JP2000332739A - Data synchronizing method and data processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time needed to obtain the synchronism after a GPS receiver is powered on by previously storing the same pattern as the appearance pattern of some elements of data included in a transmission unit and detection the synchronism of receive data according to the result of collating of received data with respect to the stored pattern. SOLUTION: A demodulation and arithmetic part 3 of the GPS receiver stores a storage part 5 with the correspondence relation between ephemeris information and almanac information in a fixed order, obtained by demodulating a receive signal of a GPS satellite broadcasts received by a GPS antenna 1 or communication antenna 8, and the time base in the form of a table. Then a unit of time synchronization is determined as one element of data of a navigation message. Then a GPS satellite broadcast is received and processed through inverse spectrum spread, and then each element of the inverse spectrum spread output signal is matched with elements stored in the storage part to complete time synchronization according to the matching result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
(Global Positioning System
m), the present invention relates to a data synchronization method and a data receiving apparatus such as a GPS receiver to which the method is preferably applied when synchronizing (time synchronizing) when receiving a navigation message from a GPS satellite.

[0002]

2. Description of the Related Art In a GPS system that measures the position of a mobile object using a plurality of artificial satellites, a spread spectrum modulation method is used as a modulation method of a signal radio wave from a satellite. For example, in the case of a consumer GPS receiver, a positioning spread calculation is performed by receiving a spread spectrum signal radio wave called a C / A code (Cose Aquisition code) from a GPS satellite (Navstar).

[0003] The C / A code of the PN sequence of the C / A code is different for each satellite, but a GPS receiver can detect in advance which satellite uses which code of which PN sequence. . In addition, the GPS receiver can determine from which satellite a signal can be received at that point and at that time by a navigation message as described later. Therefore, the GPS receiver receives radio waves from four or more satellites that can be obtained at that point and at that time, performs spectrum despreading, performs positioning calculation, and obtains its own position.

The C / A code has a transmission signal speed of 1.02.
3MHz PN (Pseudorandom Nois)
e; pseudo-random noise) sequence code (for example, Gold code), and as shown in FIG. 5A, the code of this PN sequence consists of 1023 chips for one cycle (thus, one cycle = 1). Milliseconds).

[0005] As shown in FIG. 5 (B), one bit of the satellite signal data is equivalent to 20 periods of the PN sequence code,
That is, it is transmitted in units of 20 milliseconds. That is, the data transmission speed is 50 bps. 1023 chips for one cycle of the code of the PN sequence are inverted when the bit is "1" and when the bit is "0".

[0006] As shown in FIG.
One word is formed by 0 bits (600 milliseconds). Then, as shown in FIG. 5D, one subframe (6 seconds) is formed by 100 words. As shown in FIG. 5 (E), a preamble that always has a prescribed bit pattern is inserted at the beginning of one subframe even when data is updated, and data is transmitted after this preamble. come.

Further, one frame (30 seconds) is formed by five sub-frames. And the navigation message is
The data is transmitted in data units of one frame.

The first three of the data of one frame are
Each subframe is satellite-specific information called ephemeris information. This information includes the parameters for determining the orbit of the satellite and the transmission time of the signal from the satellite. All of the GPS satellites have an atomic clock and use common time information, and the transmission time of a signal from the satellite is set to one second of the atomic clock.

The trajectory information of the ephemeris information is updated every several hours, but remains the same until the update is performed. However, by keeping the orbit information of the ephemeris information in the memory of the GPS receiver, the same information can be used with high accuracy for several hours. Since the transmission time of the signal from the satellite is updated every second, the navigation message of the remaining two subframes of one frame of data is information called almanac information, which is commonly transmitted from all satellites. is there. This almanac information is required for 25 frames to acquire all the information, and includes approximate position information of each satellite, information indicating which satellite can be used, and the like. The almanac information is updated every few months, but remains the same until the update is performed. However, by keeping this almanac information in the memory of the GPS receiver, the same information can be used with high accuracy for several months.

