JPH04156728A - Afc device for satellite communication earth station - Google Patents
Afc device for satellite communication earth stationInfo
- Publication number
- JPH04156728A JPH04156728A JP28223690A JP28223690A JPH04156728A JP H04156728 A JPH04156728 A JP H04156728A JP 28223690 A JP28223690 A JP 28223690A JP 28223690 A JP28223690 A JP 28223690A JP H04156728 A JPH04156728 A JP H04156728A
- Authority
- JP
- Japan
- Prior art keywords
- pilot signal
- time
- reference pilot
- afc
- satellite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000004891 communication Methods 0.000 title claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 19
- 230000005856 abnormality Effects 0.000 abstract description 7
- 238000000034 method Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000010355 oscillation Effects 0.000 description 3
- 230000006870 function Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、衛星通信地球局用ＡＦＣ装置に関し、特に移
動体との衛星通信を行う無線装置に使用される衛星通信
地球局用ＡＦＣ装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an AFC device for a satellite communication earth station, and particularly relates to an AFC device for a satellite communication earth station used in a radio device that performs satellite communication with a mobile object. .
一般に地球局と移動体とが衛星を介して通信を行う場合
の移動体衛星通信システムにおける送信周波数補正手段
を第３図のシステム構成図および第４図に示す地球局２
１に備えられている送信装置の送信周波数補正部２５に
より説明する。通常、地球局２１と衛星２３間で通信を
行う場合に、静止衛星であっても衛星軌道が約２４時間
を一周期とする日変化があるので、ドツプラシフトによ
る周波数誤差かあ、る。この周波数誤差の補正は、地球
上の基準局２４がら衛星経由送信される基準パイロット
信号を地球局２１が受信して送信周波数の補正を行って
いる。地球局２１の送信装置内に備えられた送信周波数
補正部２５（第４図）は、入力端子２ＣＩＡから前述の
基準パイロット信号を有する受信信号を受け、受信周波
数変換装置２６で基準パイロット信号を復調する。ＡＦ
Ｃ装置２７はこの基準パイロット信号をもとに衛星２３
に送出する送信信号の周波数にＡＦＣをかけるべくドツ
プラシフト周波数の演算等を行い周波数補正信号を作成
する。送信周波数変換装置２８はこの周波数補正信号を
受け、送信局部発振器の発振周波数を補正して出力端子
からあらかじめドツプラ補正等を行った正確な送信信号
を送出する。第３図にもどり、この送信信号は衛星２３
を経由して航空機等の移動体２２に送出される。ここで
衛星２３と移動体２２間の伝送周波数でも当然大きいド
ツプラシフトを生ずる。この大きいドツプラシフトに比
して地球局２１と衛星２３間のドツプラシフトは小さい
が、衛星と航空機間の大きいドツプラシフトの補正に対
する負担を軽減するために送信周波数補正部２５により
あらかじめ補正している。In general, the system configuration diagram in FIG. 3 and the earth station 2 shown in FIG.
The explanation will be made using the transmission frequency correction section 25 of the transmitter included in the transmitter. Normally, when communicating between the earth station 21 and the satellite 23, even if the satellite is a geostationary satellite, the orbit of the satellite changes daily with one cycle of about 24 hours, so there is a frequency error due to Doppler shift. To correct this frequency error, the earth station 21 receives a reference pilot signal transmitted via a satellite from the reference station 24 on the earth, and corrects the transmission frequency. A transmission frequency correction unit 25 (FIG. 4) provided in the transmitting device of the earth station 21 receives a reception signal having the above-mentioned reference pilot signal from the input terminal 2CIA, and demodulates the reference pilot signal with a reception frequency conversion device 26. do. AF
The C device 27 detects the satellite 23 based on this reference pilot signal.
In order to apply AFC to the frequency of the transmission signal to be sent out, a Doppler shift frequency calculation etc. is performed to create a frequency correction signal. The transmission frequency converter 28 receives this frequency correction signal, corrects the oscillation frequency of the transmitting local oscillator, and sends out from an output terminal an accurate transmission signal that has been subjected to Doppler correction, etc. in advance. Returning to Figure 3, this transmitted signal is
The data is sent to a moving body 22 such as an aircraft via. Naturally, a large Doppler shift also occurs in the transmission frequency between the satellite 23 and the mobile body 22. Although the Doppler shift between the earth station 21 and the satellite 23 is smaller than this large Doppler shift, it is corrected in advance by the transmission frequency correction unit 25 in order to reduce the burden of correcting the large Doppler shift between the satellite and the aircraft.
