JP2000199792A - Time piece and time correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a time piece and a time correction method capable of always maintaining highly accurate time. SOLUTION: A measurement processing is initiated upon receiving the wave of GPS satellites. When time data is received, after waiting for time, whether or not the difference of time between the time to be corrected by the time data obtained by the measurement processing and the time of the clock part at the moment is within the accuracy (allowable error) assured in the clock part is decided (steps S1 to S4). If it is not within the allowable error, it is decided that erroneous time data due to radio interference, such as ghosts and disturbances in time measurement and the measurement is terminated as it is without adjusting time. As a result of this, errors in time correction due to radio interference is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clock device and a time correction method for correcting the current time of the watch based on information sent from a satellite such as a GPS satellite.

[0002]

2. Description of the Related Art Conventionally, in a position measurement system using GPS, it is possible to measure its own position by acquiring satellite data such as ephemeris and almanac contained in radio waves received from a plurality of GPS satellites. Ephemeris is data such as orbital information of the transmitting satellite itself and clock correction information.
An accurate time can be obtained based on the highly accurate atomic clock time information of the S satellite. Therefore, a positioning device or the like that uses GPS can have a highly accurate clock by correcting the time of the clock of the GPS device based on the received time information (by adjusting the time). .

[0003]

However, when the above-described time adjustment is performed in a positioning device or the like, when a radio wave interference due to, for example, a ghost or interference occurs at the time of receiving a radio wave from a GPS satellite, an erroneous signal is generated. In some cases, time data can be obtained, but in that case, there is a problem that the time of the own clock is corrected based on the wrong time, and the accurate time cannot be known.

[0004] The present invention has been made in view of such a conventional problem, and has as its object to provide a timepiece device and a time correction method that can always hold highly accurate time.

[0005]

According to a first aspect of the present invention, there is provided a clock device for receiving information transmitted from a satellite, a clock unit for generating a current time, Correction means for correcting the generation time of the clock means by time data based on the information received by the reception means; and when the correction range of the generation time by the correction means is greater than a predetermined range, the correction means And control means for prohibiting the correction of the generation time of the clock means. In such a configuration, the correction unit corrects the current time using the time data based on the information received by the reception unit only when the correction range of the generation time of the clock unit is within a predetermined range. Therefore, by appropriately setting the range, an erroneous time correction can be prevented in a case where the received information has an abnormality and the time data based on the information has an error.

Further, in the timepiece device of the second aspect, the determined range is an error range unique to the timepiece means. In such a configuration, incorrect time correction is more reliably prevented.

According to a third aspect of the present invention, there is provided a time adjusting method for correcting the current time of the vehicle by using time data based on information received from a positioning satellite. It is determined whether or not the correction range of the current time is within a predetermined range, and the current time is corrected only when it is determined that the correction range is within the range. According to this method, by setting the range appropriately, erroneous time correction can be prevented in a case where there is an abnormality in the received information and there is an error in the time data based on the information.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a positioning device 1 for realizing the timepiece device of the present invention. In the present embodiment, it is assumed that the positioning device 1 is a wristwatch type that operates using a battery as a power supply.

That is, the positioning device 1 is composed of a main module 2 and a GPS module 3.
The GPS module 3 includes a GPS antenna for receiving an L1 band radio wave from a GPS satellite, a receiving unit 4 including an RF, an A / D, and the like, and a satellite such as ephemeris data and almanac data from the radio wave received by the receiving unit 4. A signal processing unit 5 including a data register, a counter, a decoder, and a CPU for controlling the data registers and counters necessary for decoding the data is provided. The signal processing unit 5 includes the CP
Read-only mask ROM for storing U program
6 and a readable and writable SR used as a register for arithmetic operation of the CPU while storing satellite data received during the position measurement work and used for calculating the current position.
AM7 is connected. The GPS module 3 is connected to the CPU 8 of the main module 2 via an input data line a and an output data line b, and stores position data indicating a current position calculated by the signal processing unit 5 and the satellite. The time data included in the data is transmitted to the CPU 8.

