1274175 九、發明說明： 【發明所屬之技術領域】 …i發明係！?用接收GPs導航衛星高性能時頻信號，控制 調杈遂端振盪器，使遠端振盪器之性能獲得大幅提昇，^ 成高精度區域性同步之目的。 逐 【先前技術】 目前最為t見的時頻源莫過於石英振1器， 各領域，然而，石英振盪器對於環境因素相當敏感，如溫度、 濕度及振動...等，在-般的應用場合，尤以溫度的影塑^ 顯著’亦即’振i器相對於標稱值的輸出頻率，容易 文變；產生偏移（0ffset)現象，為了要降低環境因 素的影響’爐溫控制型石英振盪$ (0ven.⑶ntrolled tai oscillator， OCXO)、溫度補償型石英振盪器 (Temperature_compensated crystal 〇sciUat〇r，tcx⑺及 理機補償型石英振盪器（Micr〇prc)cess()i^Qmpensated crystal 〇Scillator，MCX0)則應運而生，然而，所有的振盪 器均會老化（Aging)，導致輸出頻率相對於標稱頻率產生潭 移（Drift)，而石英振盪器更是無法幸免，其老化之情形堪^ 所^振盪器之最，其導致老化的原因有：石英晶體結構及質 2發生變化、振盪器電路特性的改變、外界物質的聚積造成 晶體之污染及劇烈之振動…等，而對於高品質之石英振盪器 而言，其老化率約1x10-V年。 ° 最佳 各類型石英振盪器之性能中，以爐溫控制型（〇CX〇) 其一天之頻率準確度約lxl(T7至lxl〇-9，一般而言，最 南σ口質的〇CX〇 ’其頻率準確度則可達i〇_1G等級，若〇cx〇 不文外力控制與調整，則1χ1〇-10之頻率不確定度顯然是難以跨越之 極限。 5 1274175 【發明目的】 本發明之目的係在於提供一種以遠端頻率控制調校之 方法，結合GP S載波相位二次差分觀測量、通訊介面、控制 器及數位/類比轉換器等，以大幅提舁位於遠端之石英振盪 器，或一般品質原子振盪器之性能，達成高精度頻率同步之 目的。 【發明内容】 本發明主要技術包括如何利用GPS載波相位二次差分 運算，估測遠端振盪器相對於參考母鐘之頻率偏差量及比例 微分控制器之設計等，茲分述如后： GPS載波相位 GPS載波相位之數學模型如（5·ι)式： ^A^PJA+c<dtJ-dTA) + m^dln+di〇p+si (5.1) 其中：1274175 IX. Description of the invention: [Technical field to which the invention belongs] ...i invention system! Using the high-performance time-frequency signal of the receiving GPs navigation satellite to control the tuning-end oscillator, the performance of the remote oscillator is greatly improved, and the purpose of high-precision regional synchronization is achieved. [Prior Art] At present, the most frequently seen time-frequency source is the quartz oscillator, in various fields. However, the quartz oscillator is quite sensitive to environmental factors, such as temperature, humidity and vibration, etc., in general applications. Occasionally, especially the temperature of the shadow ^ significant 'that is, 'the output frequency of the oscillator relative to the nominal value, easy to change; generate offset (0ffset) phenomenon, in order to reduce the impact of environmental factors 'furnace temperature control type Quartz oscillation $ (0ven.(3)ntrolled tai oscillator, OCXO), temperature compensated quartz oscillator (Temperature_compensated crystal 〇sciUat〇r, tcx(7) and processor compensated quartz oscillator (Micr〇prc)cess()i^Qmpensated crystal 〇Scillator , MCX0) came into being, however, all the oscillators will age (Aging), resulting in a shift in the output frequency relative to the nominal frequency (Drift), and the quartz oscillator is not immune, its aging situation can be ^ The most oscillators, the causes of aging are: changes in quartz crystal structure and mass 2, changes in oscillator circuit characteristics, accumulation of foreign matter, crystal contamination ... the like vibrate vigorously, and for high-quality crystal oscillator, its aging rate of about 1x10-V. ° The best performance of each type of quartz oscillator, the furnace temperature control type (〇CX〇) its frequency accuracy of about one day is about lxl (T7 to lxl〇-9, in general, the most south σ mouth of the 〇CX 〇'The frequency accuracy can reach i〇_1G level. If 〇cx〇 is not controlled and adjusted, the frequency uncertainty of 1χ1〇-10 is obviously difficult to overcome. 5 1274175 【Invention】 The object of the invention is to provide a remote frequency control calibration method, combined with GP S carrier phase secondary differential observation, communication interface, controller and digital/analog converter, etc., to greatly improve the quartz located at the far end. The performance of an oscillator, or a general quality atomic oscillator, achieves high-precision frequency synchronization. SUMMARY OF THE INVENTION The main techniques of the present invention include how to estimate the far-end oscillator relative to the reference master clock using GPS carrier phase quadratic differential operation. The frequency deviation and the design of the proportional differential controller are described as follows: The mathematical model of GPS carrier phase GPS carrier phase is (5·ι): ^A^PJA+c<dtJ-dTA) + m^ Dln+di〇p+si (5.1) its :