In receiving this GPS satellite signal,
First, using the same PN sequence code as the C / A code used in the GPS satellite to be received prepared in the receiver, the phase of the C / A code is synchronized for the signal from the GPS satellite. Despread the spectrum. When the phase is synchronized with the C / A code and despreading is performed, bits are detected, and it becomes possible to acquire a navigation message from a GPS satellite signal.

[0011] By the way, in order to perform a positioning operation with a GPS receiver, it is necessary to obtain a distance between the satellite and the receiver.
That is, the GPS receiver measures the time (signal arrival time) until the signal transmitted from the satellite at a certain time reaches the GPS receiver, and determines the speed of light (3 × 10
⁸ m / s) to calculate the distance.

Although a satellite orbits about 20,000 km on the ground, it is not enough to synchronize the phase of the C / A code to measure the signal arrival time. This is because the phase synchronization of the C / A code is a synchronization in units of 1 millisecond, and in this phase synchronization, only a component of 300 km or less is obtained. For this reason, in order to obtain a component with higher accuracy, it is necessary to measure the signal arrival time with high accuracy by synchronizing finely (time synchronization) the signals from the respective satellites.

Conventionally, in order to achieve this time synchronization,
(1) Synchronization is roughly achieved by decoding the signal emission time from the navigation message. (2) Of the navigation messages,
A preamble or the like, which is an element appearing in a prescribed pattern, is detected by a pattern matching search, and precise synchronization is established based on time information corresponding to the preamble at the time of the detection.

That is, in the case of direct spreading used for a GPS satellite signal, the autocorrelation characteristic has a sharp peak. Therefore, if the autocorrelation is obtained by pattern matching with a prescribed pattern such as the preamble, the chip time of the PN sequence is obtained. Synchronization (time synchronization) with the incoming signal can be achieved with an error of a fraction of the width. As a result, positioning calculation with a measurement error of about 100 m becomes possible.

In the meantime, for a while after the time synchronization, once the rough synchronization of the above (1) can be achieved with the clock of the GPS receiver, only the operation of (2) needs to be performed.

[0016]

The problem with the above method is that information such as a preamble can be obtained only in subframe units, that is, once every 6 seconds. Moreover,
In order to prevent erroneous locking, it is generally desirable to confirm information such as a preamble twice or more. Therefore, from a state where a signal from a satellite and a C / A code are synchronized,
The time required until the final time synchronization can be obtained is GPS
Even if the clock information of the receiver is valid, it takes 6 seconds or more.

For this reason, when trying to reduce the time required from the power-on to the start of the positioning calculation, this portion is a bottleneck. In addition, when assuming that the GPS positioning system is installed in a portable device or the like, power saving becomes a problem. However, as described above, in the conventional technology, it takes time until the start of positioning calculation. It was not enough.

In view of the above, it is an object of the present invention to provide a data synchronizing method and a data receiving apparatus capable of shortening the time required from when the power of a GPS receiver is turned on until time synchronization is achieved. I do.

[0019]

According to a first aspect of the present invention, there is provided a data synchronization method, wherein one transmission unit comprises preamble information and data following the preamble, wherein the one transmission unit comprises: The elements of the data included in the unit are kept until the appropriate update is performed.
A data synchronization method for receiving data transmitted by transmitting the same information for each of a plurality of transmission units, wherein an appearance pattern of at least a part of the data included in the transmission unit And a synchronization detecting step of comparing the received data with the stored pattern, and detecting a synchronization of the received data based on a result of the comparison. And the following.

For example, taking the case of a GPS satellite signal as an example, the same information is transmitted for several hours or several months as described above for ephemeris information and almanac information. According to the first aspect of the invention, each bit and each word of the ephemeris information and the almanac information are stored in the storing step. Each bit and each word of the ephemeris information and almanac information may be stored in a memory obtained at the previous reception, or may be obtained from an information server on a network via communication means, for example. It may be stored.

