CN109991839A - A kind of satellite calibration method based on the estimation of star clock shift iterations - Google Patents
A kind of satellite calibration method based on the estimation of star clock shift iterations Download PDFInfo
- Publication number
- CN109991839A CN109991839A CN201910277011.7A CN201910277011A CN109991839A CN 109991839 A CN109991839 A CN 109991839A CN 201910277011 A CN201910277011 A CN 201910277011A CN 109991839 A CN109991839 A CN 109991839A
- Authority
- CN
- China
- Prior art keywords
- school
- star
- increment
- satellite
- time
- 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
Classifications
-
- G—PHYSICS
- G04—HOROLOGY
- G04R—RADIO-CONTROLLED TIME-PIECES
- G04R20/00—Setting the time according to the time information carried or implied by the radio signal
- G04R20/02—Setting the time according to the time information carried or implied by the radio signal the radio signal being sent by a satellite, e.g. GPS
- G04R20/04—Tuning or receiving; Circuits therefor
-
- G—PHYSICS
- G04—HOROLOGY
- G04R—RADIO-CONTROLLED TIME-PIECES
- G04R40/00—Correcting the clock frequency
- G04R40/06—Correcting the clock frequency by computing the time value implied by the radio signal
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/18—Complex mathematical operations for evaluating statistical data, e.g. average values, frequency distributions, probability functions, regression analysis
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Mathematical Physics (AREA)
- Data Mining & Analysis (AREA)
- Mathematical Optimization (AREA)
- Pure & Applied Mathematics (AREA)
- Computational Mathematics (AREA)
- Mathematical Analysis (AREA)
- Probability & Statistics with Applications (AREA)
- Software Systems (AREA)
- Evolutionary Biology (AREA)
- Bioinformatics & Computational Biology (AREA)
- Algebra (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Databases & Information Systems (AREA)
- Operations Research (AREA)
- General Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
- Electric Clocks (AREA)
Abstract
A kind of satellite calibration method based on the estimation of star clock shift iterations, comprising steps of parameter when 1) determining increment school using earth station, instructs when the increment school of parameter when earth station sends to satellite computer with increment school according to threshold value；2) satellite computer according to when increment school parameter carry out increment school when and iteration more nova clock drift value；3) when the time carries out uniform school on the star after when according to the updated star clock drift value of the iteration to increment school；4) using uniform time correction interval as the period, step 3) is repeated, until when satellite computer receives new increment school after instruction, return step 2), continue work when satellite school.Also the iterative estimate that star clock drift is carried out while the present invention is at absolute school realizes the Step wise approximation to the drift of star clock, to reduce the frequency that earth station issues an order.
Description
Technical field
The present invention relates to a kind of satellite calibration methods based on the estimation of star clock shift iterations, belong to satellite engineering technology neck
Domain.
Background technique
Satellite computer generally uses the time on timer more nova, due to the clock drift of timer, on star the time with
Difference, that is, star of actual time the time difference will constantly increase, thus bring track determine error increase etc. adverse effect.
For with limiting star time difference, when software is widely used for increment school on current star and uniform calibration method, increment school
When, that is, earth station provide star the time difference for software disposable compensation on star, also have referred to as collection lieutenant colonel when.Uniform calibration method is i.e.
Parameter is for software cycle compensation star clock drift on star when face station provides uniform school.
But existing method is not directed to the iterative estimate to drift about to star clock, when uniform school, parameter and practical star clock drift about
It when residual error is larger, needs to issue an order when frequent progress school, brings biggish burden to earth station.
Summary of the invention
Technology of the invention solves the problems, such as: overcome the deficiencies in the prior art, proposes a kind of based on star clock shift iterations
The satellite calibration method of estimation, when the star that earth station calculates time difference error is larger or star clock drifts about when fluctuating larger, the party
Method is issued an order frequency when can reduce earth station school.