:接收機d觀測衛星j·所得之載波相位距離觀測量； 汾7 :相對於GPS時間之衛星時表偏差量； 沿；：相對於GPS時間之接收機時表偏差量； 又:波長(L1 =1575.42 MHz ； L2= 1227,60 MHz)； β :衛星與接收機天線之實際距離； :電離層效應所造成之延遲； 尤印：對流層效應所造成之延遲； c :光速； w :整數週波未定值； SA •未定之誤差量。 6 1274175 GPS載波相位的量測基礎係本地振盪器頻率與Gps載波 進行比較之頻率差，顯然，若GPS衛星與使用者接收機無相 對運動，且彼此的振盪器頻率是一致的，則接收機所觀測之 載波相位應為零，然而，衛星和使用者接收機始終存在著相 對運動，並且，源自於衛星、大氣層、接收機與不良的觀測 環境等，肖會貢獻誤差與偏差量，因而產生都卜勒偏移 (Doppler shift)效應，再者，接收機舆衛星的振盪器頻率顯 然不可能是一致的。 載波相位遠端頻率同步系統 為了要使外頻行為表現在GPS原始觀測量中，且透過載 波相位估測遠端振蘯器相對於參考母鐘之頻率偏差值 (Frequeney。驗），首μ需從接收機之心臟著手動刀：將 遠端振盪s⑽她eloek)與參考母鐘⑸顏y献） 之解分別取代原有GPS接收機内部之石英振i器頻率，對 於定位導航，甚或地理座標點量 ^ jϋ，所關注的重點在於 定位點之精準度，因此（5: receiver d observation satellite j · obtained carrier phase distance observation; 汾 7: satellite time table deviation relative to GPS time; edge;: receiver deviation time table relative to GPS time; again: wavelength (L1 =1575.42 MHz ; L2= 1227,60 MHz); β : the actual distance between the satellite and the receiver antenna; : the delay caused by the ionospheric effect; Eugene: the delay caused by the tropospheric effect; c: the speed of light; w: the integer is undetermined Value; SA • Undetermined amount of error. 6 1274175 The measurement basis of GPS carrier phase is the frequency difference between the local oscillator frequency and the GPS carrier. Obviously, if the GPS satellite has no relative motion with the user receiver and the oscillator frequency is consistent with each other, the receiver The phase of the observed carrier should be zero. However, there is always relative motion between the satellite and the user receiver, and it is derived from satellites, the atmosphere, receivers, and poor observation environments. Shaw contributes errors and deviations. The Doppler shift effect is produced. Furthermore, the oscillator frequency of the receiver 舆 satellite is obviously not consistent. The carrier phase far-end frequency synchronization system needs to make the FSB behavior appear in the GPS original observation, and estimate the frequency deviation value of the far-end vibrator relative to the reference master clock through the carrier phase (Frequeney). From the heart of the receiver, a manual knife is used: the remote oscillation s(10) her eloek) and the reference master clock (5) yan yet) respectively replace the quartz oscillator frequency inside the original GPS receiver, for positioning navigation, or even geographic coordinates Point quantity ^ jϋ, the focus of attention is on the accuracy of the positioning point, so (5
士 接收機時間相對於GPS 蛉間之偏差量則較不受關注，甚 , 盘主在差分定位運算時，經 常將此項完全消除u ’對於 .s 貝應用領域而言，包括時 頻同步與傳送，^^卻成為關鍵 喟目主要因為它隱含了本 地振盪器頻率之行為。 若兩基站接收機分別為A和 兩者共同觀測第y.號衛 7 1274175 (5.2) 一顆衛星之觀測量進行The deviation between the receiver time and the GPS time is less concerned. Even when the disk master is in the differential positioning operation, this item is often completely eliminated. For the .s application area, including time-frequency synchronization and Transfer, ^^ has become a key concern mainly because it implies the behavior of the local oscillator frequency. If the two base station receivers are respectively A and the two observe the same y. Guardian 7 1274175 (5.2) observation of a satellite