Then, after synchronizing the C / A code of the GPS signal, the bit pattern or word pattern of the received data is compared with the stored pattern for collation. As described above, since the same signal is transmitted for several hours or months for the ephemeris information and the almanac information, it is possible to detect a match between the received data and the storage pattern by this pattern matching.
That is, instead of information sent every 6 seconds in subframe units such as a preamble, 20 ms or 6
Time synchronization can be achieved at high speed with the information every 00 milliseconds.

According to a second aspect of the present invention, in the data synchronization method according to the first aspect, the received data includes:
A step of performing a check with the prescribed pattern of the preamble information, wherein the synchronization detecting step includes both a result of the comparison with the prescribed pattern of the preamble information and a result of the comparison between the stored pattern and the received data. The synchronization is detected based on

For example, in the case of a GPS satellite signal,
When the ephemeris information or almanac information is updated, a match cannot be detected even if the received data is compared with the stored pattern data in the memory until the updated data is stored in the memory. However, in the case of the second aspect of the present invention, the method further includes a step of detecting the preamble information to perform time synchronization. Therefore, even at the time of updating, synchronization is performed by time synchronization using the preamble information. You can keep taking.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a data synchronization method and a data receiving apparatus according to the present invention will be described with reference to the drawings, taking as an example a case where the above-mentioned GPS receiver synchronizes time with a GPS satellite signal. I will explain while.

In the data synchronization method according to this embodiment, the navigation message appearing at a certain time is the same information or the information that can be predicted unless the information is updated for a predetermined time. In addition to the elements such as the preamble which are always the same in the navigation message, the other parts such as bits and words of the navigation message are used for time synchronization.

That is, part or all of the navigation message to be used for time synchronization is stored in a memory in the data receiver in advance, and the C / C
After synchronizing the A code, the data stored in the memory is compared with the received data to perform time synchronization.

In the case of this embodiment, an element used when the data portion of the navigation message other than the preamble or the like is used for time synchronization can be arbitrarily set in units of 1 bit (20 ms) or more. However, in order to avoid a situation where time synchronization fails as a result of locking with an incorrect data portion, this embodiment uses a certain bit length and a combination thereof. For example, one word of the navigation message (that is, 30 bits, 600 milliseconds) is used as an element unit, and several words are used in combination. The plurality of words to be combined may be continuous words or discrete words.

Also, in this embodiment, even when the navigation message sent from the satellite changes and the navigation message cannot be used for time synchronization, the preamble is always the same regardless of the update of the navigation message. Therefore, by using a time synchronization technique similar to the conventional one using the preamble, it is possible to maintain at least the same performance as that of the conventional GPS receiver.

According to the data synchronization method of this embodiment configured as described above, time synchronization can be achieved by using a plurality of words in one subframe (within 6 seconds). As compared with the case of using, time synchronization can be performed at a higher speed.

FIG. 1 is a block diagram showing a system configuration of a GPS receiver as an embodiment of the data receiving apparatus of the present invention.

In FIG. 1, the antenna unit 1 has a GP
An S satellite signal or the like is received, and the received signal is supplied to a high-frequency signal processing unit (abbreviated as an RF unit) 2. The RF unit 2 converts the frequency of the received signal into an intermediate frequency signal of several MHz to several tens of MHz, and outputs the intermediate frequency signal to the demodulation / arithmetic unit 3. The demodulation / arithmetic unit 3 synchronizes the C / A code,
Performs demodulation (spectrum despreading) processing, synchronizes time, and executes positioning calculation. The clock unit 4 holds and updates clock information for positioning calculation in the demodulation / arithmetic unit 3.

The demodulation / arithmetic unit 3 stores ephemeris information and almanac information obtained by demodulating the received signal in the storage unit 5. In addition, the receiver of this embodiment transmits ephemeris information and almanac information to GPS.
The antenna 8 and the communication unit 7 are provided so as to be obtained from outside the satellite. The input / output unit 6 is for outputting a result or the like obtained by the positioning calculation, or for taking in necessary information.

