JP2011226866A

JP2011226866A - Gps timepiece and its method

Info

Publication number: JP2011226866A
Application number: JP2010095520A
Authority: JP
Inventors: Kenichi Matsushima; 健一松島; Shinichi Nogawa; 真一野川
Original assignee: Seiko Instruments Inc
Current assignee: Seiko Instruments Inc
Priority date: 2010-04-16
Filing date: 2010-04-16
Publication date: 2011-11-10

Abstract

PROBLEM TO BE SOLVED: To provide a timepiece and its method that solve the following problems: if all of 24 or more satellites are searched, reception and processing time for GPS signals becomes long and a large amount of power is consumed; and if satellite health information is not received, there is a possibility that a GPS time obtained from a satellite under maintenance inspection is largely shifted and therefore if it is directly reflected on an RTC time, an incorrect time will continue to be displayed until the next time a GPS signal is received.SOLUTION: By giving candidate GPS satellites from which to receive signals an order of priority based on the magnitude of the signal intensity of the GPS satellites, an optimum satellite can be selected quickly, and if a GPS time is largely shifted, more reliable and accurate time correction can be made by checking with two or more GPS satellites.

Description

本発明は、位置情報衛星などの衛星からの電波に含まれる時刻情報を基に、内部時計の時刻を修正して表示する時計に関する。 The present invention relates to a clock that corrects and displays the time of an internal clock based on time information included in radio waves from a satellite such as a position information satellite.

位置情報衛星の主たる目的は、複数の位置情報衛星の位置とそれらの位置情報衛星からの電波の遅延時間により受信点の位置を求めることである。しかし、位置情報衛星には原子時計などの極めて精度の高い時計が搭載されており、位置情報衛星からの時刻情報を基に内部時計の時刻を修正して精度の高い時刻を表示する時計が多数開示されている。（例えば特許文献１参照） The main purpose of the position information satellite is to obtain the position of the reception point from the position of a plurality of position information satellites and the delay time of radio waves from those position information satellites. However, position information satellites are equipped with extremely accurate clocks such as atomic clocks, and there are many clocks that display accurate time by correcting the time of the internal clock based on the time information from the position information satellite. It is disclosed. (For example, see Patent Document 1)

しかし、時計は建物などの電波の比較的弱い場所に設置されることも多く、１回の受信では必ずしも充分ではなく、間欠的に複数回受信して得られたデータを基に内部時計の時刻を修正して表示する時計も開示されている。（例えば特許文献２参照） However, the clock is often installed in a place with relatively weak radio waves, such as a building, and one reception is not always sufficient, and the time of the internal clock is based on data obtained by intermittent reception multiple times. A watch that corrects and displays the above is also disclosed. (For example, see Patent Document 2)

このような従来のＧＰＳ計時装置について、図３を基に説明する。 Such a conventional GPS timing device will be described with reference to FIG.

図３における従来のＧＰＳ計時装置では、位置情報衛星からの電波をアンテナにより電気信号に変換する。 In the conventional GPS timing device in FIG. 3, the radio wave from the position information satellite is converted into an electric signal by the antenna.

ＲＦ手段では、局部発振とのミキシングにより周波数をダウンコンバージョンする。 The RF means down-converts the frequency by mixing with local oscillation.

組合せ復調手段では、サーチする周波数毎に位置情報衛星からの繰り返される電波を相関器で捕捉するとともに、トラッキングしてＣＡコードの１ｍｓの各サイクルに重畳している航法メッセージデータを抽出する。 The combination demodulator captures the repeated radio waves from the position information satellite for each frequency to be searched by the correlator, and extracts the navigation message data that is tracked and superimposed on each 1 ms cycle of the CA code.

さらに、ＣＡコードの１サイクル１ｍｓ毎の航法メッセージデータのビットの境界を抽出して、各ビットを構成する２０ｍｓ分の航法メッセージデータを集約するとともに、繰り返されるサブフレームから受信して抽出した航法メッセージデータに不整合がないことを確認することにより受信データの信頼度を確保しつつ、航法メッセージデータから時刻情報を抽出する。 Furthermore, the navigation message data bit boundaries for each 1 ms cycle of the CA code are extracted, the navigation message data for 20 ms constituting each bit is aggregated, and the navigation message received and extracted from repeated subframes. Time information is extracted from the navigation message data while ensuring the reliability of the received data by confirming that there is no inconsistency in the data.

現在時刻算出手段は、航法メッセージデータから抽出した時刻情報から協定世界時刻(ＵＴＣ)を算出し、さらに現在位置で決まる時差を加味したローカル時刻を算出する。 The current time calculation means calculates a coordinated universal time (UTC) from the time information extracted from the navigation message data, and further calculates a local time taking into account the time difference determined by the current position.

ＲＴＣ手段は、一般的な水晶時計で使われる水晶発振回路を有し、その発振クロックをカウントして内部時刻(ＲＴＣ時刻)を計時する。ＧＰＳ受信で得られた正確な現在時刻を現在時刻算出手段から受け取り、ＲＴＣ時刻を修正する事ができる。ＲＴＣ手段で計時されるＲＴＣ時刻は、図１３に示すような時刻表示手段で表示される。 The RTC means has a crystal oscillation circuit used in a general crystal clock, and counts the oscillation clock to measure the internal time (RTC time). The exact current time obtained by GPS reception can be received from the current time calculation means, and the RTC time can be corrected. The RTC time counted by the RTC means is displayed by time display means as shown in FIG.

これら一連の手段は、制御手段によって制御される。 These series of means are controlled by the control means.

時刻表示手段は、現在位置で決まる時差を加味したローカル時刻を表示する必要があるので、一般的には現在時刻算出手段では時差を加算したローカル時刻を算出する。その場合、ＲＴＣ時刻も時差を加算したローカル時刻を計時し、そのまま時刻表示手段でローカル時刻を表示する。 Since the time display means needs to display the local time taking into account the time difference determined by the current position, the current time calculation means generally calculates the local time by adding the time difference. In that case, the RTC time is also measured by adding the time difference, and the local time is displayed as it is by the time display means.

一方、ＲＴＣ時刻を協定世界時刻(ＵＴＣ)で計時する事も可能であり、その場合、現在時刻算出手段は現在の協定世界時刻(ＵＴＣ)を算出してＲＴＣ時刻を補正する。時刻表示手段でローカル時刻を表示するときは、ＲＴＣ時刻に現在位置で決まる時差を加算して表示する。 On the other hand, it is also possible to measure the RTC time in the Coordinated Universal Time (UTC), in which case the current time calculating means calculates the current Coordinated Universal Time (UTC) and corrects the RTC time. When the local time is displayed by the time display means, the time difference determined by the current position is added to the RTC time and displayed.

従来のＧＰＳ計時装置による、現在時刻の修正を工程で説明すると図４のようになる。 The correction of the current time by the conventional GPS timing device will be described in the process as shown in FIG.

ＧＰＳ計時装置は、ＲＴＣの時刻精度を正確に保つために一定の周期(例えば1日に一回)でＧＰＳ信号を受信し、時刻を修正するのが一般的である。そのために、受信時刻判定工程でＧＰＳ信号を受信する時刻になるのを確認し、ＧＰＳ信号受信工程でＧＰＳ信号を受信して時刻情報を抽出し、現在時刻算出工程で現在時刻を算出する。 In general, the GPS timing device receives a GPS signal at a constant period (for example, once a day) and corrects the time in order to accurately maintain the time accuracy of the RTC. For this purpose, it is confirmed that the time for receiving the GPS signal is reached in the reception time determining step, the GPS signal is received in the GPS signal receiving step, time information is extracted, and the current time is calculated in the current time calculating step.

現在時刻が算出されたら、ＲＴＣ時刻修正工程でＲＴＣ時刻を修正し、時刻表示工程で修正した時刻を表示する。 When the current time is calculated, the RTC time is corrected in the RTC time correction process, and the corrected time is displayed in the time display process.

このような手段、あるいは工程で、位置情報衛星から時刻情報を抽出するためには、複数の位置情報衛星をサーチして捕捉し、位置情報衛星からの電波をトラッキングしながらＧＰＳ航法メッセージデータを受信し、ＴＬＭ，ＴＯＷなどの時刻情報データとサブフレームＩＤを抽出する必要がある。ＴＬＭ、ＴＯＷなどの時刻情報データを、連続するサブフレーム(例えば、第１サブフレームと第２サブフレーム)において整合が取れていた場合に、抽出した時刻情報データが正しいと判断してＲＴＣ時刻を修正し、時刻を表示し、ＧＰＳ信号の受信を終了する。もし整合がとれない場合は、整合がとれるまでサブフレームの受信を繰り返す。 In order to extract time information from position information satellites by such means or processes, a plurality of position information satellites are searched and captured, and GPS navigation message data is received while tracking radio waves from the position information satellites. It is necessary to extract time information data such as TLM and TOW and subframe ID. When the time information data such as TLM, TOW, etc. are matched in successive subframes (for example, the first subframe and the second subframe), it is determined that the extracted time information data is correct and the RTC time is calculated. Correct, display the time, and finish receiving GPS signals. If the match cannot be obtained, the reception of the subframe is repeated until the match is obtained.