従来、この種のＡＦＣ装置２７としては、第２図に示す
ように、基準パイロット信号を入力する入力端子５Ａ、
この基準パイロット信号をもとに内蔵する電圧制御発
振器（ＶＣＯ）に位相同型をかけ、Ｓ／Ｎのよい基準信
号を作成するＡＦＣ回路２．この基準信号の周波数計数
用と、後述する送信信号用の電圧制御クリスタル発振器
（ＶＣＸＯ）６の周波数計数も行う周波数カウンタ２゜
ＡＦＣ回路５の基準信号をもとに基準局及び地球局の緯
度、経度と衛星の軌道傾斜角から衛星のドツプラシフト
と衛星中継器のローカル発振器の変動を算出し、地球局
と衛星間の周波数誤差をあらかじめ付加するための補正
信号を送出するＣＰＵ３、送信信号の局部発振信号の原
振となり、前述の補正信号で補正された周波数の信号を
発振するＶＣＸＯ６，ｖｃｘｏｅの出力を第４図の送信
周波数変換装置２８に送出する出力端子７Ａを有する分
岐回路７．なお分岐回路７はこの補正周波数計数のため
に周波数カウンタ２にも分岐している。前述の基準パイ
ロット信号の周波数のデータを所定の時間間隔で少なく
とも２４時間記憶して行く記憶回路４から構成されてい
た。Conventionally, this type of AFC device 27 has an input terminal 5A for inputting a reference pilot signal, as shown in FIG.
An AFC circuit that applies phase matching to a built-in voltage controlled oscillator (VCO) based on this reference pilot signal to create a reference signal with a good S/N ratio.2. A frequency counter 2 is used to count the frequency of this reference signal and also to count the frequency of a voltage controlled crystal oscillator (VCXO) 6 for a transmission signal, which will be described later. Based on the reference signal of the AFC circuit 5, the latitude and longitude of the reference station and the earth station are determined. The CPU 3 calculates the Doppler shift of the satellite and the fluctuation of the local oscillator of the satellite repeater from the orbital inclination angle of the satellite, and sends out a correction signal to add the frequency error between the earth station and the satellite in advance, and the local oscillation signal of the transmitted signal. A branch circuit 7. having an output terminal 7A sends the outputs of the VCXO 6 and VCXOE, which serve as the source oscillation of the signal and oscillates a signal with a frequency corrected by the above-mentioned correction signal, to the transmission frequency converter 28 of FIG. Note that the branch circuit 7 also branches to the frequency counter 2 for this correction frequency counting. It consisted of a storage circuit 4 that stores frequency data of the reference pilot signal mentioned above at predetermined time intervals for at least 24 hours.
上述した従来の衛星通信地球局用ＡＦＣ装置では、基準
パイロット信号の周波数誤差のデータを定期的にサンプ
リングし、記憶回路に蓄え２４時間分蓄積した後に、衛
星のドツプラシフトの周期と衛星中継器とローカル発振
器の変動を算出し、周波数補正を行っているので、−た
ん基準パイロット信号に異常が発生したときには、復旧
するまでサンプリングデータが欠落し、周波数誤差の算
出が行えず、パイロット信号の復旧後も２４時間待たな
ければならないという欠点があった。In the above-mentioned conventional AFC device for satellite communication earth stations, data on the frequency error of the reference pilot signal is periodically sampled, stored in a memory circuit, and accumulated for 24 hours. Since fluctuations in the oscillator are calculated and frequency correction is performed, if an abnormality occurs in the -tan standard pilot signal, sampling data will be lost until it is restored, making it impossible to calculate the frequency error, and even after the pilot signal is restored. The drawback was that you had to wait 24 hours.
本発明の衛星通信地球局用ＡＦＣ装置は、衛星通信の基
準局から送出される基準パイロット信号を衛星を経由し
て地球局の無線装置が受信し、前記基準パイロット信号
をもとに前記衛星軌道の日変化によるドツプラシフト周
波数の変動等を少なくとも２４時間ごとに補正する送信
周波数補正手段を備えた衛星通信地球局用ＡＦＣ装置に
おいて、前記基準パイロット信号が受信されなかった場
合に、前記送信周波数補正手段に設けられた記憶回路か
ら２４時間前に記憶されている送信周波数補正情報を読
み出す時刻と、以降前記基準パイロット信号が復旧する
までの時間を正確に認知し、前記送信周波数補正手段が
ＡＦＣ動作を行う時刻を報知するタイマー回路を有する
。In the AFC device for a satellite communication earth station of the present invention, a radio device of the earth station receives a reference pilot signal sent from a satellite communication reference station via a satellite, and based on the reference pilot signal, the satellite orbit is adjusted. In an AFC device for a satellite communication earth station, which is equipped with a transmission frequency correction means for correcting fluctuations in the Doppler shift frequency due to daily changes at least every 24 hours, when the reference pilot signal is not received, the transmission frequency correction means The transmission frequency correction means performs the AFC operation by accurately recognizing the time to read out the transmission frequency correction information stored 24 hours ago from the provided storage circuit and the time until the reference pilot signal is restored thereafter. It has a timer circuit that notifies the time.