Next, a method of time synchronization in this embodiment will be described below.

For example, the reference document “ARINC RESE
ARCH CORP. , “Navstar GPS S
space Segment / Navigation U
ser Interfaces, "ICD-GPS-2
00, Rev. C, 1997, P129. , There is a certain order between the ephemeris information and the almanac information sent from the GPS satellites. Further, as described above, the same information is transmitted from the GPS satellites until the ephemeris information and the almanac information are updated.

From the ephemeris information and the almanac information, the approximate position of each available satellite can be known, and when a navigation message from a certain satellite is received, the received signal is used to determine the approximate element in the navigation message. Can be calculated.

From the above, in this embodiment, G
Ephemeris information or almanac information previously received by the PS receiver or obtained from the outside using the antenna 8 and the communication unit 7 and stored in the storage unit 5;
The correspondence with the time axis is obtained by calculation, and the correspondence is stored in the storage unit 5 as a table.

The unit for time synchronization is determined as one element of the data part of the navigation message. This one element may be any unit as long as it is one bit or more, for example, it may be one word unit.

After receiving the GPS signal and despreading the spectrum (after synchronizing C / A), the navigation message stored in the storage unit 5 is stored for each element of the output signal of the despread spectrum. Is checked against the corresponding element pattern to check whether both patterns match. Then, time synchronization is performed based on the result of the comparison.

However, in order to avoid erroneous synchronization, time synchronization is not performed when a pattern match is detected for a single element as a result of comparison, but the pattern match is performed for all of a plurality of predetermined elements. When time is detected, time synchronization is performed. As described above, the plurality of elements may be continuous elements or discrete elements. In the example described below, for example, one element is one word, and When a pattern match is detected for all of the words, time synchronization is established.

Further, in this embodiment, pattern matching is performed in the preamble portion as in the prior art, and the preamble portion is used for time synchronization. This is GPS
In case the navigation message held inside the receiver becomes invalid due to switching of information or unexpected situation,
Elements that are always the same in the navigation message, in this example, when a preamble appears, enable time synchronization using time information corresponding to this preamble, separately from the result of collation using a table described later. That's why.

The method of time synchronization in this embodiment will be further described with reference to the flowcharts of FIGS.

First, it is determined whether or not a navigation message is stored in the storage unit 5 and a correspondence table between the navigation message and the time axis is stored (step S1).
01). When it is determined that the navigation message is not stored in the storage unit 5 and the correspondence table is not held, in this example, whether the navigation message can be acquired from the outside through the antenna 8 and the communication unit 7 is determined. It is determined (step S102), and if not possible, this processing routine ends.

Then, if possible, it communicates with the outside using the antenna 8 and the communication unit 7 to acquire a navigation message and clock information, and stores them in the storage unit 5 (step S10).
3). Subsequently, a correspondence table between the acquired navigation message and the time axis is generated, and information of the correspondence table is stored in the storage unit 5 (step S104). And
It returns to step S101.

If it is determined in step S101 that the navigation message and the correspondence table are stored in the storage unit 5, the satellite signal is received, and the C / A code synchronization process is started (step S105). And C /
When it is determined that the synchronization of the A-code has been completed (step S106), the navigation message included in the satellite signal is decoded at any time (step S107).

When it is determined that the decoding of one element of the navigation message, for example, the bit pattern of one word is completed (step S108), it is determined whether or not one word which is one element of the decoded navigation message is a preamble. Is determined (step S109). As a result of the determination, when it is determined that the pattern is a preamble pattern, it is determined whether or not the appearance timing of the preamble pattern is appropriate (step S110). Whether the appearance timing is appropriate is determined based on whether the interval between the previously detected preamble timing and the determined preamble timing is appropriate.