AB 星，則載波相位的一次差分模型為： ΔΦ^ = - cAdTAB + AANjab + 其中Δ表示A和B兩接收機對 差分運算。 該（5.2)式中大氣所造成之延遲效應《與已被消 除，此乃假設在鄰近區域，兩基站之大氣環境擁有良好的相 關性，再者，由於⑺^和兩者均以Gps時間為參考，因此其 差分量可視為遠端振蘯器頻率和參考母鐘頻率之相位 差（Phase difference)，如圖一所示，此外，假設衛星訊號能 連續而不中斷地被接收，且無週波滑失（Cycleslip)的情形 發生，則（5·2)式之ΛΛ/^項維持不變，因此，可將（5·2)式 再進行相對於不同觀測時間之差分，而獲得載波相位時間差 分模型為： = SApJAB - cSAdT^ + SAsjab (5,3) 其中5表示相對於不同觀測時間之差分運算。 經由載波相位一次差分及時間差分運算後，源自於衛 星、大氣環境及接收機本身之誤差與偏差量已被大幅消除， 因而可精確地求得遠端振盪器與參考母鐘之頻率關係。 該（5·3)式可進一步地表示為： - SApJAB = -cSAdTAB + SAsjab (5.4) 該（5 ·4)式等號左側是已知的，主要基於時頻之應用通 8 1274175 韦為靜悲的，因此，接收機天線座標點均已事先經由精確量 測而知，故項顯然已知，而必則為載波相位實際之 觀測ϊ m，本發明所有實驗之接收機a線座標均經由 IGS測定而得，精度均能保持在數公分以内，藉由權重平均， 、、口合衛星仰角（Elevation)及訊號雜訊比（signal t〇 N〇ise 卜 —，其中 ί ι+Γ)則可被 精確地估测，由頻率準確度之定義可得知，因感㈤為遠端 振盪器頻率相對於參考母鐘頻率之相位差，所以在觀測時間 間隔r之頻率偏差值便是： (5.5) yr〇 一 τFor AB stars, the first differential model of the carrier phase is: ΔΦ^ = - cAdTAB + AANjab + where Δ denotes the difference between A and B receiver pairs. The delay effect caused by the atmosphere in (5.2) has been eliminated. This assumes that in the adjacent area, the atmospheric environment of the two base stations has a good correlation. Moreover, since (7)^ and both are in Gps time Reference, so the difference can be regarded as the phase difference between the far-end vibrator frequency and the reference master clock frequency, as shown in Figure 1. In addition, it is assumed that the satellite signal can be received continuously and without interruption, and there is no cycle. When the situation of the slips (Cycleslip) occurs, the ΛΛ/^ term of the (5·2) equation remains unchanged. Therefore, the (5·2) equation can be further differentiated with respect to different observation times to obtain the carrier phase time. The difference model is: = SApJAB - cSAdT^ + SAsjab (5,3) where 5 represents the difference operation with respect to different observation times. After the carrier phase primary differential and time difference operation, the errors and deviations from the satellite, the atmosphere and the receiver itself have been greatly eliminated, so the frequency relationship between the remote oscillator and the reference master can be accurately determined. The (5·3) formula can be further expressed as: - SApJAB = -cSAdTAB + SAsjab (5.4) The (5 · 4) equation is known to the left of the equal sign, mainly based on the application of time-frequency 8 1274175 Wei Weijing Sadly, therefore, the receiver antenna coordinate points have been known in advance by accurate measurement, so the term is obviously known, and must be the actual observation of the carrier phase ϊ m, the receiver a line coordinates of all experiments of the present invention are via The IGS measures the accuracy to be within a few centimeters, with weighted average, and the satellite elevation (Elevation) and signal-to-noise ratio (signal t〇N〇ise)—where ί Γ+Γ It can be accurately estimated. It can be known from the definition of frequency accuracy that the sense (5) is the phase difference between the far-end oscillator frequency and the reference master clock frequency, so the frequency deviation value at the observation time interval r is: 5.5) yr〇一τ