次に本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図は本発明の一実施例のブロック図である。第１図
において第２図の同一の符号は同一の構成と動作を行う
。すなわち、本実施例ではタイマー回路１を追加してい
る。FIG. 1 is a block diagram of one embodiment of the present invention. In FIG. 1, the same reference numerals as in FIG. 2 have the same structure and operation. That is, in this embodiment, a timer circuit 1 is added.
次に本実施例の動作を説明する。今、基準局２４から基
準パイロット信号が何らかの異常で受信できなかった場
合について説明する。前述したように、衛星のドツプラ
シフトによる周波数誤差は、約２４時間を一周期とする
サインカーブを取り、その値は、前日と同様に変化する
。また、衛星中継器のローカル発振器の周波数誤差の１
日当たりの変化は、微少であり前日とほぼ同一であるこ
とに着目すると、受信している基準パイロット信号に異
常が発生した場合でも、２４時間前の周波数補正データ
を取り出してＡＦＣ機能を継続する事が可能である。さ
らに、受信している基準パイロット信号が復旧するまで
の時間を正確に認識するタイマー回路５を追加すること
により、前の記憶されている補正データを使用している
２４時間ごとの補正時刻から、基準パイロット信号復旧
後に開始される補正時刻への切り換えを正確に行うこと
ができる。したがって、長時間のパイロット信号の異常
に対応することができる。Next, the operation of this embodiment will be explained. Now, a case will be described in which the reference pilot signal cannot be received from the reference station 24 due to some abnormality. As mentioned above, the frequency error due to the Doppler shift of the satellite takes a sine curve with one period of about 24 hours, and its value changes in the same way as the previous day. Also, 1 of the frequency error of the local oscillator of the satellite transponder
Focusing on the fact that changes in sunlight are slight and almost the same as the previous day, even if an abnormality occurs in the received reference pilot signal, it is possible to extract the frequency correction data from 24 hours ago and continue the AFC function. is possible. Furthermore, by adding a timer circuit 5 that accurately recognizes the time until the received reference pilot signal is restored, from the correction time every 24 hours using the previous stored correction data, It is possible to accurately switch to the correction time that starts after the reference pilot signal is restored. Therefore, it is possible to deal with abnormalities in the pilot signal over a long period of time.
以上説明したように本発明は、タイマー回路の追加とそ
れに伴う制御方法の変更により、受信している基準パイ
ロット信号に異常が発生した場合でも、復旧するまでの
時間が正確に認識できるので、２４時間前の周波数補正
データの利用時刻から正規の周波数補正時刻への切り換
えを正確に行うことができ、ＡＦＣ機能を継続できると
いう効果を有する。As explained above, in the present invention, by adding a timer circuit and changing the control method accordingly, even if an abnormality occurs in the received reference pilot signal, the time until recovery can be accurately recognized. This has the effect that it is possible to accurately switch from the usage time of the previous frequency correction data to the regular frequency correction time, and the AFC function can be continued.
第１図は本発明の一実施例のブロック図、第２図は従来
の衛星通信地球局用ＡＦＣ装置のブロック図、第３図は
一般的なシステム構成図、第４図は一般的な送信周波数
補正部の構成図である。
１・・・タイマー回路、２・・・周波数カウンタ、３・
・・ＣＰＵ、４・・・記憶回路、５・・・ＡＦＣ回路、
６・・・ＶＣＸｏ、７・・・分岐回路、２１・・・地球
局、２２・・・移動体、２３・・・衛星、２４・・・基
準局、２５・・・送信周波数補正部。Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a block diagram of a conventional AFC device for a satellite communications earth station, Fig. 3 is a general system configuration diagram, and Fig. 4 is a general transmission system. It is a block diagram of a frequency correction part. 1... Timer circuit, 2... Frequency counter, 3.
...CPU, 4...memory circuit, 5...AFC circuit,
6... VCXo, 7... Branch circuit, 21... Earth station, 22... Mobile object, 23... Satellite, 24... Reference station, 25... Transmission frequency correction unit.