The technical scheme is that
A kind of satellite calibration method based on the estimation of star clock shift iterations, comprises the following steps that
1) parameter when determining increment school using earth station, when increment school, parameter is greater than threshold value, earth station is to satellite meter
It is instructed when the increment school of parameter when calculation machine is sent with increment school；
2) when the increment school that satellite computer is sent according to earth station parameter carry out increment school when, obtain increment school when after
Time on star；And according to the more nova clock drift value of parameter iteration when increment school, the updated star clock drift value of iteration is obtained；
3) when the time carries out uniform school on the star after when according to the updated star clock drift value of the iteration to increment school；
4) using uniform time correction interval as the period, step 3) is repeated, until the satellite computer receives new increment school
After Shi Zhiling, return step 2), continue work when satellite school.
Parameter dt when the step 1) determines increment schoolmMethod, specifically:
dtm=(dt1+…+dtn)/n,
Wherein, dt1, dt2..., dtnFor every the time difference of time and actual time on the Satellite that time △ T is obtained.
The value range of the △ T is 0.5h~12h, and the value range of n is 1~48.
When the increment school that the step 2) is sent according to earth station parameter carry out increment school when, obtain increment school when after star
The method of upper time, specifically:
tm=tS+dtm,
Wherein, tSTime, t on corresponding Satellite when being instructed when increment school to receivemIt is received for satellite computer the m times
Time on star after when the increment school obtained after instruction when to increment school, m is positive integer.
The step 2) obtains the star clock that the m times iteration updates according to the more nova clock drift value of parameter iteration when increment school
The method of drift value, specifically:
driftm=driftm-1+dtm/(tm-tm-1),
Wherein, tm-1Star after when the increment school that instruction correspondence obtains when receiving the m-1 times increment school for satellite computer
Upper time, tmTime on star after when the increment school that instruction correspondence obtains when receiving the m times increment school for satellite computer,
driftm-1The corresponding star clock drift value obtained of instruction, drift when receiving the m-1 times increment school for satellite computer1=0.
Value range 10ms~2000ms of threshold value P described in step 1).
The step 3) according to the updated star clock drift value of the iteration to increment school when after star on the time carry out it is equal
Method when even school, specifically:
tJ=tW+driftm*TB,
Wherein, tWFor time, t on moment corresponding star occur when uniform schoolJTime on star after when for uniform school, TBFor
Uniform time correction interval, TB≤△T。
Compared with the prior art, the invention has the advantages that:
Parameter is iterated estimation to the drift of star clock when satellite computer of the present invention can independently pass through increment school, and uses
When obtained star clock drift carries out uniform school, frequency of issuing an order when reducing the school of earth station；Meanwhile earth station does not need to calculate
Parameter when uniform school, Project Realization are simple.
Detailed description of the invention
Fig. 1 is the method for the present invention flow chart；
Fig. 2 is one embodiment of the invention culminant star clock drift estimate value change curve；
Fig. 3 be one embodiment of the invention in twice increment school when between time interval curve.
Specific embodiment
This method is iterated estimation to the drift of star clock according to information when increment school, so that the drift of star clock tends to true value,
To improve the precision of star clock drift compensation.As the drift of star clock tends to true value, star the trend that increases of the time difference held back
System issues an order frequency to reduce ground, has saved the workload of earth station.
Further detailed description is done to the present invention with reference to the accompanying drawings and detailed description.
A kind of satellite calibration method based on the estimation of star clock shift iterations of the present invention, as shown in Figure 1, comprising the following steps that
1) parameter when determining increment school using earth station, when increment school, parameter is greater than threshold value, earth station is to satellite meter
It is instructed when the increment school of parameter when calculation machine is sent with increment school；Value range 10ms~2000ms of threshold value P.
Parameter dt when determining increment schoolmMethod, specifically:
dtm=(dt1+…+dtn)/n,
Wherein, dt1, dt2..., dtnFor every the time difference of time and actual time on the Satellite that time △ T is obtained, △ T
Value range be 0.5h~12h, n is positive integer, and the value range of n is 1~48.
2) when the increment school that satellite computer is sent according to earth station parameter carry out increment school when, obtain increment school when after
Time on star；And according to the more nova clock drift value of parameter iteration when increment school, the updated star clock drift value of iteration is obtained.