The CPU 8 controls the entire positioning device 1 using the RAM 10 as a working memory according to a control program stored in the ROM 9. The ROM 9 stores, together with the control program, wait time data used for time adjustment of the clock unit 12 described later and accuracy data indicating an error range thereof. Further, the CPU 8 includes a data storage unit 11 for storing map data and positioning system data, a transmitter such as a crystal oscillator for counting the current time, and the transmitter so that a time lag within a predetermined period falls within a predetermined range. A clock unit 1 which includes an adjustment circuit for adjusting the transmission frequency of the clock, generates a current time, and sends it to the CPU 8
2. A switch input unit 13 to which a plurality of switches for operating the positioning device 1 are connected, a small LCD or the like, and a clock display based on the time data counted by the clock unit 12 is usually used for a normal measurement. Are connected to display units 14 for displaying satellite position and reception status data of radio waves, and when the position is determined by measurement, numerical data of the position and data of the map and the current position are displayed.

Next, the operation of the positioning device 1 having the above configuration relating to time adjustment will be described with reference to the flowchart of FIG. That is, when the positioning device 1 starts operating in response to a measurement request signal from the switch input unit 16 in accordance with the operation of the user, the positioning device 1 first activates the GPS module 3 to receive, demodulate and convert a satellite radio wave into a digital signal, The measurement process such as calculating the current position from the signal is started (step S1), and the measurement process is continued for a predetermined time or a predetermined number of times until time data can be received (NO in step S2). Here, if the time data can be received, that is, if the measurement is successful (YES in step S2), a time wait is performed while the measurement result is sent from the GPS module 3 to the main module 2 (step S3). The difference between the correction time to be corrected by the time of the time data obtained in the measurement processing by the module 2 and the time in the clock unit 12 up to that time is the accuracy range secured in the clock unit 12 of the main module 2. It is determined whether the value is within the range (within the inherent error range) (step S4). The range of the accuracy of the device used for the determination here is, of course, a range in consideration of the elapsed time from the previous time adjustment, and specifically, the accuracy data stored in the ROM 9. And the date and time previously stored in the RAM 10 when the last time adjustment was performed.

If the result of the determination is YES and the result is within the above-described predetermined accuracy range, the time of the clock section 12 is corrected and the date and time at that time are set to RA.
After storing the result in M10 (step S5), the measurement ends. On the other hand, if the accuracy is not within the above-described predetermined accuracy range, it is determined that erroneous time data has been obtained due to radio interference due to ghost or interference during measurement, and the measurement is terminated without performing time adjustment. . Therefore, in the positioning device 1, erroneous time correction due to radio wave interference can be eliminated, and highly accurate time can be always maintained. Moreover, it is determined whether or not the time data obtained by the GPS module 2 is incorrect data.
Since the correction is performed on the basis of an error inherent in the clock unit 12, incorrect time correction can be prevented more reliably, and highly accurate time can be held more reliably.

Next, the operation relating to the time correction in step S5 will be described with reference to the timing chart of FIG. First, the GPS module 3 during the measurement operation
The data transfer from the to the main module 2 will be described. That is, “A”, “B”,... In FIG. 3A are accurate second carry timings obtained at the hour obtained in the above-described measurement processing.
The PS module 3 performs a current position measurement operation and data transmission to the main module 2. In other words, the GPS module 3 measures at the timing “A” and obtains the result. When the result is obtained, the measurement result, that is, the latitude / longitude data or the like is sent to the main module 2 during the period from the timing “C” to “D” in FIG. Transfer position information and time data. In the present embodiment, the timing “E” in FIG. 2B is the last position of the time data. Here, the time required for the measurement operation (the time between timings "A" to "C") has a fixed range, which is sufficiently shorter than one second, and sufficiently small as the precision of a clock used daily. . Therefore, for example, assuming that this time is a possible maximum value t1, the data transfer time t2 at the above-mentioned timings “C” to “D”
Is a basic transfer time peculiar to the system and is always constant. Therefore, a waiting time Δt (E (E) from the end of data transfer (timing “D”) to the next second carry (timing “B”). −F) can be obtained by waiting time Δt = 1000 msec−t1−data transfer time t2. In the present embodiment, the waiting time Δt is stored in the ROM 9.

The time adjustment (time correction) of the clock section 12 in the main module 2 is performed when data is transmitted from the GPS module 3 based on the second carry timing “A”, as shown in FIG. After the data acquisition timing “D”, at the moment when the waiting time Δt stored in the ROM 9 has elapsed (timing “G” in (4) of FIG. 4), the time of the clock unit 12 is changed to the timing “C”. ”To“ D ”(time data sent at the previous second carry timing“ A ”) plus one second. Thereby, extremely accurate time adjustment is performed. The timing “H” in (5) of FIG. 4 is the second carry timing of the clock unit 12 immediately before the time adjustment is performed, and the time ΔT of the timings “H” to “G” is adjusted. Timing width.

