A claim comprising generating a sequence, receiving a transmitted radio wave including a signal from the first positioning satellite and a transmitted radio wave including a signal from the second positioning satellite, and identifying the current date and time. The electronic clock according to any one of 1 to 3.
<Claim 5>
The electronic clock according to claim 2 or 4, wherein the maximum estimated deviation amount is obtained based on the elapsed time since the previous date and time information was acquired.
<Claim 6>
The control unit collates the received code string from the first positioning satellite with the first assumed code string in each relative positional relationship, and obtains a first matching code number and a second positioning. The code strings received from the satellite and the second assumed code string are collated with each relative positional relationship, and the number of second matching codes obtained for each is added up for each relative positional relationship, and for each relative positional relationship. It is characterized in that the timing at which the first assumed code string and the second assumed code string are received is detected based on the total number of matching codes and the total number of matching codes obtained by the total. The electronic clock according to any one of claims 1 to 5.
<Claim 7>
Claim 1 is characterized in that the control unit generates a part of the first assumed code string and the second assumed code string based on the code received and identified by the receiving unit. The electronic clock according to any one of 1 to 6.
<Claim 8>
The receiving unit includes a receiving unit that receives radio waves from the positioning satellite and a timing unit that counts the current date and time, and the receiving unit includes a transmission radio wave including a signal from the first positioning satellite and the first positioning satellite. It is a method of acquiring date and time information of an electronic clock that can receive a transmission radio wave including a signal from a second positioning satellite in which information is transmitted in a format different from the signal from.
Based on the date and time counted by the timing unit, a first assumed code string that is expected to be received from the first positioning satellite and a second assumed code string that is expected to be received from the second positioning satellite. The date and time information acquisition including the date and time identification step of generating and identifying the current date and time based on the timing at which at least a part of each of the first assumed code string and the second assumed code string is received. Method.
<Claim 9>
The receiving unit includes a receiving unit that receives radio waves from the positioning satellite and a timing unit that counts the current date and time, and the receiving unit includes a transmission radio wave including a signal from the first positioning satellite and the first positioning satellite. An electronic clock computer capable of receiving radio waves including signals from a second positioning satellite whose information is transmitted in a format different from the signal from.
Based on the date and time counted by the timing unit, a first assumed code string that is expected to be received from the first positioning satellite and a second assumed code string that is expected to be received from the second positioning satellite. Is generated, and at least a part of each of the first assumed code string and the second assumed code string is functioned as a date and time identification means for identifying the current date and time based on the received timing.

1 Electronic clock 40 Microcomputer 401 Host control unit 41 CPU
43 RAM
431 Date and time information acquisition history information 432 Local time setting 46 Oscillation circuit 47 Division circuit 48 Timekeeping circuit 50 Satellite radio wave reception processing unit 51 Reception unit 52 Module control unit 53 Storage unit 531 Reception control information 61 Operation reception unit 62 Display unit 621 Display screen 622 Display driver 63 Measuring unit 631 Light amount sensor 64 ROM
641 Program 70 Power supply unit A1 Antenna F Matching number F1, F1M, F1N Maximum matching number F2, F2M, F2N Second-order matching number M, N Identification code number M0, N0, NM0 Lower limit number Mcp, Ncp Collation number P1, P1M, P1N Appearance probability Pth Reference ratio r, r1, r1M, r1N Relative position

Claims (8)

A receiver that receives radio waves from positioning satellites,
A timekeeping section that counts the current date and time,
Control unit and
With
The receiving unit includes a transmission radio wave including a signal from the first positioning satellite and a transmission radio wave including a signal from a second positioning satellite in which information is transmitted in a format different from the signal from the first positioning satellite. And can be received,
The first cycle related to the transmission of date and time information in the signal from the first positioning satellite is shorter than the second cycle related to the transmission of date and time information in the signal from the second positioning satellite.
When the maximum estimated deviation amount of the date and time counted by the time measuring unit deviates from the reference width corresponding to the first cycle, the control unit is expected to receive from the first positioning satellite. A assumed code string of 1 and a second assumed code string expected to be received from the second positioning satellite are generated, and at least a part of each of the first assumed code string and the second assumed code string is An electronic clock characterized by identifying the current date and time based on the timing received. The control unit
The first assumed code string and the second assumed code string of the code length corresponding to the maximum estimated deviation amount of the date and time counted by the timekeeping unit are generated.
The first assumed code string and the second assumed code string are collated while being changed within the range of the maximum estimated deviation amount with respect to the received code string received by the receiving unit. The electronic clock according to claim 1, wherein at least a part of each of the assumed code string and the second assumed code string is specified. The electronic clock according to claim 1 or 2, wherein the signal from the first positioning satellite and the signal from the second positioning satellite have different transmission cycles of date and time information. The maximum estimated shift amount, the electronic timepiece according to claim 2 Symbol mounting, characterized in that it is determined based on the elapsed time from the acquired last time and date information. The control unit collates the received code string from the first positioning satellite with the first assumed code string in each relative positional relationship, and obtains a first matching code number and a second positioning. The code strings received from the satellite and the second assumed code string are collated with each relative positional relationship, and the number of second matching codes obtained for each is added up for each relative positional relationship, and for each relative positional relationship. It is characterized in that the timing at which the first assumed code string and the second assumed code string are received is detected based on the total number of matching codes and the total number of matching codes obtained by the total. The electronic clock according to any one of claims 1 to 4. Claim 1 is characterized in that the control unit generates a part of the first assumed code string and the second assumed code string based on the code received and identified by the receiving unit. The electronic clock according to any one of 5 to 5. The receiving unit includes a receiving unit that receives radio waves from the positioning satellite and a timing unit that counts the current date and time, and the receiving unit includes a transmission radio wave including a signal from the first positioning satellite and the first positioning satellite. It is a method of acquiring date and time information of an electronic clock that can receive a transmission radio wave including a signal from a second positioning satellite in which information is transmitted in a format different from the signal from.
When the maximum estimated deviation amount of the date and time counted by the timing unit deviates from the reference width corresponding to the first cycle, the first assumed code string and the first assumed code string that are expected to be received from the first positioning satellite and A second assumed code string that is expected to be received from the second positioning satellite is generated, and based on the timing at which at least a part of each of the first assumed code string and the second assumed code string is received. Includes a date and time identification step to identify the current date and time
The first cycle related to the transmission of date and time information in the signal from the first positioning satellite is shorter than the second cycle related to the transmission of date and time information in the signal from the second positioning satellite.
A method of acquiring date and time information, which is characterized by the fact that. The receiving unit includes a receiving unit that receives radio waves from the positioning satellite and a timing unit that counts the current date and time, and the receiving unit includes a transmission radio wave including a signal from the first positioning satellite and the first positioning satellite. An electronic clock computer capable of receiving radio waves including signals from a second positioning satellite whose information is transmitted in a format different from the signal from.
When the maximum estimated deviation amount of the date and time counted by the timing unit deviates from the reference width corresponding to the first cycle, the first assumed code string and the first assumed code string that are expected to be received from the first positioning satellite and A second assumed code string that is expected to be received from the second positioning satellite is generated, and based on the timing at which at least a part of each of the first assumed code string and the second assumed code string is received. To function as a date and time identification means to identify the current date and time
The first cycle related to the transmission of date and time information in the signal from the first positioning satellite is shorter than the second cycle related to the transmission of date and time information in the signal from the second positioning satellite.
A program characterized by that.

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