If it is determined that the timing of appearance of the preamble pattern is proper, the time information corresponding to the preamble is stored in the buffer memory as a candidate for time synchronization, and the preamble counter is incremented (step S111). When it is determined that the appearance timing of the preamble pattern is not appropriate, the preamble counter is cleared (step S112). This is to prevent erroneous time synchronization due to erroneous detection of the preamble.

If it is determined in step S109 that the decoded one element (word) is not a preamble,
The process proceeds to step S113 in FIG. Step S11
1 or after step S112, step S113
Proceed to.

In step S113, a collation operation is performed between one element of the decrypted navigation message and a stored element pattern using the created table. In this embodiment, the collation range is narrowed down to some extent with reference to the clock information of the GPS receiver, thereby shortening the collation time. The range of the narrowing down is the clock section 4 provided in the GPS receiver.
Is determined by the accuracy of the clock information.

Then, the result of the collation in step S113 is determined (step S114). As a result of this determination, if there is an element (one word) whose pattern matches in the collation range, it is determined whether or not the appearance timing of the element is appropriate (step S115). In this example, whether or not the appearance timing of this element, that is, one word is appropriate is determined based on whether or not the appearance timing of successive words is appropriate. When collation is performed on a plurality of discontinuous words, it is determined whether or not the appearance timing of the word that is known in advance is appropriate.

When it is determined that the appearance timing is appropriate, the time information corresponding to the element (word) is stored in the buffer memory as a candidate for time synchronization, and
The quick lock counter for preventing erroneous synchronization of the time synchronization using the table is incremented (step S11).
6). If it is determined that the value is not valid, the quick lock counter is cleared. This is to prevent erroneous synchronization.

If it is determined in step S113 that there is no element whose pattern matches the collation range, the flow advances to step S118. Step S11
After Step 5 and Step S116, the process proceeds to Step S118.

In step S118, it is determined whether or not the sum of the count value of the quick lock counter and the count value of the preamble counter is equal to or larger than a predetermined count value. The reason for using the sum in this way is to avoid erroneous synchronization and to increase the speed of time synchronization by including the count value of the pattern match of the preamble.

If it is determined in step S118 that the sum of the count value of the quick lock counter and the count value of the preamble counter is not equal to or greater than the specified value, the process returns to step S107, and the process proceeds to step S107. , And the same procedure as described above is repeated.

If it is determined in step S118 that the sum of the count value of the quick lock counter and the count value of the preamble counter is equal to or larger than the specified value, the process proceeds to step S119, and the process proceeds to step S111 as a time information candidate. Alternatively, time synchronization is performed using the time information corresponding to the preamble or the time information corresponding to the word which is an element of the navigation message stored in the buffer memory in step S116.

In this case, steps S109-S110-
When step S119 is reached through steps S111-S113-S114-S118, time synchronization is performed with time information temporarily stored in the buffer memory as a candidate for time information corresponding to the preamble.
In other cases, the time is synchronized with the time information temporarily stored in the buffer memory as a candidate for the time information corresponding to the word which is an element of the navigation message data portion.

For example, as shown in FIG. 2, data of a subframe of certain ephemeris information or almanac information includes a preamble and TOW (Time Of W).
eek) followed by eight words Wa, W
The case of b, Wc, Wd, We, Wf, Wg, Wh is taken as an example.

For example, assuming that the prescribed count value in step S118 is 4, for example, the result of the comparison between the received data and the data stored in the storage unit 5 is as shown in FIG. In this case, time synchronization can be achieved with time information corresponding to the word Wb corresponding to the fourth word of the subframe.

As described above, in this embodiment,
For each element of the data part of the navigation message, the matching is performed with the corresponding element part stored in the storage unit 5 in advance. If the matching result indicates that the pattern matches, the time information corresponding to the element is extracted. Store as a candidate. Then, in order to avoid erroneous synchronization, the above-described matching procedure for each element is repeated a plurality of times, and an element that matches the pattern is present in the matching range, and is continuously continuous on the time axis with the previous matching element. Make sure it is (or is in a valid position). At the same time, it is checked whether a preamble or the like appears at a constant interval.

When the collation work and the appearance position confirmation are completed as described above, final time synchronization is performed on the satellite, and the distance between the satellite and the GPS receiver is calculated. As soon as the distance from the number of satellites required for the positioning calculation (usually three satellites for two-dimensional positioning and four satellites for three-dimensional positioning) can be calculated, the positioning calculation is performed, the result is output, and the processing is terminated.

When a position is determined at intervals of several minutes to several tens of minutes in a mobile object such as a portable terminal using the data synchronization method of the above-described embodiment, the above-described GPS receiver is used. The time required to find the position can be shortened, contributing to power saving of the device.

Further, for the user, the time required for obtaining the position is shortened, so that the waiting time is reduced, and the stress accompanying use can be reduced. In addition, the power saving allows the capacity of the battery required for driving to be reduced, thereby facilitating application to ultra-small positioning / precision time measuring devices such as wristwatches.

In the above-described embodiment, the preamble counter reflecting the reference result of the preamble and the quick lock counter reflecting the reference result of one element of the navigation message are separately provided. One counter may be used.

In the above-described embodiment, the time synchronization is performed when the sum of the value of the preamble counter and the value of the quick lock counter is equal to or greater than a predetermined value. May be time-synchronized when either of the states becomes equal to or more than a predetermined value or when the value of the quick lock counter becomes equal to or more than a predetermined value.

It is needless to say that the object to which the present invention is applied is not limited to the case where the above-mentioned GPS receiver synchronizes the time when receiving the GPS satellite signal.

[0065]

As described above, according to the present invention, the time until data synchronization can be obtained can be reduced. Therefore, if the present invention is applied to a GPS receiver, the time required until the start of positioning calculation can be greatly reduced. Thus, by shortening the time from power-on to position measurement, the driving time of the GPS receiver required for position measurement is reduced, contributing to power saving. Further, since the time until the position measurement after the power is turned on is shortened, the stress of the user using the position measurement function can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a GPS receiver as an embodiment of a data receiving device according to the present invention.

FIG. 2 is a diagram for explaining an embodiment of a data synchronization method according to the present invention.

FIG. 3 is a part of a flowchart for explaining a synchronization procedure of the data synchronization method according to the embodiment of the present invention;

FIG. 4 is the remaining part of the flowchart for explaining the synchronization procedure of the embodiment of the data synchronization method according to the present invention.

FIG. 5 is a diagram for explaining a structure of a GPS satellite signal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... GPS antenna, 2 ... High frequency signal processing part, 3 ... Demodulation / calculation part, 4 ... Clock part, 5 ... Storage part, 6 ... Input / output part, 7
... Communication unit, 8 ... Communication antenna

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J062 BB05 CC07 DD05 5K047 GG34 HH01 HH15 HH53 MM12 MM24 MM56

Claims (12)

[Claims] 1. One transmission unit includes preamble information,
Consisting of data following this preamble, the elements of the data included in the one transmission unit, until an appropriate update is performed, for each of a plurality of the transmission units,
What is claimed is: 1. A data synchronization method for receiving data transmitted by transmitting the same information, wherein the same pattern as the appearance pattern of at least some elements of the data included in the transmission unit is stored in advance. And a synchronization detecting step of comparing the received data with the stored pattern, and detecting a synchronization of the received data based on a result of the comparison. Synchronization method. 2. The data synchronization method according to claim 1, further comprising a step of comparing the received data with a prescribed pattern of the preamble information, wherein the synchronization detecting step comprises: A data synchronization method, wherein synchronization is detected based on both the result of the comparison and the result of the comparison between the stored pattern and the received data. 3. One transmission unit includes preamble information and
Consisting of data following this preamble, the elements of the data included in the one transmission unit, until an appropriate update is performed, for each of a plurality of the transmission units,
A data synchronization method for receiving data transmitted by transmitting the same information, wherein the plurality of patterns are the same as an appearance pattern of at least some of a plurality of elements in the data included in the transmission unit. A counting step of comparing the received data with the stored plurality of patterns, and counting the number of times that a pattern is detected as being matched. A synchronization detection step of detecting synchronization of the received data when the count value in step (b) becomes equal to or greater than a predetermined value. 4. One transmission unit includes preamble information,
Consisting of data following this preamble, the elements of the data included in the one transmission unit, until an appropriate update is performed, for each of a plurality of the transmission units,
A data synchronization method for receiving data transmitted by transmitting the same information, wherein a plurality of patterns identical to an appearance pattern of a plurality of elements of at least a part of the data included in the transmission unit are used. A storing step of storing in advance, a first counting step of comparing the received data with the stored plurality of patterns, and counting the number of times that a pattern is detected as matching; A second counting step of comparing the received data with a prescribed pattern of the preamble information and counting the number of times that a pattern is detected to match; a count value in the first counting step; A data synchronization method for detecting synchronization of the received data based on the count value in the second counting step. 5. The data synchronization method according to claim 4, wherein a sum of a count value in said first counting step and a count value in said second counting step is equal to or greater than a predetermined value. Detecting the synchronization of the received data when the data is received. 6. The data synchronization method according to claim 1, wherein said data is a GPS navigation message, and said data synchronization is time synchronization after phase synchronization of C / A code is obtained.
The data synchronization method according to claim 5. 7. One transmission unit includes preamble information,
Consisting of data following this preamble, the elements of the data included in the one transmission unit, until an appropriate update is performed, for each of a plurality of the transmission units,
In a data receiving device that receives data transmitted by transmitting the same information, a pattern storage unit that stores in advance a data pattern that is the same as an appearance pattern of at least a part of the data included in the transmission unit. A data receiving apparatus for comparing the received data with the stored pattern and detecting synchronization of the received data based on a result of the comparison. 8. The data receiving apparatus according to claim 7, further comprising: means for comparing the received data with a prescribed pattern of the preamble information; Wherein the synchronization is detected on the basis of both the result of the comparison and the result of the comparison between the stored pattern and the received data. 9. One transmission unit includes preamble information,
Consisting of data following this preamble, the elements of the data included in the one transmission unit, until an appropriate update is performed, for each of a plurality of the transmission units,
A data receiving apparatus for receiving data transmitted by transmitting the same information, wherein a plurality of patterns identical to appearance patterns of at least some of a plurality of elements in the data included in the transmission unit are stored in advance. A pattern storage unit to store, the received data and the stored plurality of patterns are compared with each other, and counting means for counting the number of times the patterns are detected as matching, and counting by the counting means And a synchronization detecting means for detecting synchronization of the received data when the value is equal to or greater than a predetermined value. 10. One transmission unit is composed of preamble information and data following the preamble, and the data element included in the one transmission unit has one element until an appropriate update is performed. ~ For each of the plurality of transmission units, in a data receiving device that receives data transmitted by transmitting the same information, the appearance pattern of at least some of the plurality of elements in the data included in the transmission unit, A pattern storage unit that stores the same plurality of patterns in advance, and compares the received data with the stored plurality of patterns, and counts the number of times that it is detected that the patterns match. 1 counting means, and compares the received data with a prescribed pattern of the preamble information, and counts the number of times that the pattern is detected to match. A second counting unit that counts the number of times of the received data, and a synchronization detecting unit that detects synchronization of the received data based on the count value of the first counting unit and the count value of the second counting unit. A data receiving device, comprising: 11. The data receiving apparatus according to claim 10, wherein said synchronization detecting means determines a sum of a count value of said first counting means and a count value of said second counting means. A data receiving apparatus for detecting synchronization of the received data when the value becomes equal to or greater than a given value. 12. The reception data is a GPS navigation message, and the data synchronization is time synchronization after phase synchronization of a C / A code is obtained. 12. The data receiving device according to any one of the eleventh to eleventh aspects.