That is, in the present embodiment, the GPS
Since the main module 2 adjusts the time based on the transfer timing of the data sent from the module 3, time synchronization between the main module 2 and the GPS module 3 for informing the latter of the correct second carry timing at the correct time. Even without a signal data line, extremely accurate time adjustment is possible. Therefore, the data line is not required, and the peripheral circuit of the CPU required for the interrupt processing of the time synchronization signal is not required. Therefore, the mounting area and the number of components of the system in the apparatus can be reduced, and It is possible to reduce the size and cost.

In the above-described time setting operation, when the measuring operation is performed under the same condition, the time setting can be performed with almost the same accuracy every time. This is because when the measurement operations are the same, the above-described measurement time t1 (the time between timings “A” to “C”) is substantially uniform. Therefore, if the positioning device 1 is provided in advance with a time setting mode in which the above-described time setting operation is performed in response to a predetermined switch operation by the user, for example, the user performs the predetermined operation at the same time every day at the same place. By doing so, the time can be adjusted with the same accuracy every day.

Further, higher accuracy can be obtained as follows. That is, as a preparation stage,
After performing the above-mentioned time setting operation manually or automatically, the second time adjusting operation is performed again using a time signal of a television or a radio or a time signal of a telephone which emits an accurate time in daily life. At this time, the time difference ta between the time according to the time signal and the time of the clock unit 12 up to that time is stored in the RAM 10. That is, the time difference ta is equal to the measurement time t1 (timing “A” to
(Time between “C”). Then, at the time of the subsequent measurement (or at the time of the time correction process), the time difference ta stored in the RAM 10 is read, and a new waiting time Δt is calculated based on the waiting time Δt = 1000 msec−t1−data transfer time t2−ta. .

Then, the above-described time adjustment operation is performed using the waiting time Δt. Alternatively, in the preparation stage, a new waiting time Δt is calculated, and the calculated waiting time Δt is stored in the RAM 1.
0 beforehand, and RAM1
The above-described time adjustment operation is performed using the waiting time Δt read from 0. Thus, as described above, the waiting time data (12a) of the ROM 9 determined assuming the measurement time t1 (the time between the timings “A” to “C”) as the possible maximum value t1 is used. Compared to the case, the generation time of the clock means can be corrected at a timing closer to the clock timing at the hour. Therefore, more accurate time adjustment can be performed.

In this embodiment, the present invention is applied to a wristwatch-type measuring device 1. However, the present invention is based on time information sent from a positioning satellite such as a GPS satellite. The same effect can be obtained even when the time is adjusted or obtained in another device.

[0020]

As described above, in the present invention,
Only when the correction range of the current time is within a predetermined range, the current time is corrected by the time data based on the received information, so that the received information is abnormal and is based on the information. The incorrect time correction when the time data is incorrect is prevented. Therefore, it is possible to always hold highly accurate time. Further, in a clock device in which the determined range is set to an error range specific to the clock means for generating the current time, erroneous time correction can be completely prevented, so that high-precision time is more reliably held. It becomes possible.

[0021]

[Brief description of the drawings]

FIG. 1 is a block diagram of a positioning device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation related to time adjustment.

FIG. 3 is a timing chart showing time setting timing.

FIG. 4 is a timing chart showing a time alignment determination.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positioning apparatus 2 Main module 3 GPS module 9 ROM 10 RAM 12 Clock part

Claims (3)

[Claims] 1. A receiving means for receiving information sent from a satellite, a clock means for generating a current time, and a time generated by the clock means is corrected by time data based on the information received by the receiving means. Correction means, and control means for prohibiting the correction means from correcting the generation time of the clock means when the correction width of the generation time by the correction means is equal to or greater than a predetermined range. Clock device to do. 2. The timepiece device according to claim 1, wherein the determined range is an error range unique to the clock means. 3. A time correction method for correcting a current time of the vehicle based on time data based on information received from a positioning satellite, wherein prior to the correction of the current time, a correction range of the current time is within a predetermined range. A time correction method for determining whether or not the time is present and correcting the current time only when it is determined that the time is within the range.