The method of time on star after when acquisition increment school, specifically:
tm=tS+dtm,
Wherein, tSTime, t on corresponding Satellite when being instructed when increment school to receivemIt is received for satellite computer the m times
Time on star after when the increment school obtained after instruction when to increment school.When general computer system is updated according to timer chip
Between, so that time cycle property be made on star to increase, when increment school, makes the error of time and actual time on star become smaller.
The method for obtaining the star clock drift value of the m times iteration update, specifically:
When satellite computer instructs when receiving increment school for the first time, t is set1Time on star after when for increment school, drift1Deng
In 0.Following star clock shift iterations are carried out after instructing when receiving increment school satellite the m times to calculate:
driftm=driftm-1+dtm/(tm-tm-1),
Wherein, tm-1Star after when the increment school that instruction correspondence obtains when receiving the m-1 times increment school for satellite computer
Upper time, tmTime on star after when the increment school that instruction correspondence obtains when receiving the m times increment school for satellite computer,
driftm-1The instruction corresponding star clock drift value obtained when receiving the m-1 times increment school for satellite computer.
3) when the time carries out uniform school on the star after when according to the updated star clock drift value of the iteration to increment school, tool
Body are as follows:
tJ=tW+driftm*TB,
Wherein, tWFor time, t on moment corresponding star occur when uniform schoolJTime on star after when for uniform school.
4) with uniform time correction interval TBFor the period, i.e., every TBOne secondary star clock drift compensation, uniform school are carried out to the time on star
When interval determine the frequency of compensation, repeat step 3), until when the satellite computer receives new increment school after instruction,
Return step 2), continue work when satellite school, TB≤△T。
Embodiment
In order to simplify statement, remember that the time is all 0 on the actual time and star of initial time, thus star the time difference be 0, at this time
Ground instructs when issuing increment school, parameter 0ms.When satellite computer receives increment school after instruction, the according to step 3
Operation when once receiving increment school after instruction, sets t1It is 0, drift1Equal to 0.
It is assumed that the star clock of satellite drifts about as 100ms per hour, analyzed below according to this example.
According to the concrete condition of earth station and certain model satellite, setting threshold value P is 500ms, and setting △ T is 1 hour, n 3, TB
It is 0.5 hour.Earth station's every 1 hour calculating star time difference (actual time subtracts the time on star), due to the star clock of 100ms/h
The presence of drift, the time difference constantly becomes larger with leading to star；In view of the presence of measurement error, the data measured are as shown in table 1:
Table 1
| Actual time | The true star ground time difference | With the measuring star time difference |
| 1h | 100ms | 80ms |
| 2h | 200ms | 230ms |
| 3h | 300ms | 350ms |
| 4h | 400ms | 360ms |
| 5h | 500ms | 450ms |
| 6h | 600ms | 540ms |
| 7h | 700ms | 690ms |
Step 1): earth station's with the calculating star time difference and instruction when injecting increment school.Dt is found in 7h2=(450+540+
690)/3=560ms > threshold value P=500ms, instruction when being then filled with the increment school that parameter is 560ms to satellite computer.
Step 2): it is calibrated after being instructed when satellite computer receives increment school.
The time becomes t on this clock star2=tS+dt2=7h-700ms+560ms=7h-140ms
Step 3): more nova clock drift.
drift2=drift1+dt2/(t2–t1)=0+560ms/ (7h-140ms-0) ≈ 80ms/h
In order to simplify statement, ignore 140ms in above formula.Numerical error very little caused by the simplification will not influence this
The logical relation of method.
Step 4): when carrying out periodically uniform school according to newest star clock drift estimate value.
Every TBAmendment in=0.5 hour is primary:
tJ=tW+driftm*TB=tW+ 80ms/h*0.5h=tW+40ms
Effect when this example lieutenant colonel is as shown in table 2:
Table 2
" time on star after when uniform school " -100ms/ in upper table, before " time on star before when uniform school "=half an hour
h*0.5h；" time on star before when uniform school "+40ms of " time on star after when uniform school "=same row；" true star the time difference "
=" actual time "-" time on star after when uniform school ".
As it can be seen that since compensation rate 80ms/h and true star clock drift 100ms/h differs 20ms/h, cause on star the time with very
Difference between in real time constantly increases.
The second wheel iteration is carried out below, and the data measured are as shown in table 3:
Table 3
| Actual time | The true star ground time difference | With the measuring star time difference |
| 7h | 140ms | 80ms |
| 8h | 160ms | 230ms |
| … | … | … |
| 25h | 500ms | 460ms |
| 26h | 520ms | 550ms |
| 27h | 540ms | 550ms |
Since star clock drift 80ms/h compensates true drift 100ms/h, so that the star ground trend that increases of the time difference
Contained, at the 27th hour, the star that ground measures the time difference exceed threshold value 500ms, the time interval instructed twice is 20
Hour, it is reduced within 7 hours much than last.
Restart the following steps:
Step 1): earth station's with the calculating star time difference and instruction when injecting increment school.Dt is found in 27h3=(460+550+
550)/3=520ms > threshold value P=500ms, instruction when being then filled with the increment school that parameter is 520ms to satellite computer.
Step 2): it is calibrated after being instructed when satellite computer receives increment school.
The time becomes t on this clock star3=tS+dt3=27h-540ms+520ms=27h-20ms
Drift3=drift2+dt3/(t3–t2)=80ms/h+520ms/ [(27h-20ms)-(7h-140ms)] ≈
106ms/h
Step 4): when carrying out periodically uniform school according to newest star clock drift estimate value.
tJ=tW+driftm*TB=tW+ 106ms/h*0.5h=tW+53ms
Effect when this example lieutenant colonel is as shown in table 4:
Table 4
Subsequent star time difference data it is as shown in table 5:
Table 5
| Actual time | The true star ground time difference |
| 27h | 20ms |
| 28h | 14ms |
| … | … |
| 114h | -502ms |
As it can be seen that after second injection instruction, the error of star clock drift becomes -6ms/h, the star ground trend that increases of the time difference
Further containment is obtained.Absolute value of the difference is just greater than 500ms when in star true after 114-27=87 hours, accordingly
The time interval of face injection instruction is further enlarged, and the burden of earth station further becomes smaller.
As shown in Fig. 2, 2 line of curve indicates that true star clock drift 100ms/h, curve 1 indicate star clock drift estimate value
driftm.It can be seen that star clock drift estimate value gradually converges on true value.
Time interval between when Fig. 3 indicates increment school twice, it is seen that earth station issues an order time interval exponential increase.
Upper example explanation, if the drift of star clock is an invariant, i.e. 100ms/h is not changed over time, even if there are biggish
Star the time difference measurement error, method described herein can make star clock drift gradually converge on true value, so that ground be made to infuse
The time interval instructed when entering increment school tends to be infinitely great.
In fact, star clock drift be not a constant value, it include star the time difference calculate error, star clock chip temperature diurnal
Phase fluctuation, star clock chip temperature annual period fluctuate equal error, but this method still can reduce the frequency that earth station issues an order.
For the satellite of some model, when earth station uses traditional increment school and uniform calibration method, period when school
At two days or so, the special period even needed one day school, and when frequent school, which issues an order, brings biggish burden to earth station.Make
After the satellite calibration method as described herein based on the estimation of star clock shift iterations, frequency when school is reduced to a Monday school,
The biggish burden for reducing earth station.
The content that description in the present invention is not described in detail belongs to the well-known technique of professional and technical personnel in the field.
Claims (8)
1. a kind of satellite calibration method based on the estimation of star clock shift iterations, which is characterized in that comprise the following steps that
1) parameter when determining increment school using earth station, when increment school, parameter is greater than threshold value, earth station is to satellite computer
It is instructed when the increment school of parameter when sending with increment school；
2) when the increment school that satellite computer is sent according to earth station parameter carry out increment school when, obtain increment school when after star on
Time；And according to the more nova clock drift value of parameter iteration when increment school, the updated star clock drift value of iteration is obtained；
3) when the time carries out uniform school on the star after when according to the updated star clock drift value of the iteration to increment school；
4) using uniform time correction interval as the period, step 3) is repeated, until the satellite computer refers to when receiving new increment school
After order, return step 2), continue work when satellite school.
2. a kind of satellite calibration method based on the estimation of star clock shift iterations according to claim 1, which is characterized in that institute
State parameter dt when step 1) determines increment schoolmMethod, specifically:
dtm=(dt1+…+dtn)/n,
Wherein, dt1, dt2..., dtnFor every the time difference of time and actual time on the Satellite that time △ T is obtained.
3. a kind of satellite calibration method based on the estimation of star clock shift iterations according to claim 2, which is characterized in that institute
The value range for stating △ T is 0.5h~12h, and the value range of n is 1~48.
4. a kind of satellite calibration method based on the estimation of star clock shift iterations according to claim 3, which is characterized in that institute
When stating the increment school that step 2) is sent according to earth station parameter carry out increment school when, obtain increment school when after star on the time side
Method, specifically:
tm=tS+dtm,
Wherein, tSTime, t on corresponding Satellite when being instructed when increment school to receivemIncreasing is received for satellite computer the m times
Time on star after when the increment school obtained after instruction when measuring school, m is positive integer.
5. a kind of satellite calibration method based on the estimation of star clock shift iterations according to claim 3, which is characterized in that institute
Step 2) is stated according to the more nova clock drift value of parameter iteration when increment school, obtains the side for the star clock drift value that the m times iteration updates
Method, specifically:
driftm=driftm-1+dtm/(tm-tm-1),
Wherein, tm-1When on the star after when the increment school that instruction correspondence obtains when receiving the m-1 times increment school for satellite computer
Between, tmTime on star after when the increment school that instruction correspondence obtains when receiving the m times increment school for satellite computer,
driftm-1The corresponding star clock drift value obtained of instruction, drift when receiving the m-1 times increment school for satellite computer1=0.
6. a kind of satellite calibration method based on the estimation of star clock shift iterations, feature according to one of claim 2~5
It is, value range 10ms~2000ms of threshold value P described in step 1).
7. a kind of satellite calibration method based on the estimation of star clock shift iterations according to claim 6, which is characterized in that institute
State step 3) according to the updated star clock drift value of the iteration to increment school when after star on side of time when carrying out uniform school
Method, specifically:
tJ=tW+driftm*TB,
Wherein, tWFor time, t on moment corresponding star occur when uniform schoolJTime on star after when for uniform school, TBIt is uniform
Time correction interval.
8. a kind of satellite calibration method based on the estimation of star clock shift iterations according to claim 7, which is characterized in that institute
State TB≤△T。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910277011.7A CN109991839B (en) | 2019-04-08 | 2019-04-08 | Satellite timing method based on satellite clock drift iterative estimation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910277011.7A CN109991839B (en) | 2019-04-08 | 2019-04-08 | Satellite timing method based on satellite clock drift iterative estimation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109991839A true CN109991839A (en) | 2019-07-09 |
| CN109991839B CN109991839B (en) | 2020-09-18 |
Family
ID=67132555
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910277011.7A Active CN109991839B (en) | 2019-04-08 | 2019-04-08 | Satellite timing method based on satellite clock drift iterative estimation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109991839B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1422384A (en) * | 2000-03-30 | 2003-06-04 | 摩托罗拉公司 | Determining time in a GPS receiver |
| CN101383653A (en) * | 2008-10-30 | 2009-03-11 | 航天东方红卫星有限公司 | Automatic time synchronizing method on satellite |
| CN102385307A (en) * | 2011-09-26 | 2012-03-21 | 北京空间飞行器总体设计部 | Clock error measuring method of satellite-to-earth time system |
| CN102981402A (en) * | 2012-11-20 | 2013-03-20 | 北京控制工程研究所 | Method for calibrating satellite-to-ground time |