しかし位置情報衛星からの電波が弱い場合には、連続するサブフレームの受信データの整合がとれるまでに長い時間を要したり、また受信感度を高くするために相関手段を長くしたりすると、１つの周波数で相関を得るための時間が長くなるばかりでなく、捕捉できる周波数の範囲が狭くなり、サーチする周波数の数が多くなることによる相乗効果で、サーチに要する時間が著しく長くなる。ＧＰＳ計時装置を、乾電池やボタン型電池などで駆動する場合、ＧＰＳ信号の受信処理時間が長くなる事で電池の消耗が激しくなり電池寿命が極端に短くなる。 However, if the radio waves from the position information satellite are weak, it takes a long time to match the received data of consecutive subframes, or if the correlation means is lengthened to increase the reception sensitivity, 1 Not only does it take longer to obtain a correlation at one frequency, but the range of frequencies that can be captured is narrowed, and the synergistic effect of increasing the number of frequencies to be searched increases the time required for searching significantly. When the GPS timing device is driven by a dry battery, a button-type battery, or the like, the GPS signal reception processing time becomes long, so that the battery is consumed rapidly and the battery life is extremely shortened.

位置情報衛星は２４個以上が地球を周回しており、地上の特定位置で衛星信号を受信する場合、受信する時刻によってどの衛星信号が受信可能であるかが変わる。そのために衛星信号の航法メッセージデータにアルマナック情報が重畳してあり、アルマナック情報を入手すれば全衛星の軌道計算ができ、地球上の現在位置で受信に最適な衛星を選ぶ事ができる。しかしアルマナック情報は時刻情報よりも圧倒的に情報量が多いので、電波の受信状態が悪い時にアルマナック情報を正確に入手するのは時刻情報の入手よりも困難である。 24 or more position information satellites orbit the earth, and when satellite signals are received at a specific position on the ground, which satellite signals can be received depends on the reception time. For this purpose, almanac information is superimposed on the navigation message data of the satellite signal. If the almanac information is obtained, the orbits of all satellites can be calculated, and the most suitable satellite for reception can be selected at the current position on the earth. However, since the almanac information is overwhelmingly larger than the time information, it is more difficult to obtain the almanac information accurately than the time information when the radio wave reception state is poor.

衛星信号からアルマナック情報を受信しない場合は２４個以上の全衛星が信号受信の対象になり、また受信する場所と周囲の建物構造によって衛星の信号強度も変わるので、受信可能な衛星をサーチし時刻情報を抽出するまでの受信処理時間は長くなり多くの電力を消費する。 If almanac information is not received from the satellite signal, all 24 or more satellites will be subject to signal reception, and the signal strength of the satellite will also change depending on the receiving location and the surrounding building structure. The reception processing time until information is extracted becomes long and consumes a lot of power.

また、保守点検中の衛星の信号を受信した場合は、信号から抽出する時刻情報が保守点検の為に大きくシフトしている事があり得る。 In addition, when the signal of the satellite under maintenance inspection is received, the time information extracted from the signal may be greatly shifted due to the maintenance inspection.

特開平１０−８２８７５号公報Japanese Patent Laid-Open No. 10-82875

アルマナック情報を受信しない場合は、２４個以上の全衛星を対象にして受信可能な衛星をサーチする事になるので、ＧＰＳ信号の受信処理時間が長くなり多くの電力を消費する。また、衛星の健康情報を受信しない場合は保守点検中の衛星信号を受信する可能性もあるので、受信によって得られるＧＰＳ時刻は大きくシフトしている可能性がある。そのＧＰＳ時刻をそのままＲＴＣ時刻に反映させると次のＧＰＳ信号受信まで間違った時刻表示を続けてしまう。 When the almanac information is not received, the receivable satellites are searched for all 24 or more satellites, so that the GPS signal reception processing time is increased and a large amount of power is consumed. In addition, when satellite health information is not received, there is a possibility that a satellite signal during maintenance inspection may be received, and therefore the GPS time obtained by reception may be greatly shifted. If the GPS time is reflected on the RTC time as it is, an incorrect time display is continued until the next GPS signal reception.

複数の位置情報衛星から電波を受信するＲＦ手段、特定の衛星をサーチして航法メッセージデータを復調する組み合わせ復調手段、航法メッセージデータから時刻情報を抽出しローカル時刻を算出するローカル時刻算出手段、内部時計の時刻を計時するＲＴＣ手段、ＲＴＣ手段による内部時刻を表示する時刻表示手段、前記すべての手段を制御する制御手段を有する時計であり、組み合わせ復調手段から受信する信号の強度を検出する信号強度検出手段を有し、信号強度に従って衛星受信の候補を順位付けると共に、現在時刻算出手段により得られたＧＰＳ時刻からＲＴＣ手段によるＲＴＣ時刻の補正量を算出し、特定の補正量許容範囲と比較する補正量比較手段を有し、時刻の補正量が特定の補正量許容範囲よりも大きい時に２種類以上の衛星の航法メッセージデータを受信してＲＴＣ時刻を補正する。 RF means for receiving radio waves from a plurality of position information satellites, combination demodulation means for searching for specific satellites and demodulating navigation message data, local time calculation means for extracting time information from navigation message data and calculating local time, internal RTC means for measuring the time of the clock, time display means for displaying the internal time by the RTC means, and a control means for controlling all the means, and a signal strength for detecting the strength of the signal received from the combination demodulating means It has detection means, ranks satellite reception candidates according to the signal strength, calculates the RTC time correction amount by the RTC means from the GPS time obtained by the current time calculation means, and compares it with a specific correction amount allowable range There are correction amount comparison means, and when the correction amount of time is larger than a specific correction amount allowable range, two or more types To receive a star of the navigation message data to correct the RTC time.

例えば、第１候補に順位付けられた衛星で得たＧＰＳ時刻による時刻補正量が特定の補正量許容範囲よりも大きい時は、引き続き第２候補の衛星を受信してＲＴＣ時刻の補正量を算出し、第２候補の衛星による時刻補正量が特定の補正量許容範囲よりも小さいなら第２候補によるＧＰＳ時刻でＲＴＣ時刻を補正すると共に、時刻補正量が大きかった第１候補の衛星を衛星受信の候補から外し、第２候補の衛星を第１候補にする。 For example, when the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the correction amount of the RTC time. If the time correction amount by the second candidate satellite is smaller than the specific correction amount allowable range, the RTC time is corrected by the GPS time by the second candidate, and the first candidate satellite having a large time correction amount is received by satellite. And the second candidate satellite is made the first candidate.

第１候補に順位付けられた衛星で得たＧＰＳ時刻による時刻補正量が特定の補正量許容範囲よりも大きい時に、引き続き第２候補の衛星を受信してＲＴＣ時刻の補正量を算出し、第２候補の衛星による時刻補正量が特定の補正量許容範囲よりも大きくて、第１候補の衛星による時刻補正量と同じなら、第１候補あるいは第２候補によるＧＰＳ時刻でＲＴＣ時刻を補正する。 When the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the correction amount of the RTC time. If the time correction amount by the two candidate satellites is larger than the specific correction amount allowable range and is the same as the time correction amount by the first candidate satellite, the RTC time is corrected by the GPS time by the first candidate or the second candidate.

補正方法としては、定期的にＧＰＳ信号を受信する事により内部時刻を補正する補正方法であり、内部時計がＧＰＳ信号を受信する予定の時刻になった事を判定する工程と、ＧＰＳ信号の受信工程と、ＧＰＳ信号の時刻情報から現在時刻を算出する工程と、正確なＧＰＳ時刻とＲＴＣによる内部時計の時刻との差から時刻補正量を算出する工程があり、さらにＧＰＳ信号の信号強度を判定する工程により信号強度に従って衛星受信の候補を順位付ける工程と、時刻補正量と特定の補正量許容範囲を比較する補正量比較工程を有し、時刻補正量が特定の補正量許容範囲よりも大きい時に２種類以上の衛星の航法メッセージデータを受信してＲＴＣ時刻を補正する。 The correction method is a correction method for correcting the internal time by periodically receiving a GPS signal, the step of determining that the internal clock is scheduled to receive the GPS signal, and the reception of the GPS signal. A step, a step of calculating the current time from the time information of the GPS signal, and a step of calculating a time correction amount from the difference between the accurate GPS time and the time of the internal clock by the RTC, and further determining the signal strength of the GPS signal A step of ranking satellite reception candidates according to signal strength and a correction amount comparison step of comparing a time correction amount with a specific correction amount allowable range, and the time correction amount is larger than the specific correction amount allowable range. Sometimes the navigation message data of two or more kinds of satellites is received to correct the RTC time.

例えば、第１候補に順位付けられた衛星で得たＧＰＳ時刻による時刻補正量が特定の補正量許容範囲よりも大きい時に、引き続き第２候補の衛星を受信してＲＴＣ時刻の補正量を算出し、第２候補の衛星による時刻補正量が特定の補正量許容範囲よりも小さいなら第２候補によるＧＰＳ時刻でＲＴＣ時刻を補正すると共に、時刻補正量が大きかった第１候補の衛星を衛星受信の候補から外し、第２候補の衛星を第１候補にする。 For example, when the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the RTC time correction amount. If the time correction amount by the second candidate satellite is smaller than the specific correction amount allowable range, the RTC time is corrected by the GPS time by the second candidate, and the first candidate satellite having a large time correction amount is received by satellite reception. Remove from the candidate and make the second candidate satellite the first candidate.

本発明によれば、信号強度が強い衛星番号から優先的に受信することで、受信処理に要する時間が短くなる事により電力の消費が少なくなる。更に、ＧＰＳ時刻による時刻の補正量が特定の補正量許容範囲よりも大きい時に２種類以上のＧＰＳ衛星の航法メッセージデータを受信する事で、ＧＰＳ衛星が保守点検に入ってＧＰＳ時刻がシフトしたのか、あるいはＲＴＣ時刻が何らかの原因でシフトしたのかが判断できる。 According to the present invention, by preferentially receiving from a satellite number having a strong signal strength, power consumption is reduced by shortening the time required for reception processing. Furthermore, whether the GPS time was shifted to the GPS check time when the GPS satellites entered maintenance and inspection by receiving navigation message data of two or more types of GPS satellites when the time correction amount based on the GPS time was larger than the specific correction amount allowable range. Alternatively, it can be determined whether the RTC time has shifted for some reason.

また、衛星信号から航法メッセージデータのアルマナック情報を入手しなくても、受信に適した衛星の候補を順位付けられるので、ＧＰＳ信号を繰り返し受信する時の受信処理時間を短くでき、電池の消耗を最小限にし電池寿命を長くできる。 In addition, satellite candidates suitable for reception can be ranked without obtaining almanac information of navigation message data from satellite signals, so that the reception processing time when receiving GPS signals repeatedly can be shortened, and battery consumption is reduced. Minimizes battery life.

また、衛星の健康情報を受信しなくても、たとえ保守点検中の衛星信号を受信した場合でも、受信して得たＧＰＳ時刻をＲＴＣ時刻に反映させる前にＧＰＳ時刻の信頼度を事前確認できるので、より信頼性の高い高精度な時刻補正のできるＧＰＳ計時装置を実現することができる。 Even if satellite health information is not received, the reliability of the GPS time can be confirmed in advance before the GPS time obtained by the reception is reflected in the RTC time even if a satellite signal during maintenance inspection is received. Therefore, it is possible to realize a GPS timing device capable of highly reliable time correction with higher reliability.

本発明に係るＧＰＳ計時装置の好適な一実施例を示すブロック図1 is a block diagram showing a preferred embodiment of a GPS timing device according to the present invention. 本発明に係るＧＰＳ計時装置の好適な一実施例を示す工程フロー図Process flow diagram showing a preferred embodiment of a GPS timing device according to the present invention. 従来のＧＰＳ計時装置のブロック構成図Block diagram of a conventional GPS timing device 従来のＧＰＳ計時装置の工程フロー図Process flow diagram of conventional GPS timing device 本発明に係るＧＰＳ信号強度とＧＰＳ受信間隔を示すグラフGraph showing GPS signal strength and GPS reception interval according to the present invention 本発明に係る時刻補正の方法を示すフロー図Flow chart showing a time correction method according to the present invention. 本発明に係る受信衛星の候補順位の例Examples of candidate ranks of receiving satellites according to the present invention 本発明に係る受信衛星の候補順位の例Examples of candidate ranks of receiving satellites according to the present invention 本発明に係る時刻補正量と特定の補正量許容範囲を比較する説明図Explanatory drawing which compares the time correction amount and specific correction amount tolerance | permissible_range which concern on this invention 本発明に係る時刻補正量と特定の補正量許容範囲を比較する説明図Explanatory drawing which compares the time correction amount and specific correction amount tolerance | permissible_range which concern on this invention 本発明に係る航法メッセージデータのタイミングを示すタイミング図Timing diagram showing timing of navigation message data according to the present invention 本発明に係る航法メッセージデータのタイミングを示す図The figure which shows the timing of the navigation message data based on this invention 本発明に係る時刻表示手段の実施例を示す外観図External view showing an embodiment of a time display means according to the present invention

本発明によるＧＰＳ計時装置の構成や動作を詳細に説明する前に、本発明によるＧＰＳ計時装置が位置情報衛星から受信する航法メッセージデータについて予め説明する。なお、本実施例の以降の説明では、＜＞を大見出し、［］を中見出し、（）を小見出しとして用いている。 Before describing in detail the configuration and operation of the GPS timing device according to the present invention, the navigation message data received from the position information satellite by the GPS timing device according to the present invention will be described in advance. In the following description of the present embodiment, <> is used as a major heading, [] is used as a middle heading, and () is used as a minor heading.

＜航法メッセージデータ＞
［航法メッセージデータのタイミング］
図１１に示す位置情報衛星からの航法メッセージデータのタイミングについて説明する。 <Navigation message data>
[Timing of navigation message data]
The timing of the navigation message data from the position information satellite shown in FIG. 11 will be described.

航法メッセージデータの全体は、ページ番号Ｐ１〜２５を含む２５フレームにより構成される。各フレームは、サブフレーム番号ＳＦ１〜５の５つのサブフレームにより構成される。サブフレーム番号ＳＦ４，５の２つのサブフレームには、ページ番号Ｐ１〜２５の２５ページがあり、フレーム毎にページが切り換わる。各サブフレームは、ワード番号Ｗ１〜１０の１０ワードにより構成される。また、各ワードはビット番号ｂ１〜３０の３０ビットにより構成される。各ワードの初めの２４ビットはデータでＭＳＢから順に送られる。各ワードの最後の６ビットはパリティである。（ここで、各ビットはＣＡ１〜２０の１０２３チップのＣ／Ａコードの２０サイクル分繰り返される。） The entire navigation message data is composed of 25 frames including page numbers P1-25. Each frame is composed of five subframes having subframe numbers SF1 to SF5. The two subframes with subframe numbers SF4 and 5 have 25 pages with page numbers P1 to P25, and the page is switched for each frame. Each subframe is composed of 10 words having word numbers W1 to W10. Each word is composed of 30 bits of bit numbers b1-30. The first 24 bits of each word are sent in order from the MSB as data. The last 6 bits of each word are parity. (Here, each bit is repeated for 20 cycles of the C / A code of 1023 chips of CA1-20.)

ここでＣ／Ａコードの１サイクルは１ｍ秒であるため、各ビットの時間は２０ｍ秒で、各ワードの時間は０．６秒で、各サブフレームの時間は６秒で、各フレームの時間は３０秒で、航法メッセージデータ全体の時間は１２．５分である。これらが全て時系列的に位置情報衛星から送信され、航法メッセージデータの全体が、その値が随時更新されながら、繰り返される。 Here, since one cycle of the C / A code is 1 ms, the time of each bit is 20 ms, the time of each word is 0.6 seconds, the time of each subframe is 6 seconds, and the time of each frame Is 30 seconds, and the total time of the navigation message data is 12.5 minutes. All of these are transmitted from the position information satellite in time series, and the entire navigation message data is repeated while its value is updated as needed.

［時刻の取得に必要な航法メッセージデータ］
図１２に、時刻の取得に必要な航法メッセージデータの時系列的な位置を示す。図１２では、各項目について、サブフレーム番号，ページ番号，ワード番号とビット番号が時系列的な位置を示している。 [Navigation message data required for time acquisition]
FIG. 12 shows the time-series position of the navigation message data necessary for obtaining the time. In FIG. 12, for each item, the subframe number, page number, word number, and bit number indicate the time-series positions.

ここで、ＴＬＭは、予め定められたプリアンブルを含み各サブフレームの最初のワードの位置であることを示すものである。ＴＯＷは、週の初めからの経過時間を示すものである。サブフレームＩＤは、サブフレームの番号を示すものである。ＷＮは、週番号を示すものである。健康状態は、位置情報衛星から送られる航法メッセージデータの信頼性を示すものである。ＵＴＣは、ＧＰＳ時刻からグリニッジ標準時を求めるために必要なパラメータである。なお、各ワードの２５〜３０番目のビットは、パリティデータである。 Here, TLM indicates a position of the first word of each subframe including a predetermined preamble. TOW indicates the elapsed time from the beginning of the week. The subframe ID indicates a subframe number. WN indicates a week number. The health status indicates the reliability of the navigation message data sent from the position information satellite. UTC is a parameter necessary for obtaining Greenwich Mean Time from GPS time. Note that the 25th to 30th bits of each word are parity data.

＜ＧＰＳ計時装置の構成＞
図１は、本発明によるＧＰＳ計時装置全体のブロック構成の好適な一例を示したものである。これより、図１を基にＧＰＳ計時装置を構成する各手段について、詳細に説明する。 <Configuration of GPS timing device>
FIG. 1 shows a preferred example of a block configuration of the entire GPS timing device according to the present invention. Hereafter, each means which comprises a GPS time measuring apparatus is demonstrated in detail based on FIG.

［アンテナ］
図１において、アンテナ１０２は、位置情報衛星からのギガヘルツ帯の電波を高周波信号１１１に変換し、ＲＦ手段１０３に出力する。 [antenna]
In FIG. 1, an antenna 102 converts a gigahertz band radio wave from a position information satellite into a high frequency signal 111 and outputs it to the RF means 103.

［ＲＦ手段］
ＲＦ手段１０３は、アンテナ１０２からの高周波信号１１１を組み合わせ復調手段１０４で処理しやすい低い周波数にダウンコンバージョンする。このため、ＲＦ手段では、局部発振との積により生じる和と差の周波数成分からフィルタにより差の成分を抽出することにより周波数のダウンコンバージョンを行う。局部発振には、周波数精度が高い温度補償型水晶発振器（ＴＣＸＯ）を基にＰＬＬを用いる。なお、ＲＦ手段では、必要に応じてローノイズなアンプを挿入して増幅しても良い。 [RF means]
The RF unit 103 down-converts the high-frequency signal 111 from the antenna 102 to a low frequency that can be easily processed by the combined demodulation unit 104. For this reason, the RF means performs frequency down-conversion by extracting the difference component with a filter from the sum and difference frequency components generated by the product with the local oscillation. For local oscillation, a PLL is used based on a temperature compensated crystal oscillator (TCXO) with high frequency accuracy. In the RF means, a low noise amplifier may be inserted and amplified as necessary.

［組合せ復調手段］
組合せ復調手段１０４では、サーチする周波数毎に位置情報衛星からの繰り返される電波を相関器で捕捉するとともに、トラッキングしてＣＡコードの１ｍｓの各サイクルに重畳している航法メッセージデータを抽出する。 [Combined demodulation means]
The combinational demodulating means 104 captures the repeated radio waves from the position information satellite for each frequency to be searched by the correlator, and extracts the navigation message data superposed on each 1 ms cycle of the CA code by tracking.

［現在時刻算出手段］
現在時刻算出手段１０５は、航法メッセージデータから抽出した時刻情報から現在の協定世界時刻(ＵＴＣ)を算出し、さらに現在位置で決まる時差を加味したローカル時刻を算出する。 [Current time calculation means]
The current time calculation means 105 calculates the current coordinated universal time (UTC) from the time information extracted from the navigation message data, and further calculates the local time taking into account the time difference determined by the current position.

［ＲＴＣ手段］
ＲＴＣ手段１０６は、一般的な水晶時計で使われる水晶発振回路を有し、その発振クロックをカウントして内部時刻（＝ＲＴＣ時刻)を計時する。ＧＰＳ受信で得られた正確な時刻を現在時刻算出手段から受け取り、計時時刻を修正する事ができる。 [RTC means]
The RTC means 106 has a crystal oscillation circuit used in a general crystal clock, and counts the oscillation clock to measure the internal time (= RTC time). Accurate time obtained by GPS reception can be received from the current time calculation means, and the time measured can be corrected.

［補正量比較手段］
補正量比較手段１１０は、ＧＰＳ受信で得られたＧＰＳ時刻とＲＴＣ手段によるＲＴＣ時刻の差を時刻補正量とし、時刻補正量と特定の補正量許容範囲を比較し、制御手段１１０に比較した結果を出力する。制御手段１１０は補正量比較手段１１０に特定の補正量許容範囲を設定する。 [Correction amount comparison means]
The correction amount comparison unit 110 uses the difference between the GPS time obtained by GPS reception and the RTC time by the RTC unit as a time correction amount, compares the time correction amount with a specific correction amount allowable range, and compares the result with the control unit 110 Is output. The control unit 110 sets a specific correction amount allowable range in the correction amount comparison unit 110.

［時刻表示手段］
時刻表示手段１０７の例を示したものが図１３である。時刻表示手段１０７は、ＲＴＣ手段による内部時刻を表示する。表示時刻の更新は、例えば毎正秒ごとに行う。時刻表示手段１０７の表示方法は、例えば、図１３ａ．に示すようなデジタル式の時刻表示器でも良いし、図１３ｂ.に示すようなアナログ式の時刻表示でも良い。また、本発明によるＧＰＳ計時装置は、置き時計でも掛け時計でも腕時計でも良い。 [Time display means]
FIG. 13 shows an example of the time display means 107. The time display means 107 displays the internal time by the RTC means. The display time is updated, for example, every regular second. The display method of the time display means 107 is, for example, FIG. It may be a digital time display as shown in Fig. 13 or an analog time display as shown in Fig. 13b. The GPS timing device according to the present invention may be a table clock, a wall clock, or a wristwatch.

なお、ＲＴＣ時刻は協定世界時刻(ＵＴＣ)で計時する事も可能であり、その場合、現在時刻算出手段は現在の協定世界時刻(ＵＴＣ)を算出してＲＴＣ手段を補正する。時刻表示手段でローカル時刻を表示するときは、現在位置で決まる時差をＲＴＣ時刻に加算して表示すればよい。 Note that the RTC time can also be measured in Coordinated Universal Time (UTC), in which case the current time calculating means calculates the current Coordinated Universal Time (UTC) and corrects the RTC means. When the local time is displayed by the time display means, the time difference determined by the current position may be added to the RTC time and displayed.

［信号強度検出手段］
信号強度検出手段１０９は、組合せ復調手段１０４でサーチして受信したＧＰＳ信号の信号強度を検出するものである。信号強度(強／中／弱)を制御手段１０８に出力する。 [Signal strength detection means]
The signal strength detection unit 109 detects the signal strength of the GPS signal received by searching by the combinational demodulation unit 104. The signal strength (strong / medium / weak) is output to the control means 108.

［制御手段］
制御手段１０８は全体のステータス及びシーケンスを管理する。電波強度検出手段１０９からＧＰＳ信号の信号強度(強／中／弱)を入力し、信号強度によってＧＰＳ信号の受信間隔を変え、時刻補正量と比較する特定の補正量許容範囲を決める。時刻補正量が特定の補正量許容範囲を超えているか否かで、ＲＴＣ時刻の補正方法を決め、また衛星受信の候補の順位を入れ替える。さらに表示時刻の補正方法を変えるための制御を行う。 [Control means]
The control means 108 manages the overall status and sequence. The signal strength (strong / medium / weak) of the GPS signal is input from the radio wave strength detection means 109, the reception interval of the GPS signal is changed according to the signal strength, and a specific correction amount allowable range to be compared with the time correction amount is determined. The RTC time correction method is determined depending on whether or not the time correction amount exceeds a specific correction amount allowable range, and the ranks of candidates for satellite reception are switched. Further, control for changing the display time correction method is performed.

＜ＧＰＳ計時装置の動作＞
本発明によるＧＰＳ計時装置の、表示時刻の修正工程を図２を基に説明する。 <Operation of GPS timing device>
The display time correction process of the GPS timing device according to the present invention will be described with reference to FIG.

［受信時刻判定工程］
ＧＰＳ計時装置は、ＲＴＣの時刻精度を正確に保つために一定の時間間隔でＧＰＳ信号を受信し時刻を修正する。その時間間隔は、1時間／12時間／1日／5日など、求める精度によって変わり得る。１時間毎なら毎正時、１日単位なら毎日夜中の２時、という形で予めＧＰＳ信号の受信時刻を設定しておく。受信時刻判定工程２０１は、ＲＴＣ時刻が予め設定されたＧＰＳ受信時刻になったか否かを判定する工程である。 [Reception time judgment process]
The GPS timing device receives GPS signals at regular time intervals and corrects the time in order to accurately maintain the RTC time accuracy. The time interval may vary depending on the accuracy required, such as 1 hour / 12 hours / 1 day / 5 days. The reception time of the GPS signal is set in advance in the form of every hour at every hour, every day at 2:00 every day at night. The reception time determination step 201 is a step of determining whether or not the RTC time has reached a preset GPS reception time.

［ＧＰＳ信号受信工程］
ＧＰＳ信号受信工程２０２は、受信時刻判定工程２０１によってＧＰＳ信号を受信する時刻になったと判定された場合に、ＧＰＳ信号を受信する工程である。具体的には、位置情報衛星から時刻情報を抽出するために複数の位置情報衛星をサーチして特定の衛星を捕捉し、衛星からの電波をトラッキングしながらＧＰＳ航法メッセージデータを受信し、ＴＬＭ，ＴＯＷなどの時刻情報データとサブフレームＩＤを抽出する。ＴＬＭ、ＴＯＷなどの時刻情報データを、連続するサブフレーム(例えば、第１サブフレームと第２サブフレーム)において整合が取れていた場合に、抽出した時刻情報データが正しいと判断して、ＧＰＳ信号の受信を終了する。もし整合がとれない場合は、整合がとれるまでサブフレームの受信を繰り返す。 [GPS signal receiving process]
The GPS signal reception step 202 is a step of receiving a GPS signal when it is determined by the reception time determination step 201 that it is time to receive a GPS signal. Specifically, in order to extract time information from a position information satellite, a plurality of position information satellites are searched to capture a specific satellite, GPS navigation message data is received while tracking radio waves from the satellite, TLM, Extract time information data such as TOW and subframe ID. When the time information data such as TLM, TOW, etc. are matched in successive subframes (for example, the first subframe and the second subframe), it is determined that the extracted time information data is correct, and the GPS signal The reception of is terminated. If the match cannot be obtained, the reception of the subframe is repeated until the match is obtained.

［信号強度検出工程］
信号強度検出工程２０３は、ＧＰＳ信号受信工程２０２によって捕捉された特定衛星のＧＰＳ信号強度を検出する工程である。 [Signal strength detection process]
The signal strength detection step 203 is a step of detecting the GPS signal strength of the specific satellite captured by the GPS signal reception step 202.

［現在時刻算出工程］
現在時刻算出工程２０４は、ＧＰＳ航法メッセージデータから抽出した時刻情報から協定世界時刻(ＵＴＣ)を算出し、さらに現在位置で決まる時差を加味したローカル時刻を算出する工程である。 [Current time calculation process]
The current time calculation step 204 is a step of calculating the coordinated universal time (UTC) from the time information extracted from the GPS navigation message data, and further calculating the local time taking into account the time difference determined by the current position.

［時刻補正量算出工程］
時刻補正量算出工程２０５は、現在時刻算出工程２０４で得られるＧＰＳ時刻と、内部時刻（＝ＲＴＣ時刻）の差を時刻補正量として算出する工程である。 [Time correction calculation process]
The time correction amount calculation step 205 is a step of calculating a difference between the GPS time obtained in the current time calculation step 204 and the internal time (= RTC time) as a time correction amount.

［補正量比較工程］
補正量比較工程２０６は、時刻補正量算出工程２０５で得られる時刻補正量と特定の補正量許容範囲を比較する工程であり、BlackList判定工程２０７や衛星候補判定工程２０８に比較結果を伝える。特定の補正量許容範囲とは、自己時計ＲＴＣが水晶発振で刻む時刻の精度で決まる時刻誤差の許容値である。一般的に水晶時計の時刻精度は１ヶ月で３０秒以内であり、１日で１秒以上ずれる事は珍しい。従って、前回ＧＰＳ信号を受信して設定したＧＰＳ時刻から1日以内なら特定の補正量許容範囲を例えば１秒とし、５日以内なら特定の補正量許容範囲を例えば５秒として時刻補正量と比較する。 [Correction amount comparison process]
The correction amount comparison step 206 is a step of comparing the time correction amount obtained in the time correction amount calculation step 205 with a specific correction amount allowable range, and transmits the comparison result to the BlackList determination step 207 and the satellite candidate determination step 208. The specific correction amount allowable range is a time error allowable value determined by the accuracy of the time that the self-timer RTC ticks by crystal oscillation. In general, the time accuracy of a quartz clock is within 30 seconds in one month, and it is rare that it is shifted by more than 1 second in one day. Therefore, if it is within one day from the GPS time set by receiving the previous GPS signal, the specific correction amount allowable range is, for example, 1 second, and if within 5 days, the specific correction amount allowable range is, for example, 5 seconds and compared with the time correction amount. To do.

［BlackList判定工程］
BlackList判定工程２０７は、補正量比較工程２０６において時刻補正量と特定の補正量許容範囲を比較し、時刻補正量が特定の補正量許容範囲を超えていた時に、ＧＰＳ受信して得たＧＰＳ時刻が保守点検衛星による誤った時刻である可能性が高いと判断し、受信したＧＰＳ衛星の衛星番号をBlackListに登録し次回の衛星受信の候補から除外する。但し、別のＧＰＳ衛星で得たＧＰＳ時刻でも同様に、時刻補正量が特定の補正量許容範囲よりも大きい場合は、BlackListに登録したＧＰＳ衛星の衛星番号をBlackListの登録から解除し、再び衛星受信の候補に戻す。 [BlackList judgment process]
The BlackList determination step 207 compares the time correction amount with a specific correction amount allowable range in the correction amount comparison step 206, and when the time correction amount exceeds the specific correction amount allowable range, the GPS time obtained by GPS reception Therefore, the satellite number of the received GPS satellite is registered in the BlackList and excluded from candidates for the next satellite reception. However, if the time correction amount is larger than the specific correction amount allowable range, the GPS satellite number registered in the BlackList is canceled from the BlackList registration and the satellite is again registered. Return to candidates for reception.

［衛星候補判定工程］
衛星候補判定工程２０８は、信号強度検出工程２０３で得られた特定衛星のＧＰＳ信号強度によって、受信するＧＰＳ衛星の候補を優先順序をつけるための工程である。信号強度が強いＧＰＳ衛星は、次回の受信でも安定受信できる可能性が高いと判断して次回の衛星受信の候補に入れると共に優先順序を高くする。逆に信号強度が弱いＧＰＳ衛星は、次回の受信でも安定受信が困難と見なして次回の衛星受信の候補から外す、あるいは優先順序を低くする。 [Satellite candidate judgment process]
The satellite candidate determination step 208 is a step for prioritizing the GPS satellite candidates to be received based on the GPS signal strength of the specific satellite obtained in the signal strength detection step 203. A GPS satellite having a strong signal strength is determined to have a high possibility of being able to be stably received at the next reception, and is put into a candidate for the next satellite reception, and the priority order is increased. Conversely, GPS satellites with weak signal strength are regarded as difficult to receive stably even at the next reception, and are excluded from candidates for the next satellite reception, or the priority order is lowered.

［ＲＴＣ時刻修正工程］
ＲＴＣ時刻修正工程２０９は、ＧＰＳ受信して得たＧＰＳ時刻でＲＴＣ時刻を修正し、ＲＴＣ時刻を表示時刻とする。 [RTC time correction process]
The RTC time correction step 209 corrects the RTC time with the GPS time obtained by receiving the GPS, and sets the RTC time as the display time.

［時刻表示工程］
時刻表示工程２１０は、ＲＴＣ時刻修正工程２０９で修正された表示時刻を表示する工程である。時刻の表示は、例えば毎正秒ごとに更新するようにすれば良い。 [Time display process]
The time display process 210 is a process of displaying the display time corrected in the RTC time correction process 209. The display of the time may be updated every regular second, for example.