•為了滿足本發明所提之演算法，顯然兩基站之頻率源必 刀引取代GPS接收機内部之石英振盪器頻率，然而，一般 =單頻⑽接收機，並無外頻輸入介面，所以，如何將外頻 提仏GPS接收機作為基頻，則為系統架構首要面對的課題， 本系統所採用之GPS接收機為公司所生產之單頻η 通道導航用接收機，其内部基頻是由_般品f的石英振盡器 所產生，頻率為2G.46GMHz，然而，常見的頻率標準，如溫 控石英振i器（OCXO)、師、子振1器（Rubidium)及絶: 子振里器（CeSiUm)等’其標準輸出通常為5 MHz或1〇 MHz，因此，要如何將外頻轉換為2g.偏账，並且盡可能 維持原有鮮之性能，實為本线架構之另—課題。 9 1274175 為了要將外頻輸入至GPS接收機，首先必需慎選頻率轉 換器，將5 MHz或10 MHz轉換為20.460 MHz，經由多方評 估、比較後，採用了 N〇VateChTM公司之數位混合器（Direct Digital Synthesizer，DDS)，其型號為 DDS5m，並且為 了要測 試其頻率轉換之性能，則利用高性能之鉋原子鐘頻率，配合 時間間隔計數器進行量測分析，結果顯示，DDS5m的轉換性 旎至為優越，其輸出頻率之性能，包括準確度與穩定度，相 較於原有之外頻性能則至為相近，因此，可完全符合本系統 架構之需求。 克服頻率轉換問題後，進而評估GPS接收機内部之電路 結構，將原有作為基頻用途之石英振盪器移除，然後透過適 當選定之耦合電容，則可將外頻引入Gps接收機，如圖二所 示0• In order to satisfy the algorithm proposed by the present invention, it is obvious that the frequency source of the two base stations must replace the quartz oscillator frequency inside the GPS receiver. However, the general = single frequency (10) receiver has no external frequency input interface, so How to use the external frequency to raise the GPS receiver as the fundamental frequency is the primary problem faced by the system architecture. The GPS receiver used in this system is the receiver of the single-frequency η channel navigation produced by the company. The internal fundamental frequency is Produced by a quartz resonator of _like product f, the frequency is 2G.46GMHz, however, common frequency standards, such as temperature-controlled quartz oscillator (OCXO), division, Rubidium and absolute: The standard output of the oscillator (CeSiUm), etc. is usually 5 MHz or 1 〇MHz. Therefore, how to convert the FSB to 2g. and maintain the original performance as much as possible. Another - subject. 9 1274175 In order to input the FSB to the GPS receiver, the frequency converter must be carefully selected to convert 5 MHz or 10 MHz to 20.460 MHz. After multi-party evaluation and comparison, N数VateChTM digital mixer is used. Direct Digital Synthesizer (DDS), model DDS5m, and in order to test its frequency conversion performance, using high-performance planing atomic clock frequency, with time interval counter for measurement analysis, the results show that the conversion of DDS5m is Superiority, its output frequency performance, including accuracy and stability, is similar to the original external frequency performance, so it can fully meet the needs of the system architecture. After overcoming the frequency conversion problem, the circuit structure inside the GPS receiver is further evaluated, the original quartz oscillator used as the fundamental frequency is removed, and then the external frequency is introduced into the GPS receiver through the appropriately selected coupling capacitor, as shown in the figure. Two shown 0
比例微分控制器之設計 基於結構簡單且易於實現，則採用比例微分控制 (Pr〇P〇rti〇nal-Derivative，PD)實現控制器，本系統採用之PD 控制器方塊如圖三所示，控制信號之輸人變數分別為頻率偏 差值从其變量而結構則為兩者之線性組合，且其增益 個符合頻率同步應用之 PD控 可適當加以調整。為了設計— 制器，僅需要調整尺及匕兩個失奴甘丄， J啕個參數，基本上，可以遵循以 下之準則调整此控制器，亦即，辦+ p & 增加尤值可降低系統之誤差， 1274175 但可旎無法讓系統穩定；而增加h則可以改善系統之穩定 度，經由試誤法，我們可以適當地決定火及心，並且獲得良 好的結果。 【實施方式】 明參考圖二，本發明所提供之利用GPS訊號達成高精度 頻率同步系統，包括： GPS接收機〇2 ·為美國Ashtech公司之單頻多通道GPS 鲁接收機，型號為G_〗2。丨2係一般價位之導航型接收機， 能提供即時的GPS原始觀測量，包括虛擬距離及載波相位 等，其速率可達20 ΡΙζ。為了要滿足高精度頻率同步之需求， 接收機原始觀測量的解析度，顯然扮演著重要的角色。從 G 12的規格可得知，在仰角大於〖〇度之觀測條件下，其〔/A 碼之觀測精度約為25公分；L1載波相位觀測精度則為〇·9 毫米（mm)，亦即，時間精度約為3χ1(Γΐ2秒，因此可滿足需 鲁再者由於G-12並無外頻輸入介面，因而，勢必要將 其内部基頻為20.460 MHz之溫度補償式振盪器（TCX〇)移 除再利用頻率混合器將外頻（典型為5 MHz或1 〇 MHz) •轉換成2〇·46〇ΜΗζ，提供給G_12扮演原基頻的角色。 頻率混合器 12 (Direct Digital Synthesizer，DDS):為美 國NOVATECH公司之多功能頻率混合器，型號為刪5瓜。 其頻率輸出範圍為100 Hz〜40 MHz (in 0.025 Hz steps)。 DDS5m的&格頗為低廉，且經測試，其相位雜訊 11 1274175 noise)相當低，。 石英振盪器11:為美國Datum公司之爐溫控制型石英 振盪器（〇ven Controlled Quartz Oscillator, 〇cx〇)，型穿為 FTS 1130’係一般品質之OCXO’短期頻率穩定度可達l〇—9等 級0The design of the proportional differential controller is based on the simple structure and easy to implement. The controller is implemented by proportional differential control (Pr〇P〇rti〇nal-Derivative, PD). The PD controller block used in this system is shown in Figure 3. The input variable of the signal is the linear combination of the frequency deviation value from its variable and the structure, and the gain of the PD control in accordance with the frequency synchronization application can be appropriately adjusted. In order to design the controller, it is only necessary to adjust the ruler and the two slaves, J parameters. Basically, the controller can be adjusted according to the following criteria, that is, + p & System error, 1274175 but can not make the system stable; increase h can improve the stability of the system, through trial and error, we can properly determine the fire and heart, and get good results. [Embodiment] Referring to FIG. 2, the present invention provides a high-precision frequency synchronization system using a GPS signal, including: a GPS receiver 〇2. · A single-frequency multi-channel GPS Lu receiver from Ashtech, USA, model G_ 2. The 丨2 is a general-purpose navigation receiver that provides instant GPS raw observations, including virtual distance and carrier phase, at speeds up to 20 ΡΙζ. In order to meet the requirements of high-precision frequency synchronization, the resolution of the receiver's original observations obviously plays an important role. It can be known from the specification of G 12 that the observation accuracy of the [/A code is about 25 cm under the observation condition that the elevation angle is larger than the 〇 degree; the observation accuracy of the L1 carrier phase is 〇·9 mm (mm), that is, The time precision is about 3χ1 (Γΐ2 seconds, so it can meet the needs of the Luru. Since the G-12 has no FSB input interface, it is necessary to have its internal base frequency of 20.460 MHz temperature compensated oscillator (TCX〇). Remove the reuse frequency mixer to convert the FSB (typically 5 MHz or 1 〇MHz) • to 2〇·46〇ΜΗζ, providing the G_12 to play the role of the original fundamental frequency. Frequency Mixer 12 (Direct Digital Synthesizer, DDS) ): It is a multi-function frequency mixer of NOVATECH Company of USA, the model is deleted. The frequency output range is 100 Hz~40 MHz (in 0.025 Hz steps). The DDS5m & grid is quite low and tested. Phase noise 11 1274175 noise) is quite low. Quartz Oscillator 11: 〇 Control Controlled Quartz Oscillator (〇cx〇), Datum Company of the United States, the type of wearing FTX 1130' is a general quality OCXO' short-term frequency stability up to l〇- 9 level 0
參考母鐘（Reference clock) 03 :本發明之基站參考母 鐘’以及進行性能評估之參考頻率，均採用位於中華電信股 份有限公司電信研究所之國家時間與頻率標準實驗室原級 高性能鉋原子鐘，型號為HP5071A，其基本性能如表一所示。 氫微射原子鐘（H-maser)，同樣是位於我國國家時間與 頻率標準實驗室，事實上， 目月商用之原子鐘，以氫微射原Reference clock 03: The reference base clock of the present invention and the reference frequency for performing performance evaluation are all based on the national time and frequency standard laboratory original high-performance planing atomic clock located in the Telecommunication Research Institute of Chunghwa Telecom Co., Ltd. The model number is HP5071A, and its basic performance is shown in Table 1. Hydrogen micro-atomic atomic clock (H-maser), also located in China's national time and frequency standard laboratory, in fact, the atomic clock of the commercial month, with hydrogen micro-origin