| CN103592842A (en) * | 2013-11-08 | 2014-02-19 | 贵州电力试验研究院 | Intelligent substation clock synchronization reliability method capable of improving network sampling |
| CN104330806A (en) * | 2014-09-22 | 2015-02-04 | 中国科学院国家授时中心 | Inter-satellite system difference calibration method based on Ka range finding mode |
| WO2016007590A1 (en) * | 2014-07-10 | 2016-01-14 | Watry Krissa | Electronic, interactive space-based toy system |
| CN109542084A (en) * | 2018-11-19 | 2019-03-29 | 北京航空航天大学 | A kind of satellite-based augmentation system integrity fault simulation method |
-
2019
- 2019-04-08 CN CN201910277011.7A patent/CN109991839B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1422384A (en) * | 2000-03-30 | 2003-06-04 | 摩托罗拉公司 | Determining time in a GPS receiver |
| CN101383653A (en) * | 2008-10-30 | 2009-03-11 | 航天东方红卫星有限公司 | Automatic time synchronizing method on satellite |
| CN102385307A (en) * | 2011-09-26 | 2012-03-21 | 北京空间飞行器总体设计部 | Clock error measuring method of satellite-to-earth time system |
| CN102981402A (en) * | 2012-11-20 | 2013-03-20 | 北京控制工程研究所 | Method for calibrating satellite-to-ground time |
| CN103592842A (en) * | 2013-11-08 | 2014-02-19 | 贵州电力试验研究院 | Intelligent substation clock synchronization reliability method capable of improving network sampling |
| WO2016007590A1 (en) * | 2014-07-10 | 2016-01-14 | Watry Krissa | Electronic, interactive space-based toy system |
| CN104330806A (en) * | 2014-09-22 | 2015-02-04 | 中国科学院国家授时中心 | Inter-satellite system difference calibration method based on Ka range finding mode |
| CN109542084A (en) * | 2018-11-19 | 2019-03-29 | 北京航空航天大学 | A kind of satellite-based augmentation system integrity fault simulation method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109991839B (en) | 2020-09-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105629263B (en) | A kind of troposphere atmosphere delay estimation error correcting method and correction system | |
| CN105242233B (en) | A kind of quick correction method of single-phase electric energy meter | |
| CN108983325B (en) | Rainfall runoff forecasting method | |
| CN101964689A (en) | Method for improving time accuracy of electric energy information acquisition system | |
| Tejaswini et al. | Calibration and validation of swat model for Kunthipuzha basin using SUFI-2 algorithm | |
| CN108596998A (en) | A kind of rainfall runoff correlation drawing drawing method based on Copula functions | |
| CN106292267A (en) | A kind of GNSS high accuracy time service terminal system and time service method | |
| CN103995268A (en) | Satellite navigation receiver local time correction method and positioning method | |
| CN204631463U (en) | A kind of gps clock synchro system of radiation source Monitoring and Positioning | |
| CN108957494A (en) | A kind of satellite-based high-precision continuous time acquisition methods | |
| CN109991839A (en) | A kind of satellite calibration method based on the estimation of star clock shift iterations | |
| CN104102836A (en) | Method for quickly estimating robust state of power system | |
| CN102981402A (en) | Method for calibrating satellite-to-ground time | |
| CN111913197A (en) | Application method of GPS _ BDS dual-mode time service technology in power distribution network automation | |
| CN101541073A (en) | Method for compensating network node crystal oscillation frequency error of wireless sensor | |
| CN104614734A (en) | Beidou space-based high-precision differential telegraph text generation method | |
| CN103793618A (en) | Thermosphere atmospheric density correction method | |
| Adler et al. | The new version 2.3 of the Global Precipitation Climatology Project (GPCP) monthly analysis product | |
| CN107168926B (en) | Consider the Flood Frequency Analysis method that reservoir operation influences | |
| CN109472295B (en) | Pearson correlation coefficient-based WAMS/SCADA system time synchronization sorting method | |
| CN113900367B (en) | Hydrogen atomic clock frequency control system and method | |
| CN109869137A (en) | A kind of pumpingh well fixed output quota mode control method based on flowmeter and indicator card | |
| CN105335870A (en) | Live pig price trend prediction method | |
| CN108733622A (en) | Ionized layer TEC single station forecasting method based on auto-correlation unequal interval iterative method | |
| Deminov et al. | Effective solar activity index for the median of the critical frequency of the F 2 layer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |