CN103293947A - Satellite-ground laser time comparison system - Google Patents
Satellite-ground laser time comparison system Download PDFInfo
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- CN103293947A CN103293947A CN2013101822691A CN201310182269A CN103293947A CN 103293947 A CN103293947 A CN 103293947A CN 2013101822691 A CN2013101822691 A CN 2013101822691A CN 201310182269 A CN201310182269 A CN 201310182269A CN 103293947 A CN103293947 A CN 103293947A
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Abstract
The invention relates to a satellite-ground laser time comparison system comprising ground equipment and satellite-borne equipment. The ground equipment sends laser pulse signals to a satellite, records a time value (TG) of a ground clock when the laser pulse signals are sent from the ground, records a time value (TB) of the ground clock when the ground receives the laser pulse signals reflected by the satellite, receives a time value (TS) of a satellite clock when the satellite receives the laser pulse signals, and calculates clock correction delta T of the satellite clock and the ground clock according to the above three time values. The satellite-borne equipment receives the laser pulse signals, reflects the laser pulse signals back to the ground, measures the time value (TS) of the satellite clock when the satellite receives the laser pulse signals, and sends the time value (TS) of the satellite clock when the satellite receives the laser pulse signals to the ground equipment. With the satellite-ground laser time comparison system, the laser time comparison technology is adopted, satellite-ground clock correction can be measured highly accurately, laser time comparison can be realized, and further satellite-ground time synchronization can be realized.
Description
Technical field
The present invention relates to the Laser Time Synchronization technology, relate in particular to a kind of for the star ground Laser Time comparison system that realizes star ground Laser Time Synchronization.
Background technology
As everyone knows, the comparison of the atomic clock on satellite or the space station (rubidium atomic clock, hydrogen atomic clock, cold atomic clock etc.) and ground atomic clock and be very important synchronously accurately.
Satellite and ground elapsed time commonly used are realized by radio synchronously, its principle of work is: satellite and land station produce by radio transmitter in the clock face moment of oneself respectively and mark signal concurrent sowing time, then by radio receiver record emission time scale through one section propagation delay after ground and satellite observe the moment or the time difference (descending pseudorange value and up pseudorange value) of the relative local clock of the other side's markers respectively, satellite is issued land station with oneself record result (up pseudorange value) by communication link, land station just can calculate star ground clock correction by above observation data (up pseudorange value and descending pseudorange value), and then realizes that satellite and ground elapsed time are synchronous.
The main error of the two-way time comparison method of above-mentioned this radio comprises: radio receiver quantification and noise error, equipment null value drift error and atmosphere additional delay residual error, free space propagation delay time estimation error etc., wherein, noise error, equipment null value drift error and atmosphere delay residual error to the radio time ratio to having the greatest impact; Specifically:
1, noise error refers to that thermonoise causes that radio receiver extracts the phase error of data base sequence clock, and the Design of Signal of this and receiver and the signal processing mode of receiving end are relevant, generally about 1 nanosecond;
2, the system of equipment null value sensing up-downgoing channel is poor, if the up-downgoing channel design is symmetry extremely, this error can effectively be suppressed, but general spaceborne and terrestrial radio receiver designs all not exclusively symmetry, therefore this error need be carried out the null value demarcation, because the null value drift of equipment is relevant with channel width and temperature variation, generally this error can be controlled in below 5 nanoseconds;
3, atmosphere additional delay residual error mainly refers to the signal delay that causes at ionospheric refraction, this delay is relevant with local time and season, peak value is in local time 2 pm, the ionosphere delay error maximum, fluctuation is also maximum, and night, error was little, and it is also less to fluctuate, and the time synchronization error that ionosphere causes was about for 0.5 nanosecond.
Summary of the invention
In order to solve the problem that above-mentioned prior art exists, the present invention aims to provide a kind of star ground Laser Time comparison system, to measure star ground clock correction accurately, realizes the Laser Time comparison, and then realizes star ground time synchronized.
A kind of star of the present invention ground Laser Time comparison system, it comprises:
Uphole equipment, it launches laser pulse signal to satellite, and the moment value T of the ground clock during record ground surface launching laser pulse signal
G, the moment value T of the ground clock when recording the described laser pulse signal that ground receives reflected back from the satellite simultaneously
B, and the moment value T of the satellite clock when receiving described laser pulse signal and arriving satellite
S, calculate the clock correction Δ T of satellite clock and ground clock according to formula (1)-(5),
Δ T=T
G+ t
Up-T
S(1),
t
Up=(t-Δ)/2 (2),
t=T
B-T
G （3），
Δ=V
Φt/2·cosH·sinA （4），
V
Φ=ωa·cosΦ （5），
Wherein, t
UpFor described laser pulse signal arrives the required time of satellite from ground, t is the flight time that described laser pulse signal comes and goes between satellite and ground, and Δ is the modified value of the Sagnac effect that caused by earth rotation, V
ΦFor geodetic latitude is the earth rotation linear velocity at Φ place, a is earth radius, and ω is earth rotation speed, and H and A are respectively satellite with respect to height and the orientation angles on ground; And
Satellite borne equipment, it receives described laser pulse signal, and with this laser pulse signal by reflected back ground, former road, the moment value T of the satellite clock when measuring described laser pulse signal simultaneously and arriving satellite
S, and the moment value T of the satellite clock when this laser pulse signal arrived satellite
SUnder reach described uphole equipment.
In above-mentioned star ground Laser Time comparison system, described uphole equipment comprises:
Produce the laser instrument of described laser pulse signal;
With the laser rangefinder telescope that described laser instrument is connected, it on the one hand is emitted to satellite with described laser pulse signal, receives the described laser pulse signal of reflected back from the satellite on the other hand;
With the photon detection system that described laser rangefinder telescope is connected, it is exported after the described laser pulse signal of reflected back is converted to electric signal from the satellite described;
The ground timer that is connected with described photon detection system, it receives the ground elapsed time frequency reference signal of ground elapsed time frequency system output, and on the one hand according to this frequency reference signal and described laser pulse signal, the moment of the ground clock during record described ground surface launching laser pulse signal is worth T ground elapsed time
G, on the other hand according to described ground elapsed time frequency reference signal and the electric signal of described photon detection system output, the moment value T of the ground clock when recording the described laser pulse signal that described ground receives reflected back from the satellite
B
The ground data transmission system, the moment value T of the satellite clock when it receives described laser pulse signal and arrives satellite
SAnd
With the ground control system that described ground timer and ground data transmission system are connected, it calculates the clock correction Δ T of described satellite clock and ground clock.
In above-mentioned star ground Laser Time comparison system, described satellite borne equipment comprises:
Laser reflector, it receives described laser pulse signal, and this laser pulse signal is pressed reflected back ground, former road;
Laser time difference measurement instrument, it surveys described laser pulse signal, and according to the satellite time frequency reference signal of spaceborne temporal frequency system output, the moment value T of the satellite clock when measuring described laser pulse signal and arriving satellite
SAnd
With the spaceborne data transmission system that described laser time difference measurement instrument is connected, the moment value T of its reception and the satellite clock when described laser pulse signal arrived satellite
SUnder reach described uphole equipment.
In above-mentioned star ground Laser Time comparison system, described laser time difference measurement instrument comprises:
Laser detector, it surveys described laser pulse signal, and exports after this laser pulse signal is converted into electric signal; And
The laser timer that is connected with described laser detector, it measures the time interval TI of the reference pulse signal that comprises in the electric signal of described laser detector output and the described satellite time frequency reference signal on the one hand, and according to this time interval TI, the moment value T of the satellite clock when measuring and exporting described laser pulse signal and arrive satellite to described spaceborne data transmission system
SOn the other hand according to the steering order of being sent by described uphole equipment of described spaceborne data transmission system output, to described laser detector output gate-control signal.
In above-mentioned star ground Laser Time comparison system, described laser detector comprises:
Avalanche diode, its input end receives a reversed bias voltage, and its output terminal is by an output resistance ground connection, and this output terminal also receives described gate-control signal; And
High-speed comparator with two input ends, an one input end is connected with the output terminal of described avalanche diode, its another input end receives a datum, and its output terminal is connected with described laser timer on the one hand, is connected to the output terminal of described avalanche diode on the other hand.
In above-mentioned star ground Laser Time comparison system, described laser timer comprises:
With the data disposable plates that described spaceborne data transmission system communicates to connect, the moment value T of the satellite clock when it is on the one hand exported described laser pulse signal and arrive satellite to described spaceborne data transmission system
S, receive the steering order of being sent by described uphole equipment of described spaceborne data transmission system output on the other hand;
With the time difference measurement plate that described data disposable plates is connected, the moment value T of the satellite clock when it is measured on the one hand and exports described laser pulse signal and arrive satellite to described data disposable plates
S, the steering order of being sent by described uphole equipment that receives according to described data disposable plates on the other hand is to described laser detector output gate-control signal.
In above-mentioned star ground Laser Time comparison system, described data disposable plates comprises interconnective CPU (central processing unit) and communication data processing module.
In above-mentioned star ground Laser Time comparison system, described time difference measurement plate comprises interconnective field programmable gate array and time-to-digit converter.
In above-mentioned star ground Laser Time comparison system, described laser timer also comprises to the power module of described data disposable plates and the power supply of time difference measurement plate.
Owing to adopted above-mentioned technical solution, the present invention to adopt Laser Time comparison technology, it is right namely to carry out star ground time ratio by the transmission of employing laser pulse signal; In the transmittance process of laser pulse signal, because its pulse width is narrow, so the precision height of laser acquisition, because therefore laser wave length frequency height is subjected to the influence of atmospheric ionized layer little, thereby can accurately revises the star ground time, make it synchronous again; And the drift of the uncertainty of laser equipment time delay and time delay is all smaller, therefore by with the two-way time comparison result of laser of the present invention (being the clock correction Δ T of satellite clock and ground clock) and the comparison result comparison of existing star ground two-way time of radio, can check the two-way time ratio of radio to the systematic error that exists in the system and the stability of twoway radio time delay.
Description of drawings
Fig. 1 is the schematic diagram of star of the present invention ground Laser Time comparison technology;
Fig. 2 is the structured flowchart of a kind of star of the present invention ground Laser Time comparison system;
Fig. 3 is the structured flowchart of laser time difference measurement instrument among the present invention;
Fig. 4 is the theory diagram of laser detector in the laser time difference measurement instrument of the present invention;
Fig. 5 is the theory diagram of laser timer in the laser time difference measurement instrument of the present invention;
Schematic diagram when Fig. 6 is the survey of laser timer in the laser time difference measurement instrument of the present invention.
Embodiment
Below in conjunction with accompanying drawing, provide preferred embodiment of the present invention, and be described in detail.
At first according to Fig. 1, the principle of star of the present invention ground Laser Time being compared technology describes.
Laser two-way time ratio in star ground to the ultimate principle of technology is: laser pulse signal is launched to satellite in ground, after this laser pulse signal arrives satellite, and the moment value of the satellite clock when satellite borne equipment is noted this laser pulse signal arrival satellite; Simultaneously, satellite borne equipment is with this laser pulse signal reflected back ground, and uphole equipment is noted the moment value of the ground clock when launching this laser pulse signal and receiving the laser pulse signal that returns respectively; And, the moment value of the satellite clock when uphole equipment also receives the laser pulse signal that gets off from satellite transmission and arrives satellite, can obtain clock correction between satellite clock and the ground clock according to the moment value of the moment value of this satellite clock and two ground clocks, thereby the time ratio of finishing between the star ground is right.
As shown in Figure 1, (moment value of ground clock) is T when ground
CGThe time, (moment value of satellite clock) is T during satellite
CS, the time difference during when establishing satellite and ground is Δ T, therefore, and T when satellite
CSThrough behind the Δ T, T in the time of will be with ground
CGIdentical, that is to say T
CS+ Δ T=T
CG, that is, be T when ground
CGThe time, T during satellite
CS=T
CG-Δ T.
The moment of surface-emission laser pulse signal value is T hypothetically
G, this laser pulse signal arrives satellite after after a while, and the moment value of the satellite clock of this moment is T
S, simultaneously, this laser pulse signal is reflected back toward ground, and the moment value of the ground clock when this laser pulse signal arrives ground is T
BAccording to the satellite laser ranging (SLR) principle, the flight time t(that can be come and gone between satellite and ground by laser pulse signal is t=T
B-T
G) calculate this laser pulse signal from the required time t of ground arrival satellite
Up, specifically, because the flight time t that laser pulse signal comes and goes between satellite and ground arrives the required time t of satellite by laser pulse signal from ground
UpTurn back to the required time t in ground with laser pulse signal from satellite
DescendingForm, therefore, t
Up=t-t
DescendingAgain because the caused Sagnac effect of earth rotation (Sagnac effect) makes t
UpAnd t
DescendingUnequal, and both differ an amount and are designated as Δ, that is, and and t
Descending=t
Up-Δ, so t
Up=(t-Δ)/2, wherein, the modified value Δ=V of the Sagnac effect that is caused by earth rotation
ΦT/2cosHsinA, V
ΦFor geodetic latitude is the earth rotation linear velocity at Φ place, and V
Φ=ω acos Φ, a are earth radius, and ω is earth rotation speed, and H and A are respectively satellite with respect to height and the orientation angles on ground.Therefore, be T when moment of satellite clock value
SThe time, the moment value of ground clock is T
G+ t
Up, that is, and T
S=T
G+ t
Up-Δ T; Can obtain the time difference Δ T=T of satellite clock and ground clock thus
G+ t
Up-T
S
Based on above-mentioned principle, the present invention, i.e. a kind of star ground Laser Time comparison system comprises uphole equipment and satellite borne equipment, wherein:
Uphole equipment is mainly used in to satellite emission laser pulse signal, and records the moment value T of the ground clock when launching laser pulse signal
G, the moment value T of the ground clock when recording the laser pulse signal that ground receives reflected back from the satellite simultaneously
B, and receive the data that pass under the satellite equipment, the moment value T of the satellite clock when namely this laser pulse signal arrives satellite
S, obtain the clock correction Δ T of satellite clock and ground clock according to above-mentioned three data computation at last, thereby finish the comparison work of star ground clock, utilize this clock correction can realize star ground Laser Time Synchronization;
Satellite borne equipment is mainly used in receiving the laser pulse signal of uphole equipment emission, and this laser pulse signal is pressed reflected back ground, former road, the moment value T of the satellite clock when measuring this laser pulse signal arrival satellite simultaneously
S, the moment with this satellite clock is worth T at last
SUnder reach uphole equipment.
As shown in Figure 2, uphole equipment comprises the laser instrument 1 that is arranged on the ground laser ranging station, laser rangefinder telescope 2, ground elapsed time frequency system 3, photon detection system 4, ground timer 5, ground data transmission system 6 and ground control system 7; Specifically:
Laser instrument 1 produces laser pulse signal;
After being converted to electric signal, exports the laser pulse signal that returns that photon detection system 4 receives laser rangefinder telescope 2;
Ground timer 5 receive ground elapsed time frequency system 3 outputs ground elapsed time the frequency reference signal the basis on, on the one hand according to the laser pulse signal of laser instrument 1 output, the moment value T of the ground clock during record ground surface launching laser pulse signal
G, on the other hand according to the electric signal of photon detection system 4 output, the moment value T of the ground clock when record ground receives the laser pulse signal of reflected back from the satellite
B
The moment value T of the satellite clock when ground data transmission system 6 receives the laser pulse signal that passes under the satellite equipment and arrives satellite
SThis ground data transmission system 6 can also be exported the steering order of ground control system 7 to satellite equipment;
The moment value T of the ground clock of ground control system 7 during according to the ground surface launching laser pulse signal of ground timer 5 output
GThe moment value T of the ground clock when receiving the laser pulse signal of reflected back from the satellite with ground
B, and the moment value T of the satellite clock of the laser pulse signal of ground data transmission system 6 output when arriving satellite
S, calculate laser pulse signal and arrive the required time t of satellite from ground
Up, and finally calculate the clock correction Δ T of satellite clock and ground clock, thus the comparison of star ground time finished, to realize the synchronous of star ground Laser Time; Ground control system 7 also can be controlled laser rangefinder telescope 2 and according to satellite alert information satellite be followed the tracks of and monitored.
As shown in Figure 2, satellite borne equipment comprises laser reflector 8, laser time difference measurement instrument 9, spaceborne temporal frequency system 10 and the spaceborne data transmission system 11 that is arranged on the satellite; Specifically:
The laser pulse signal of laser time difference measurement instrument 9 exploring laser light range-finding telescopes 2 emission, and according to the satellite time frequency reference signal of spaceborne temporal frequency system 10 outputs, the moment value T of the satellite clock when measuring laser pulse signal and arriving satellite
S
The moment value T of the satellite clock the when laser pulse signal of spaceborne data transmission system 11 reception laser time difference measurement instrument 9 outputs arrives satellite
S, and reach ground data transmission system 6 under the moment value of resource situation selection suitable manner with this satellite clock according to satellite; Spaceborne data transmission system 11 can also be according to the steering order of the ground control system 7 of ground data transmission system 6 output, and laser time difference measurement instrument 9 and other satellite borne equipments are instructed operations such as control and pattern switching.
In the present embodiment, the reflector array that laser reflector 8 is made up of one group of fused quartz material pyramid, each pyramid is to have three orthogonal kaleidoscope prisms of right angle face, its optical characteristics is as follows: beam of laser is from bottom surface (i.e. three the right angle faces fourth face in addition) incident of kaleidoscope prism, after the reflection through three right angle faces, penetrate from the bottom surface successively.This outgoing beam is parallel with incoming laser beam, but direction is opposite.Therefore, the laser reflector 8 that is installed on the satellite can make uphole equipment receive stronger laser light reflected pulse signal, thereby be convenient to uphole equipment and realize the high-precision laser range-finding measurement relevant with other, for example, in the present invention, uphole equipment utilizes the laser pulse signal on laser reflector 8 reflected back ground can calculate laser pulse signal and arrives the required time t of satellite from ground
Up
As shown in Figure 3, the laser time difference measurement instrument 9 among the present invention specifically comprises laser detector 91 and high-precision laser timer 92, wherein:
The time interval TI of the reference pulse signal (being pps pulse per second signal) that comprises in the satellite time frequency reference signal of the electric signal that laser timer 92 is mainly used in measuring laser detector 91 outputs and 10 outputs of spaceborne temporal frequency system, thus the moment of the satellite clock when obtaining laser pulse signal and arriving satellite be worth T
S, and to the moment value T of spaceborne data transmission system 11 these satellite clocks of output
SCan also receive the steering order on the ground of spaceborne data transmission system 11 outputs in addition, to carry out corresponding control operation, for example laser timer 92 can be exported gate-control signals to laser detector 91 according to the steering order on ground, with the sensitive time of control laser detector 91; Laser timer 92 communicates to connect by cable and spaceborne temporal frequency system 10 and spaceborne data transmission system 11.
As shown in Figure 4, the core component that laser detector 91 adopts among the present invention is avalanche diode (Single Photon Avalanche Diode, SPAD), the avalanche diode among the present invention need use the product that is fit to be applied to space industry by irradiation test and empirical tests.
Because this avalanche diode sensitiveness to light reaches the single photon level, therefore be called single-photon avalanche diode again; Owing to recovering very slow after the avalanche diode snowslide automatically or can not recovering automatically, therefore must control its both end voltage and make it stop avalanche condition, otherwise be easy to damage avalanche diode.In view of the foregoing, need on the principle output of avalanche diode is fed back on its avalanche voltage, thereby when the avalanche diode snowslide, by its feedback circuit avalanche voltage is reduced, and then the snowslide of avalanche diode is stopped.
Based on above-mentioned situation, the circuit structure of laser detector 91 specifically comprises avalanche diode 911 and high-speed comparator 912 in the present embodiment, wherein:
The input end of avalanche diode 911 (anode) receives a reversed bias voltage, and its output terminal (negative electrode) is by output resistance R
aGround connection, this output terminal also receive the gate-control signal of laser timer 92 outputs;
An input end of high-speed comparator 912 is connected with the output terminal of avalanche diode 911, and its another input end receives a datum U
Ref, its output terminal is connected with laser timer 92 on the one hand, is connected to the output terminal of avalanche diode 911 on the other hand, thereby forms feedback circuit.
The principle of work of foregoing circuit structure is as follows:
Because the avalanche current size that produces after avalanche diode 911 snowslides is not fixed value, therefore, as datum U
RefDuring the value of the output voltage the when value of choosing does not have snowslide near avalanche diode 911, the any faint avalanche current of avalanche diode 911 all may be detected and export corresponding electric signal by high-speed comparator 912, and can think that the remolding sensitivity of laser detector 91 is higher this moment.But because itself there is reverse dark current in avalanche diode 911, therefore, the output that its high sensitivity will make its dark current produce is detected by high-speed comparator 912, thereby increases the dark noise of laser detector 91.
The needed time of wait avalanche condition that returns to sensitivity after avalanche diode 911 snowslides is called Dead Time.Be subjected to the influence of Dead Time, if before laser pulse signal arrives, avalanche diode 911 is owing to snowslide takes place in noise, and do not return to the avalanche condition for the treatment of of sensitivity as yet, and then this laser pulse signal just can't be detected by laser detector 91.Therefore, in the present invention, send gate-control signal with fixing frequency to laser detector 91 by laser timer 92, with the sensitive time of control laser detector 91, it before emitting, the efficient laser pulse signal is not worked, and just be in sensitive state at the efficient laser pulse signal before at hand, simultaneously, x time by uphole equipment control laser pulse signal, the moment that makes laser pulse signal arrive laser detector 91 just in time is positioned at after gate-control signal sends, like this with regard to having avoided noise to cause snowslide to the influence of effective detection.
In addition, because avalanche diode 911 is longer from the time that avalanche condition end snowslide returns to highly sensitive state, therefore, the output signal of high-speed comparator 912 is fed back to the output terminal of avalanche diode 911, thereby impel avalanche diode 911 after snowslide output, can finish snowslide as early as possible, and return to highly sensitive state and wait for snowslide next time.
In the present embodiment, reach 100ps by the avalanche diode 911 that adopts single-photon sensitivity and the time measurement precision that high-speed comparator 912 can make laser detector 91.
As shown in Figure 5, laser timer 92 comprises power module 921, data disposable plates 922 and time difference measurement plate 923 among the present invention, wherein:
Data disposable plates 922 communicates to connect with spaceborne data transmission system 11, the moment value T of the satellite clock when arriving satellite to spaceborne data transmission system 11 output laser pulse signals on the one hand
S, receive the steering order on the ground of spaceborne data transmission system 11 outputs on the other hand, comprising control time difference measurement plate 923 to laser detector 91 output gate-control signals; Data disposable plates 922 specifically comprises interconnective CPU (central processing unit) 9221(Central Processing Unit, CPU) and communication data processing module 9222, wherein, CPU (central processing unit) 9221 comprises address bus and data bus, and by this two kinds of buses and communication data processing module 9222, time difference measurement plate 923 and power module 921 communicate, and this CPU (central processing unit) 9221 receives the director data of spaceborne data transmission system 11 by communication data processing module 9222, system time information, and sending measurement through the identification back to time difference measurement plate 923, stop, time synchronized, pattern control, send instructions such as laser detector 91 gate outputs; Time difference measurement plate 923 receives instruction and carries out corresponding operation, and returns corresponding status word, and the moment value T of the satellite clock when according to agreement laser pulse signal being arrived satellite
SSend to communication data processing module 9222 by bus, can send to spaceborne data transmission system 11 by this communication data processing module 9222 and carry out data down transmission;
Time difference measurement plate 923 is connected with data disposable plates 922 with internal communication protocol using by bus, it receives the electric signal of laser detector 91 outputs and the satellite time frequency reference signal of spaceborne temporal frequency system 10 outputs, and measure the time interval TI of the reference pulse signal that comprises in this electric signal and the satellite time frequency reference signal, and then the moment value T of the satellite clock when obtaining laser pulse signal and arriving satellite
S, and with moment of this satellite clock value T
STransfer to data disposable plates 922; Time difference measurement plate 923 specifically comprises interconnective field programmable gate array 9231(Field-Programmable Gate Array, FPGA) and time-to-digit converter 9232(Time to Digital Convertor, TDC), and thus realize above-mentioned functions.
This shows that time difference measurement plate 923 is as the critical component of laser timer 92, when having realized that high precision is surveyed; See also Fig. 6, the principle of work of time difference measurement plate 923 is as follows:
Time difference measurement plate 923 adopts the interpolation time study method, the base during as reference with the temporal frequency reference signal of outside input, two input pulses that need timing (for example above the electric signal exported of described laser detector 91 and satellite time frequency reference signal in contained reference pulse signal) corresponding with reference to the time time interval on the base be divided into big fractional part Δ t and fine portion Δ t
1, Δ t
2Big fractional part Δ t can utilize general counter that the pulse (main pulse when being also referred to as) of the temporal frequency reference signal of outside input is counted acquisition, fine portion Δ t
1With Δ t
2Small time interval when two input pulses that refer to need timing are respectively and thereafter nearest between the main pulse; Thus, as shown in Figure 6, need the time interval TI=Δ t+ Δ t of two input pulses of timing
1-Δ t
2
Based on above-mentioned principle, the principle of each parts is as follows in the time difference measurement plate 923:
Spaceborne temporal frequency system 10 sends satellite time frequency reference signal into time difference measurement plate 923, after the signal processing, this satellite time frequency reference signal enters field programmable gate array 9231, base during as reference, also send in the field programmable gate array 9231 as end signal simultaneously with reference pulse signal (pps pulse per second signal) contained in satellite time frequency reference signal signal to start with, and with the electric signal (laser pulse signal that corresponding laser detector 91 detects) of laser detector 91 outputs; After field programmable gate array 9231 receives commencing signal, this commencing signal is sent into time-to-digit converter 9232, by its internal counter the time main pulse after the commencing signal is slightly counted simultaneously, after field programmable gate array 9231 receives end signal, equally this end signal is sent into time-to-digit converter 9232, stop simultaneously to the time main pulse counting, so far can obtain Δ t; After time digital quantizer 9232 receives commencing signal, note this commencing signal and the precise time-time-interval Δ t between main pulse when nearest thereafter
1, after time digital quantizer 9232 receives end signal, note this end signal and the precise time-time-interval Δ t between main pulse when nearest thereafter
2So far can obtain the time interval TI between pps pulse per second signal and the electric signal.When the internal counter of programmable gate array 9231 is counted pulse per second (PPS) at the scene, can obtain the time information of each pulse per second (PPS), the moment value T of the satellite clock in the time of can obtaining laser pulse signal arrival satellite according to this time information, pps pulse per second signal itself and time interval TI by known method
S
Generally speaking, spaceborne temporal frequency system 10 can provide the satellite time frequency reference signal of 10MHz and be included in standard 1pps(pulse per second in this satellite time frequency reference signal to laser timer 92) pps pulse per second signal, and the moment of second signal value.If the time interval between the laser timer 92 direct laser pulse signals of measuring the pps pulse per second signal of 1pps and receiving then has only a measurement data p.s., data volume can be very little.Therefore in fact can be produced the pulse signal (usually according to determining the frequency of this pulse signal with the matching principle of the output frequency of laser instrument 1) of 20pps, 100pps or other frequencies by the field programmable gate array 9231 of laser timer 92 inside according to the satellite time frequency reference signal of 10MHz, measure the time interval of this pulse signal and laser pulse signal, thereby can obtain several measurement data at per second.
In sum, the present invention is by loading the laser time difference measurement instrument that adopts single photon laser pulse detection method at satellite, the precision that has effectively improved laser ranging (facts have proved, measuring accuracy of the present invention is than the measuring accuracy high order of magnitude of existing radio time ratio to system), reduced uncertainty and the drift of laser ranging time delay simultaneously; By with the two-way time comparison result of laser of the present invention and comparison result of existing star ground two-way time of radio relatively, can check the two-way time ratio of radio to the systematic error that exists in the system and the stability of twoway radio time delay; The two-way time comparison result of laser according to the present invention also can be in real time on the star or the time system at different measuring station carry out synchronous calibration and comparison, be equipped with under the condition of time ratio to uphole equipment at multistation, the time synchronized of carrying out between each station lays the first stone.
Above-described, be preferred embodiment of the present invention only, be not in order to limiting scope of the present invention, the above embodiment of the present invention can also make a variety of changes.Be that simple, the equivalence that every claims according to the present patent application and description are done changes and modification, all fall into the claim protection domain of patent of the present invention.The present invention not detailed description be the routine techniques content.
Claims (9)
1. a star ground Laser Time is compared system, it is characterized in that this system comprises:
Uphole equipment, it launches laser pulse signal to satellite, and the moment value T of the ground clock during record ground surface launching laser pulse signal
G, the moment value T of the ground clock when recording the described laser pulse signal that ground receives reflected back from the satellite simultaneously
B, and the moment value T of the satellite clock when receiving described laser pulse signal and arriving satellite
S, calculate the clock correction Δ T of satellite clock and ground clock according to formula (1)-(5),
Δ T=T
G+ t
Up-T
S(1),
t
Up=(t-Δ)/2 (2),
t=T
B-T
G （3），
Δ=V
Φt/2·cosH·sinA （4），
V
Φ=ωa·cosΦ （5），
Wherein, t
UpFor described laser pulse signal arrives the required time of satellite from ground, t is the flight time that described laser pulse signal comes and goes between satellite and ground, and Δ is the modified value of the Sagnac effect that caused by earth rotation, V
ΦFor geodetic latitude is the earth rotation linear velocity at Φ place, a is earth radius, and ω is earth rotation speed, and H and A are respectively satellite with respect to height and the orientation angles on ground; And
Satellite borne equipment, it receives described laser pulse signal, and with this laser pulse signal by reflected back ground, former road, the moment value T of the satellite clock when measuring described laser pulse signal simultaneously and arriving satellite
S, and the moment value T of the satellite clock when this laser pulse signal arrived satellite
SUnder reach described uphole equipment.
2. star according to claim 1 ground Laser Time comparison system is characterized in that described uphole equipment comprises:
Produce the laser instrument of described laser pulse signal;
With the laser rangefinder telescope that described laser instrument is connected, it on the one hand is emitted to satellite with described laser pulse signal, receives the described laser pulse signal of reflected back from the satellite on the other hand;
With the photon detection system that described laser rangefinder telescope is connected, it is exported after the described laser pulse signal of reflected back is converted to electric signal from the satellite described;
The ground timer that is connected with described photon detection system, it receives the ground elapsed time frequency reference signal of ground elapsed time frequency system output, and on the one hand according to this frequency reference signal and described laser pulse signal, the moment of the ground clock during record described ground surface launching laser pulse signal is worth T ground elapsed time
G, on the other hand according to described ground elapsed time frequency reference signal and the electric signal of described photon detection system output, the moment value T of the ground clock when recording the described laser pulse signal that described ground receives reflected back from the satellite
B
The ground data transmission system, the moment value T of the satellite clock when it receives described laser pulse signal and arrives satellite
SAnd
With the ground control system that described ground timer and ground data transmission system are connected, it calculates the clock correction Δ T of described satellite clock and ground clock.
3. star according to claim 1 and 2 ground Laser Time comparison system is characterized in that described satellite borne equipment comprises:
Laser reflector, it receives described laser pulse signal, and this laser pulse signal is pressed reflected back ground, former road;
Laser time difference measurement instrument, it surveys described laser pulse signal, and according to the satellite time frequency reference signal of spaceborne temporal frequency system output, the moment value T of the satellite clock when measuring described laser pulse signal and arriving satellite
SAnd
With the spaceborne data transmission system that described laser time difference measurement instrument is connected, the moment value T of its reception and the satellite clock when described laser pulse signal arrived satellite
SUnder reach described uphole equipment.
4. star according to claim 3 ground Laser Time comparison system is characterized in that described laser time difference measurement instrument comprises:
Laser detector, it surveys described laser pulse signal, and exports after this laser pulse signal is converted into electric signal; And
The laser timer that is connected with described laser detector, it measures the time interval TI of the reference pulse signal that comprises in the electric signal of described laser detector output and the described satellite time frequency reference signal on the one hand, and according to this time interval TI, the moment value T of the satellite clock when measuring and exporting described laser pulse signal and arrive satellite to described spaceborne data transmission system
SOn the other hand according to the steering order of being sent by described uphole equipment of described spaceborne data transmission system output, to described laser detector output gate-control signal.
5. star according to claim 4 ground Laser Time comparison system is characterized in that described laser detector comprises:
Avalanche diode, its input end receives a reversed bias voltage, and its output terminal is by an output resistance ground connection, and this output terminal also receives described gate-control signal; And
High-speed comparator with two input ends, an one input end is connected with the output terminal of described avalanche diode, its another input end receives a datum, and its output terminal is connected with described laser timer on the one hand, is connected to the output terminal of described avalanche diode on the other hand.
6. according to claim 4 or 5 described star ground Laser Time comparison systems, it is characterized in that described laser timer comprises:
With the data disposable plates that described spaceborne data transmission system communicates to connect, the moment value T of the satellite clock when it is on the one hand exported described laser pulse signal and arrive satellite to described spaceborne data transmission system
S, receive the steering order of being sent by described uphole equipment of described spaceborne data transmission system output on the other hand;
With the time difference measurement plate that described data disposable plates is connected, the moment value T of the satellite clock when it is measured on the one hand and exports described laser pulse signal and arrive satellite to described data disposable plates
S, the steering order of being sent by described uphole equipment that receives according to described data disposable plates on the other hand is to described laser detector output gate-control signal.
7. star according to claim 6 ground Laser Time comparison system is characterized in that described data disposable plates comprises interconnective CPU (central processing unit) and communication data processing module.
8. star according to claim 6 ground Laser Time comparison system is characterized in that described time difference measurement plate comprises interconnective field programmable gate array and time-to-digit converter.
9. according to claim 7 or 8 described star ground Laser Time comparison systems, it is characterized in that described laser timer also comprises to the power module of described data disposable plates and the power supply of time difference measurement plate.
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| CN103454911A (en) * | 2013-09-16 | 2013-12-18 | 中国航天科工集团第二研究院二〇三所 | Rough synchronization method for satellite bidirectional time comparison |
| CN106154246A (en) * | 2015-04-27 | 2016-11-23 | 中国人民解放军63921部队 | Echo photon signal real-time processing method |
| CN107783140A (en) * | 2016-08-25 | 2018-03-09 | 左罗 | High-precision laser range finder and its distance-finding method |
| CN109756321A (en) * | 2017-11-01 | 2019-05-14 | 中兴通讯股份有限公司 | A kind of time synchronism apparatus and method |
| CN109791195A (en) * | 2016-09-22 | 2019-05-21 | 苹果公司 | The adaptive transmission power control reached for light |
| CN109991837A (en) * | 2019-03-22 | 2019-07-09 | 中国科学技术大学 | It is a kind of to regard the system and method for carrying out two places clock comparison altogether using laser |
| CN110471094A (en) * | 2019-07-17 | 2019-11-19 | 中国电子科技集团公司第五十四研究所 | It is a kind of to digitize the time Compare System and comparison method handled in real time |
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| CN111142366A (en) * | 2019-12-19 | 2020-05-12 | 中国电波传播研究所（中国电子科技集团公司第二十二研究所） | Novel short wave time service method |
| CN111505658A (en) * | 2020-04-16 | 2020-08-07 | 中国科学院上海天文台 | Pulse group type laser ranging method with adjustable repetition frequency |
| CN111708059A (en) * | 2020-06-24 | 2020-09-25 | 中国科学院国家天文台长春人造卫星观测站 | Laser time transfer processing method, system, storage medium, device and application |
| CN112817022A (en) * | 2020-12-23 | 2021-05-18 | 浙江吉利控股集团有限公司 | Low-orbit satellite time-frequency synchronization method, system, electronic equipment and storage medium |
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| CN115639743A (en) * | 2022-10-19 | 2023-01-24 | 中国科学院国家授时中心 | Space-based time reference establishing method and system based on whole network time comparison |
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| CN106154246A (en) * | 2015-04-27 | 2016-11-23 | 中国人民解放军63921部队 | Echo photon signal real-time processing method |
| CN106154246B (en) * | 2015-04-27 | 2018-11-27 | 中国人民解放军63921部队 | Echo photon signal real-time processing method |
| CN107783140A (en) * | 2016-08-25 | 2018-03-09 | 左罗 | High-precision laser range finder and its distance-finding method |
| CN109791195A (en) * | 2016-09-22 | 2019-05-21 | 苹果公司 | The adaptive transmission power control reached for light |
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| CN109991837B (en) * | 2019-03-22 | 2020-10-27 | 中国科学技术大学 | System and method for comparing two-place clocks by using laser common view |
| CN109991837A (en) * | 2019-03-22 | 2019-07-09 | 中国科学技术大学 | It is a kind of to regard the system and method for carrying out two places clock comparison altogether using laser |
| CN110471094A (en) * | 2019-07-17 | 2019-11-19 | 中国电子科技集团公司第五十四研究所 | It is a kind of to digitize the time Compare System and comparison method handled in real time |
| CN110865200A (en) * | 2019-11-25 | 2020-03-06 | 北京无线电计量测试研究所 | Earth rotation angular rate measuring method |
| CN111142366A (en) * | 2019-12-19 | 2020-05-12 | 中国电波传播研究所（中国电子科技集团公司第二十二研究所） | Novel short wave time service method |
| CN111505658A (en) * | 2020-04-16 | 2020-08-07 | 中国科学院上海天文台 | Pulse group type laser ranging method with adjustable repetition frequency |
| CN111505658B (en) * | 2020-04-16 | 2023-04-07 | 中国科学院上海天文台 | Pulse group type laser ranging method with adjustable repetition frequency |
| CN111708059A (en) * | 2020-06-24 | 2020-09-25 | 中国科学院国家天文台长春人造卫星观测站 | Laser time transfer processing method, system, storage medium, device and application |
| CN111708059B (en) * | 2020-06-24 | 2023-08-08 | 中国科学院国家天文台长春人造卫星观测站 | Laser time transfer processing method, system, storage medium, device and application |
| CN112817022A (en) * | 2020-12-23 | 2021-05-18 | 浙江吉利控股集团有限公司 | Low-orbit satellite time-frequency synchronization method, system, electronic equipment and storage medium |
| CN115060979A (en) * | 2022-06-24 | 2022-09-16 | 华印世纪(北京)文化发展有限公司 | Time comparison method and device and electronic equipment |
| CN115639743A (en) * | 2022-10-19 | 2023-01-24 | 中国科学院国家授时中心 | Space-based time reference establishing method and system based on whole network time comparison |
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