子鐘的短期頻率穩定度最高，其1秒之穩定度可達ΐχΐ〇ΐ3。 如圖二之系統架構，主要分成參考站與遠端站二部份。 有關參考站之實施，首先將原級铯原子鐘〇3之頻率，透過 卿12轉換為20.糊ΜΗζ，提供Gps接收機〇2成為其基 頻 空曠處 無論參考站或遠端站之GPS天線G1，均必需置於視野 以利衛星之觀測 參考站之PC 05除了與GPS接收機 ’並且其座標點需事先加以測定， 面連接04，進行 載波相位觀測資料 送至遠端站PC 〇7 以RS-232串列通訊介 GPS導航訊息之收錄外，並且將參考站之 ，透過有線或無線之通訊網路〇6即時傳 ，至於遠端站之實施，首先將OCXO 11頻 12 1274175 率’透過DDS 12轉換為2〇 46〇 mhz，提供GPS接收機〇2 成為其基頻，遠端站之PC 〇7除擔任Gps導航訊息之收集與 接收來自參考站之訊息外，主要在於實現頻率偏差量之估測 〇8及PD控制器〇9，亦即，利用載波相位二次差分運算，估 、測遠端振盪器相對於參考母鐘之頻率偏差量，參考此偏差量 •及其相對於時間之變量，PD控制器則輸出致動信號，透過 數位/類比轉換器10調整遠端振盪器u同步於參考母鐘 B 〇3’達成高精度頻率同步之目的。 為了要了解本發明對於頻率同步應用之潛力，發明人利 用氫微射（H-maser)原子鐘，以共同頻率信號輸入至兩台 GPS接收機，並且以短基線結構評估系統之頻率穩定度，結 果顯示無論在短期或是長期均擁有極高之頻率穩定度；在量 測時間間隔r等於1秒之穩定度約為1><1〇_11;而一天的頻率 _ 穩定度則高達約2x10+，結果如圖四所示。 此外，為了要進行性能之比較，發明人採用了一台高精 度之時間間隔計數器（型號為SRS_62〇)量測未加控制調整 -之遠端振盪器頻率（OCXO)相對於國家實驗室參考母鐘頻 •率之相位差，將約一天的量測資料進行一次線性回歸 (UneaiMeast-squarefit)運算，所估測頻率準確度（叉_δγΑ) 約為2·23χ10—9，如圖五所示，再者，發明人選擇了一部高性 此之傳統式GPSDO，以相同的方式測試其性能，、结果顯示一 13 1274175 天之頻率準確度約為3xl〇-13，如圖六所示。 由上述結果可了解到，未接受控制調整之OCXO，無論 在短期或長期，其頻率品質並不穩定，因此無法滿足高精度 之需求；至於傳統之GPSDO，乃採單機觀測GPS電碼達成 振盪器訓練的目的，雖然擁有較高之長期穩定度，但是其短 期穩定度並不理想。 至於本發明所提供之利用GPS訊號達成高精度頻率同步 • 系統，在兩基站天線相隔數十公尺的實驗中，遠端振盪器頻 率可被自動調整同步於參考母鐘，且同樣利用SRS-620時間 間隔計數器量測遠端振盪器頻率相對於國家實驗室參考母 鐘頻率之相位差，經PD控制器控制所獲得約一天之結果如 圖七所示。將此相位量測資料進行一次線性回歸運算，所估 測遠端振盪器之頻率準確度約為3χ10_14，亦即，本發明能將 原本頻率準確度約2.23x10—9之遠端振盪器，提昇性能至少4 _個數量級（10000倍）。 將上述之相位量測資料，包括未受控制之OCXO、 GPSDO及經控制調整後之OCXO，利用修訂之亞倫方差 (MDEV(t))進行頻率穩定度分析，結果如圖八所示。 由圖八可明顯得知，未受控制之OCXO並不穩定；雖 然GPSDO能有較好的長期性能，但是其短期（r = l〜50s)與 中期（r = 50〜10000^)性能同樣不甚理想；反觀經本發明控制 14 1274175 調整後之OCXO (OCXO-C)，無論短期或長期，穩定度均相 當高，其一天之穩定度甚至接近一般品質之鉋原子鐘。 【特點及功效】 本發明提出之一種利用GPS訊號達成高精度頻率同步系 統’具有下列優點： 1· 採用GPS載波相位二次差分運算，可精確估算遠端振 - 盪器相對於參考母鐘之頻率偏差量，參考此偏差量， PD控制器則輸出一致動信號，透過D/A轉換器，控 • 制調校遠端振盪器，實驗結果顯示，可將一般^質: 0CX0，大幅提昇性能達4個數量級（1 0000倍）。' 2· 本發明可使石英振盪器之性能獲得大幅提昇，甚至可 媲美一般品質之原子鐘，因而符合高精度需求。 3·本發明利用GPS載波相位二次差分觀測量估測頻率偏 差量，不但精度高，且節省成本。 4·本發明除了參考母鐘及受控之遠端振盪器，其餘均易 於以廉價、小體積之元件所取代，如廉價之Gps接 模組、微電腦（MCU)、高解析之數位/類比轉換曰 • 及霞晶片等，成本將有機會落於數仟元台擎，=見 本發明之實用性及競爭優勢。 " 【圖式簡單說明】 有關本發明技術内容之圖表說明如下，其中實施例之基 本結構，則如圖二所示： 圖一、遠端振1器頻率相料參考母鐘頻率之相位差 AdTAB示意。 圖二、系統方塊圖。 圖三、PD控制器系統方塊圖。 15 1274175 表一、HP5071A之基本性能。 圖四、短基線結構之H-masei*共同頻率信號頻率穩定度 分析。 圖五、未接受控制調整之OCXO典型性能。 圖六、傳統之GPSDO典型性能。 圖七、PD控制之結果。 圖八、OCXO、GPSDO及受控之OCXO頻率穩定度分析。 【主要元件符號說明】 01 單頻 GPS 天線（GPS Antenna)。 02 單頻 GPS 接收機（GPS Receiver)。 03 铯原子鐘（Cesium Atomic Clock)。 04 串列通訊介面（RS-232)。 05 參考站個人電腦（PC)。 06 有線或無線通訊介面（Wired and Wireless Data Link)。 07 遠端站個人電腦（PC)。 08 二次差分頻率偏差量估測（Frequency Offset Estimation)。 .----- 09 $彳微分控制器（PD Controller)。 一——--^ 10 數位/類比轉換器（D/AConverter)。 _-^--- 11 一般品質振盪器（OCXO)。 ____----- 12 ___—---- 頻率混合器（Direct Digital Synthesizer，DDS)。 16The sub-clock has the highest short-term frequency stability, and its stability in 1 second can reach ΐχΐ〇ΐ3. The system architecture in Figure 2 is mainly divided into two parts: the reference station and the remote station. For the implementation of the reference station, the frequency of the original 铯 atomic clock 〇3 is first converted to 20 ΜΗζ by the qing 12, providing the GPS receiver 〇 2 to become its base frequency space, regardless of the GPS antenna G1 of the reference station or the remote station. , all must be placed in the field of view to facilitate the observation station of the satellite PC 05 in addition to the GPS receiver 'and its coordinate point needs to be measured in advance, the surface is connected to 04, the carrier phase observation data is sent to the remote station PC 〇7 to RS -232 serial communication GPS navigation message is included, and will be referenced to the station, through the wired or wireless communication network 〇6 instant transmission, as for the implementation of the remote station, first OCXO 11 frequency 12 1274175 rate 'through DDS 12 Converted to 2〇46〇mhz, providing GPS receiver 〇2 becomes its fundamental frequency, PC of the remote station 〇7 is mainly used to collect and receive GPS information from the reference station, mainly to estimate the frequency deviation. 〇8 and PD controller 〇9, that is, using the carrier phase quadratic difference operation to estimate and measure the frequency deviation of the remote oscillator relative to the reference master clock, refer to the deviation amount and its variable with respect to time The PD controller outputs an actuation signal, and the digital/analog converter 10 adjusts the remote oscillator u to synchronize with the reference master clock B 〇 3' to achieve high-precision frequency synchronization. In order to understand the potential of the present invention for frequency synchronization applications, the inventors used a hydrogen micro-emission (H-maser) atomic clock to input a common frequency signal to two GPS receivers, and evaluated the frequency stability of the system with a short baseline structure. It shows extremely high frequency stability in both short-term and long-term; stability is equal to 1><1〇_11 in measuring time interval r equal to 1 second; and frequency _ stability is as high as 2x10+ in one day The result is shown in Figure 4. In addition, in order to compare the performance, the inventor used a high-precision time interval counter (model SRS_62〇) to measure the uncontrolled adjustment - the remote oscillator frequency (OCXO) relative to the national laboratory reference mother The phase difference of the clock frequency and rate, a linear regression (UneaiMeast-squarefit) operation of about one day of measurement data, the estimated frequency accuracy (fork _δγΑ) is about 2·23χ10-9, as shown in Figure 5. Furthermore, the inventor chose a high-quality traditional GPSDO to test its performance in the same way. The result shows that the frequency accuracy of a 13 1274175 day is about 3xl〇-13, as shown in Figure 6. It can be understood from the above results that the OCXO that has not undergone control adjustment, its frequency quality is not stable in the short or long term, so it cannot meet the demand of high precision; as for the traditional GPSDO, the single-machine observation GPS code reaches the oscillator training. The purpose, although with a high degree of long-term stability, is not ideal for short-term stability. As for the high-precision frequency synchronization system using the GPS signal provided by the present invention, in the experiment where the two base station antennas are separated by several tens of meters, the remote oscillator frequency can be automatically adjusted to be synchronized with the reference master clock, and the SRS- is also utilized. The 620 time interval counter measures the phase difference of the far-end oscillator frequency relative to the national laboratory reference master clock frequency, and the result obtained by the PD controller is about one day as shown in FIG. Performing a linear regression operation on the phase measurement data, the estimated frequency accuracy of the remote oscillator is about 3χ10_14, that is, the present invention can improve the remote oscillator with an original frequency accuracy of about 2.23x10-9. Performance is at least 4 _ orders of magnitude (10,000 times). The phase measurement data described above, including the uncontrolled OCXO, GPSDO, and the controlled OCXO, are analyzed for frequency stability using the modified Aaron variance (MDEV(t)). The results are shown in Figure 8. It can be clearly seen from Figure 8 that the uncontrolled OCXO is not stable; although GPSDO can have good long-term performance, its short-term (r = l~50s) and mid-term (r = 50~10000^) performance are not the same. It is ideal; in contrast, the OCXO (OCXO-C) adjusted by the control of the present invention 14 1274175 has a relatively high stability in both short-term and long-term, and its stability is even close to the general-quality planing atomic clock. [Features and Efficacy] The present invention proposes a high-precision frequency synchronization system using GPS signals to have the following advantages: 1. Using GPS carrier phase quadratic differential operation, it is possible to accurately estimate the far-end oscillator to be relative to the reference master clock. The frequency deviation amount, referring to the deviation amount, the PD controller outputs a coincidence signal, and controls the remote oscillator through the D/A converter. The experimental results show that the general quality: 0CX0 can greatly improve the performance. Up to 4 orders of magnitude (10000 times). '2· The present invention can greatly improve the performance of the quartz oscillator, and even comparable to the atomic clock of a general quality, thus meeting the high precision requirements. 3. The present invention utilizes GPS carrier phase quadratic differential view measurement to estimate the frequency offset amount, which not only has high precision but also saves cost. 4. In addition to the reference clock and the controlled remote oscillator, the present invention is easily replaced by inexpensive, small-sized components such as inexpensive Gps modules, microcomputers (MCUs), and high-resolution digital/analog conversion.曰• 和霞 wafers, etc., the cost will have the opportunity to fall in the number of units, = see the practicality and competitive advantage of the present invention. "Simple Description of the Drawings] A diagram illustrating the technical contents of the present invention is as follows, wherein the basic structure of the embodiment is as shown in Figure 2: Figure 1. Phase difference of the reference frequency of the far-end vibrator AdTAB indicated. Figure 2, system block diagram. Figure 3. Block diagram of the PD controller system. 15 1274175 Table 1, the basic performance of the HP5071A. Figure 4. H-masei* common frequency signal frequency stability analysis of short baseline structures. Figure 5. Typical performance of OCXO without control adjustment. Figure 6. Typical GPSDO performance. Figure 7. Results of PD control. Figure 8. OCXO, GPSDO, and controlled OCXO frequency stability analysis. [Main component symbol description] 01 Single frequency GPS antenna (GPS Antenna). 02 Single frequency GPS receiver (GPS Receiver). 03 Cesium Atomic Clock. 04 Serial communication interface (RS-232). 05 Reference Station Personal Computer (PC). 06 Wired or Wireless Data Link. 07 Remote Station Personal Computer (PC). 08 Secondary Difference Frequency Estimation (Frequency Offset Estimation). .----- 09 $彳Differential Controller (PD Controller). One --- ^ 10 digital / analog converter (D / AConverter). _-^--- 11 General Quality Oscillator (OCXO). ____----- 12 ___----- Frequency Mixer (Direct Digital Synthesizer, DDS). 16