Claims (1)
衛星を経由して地球局の無線装置が受信し、前記基準パ
イロット信号をもとに前記衛星軌道の日変化によるドッ
プラシフト周波数の変動等を少なくとも２４時間ごとに
補正する送信周波数補正手段を備えた衛星通信地球局用
ＡＦＣ装置において、前記基準パイロット信号が受信さ
れなかった場合に、前記送信周波数補正手段に設けられ
た記憶回路から２４時間前に記憶されている送信周波数
補正情報を読み出す時刻と、以降前記基準パイロット信
号が復旧するまでの時間を正確に認知し、前記送信周波
数補正手段がＡＦＣ動作を行う時刻を報知するタイマー
回路を有することを特徴とする衛星通信地球局用ＡＦＣ
装置。A radio device of an earth station receives a reference pilot signal transmitted from a satellite communication reference station via a satellite, and based on the reference pilot signal, it calculates at least 24 times the fluctuation of the Doppler shift frequency due to daily changes in the satellite orbit. In an AFC device for a satellite communication earth station, which is equipped with a transmission frequency correction means that corrects each time, when the reference pilot signal is not received, a memory circuit provided in the transmission frequency correction means stores the signal 24 hours ago. The present invention is characterized by comprising a timer circuit that accurately recognizes the time to read the transmitted frequency correction information and the time until the reference pilot signal is restored thereafter, and notifies the time when the transmission frequency correction means performs the AFC operation. AFC for satellite communication earth station
Device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28223690A JP3033176B2 (en) | 1990-10-19 | 1990-10-19 | AFC device for satellite communication earth station |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28223690A JP3033176B2 (en) | 1990-10-19 | 1990-10-19 | AFC device for satellite communication earth station |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04156728A true JPH04156728A (en) | 1992-05-29 |
| JP3033176B2 JP3033176B2 (en) | 2000-04-17 |
Family
ID=17649831
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28223690A Expired - Lifetime JP3033176B2 (en) | 1990-10-19 | 1990-10-19 | AFC device for satellite communication earth station |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3033176B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5634205A (en) * | 1994-04-19 | 1997-05-27 | Uniden Corporation | Radio equipment based on AFC system with temperature detection and method of automatic frequency control |
| JP2009201143A (en) * | 1996-09-30 | 2009-09-03 | Qualcomm Inc | Method and apparatus for precorrecting timing and frequency in communication systems |
-
1990
- 1990-10-19 JP JP28223690A patent/JP3033176B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5634205A (en) * | 1994-04-19 | 1997-05-27 | Uniden Corporation | Radio equipment based on AFC system with temperature detection and method of automatic frequency control |
| JP2009201143A (en) * | 1996-09-30 | 2009-09-03 | Qualcomm Inc | Method and apparatus for precorrecting timing and frequency in communication systems |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3033176B2 (en) | 2000-04-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5663715A (en) | Synchronized paging system | |
| US7155183B2 (en) | Method and apparatus for adjusting reference oscillator frequency in a mobile wireless device | |
| JP4164662B2 (en) | Portable terminal and GPS time keeping method | |
| CN1936616B (en) | Receiver of signals from GPS system and method for processing GPS system signals | |
| CN110247697B (en) | Method for improving frequency utilization rate of low-earth-orbit communication satellite system | |
| US4602375A (en) | Onboard clock correction by means of drift prediction | |
| US7327699B1 (en) | Method and device for synchronisation of distant clocks to a central clock via satellite | |
| MXPA01002489A (en) | Position location with a low tolerance oscillator. | |
| US20070205939A1 (en) | Apparatus and method for sharing a TCXO of a mobile terminal using a global positioning system in a mobile communication system | |
| MXPA01002492A (en) | Simplified receiver with rotator for performing position location. | |
| US6633590B1 (en) | Method of synchronizing a reference clock of a ground station and a clock of a remote system | |
| EP1543626B1 (en) | Method of and apparatus for reducing frequency errors associated with an inter-system scan | |
| JPH1028294A (en) | Mobile radio with clock display function | |
| US6240276B1 (en) | Compensating for errors in tuning frequency of a global positioning satellite (GPS) receiver | |
| US5878330A (en) | Satellite communications system including automatic frequency control | |
| JPH04156728A (en) | Afc device for satellite communication earth station | |
| US7499512B2 (en) | Clock transmission apparatus for network synchronization between systems using an even-second clock and an Unshielded Twisted Pair (UTP) | |
| WO1997044915A9 (en) | Automatic frequency control system | |
| US20050227630A1 (en) | System for synchronizing a portable transceiver to a network | |
| US7064619B1 (en) | Method and apparatus for restarting a GPS-based timing system without a GPS signal | |
| JPH05281330A (en) | Method for acquiring radio wave from satellite of gps receiver | |
| JP4297400B2 (en) | Intermittent satellite signal positioning system | |
| EP1548963A2 (en) | Reference clock recovery apparatus and method | |
| US20230170986A1 (en) | Control Method and Control Device for Link Switching | |
| US11134490B2 (en) | Electronic apparatus |