＜より具体的な説明＞
ＧＰＳ信号から時刻情報を抽出するためには、複数の位置情報衛星をサーチして特定の衛星信号を捕捉し、その信号をトラッキングしながらＧＰＳ航法メッセージデータを受信し、ＴＬＭ，ＴＯＷなどの時刻情報データとサブフレームＩＤを抽出する必要がある。位置情報衛星の信号はギガヘルツ帯の高周波信号なので、受信用ＲＦ回路の消費電流は一般的に大きく、受信処理時間が長いと消費する電力も大きい。電波が弱い場合は、特定の衛星信号を補足するまでに長い時間を要し、またノイズに埋もれた必要情報を抽出するための繰り返し回数が増えて、一連の受信処理時間は長くなり電力の消費は大きくなる。ＧＰＳ計時装置を乾電池やボタン型電池などで駆動するには、一連の受信処理時間を短くする必要があり、特にＧＰＳ信号強度が弱いときは受信処理時間が長くなるので、時刻修正のためのＧＰＳ受信間隔を長くすると電力の消費を抑える事ができる。例えば図５のグラフで示すように、ＧＰＳ信号強度が強いＡの場合は１日間隔で受信し、ＧＰＳ信号強度が弱いＢの場合は５日間隔で受信する。 <More specific explanation>
In order to extract time information from a GPS signal, a plurality of position information satellites are searched to acquire a specific satellite signal, GPS navigation message data is received while tracking the signal, and time information such as TLM and TOW is received. It is necessary to extract data and subframe ID. Since the signal of the position information satellite is a high frequency signal in the gigahertz band, the current consumption of the receiving RF circuit is generally large, and the power consumed when the reception processing time is long is large. When the radio wave is weak, it takes a long time to capture a specific satellite signal, and the number of repetitions for extracting necessary information buried in noise increases, so that a series of reception processing time becomes longer and power consumption is increased. Will grow. In order to drive a GPS timing device with a dry battery or a button-type battery, it is necessary to shorten a series of reception processing times. In particular, when the GPS signal strength is weak, the reception processing time becomes long. Increasing the reception interval can reduce power consumption. For example, as shown in the graph of FIG. 5, when the GPS signal strength is A, the signal is received at intervals of one day, and when B is weak, the signal is received at intervals of five days.

２４個以上あるＧＰＳ衛星のうちどの衛星を選んで受信しても時刻情報を得られるが、現実に捕捉できる衛星は、特定の時刻において５個前後である。しかも各衛星の位置によってはＧＰＳ受信の信号強度が異なり、またギガヘルツ帯の搬送波周波数が微妙にずれたりするので、定期的に受信する場合は、計画的に受信する衛星の候補を選ぶのが望ましい。衛星信号からアルマナック情報を入手すれば全衛星の軌道計算ができ、現在位置で受信に最適な衛星を選べるが、アルマナック情報は時刻情報よりも圧倒的に情報量が多いので、電波の受信状態が悪い時にアルマナック情報を正確に入手するのは時刻情報を入手するよりも困難である。衛星信号からアルマナック情報を受信しない場合は２４個以上の全衛星が信号受信の対象になり、また受信する場所と周囲の建物構造によって衛星の信号強度も変わるので、全衛星を対象にサーチする必要がある。 The time information can be obtained by selecting any of the 24 or more GPS satellites to receive, but the number of satellites that can be actually captured is around 5 at a specific time. Moreover, depending on the position of each satellite, the signal strength of GPS reception varies, and the carrier frequency in the gigahertz band slightly shifts. Therefore, when receiving periodically, it is desirable to select satellite candidates to receive systematically. . Obtaining almanac information from satellite signals can calculate the orbit of all satellites, and you can select the optimal satellite for reception at the current position, but almanac information is overwhelmingly more information than time information, so the reception status of radio waves is Obtaining almanac information accurately at a worse time is more difficult than obtaining time information. If almanac information is not received from the satellite signal, all 24 or more satellites will be subject to signal reception, and the signal strength of the satellite will also change depending on the receiving location and surrounding building structure, so it is necessary to search for all satellites There is.

アルマナック情報無しで受信するＧＰＳ衛星の候補を選ぶために、まず受信する時刻を決めておいて、その時刻にＧＰＳ受信できるＧＰＳ衛星番号と信号強度を記憶する。そこで例えば信号強度の強い衛星番号から順に受信する候補を順序付ける。候補順位の高い衛星番号のＧＰＳ衛星から捕捉し、その信号をトラッキングしながらＧＰＳ航法メッセージデータを受信して時刻情報を得る。時刻情報を得るのに成功したなら、次回の受信もその受信時刻と衛星番号を生かす事により、ＧＰＳ信号の受信処理時間を短くできる。 In order to select a candidate for a GPS satellite to be received without almanac information, a reception time is first determined, and a GPS satellite number and signal strength at which GPS can be received at that time are stored. Therefore, for example, candidates to be received are ordered in order from the satellite number with the strong signal strength. A GPS satellite with a higher candidate rank is captured and GPS navigation message data is received while tracking the signal to obtain time information. If the time information is obtained successfully, the reception processing time of the GPS signal can be shortened by utilizing the reception time and the satellite number for the next reception.

ＧＰＳ衛星は時間と共に位置を変えるので、受信時の信号強度も時間と共に変化する。初回の信号強度を測定した時刻がＡＭ９：００だとすると、次回以降の受信もＡＭ９：００頃が望ましい。正確に言うと、ＧＰＳ衛星の周回周期が１１時間５８分なので、２３時間５６分後には同じ衛星がほぼ同じ位置に現れる。従って、前回受信できた特定のＧＰＳ衛星を、１日あたり４分ずつ受信時刻を早くしながら繰り返し受信すると、衛星を捕捉する条件が同じにできるので短時間でＧＰＳ信号を捕捉して受信する事ができる。 Since the GPS satellite changes its position with time, the signal strength at the time of reception also changes with time. Assuming that the time when the first signal strength is measured is AM 9:00, it is desirable that the reception after the next time is AM 9:00. To be precise, since the orbital period of the GPS satellite is 11 hours and 58 minutes, the same satellite appears at substantially the same position after 23 hours and 56 minutes. Therefore, if a specific GPS satellite that could be received last time is received repeatedly with an earlier reception time of 4 minutes per day, the conditions for capturing the satellite can be made the same, so the GPS signal can be captured and received in a short time. Can do.

ＧＰＳ信号から時刻情報を抽出してＧＰＳ時刻を得た時、衛星の健康情報を受信しない場合は保守点検中の衛星信号を受信する可能性もあるので、受信によって得られるＧＰＳ時刻は大きくシフトしている可能性がある。そのＧＰＳ時刻をそのままＲＴＣ時刻に反映させると次のＧＰＳ信号受信まで間違った時刻表示を続けてしまう。その間違った時刻表示を避けるために、ＧＰＳ受信で得たＧＰＳ時刻とＲＴＣ時刻の差を時刻補正量として算出し、その時刻補正量と特定の補正量許容範囲（ＬＩＭＩＴ値）を比較する。時刻補正量が特定の補正量許容範囲を超えている場合は、直前に受信した衛星番号のＧＰＳ時刻が間違っている可能性があるとして、引き続き別の衛星番号のＧＰＳ衛星を受信してＧＰＳ時刻をＲＴＣ時刻と比較する。２種類のＧＰＳ衛星から得た２種類のＧＰＳ時刻が、どちらも同じ時刻ならＲＴＣ時刻をＧＰＳ時刻に修正し、どちらか一方がＲＴＣ時刻から大きくシフトしていたら、そのＧＰＳ衛星番号は保守点検中で時刻情報が間違っていると判断する。 When the time information is extracted from the GPS signal and the GPS time is obtained, if the satellite health information is not received, there is a possibility that the satellite signal under maintenance inspection may be received. There is a possibility. If the GPS time is reflected on the RTC time as it is, an incorrect time display is continued until the next GPS signal reception. In order to avoid the erroneous time display, the difference between the GPS time obtained by GPS reception and the RTC time is calculated as a time correction amount, and the time correction amount is compared with a specific correction amount allowable range (LIMIT value). If the time correction amount exceeds a specific correction amount allowable range, it is possible that the GPS time of the satellite number received immediately before is likely to be incorrect. Is compared with the RTC time. If the two types of GPS time obtained from two types of GPS satellites are both the same time, the RTC time is corrected to the GPS time, and if either one is significantly shifted from the RTC time, the GPS satellite number is under maintenance It is determined that the time information is incorrect.

図６のフローチャートは、本発明の工程をより詳細に説明するものである。 The flowchart of FIG. 6 explains the process of the present invention in more detail.

初めてＧＰＳ衛星の信号を受信するときは、フロー６０１において全ＧＰＳ衛星を対象にして信号を受信し信号強度を検出する。フロー６０２においてその信号強度によって今後受信するＧＰＳ衛星の候補を順位付けする。例えば図７に示すようにＧＰＳ＿４，２，１３，８，のそれぞれの受信信号の信号強度が、７，６，４，２，であったならば、候補１はＧＰＳ＿４、候補２はＧＰＳ＿２、候補３はＧＰＳ＿１３、候補４はＧＰＳ＿８、となる。 When receiving a GPS satellite signal for the first time, in step 601, the signals are received for all GPS satellites and the signal strength is detected. In the flow 602, GPS satellite candidates to be received in the future are ranked according to their signal strengths. For example, as shown in FIG. 7, if the signal strength of each received signal of GPS_4, 2, 13, 8, is 7, 6, 4, 2, candidate 1 is GPS_4, candidate 2 is GPS_2, candidate 3 is GPS_13, and candidate 4 is GPS_8.

フロー６０４において初回の受信を行う。候補１であるＧＰＳ＿４を受信し、航法メッセージデータからＧＰＳ時刻を算出する。初回受信なのでＲＴＣ時刻は未定であり、時刻補正量はゼロと見なしてＧＰＳ時刻をＲＴＣ時刻に設定する。初回受信で設定されたＲＴＣ時刻がＡＭ９：００だとすると、２回目以降の受信は１日あたり４分早めて受信するのが望ましい。 In the flow 604, the first reception is performed. GPS_4 that is candidate 1 is received, and GPS time is calculated from the navigation message data. Since it is the first reception, the RTC time is undecided, the time correction amount is regarded as zero, and the GPS time is set as the RTC time. If the RTC time set for the first reception is AM 9:00, it is desirable that the second and subsequent receptions be received four minutes earlier per day.

２回目の受信を翌日のＡＭ８：５６とすると、フロー６０３においてその時刻になるのを待ってからフロー６０４において候補１であるＧＰＳ＿４を受信し、航法メッセージデータからＧＰＳ時刻を算出してＲＴＣ時刻との差(＝時刻補正量)を算出する。続いて、フロー６０５において時刻補正量と特定の補正量許容範囲(＝Ｌｉｍｉｔ範囲)を比較し、時刻補正量がＬｉｍｉｔ範囲を超えてなければフロー６１０においてＲＴＣ時刻をＧＰＳ＿４の受信で得られたＧＰＳ時刻に置き換える。 If the second reception is AM8: 56 on the next day, after waiting for that time in flow 603, GPS_4 that is candidate 1 is received in flow 604, GPS time is calculated from navigation message data, and RTC time is calculated. Difference (= time correction amount) is calculated. Subsequently, the time correction amount is compared with a specific correction amount allowable range (= Limit range) in flow 605, and if the time correction amount does not exceed the Limit range, the RTC time is obtained by receiving GPS_4 in flow 610. Replace with time.

時刻補正量がＬｉｍｉｔ範囲を超えている場合は、ＲＴＣ時刻はそのまま変更せず、フロー６０６において候補１のＧＰＳ＿４を異常な候補として一旦ＢｌａｃｋＬｉｓｔに入れ、フロー６０７において候補２であるＧＰＳ＿２を受信する。 When the amount of time correction exceeds the Limit range, the RTC time is not changed as it is, and GPS_4 of candidate 1 is temporarily entered as an abnormal candidate in flow 606, and GPS_2 that is candidate 2 is received in flow 607.

候補２のＧＰＳ＿２の受信でＧＰＳ時刻を得たら時刻補正量を算出し、フロー６０８において時刻補正量とＬｉｍｉｔ値を比較し、時刻補正量がＬｉｍｉｔ範囲を超えてなければフロー６１０においてＲＴＣ時刻を候補２によるＧＰＳ時刻に置き換える。フロー６１１に示す衛星候補判定においては、ＢｌａｃｋＬｉｓｔに入ったＧＰＳ＿４を除くＧＰＳ受信候補の中で再度順位をつける。図８は、当初候補１であったＧＰＳ＿４が候補から除かれた後の候補順位を示す。 When the GPS time is obtained by receiving GPS_2 of candidate 2, the time correction amount is calculated, the time correction amount is compared with the limit value in flow 608, and if the time correction amount does not exceed the limit range, the RTC time is selected in flow 610. Replace with GPS time by 2. In the satellite candidate determination shown in the flow 611, the rank is again set among the GPS reception candidates except for the GPS_4 included in the BlackList. FIG. 8 shows the candidate ranking after GPS_4 that was initially candidate 1 was removed from the candidates.

一方、フロー６０８において、候補２のＧＰＳ＿２の受信でも時刻補正量がＬｉｍｉｔ値を超えた場合は、ＲＴＣ時刻がＧＰＳ＿４とＧＰＳ＿２の２種類のＧＰＳ時刻と大きく異なった事になり、ＲＴＣ時刻が何らかの原因で大きくずれたと判断し、フロー６１０においてＲＴＣ時刻を候補１あるいは候補２の受信によるＧＰＳ時刻に置き換える。その場合、ＧＰＳ＿４は異常な候補ではないと判断し、フロー６０９においてＧＰＳ＿４をＢｌａｃｋＬｉｓｔから元の候補１に戻す。フロー６１１に示す衛星候補判定においては、ＢｌａｃｋＬｉｓｔから候補に戻ったＧＰＳ＿４を含めたＧＰＳ受信候補の中で再度順位をつけるので、候補順位は図７のごとくなる。フロー６１１に示す衛星候補判定では、ＢｌａｃｋＬｉｓｔに入った衛星を除いて受信候補の候補順位を決定するが、その後繰り返されるＧＰＳ信号受信で信号強度が変化した場合、候補順位を入れ替えるという事もありうる。 On the other hand, in the flow 608, when the time correction amount exceeds the limit value even when the candidate 2 receives GPS_2, the RTC time is significantly different from the two types of GPS time of GPS_4 and GPS_2, and the RTC time is caused by some cause In step 610, the RTC time is replaced with the GPS time by receiving candidate 1 or candidate 2. In this case, it is determined that GPS_4 is not an abnormal candidate, and GPS_4 is returned from BlackList to the original candidate 1 in flow 609. In the satellite candidate determination shown in the flow 611, since the ranking is made again among the GPS reception candidates including the GPS_4 returned to the candidate from the BlackList, the candidate ranking is as shown in FIG. In the satellite candidate determination shown in the flow 611, candidate ranks of reception candidates are determined excluding satellites that have entered BlackList. However, if the signal strength changes due to repeated GPS signal reception, the candidate ranks may be switched. .

図９は、時刻補正量と特定の補正量許容範囲の比較とＲＴＣ時刻の修正判断を示したものである。ＧＰＳ信号をＡＭ８：５６に受信する時、時刻補正量の許容範囲が±２秒で、候補１のＧＰＳ＿４によるＧＰＳ時刻が７秒進んでいたなら、時刻補正量が補正量許容範囲を超えているので候補１によるＧＰＳ時刻は採用せず、続けて候補２のＧＰＳ＿２を受信する。候補２のＧＰＳ＿２によるＧＰＳ時刻が１秒の遅れなら、時刻補正量が補正量許容範囲内に納まっているのでＧＰＳ＿２によるＧＰＳ時刻でＲＴＣ時刻を補正する。この場合、ＧＰＳ＿４の時刻だけが他のＧＰＳ衛星の時刻とずれているので、ＧＰＳ＿４はメンテナンス中と見なしてＢｌａｃｋＬｉｓｔに入れ、ＧＰＳ受信の候補から外す。そして、図８に示すように候補２と候補３だったＧＰＳ＿２とＧＰＳ＿１３をそれぞれ候補１と候補２へと、候補の順位を上げる。 FIG. 9 shows a comparison between a time correction amount and a specific correction amount allowable range, and a correction determination of the RTC time. When the GPS signal is received at AM8: 56, if the allowable range of the time correction amount is ± 2 seconds and the GPS time by the candidate GPS_4 has advanced by 7 seconds, the time correction amount exceeds the correction amount allowable range. Therefore, the GPS time by candidate 1 is not adopted, and GPS_2 of candidate 2 is subsequently received. If the GPS time of candidate 2's GPS_2 is delayed by 1 second, the RTC time is corrected with the GPS time of GPS_2 because the time correction amount is within the correction amount allowable range. In this case, since only the time of GPS_4 is different from the time of other GPS satellites, GPS_4 is considered to be under maintenance and is placed in BlackList and excluded from GPS reception candidates. Then, as shown in FIG. 8, the candidate ranks are increased to candidates 1 and 2 from GPS_2 and GPS_13 which were candidates 2 and 3, respectively.

図１０は、ＲＴＣ時刻と比べて２つ以上のＧＰＳ衛星の時刻が許容範囲を超えた場合を説明するものである。ＧＰＳ信号をＡＭ８：５６に受信する時、時刻補正量の許容範囲が±２秒で、候補１のＧＰＳ＿４によるＧＰＳ時刻が５秒進んでいたなら、時刻補正量が補正量許容範囲を超えているので候補１によるＧＰＳ時刻は採用せず、続けて候補２のＧＰＳ＿２を受信する。候補２のＧＰＳ＿２によるＧＰＳ時刻も５秒進んでおり、候補１と候補２の２つ以上のＧＰＳ衛星の時刻が許容範囲を超えている。この場合は、ＲＴＣ時刻が何らかの影響で間違った時刻を計時していると見なして、候補２のＧＰＳ時刻でＲＴＣ時刻を補正する。候補１のＧＰＳ＿４と候補２のＧＰＳ＿２は、共に次回の受信候補にも有効であると判断し、BlackListの対象は無しとし、図７に示す受信候補の順位となる。 FIG. 10 illustrates a case where the time of two or more GPS satellites exceeds the allowable range compared to the RTC time. When the GPS signal is received at AM8: 56, if the allowable range of the time correction amount is ± 2 seconds and the GPS time by the candidate GPS_4 has advanced by 5 seconds, the time correction amount exceeds the correction amount allowable range. Therefore, the GPS time by candidate 1 is not adopted, and GPS_2 of candidate 2 is subsequently received. The GPS time by GPS_2 of candidate 2 is also advanced by 5 seconds, and the time of two or more GPS satellites of candidate 1 and candidate 2 exceeds the allowable range. In this case, assuming that the RTC time is measuring the wrong time due to some influence, the RTC time is corrected with the GPS time of the candidate 2. Both GPS_4 of candidate 1 and GPS_2 of candidate 2 are determined to be effective for the next reception candidate, and there is no BlackList target, and the reception candidate rank shown in FIG. 7 is obtained.

図９で説明したケースは、候補１のＧＰＳ＿４をメンテナンス中と判断してＢｌａｃｋＬｉｓｔに入れ、ＧＰＳ受信の候補から外したものである。しかし、大きくシフトしたＧＰＳ時刻は、もしかするとＧＰＳ受信処理の途中でノイズが入り込んで誤ったＧＰＳ時刻を算出した可能性も考えられる。そのため、候補１の衛星を受信して算出した時刻補正量が補正量許容範囲を超えていたときは、再度候補１の衛星から時刻情報を抽出してＧＰＳ時刻を再確認するのが望ましい。それでも時刻補正量が補正量許容範囲を超えていたときは、候補１のＧＰＳ＿４をメンテナンス中と判断してＢｌａｃｋＬｉｓｔに入れ、次の候補２の衛星を受信する事により、間違いのない確実な時刻補正が可能となる。 In the case described with reference to FIG. 9, GPS_4 of candidate 1 is determined to be under maintenance, is placed in BlackList, and is excluded from GPS reception candidates. However, it is possible that the GPS time greatly shifted may have been calculated due to noise entering the GPS reception process. Therefore, when the time correction amount calculated by receiving the candidate 1 satellite exceeds the correction amount allowable range, it is desirable to extract the time information from the candidate 1 satellite again and reconfirm the GPS time. If the time correction amount still exceeds the allowable correction amount range, it is determined that the candidate 1's GPS_4 is under maintenance, put in the BlackList, and the next candidate 2 satellite is received. Is possible.

＜まとめ＞
以上に示したように、本発明によれば、信号強度が強い衛星番号から優先的に受信することで、受信処理に要する時間が短くなる事により電力の消費を少なくできる。更に、ＧＰＳ時刻による時刻の補正量が特定の補正量許容範囲よりも大きい時に２種類以上のＧＰＳ衛星の航法メッセージデータを受信する事で、ＧＰＳ衛星が保守点検に入ってＧＰＳ時刻がシフトしたのか、あるいはＲＴＣ時刻が何らかの原因でシフトしたのかが判断できる。 <Summary>
As described above, according to the present invention, by preferentially receiving from a satellite number having a strong signal strength, power consumption can be reduced by shortening the time required for reception processing. Furthermore, whether the GPS time was shifted to the GPS check time when the GPS satellites entered maintenance and inspection by receiving navigation message data of two or more types of GPS satellites when the time correction amount based on the GPS time was larger than the specific correction amount allowable range. Alternatively, it can be determined whether the RTC time has shifted for some reason.

また、衛星の健康情報を受信しなくても、たとえ保守点検中の衛星信号を受信した場合でも、受信して得たＧＰＳ時刻をＲＴＣ時刻に反映させる前に２つ以上のＧＰＳ衛星によるＧＰＳ時刻を事前確認することで、より信頼性の高い高精度な時刻補正のできるＧＰＳ計時装置を実現することができる。 Even if satellite health information is not received, even if a satellite signal during maintenance inspection is received, the GPS time obtained by two or more GPS satellites before reflecting the received GPS time in the RTC time. By confirming in advance, it is possible to realize a GPS timing device that can perform highly accurate time correction with higher reliability.

１０１本発明によるＧＰＳ計時装置全体
１０２アンテナ
１０３ＲＦ手段
１０４組合わせ復調手段
１０５現在時刻算出手段
１０６ＲＴＣ手段
１０７時刻表示手段
１０８制御手段
１０９信号強度検出手段
１１０補正量比較手段
２０１受信時刻判定工程
２０２ＧＰＳ信号受信工程
２０３信号強度検出工程
２０４現在時刻算出工程
２０５時刻補正量算出工程
２０６補正量比較工程
２０７ BlackList判定工程
２０８衛星候補判定工程
２０９ＲＴＣ時刻修正工程
２１０時刻表示工程
３０１従来のＧＰＳ計時装置全体
３０２アンテナ
３０３ＲＦ手段
３０４組合わせ復調手段
３０５現在時刻算出手段
３０６ＲＴＣ手段
３０７時刻表示手段
３０８制御手段
４０１受信時刻判定工程
４０２ＧＰＳ信号受信工程
４０３現在時刻算出工程
４０４ＲＴＣ時刻修正工程
４０５時刻表示工程 101 Overall GPS timing device according to the present invention 102 Antenna 103 RF means 104 Combined demodulation means 105 Current time calculation means 106 RTC means 107 Time display means 108 Control means 109 Signal intensity detection means 110 Correction amount comparison means 201 Reception time determination step 202 GPS Signal reception step 203 Signal strength detection step 204 Current time calculation step 205 Time correction amount calculation step 206 Correction amount comparison step 207 BlackList determination step 208 Satellite candidate determination step 209 RTC time correction step 210 Time display step 301 Entire conventional GPS timing device 302 Antenna 303 RF means 304 Combination demodulation means 305 Current time calculation means 306 RTC means 307 Time display means 308 Control means 401 Reception time determination step 402 GPS signal reception step 403 Current time Calculation step 404 RTC time correction step 405 Time display step

Claims

RF means for receiving radio waves from a plurality of position information satellites, combination demodulation means for searching for specific satellites and demodulating navigation message data, local time calculation means for extracting time information from navigation message data and calculating local time, internal RTC means for measuring the time of the clock, time display means for displaying the internal time by the RTC means, and a control means for controlling all the means, and a signal strength for detecting the strength of the signal received from the combination demodulating means It has detection means, ranks satellite reception candidates according to the signal strength, calculates the RTC time correction amount by the RTC means from the GPS time obtained by the current time calculation means, and compares it with a specific correction amount allowable range There are correction amount comparison means, and when the correction amount of time is larger than a specific correction amount allowable range, two or more types GPS timing device, characterized in that to correct the RTC time to receive the star of the navigation message data.

When the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the correction amount of the RTC time. If the time correction amount by the two candidate satellites is smaller than the specific correction amount allowable range, the RTC time is corrected by the GPS time by the second candidate, and the first candidate satellite having the large time correction amount is selected from the satellite reception candidates. The GPS timing device according to claim 1, wherein a second candidate satellite is made a first candidate.

When the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the correction amount of the RTC time. If the time correction amount by the two candidate satellites is larger than the specific correction amount allowable range and is the same as the time correction amount by the first candidate satellite, the RTC time is corrected by the GPS time by the first candidate or the second candidate. The GPS timing device according to claim 1, wherein:

A correction method for correcting the internal time by periodically receiving a GPS signal, a step of determining that the internal clock is scheduled to receive a GPS signal, a step of receiving a GPS signal, and a GPS signal There is a step of calculating the current time from the time information of the current time, a step of calculating the time correction amount from the difference between the accurate GPS time and the time of the internal clock by the RTC, and further determining the signal strength of the GPS signal. And a correction amount comparison step of comparing the time correction amount with a specific correction amount allowable range, and when the time correction amount is larger than the specific correction amount allowable range, A GPS timing method comprising a step of receiving satellite navigation message data and correcting an RTC time.

When the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the correction amount of the RTC time. If the time correction amount by the two candidate satellites is smaller than the specific correction amount allowable range, the RTC time is corrected by the GPS time by the second candidate, and the first candidate satellite having the large time correction amount is selected from the satellite reception candidates. 5. The GPS timing method according to claim 4, wherein the second candidate satellite is made the first candidate.

When the time correction amount based on the GPS time obtained from the satellites ranked as the first candidate is larger than the specific correction amount allowable range, the second candidate satellite is continuously received to calculate the correction amount of the RTC time. If the time correction amount by the two candidate satellites is larger than the specific correction amount allowable range and is the same as the time correction amount by the first candidate satellite, the RTC time is corrected by the GPS time by the first candidate or the second candidate. The GPS timing method according to claim 4, wherein: