CN112242866A - Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement - Google Patents
Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement Download PDFInfo
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Abstract
The invention provides a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement, which comprises: the one-way ranging value resolving module is configured to obtain one-way ranging values of a plurality of satellites through inter-satellite link measurement and store the one-way ranging values; the star clock fluctuation monitoring algorithm module is configured to monitor whether the star clock generates abnormal fluctuation or not through a star clock fluctuation monitoring algorithm; the satellite clock fluctuation monitoring and alarming module is configured to autonomously alarm a user if the satellite clock fluctuation monitoring algorithm module monitors that the satellite clock generates abnormal fluctuation; and the star clock fluctuation value fitting algorithm module is configured to calculate a star clock fluctuation value through a star clock fluctuation value fitting algorithm, and carry out error adjustment on the star clock according to the star clock fluctuation value.
Description
Technical Field
The invention relates to the technical field of Beidou satellites, in particular to a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement.
Background
At present, four global navigation positioning systems are established internationally, namely a GPS system in the United states, a Beidou navigation system in China, a Galileo system in Europe and a Glonass system in Russia, and provide high-precision positioning and time service functions for users in the global range. The basic principles of satellite navigation are: the navigation satellite is a high-precision space-time reference, has extremely high position precision and time precision, and can reversely analyze self position and time information according to the arrival time of a plurality of received satellite navigation signals on the ground.
The high-precision position of the satellite is realized by a ground precision measuring orbit, the high-precision time is maintained by a satellite-borne atomic clock and a satellite-borne time-frequency system, and the satellite-borne atomic clock has the possibility of abnormal fluctuation due to the technical complexity and the harsh space environment. Once the satellite-borne atomic clock fluctuates abnormally, the satellite broadcasts navigation signals with wrong time reference, and if the warning or fault removal cannot be given to a user in time, the service precision of the user is seriously influenced.
The ground disposal method after abnormal fluctuation of the Beidou third satellite-borne atomic clock at present is as follows: when the satellite runs to the visible range in the environment, the ground operation and control station monitors the abnormal fluctuation of the satellite clock, injects a satellite availability identification as an 'unavailable' instruction into the satellite, gives an alarm to a user in a navigation signal, then the ground operation and control station carries out planet-ground two-way ranging through an L channel, calculates a satellite-borne atomic clock fluctuation value after accumulating certain data, injects a correction value into the satellite to correct the satellite-borne atomic clock error, and finally injects the satellite availability identification as an 'available' instruction into the satellite to finish the satellite fault recovery.
The method for disposing the satellite-borne atomic clock after abnormal fluctuation has the following defects: firstly, the abnormal fluctuation value of the satellite-borne atomic clock can be calculated only after a ground operation and control station enters a planet ground through an L channel for two-way distance measurement and accumulates certain observed values, then the ground operation and control station injects a satellite to correct the error of the satellite-borne atomic clock, and the process of the world loop needs a certain time, is slow in response and needs to occupy resources such as precious personnel, measurement stations and equipment; in addition, since China cannot distribute stations globally, the ground station can operate the satellite only when the satellite runs into the environment, and if abnormal fluctuation of a satellite-borne atomic clock occurs overseas, the satellite often needs to wait for hours to dozens of hours for entering the environment, so that quick response cannot be realized, and user service is seriously affected.
Disclosure of Invention
The invention aims to provide a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement, and aims to solve the problem that an existing satellite-borne atomic clock cannot respond quickly after abnormal fluctuation occurs.
In order to solve the technical problem, the invention provides a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement, which comprises:
the one-way ranging value resolving module is configured to obtain one-way ranging values of a plurality of satellites through inter-satellite link measurement and store the one-way ranging values;
the star clock fluctuation monitoring algorithm module is configured to monitor whether the star clock generates abnormal fluctuation or not through a star clock fluctuation monitoring algorithm;
the satellite clock fluctuation monitoring and alarming module is configured to autonomously alarm a user if the satellite clock fluctuation monitoring algorithm module monitors that the satellite clock generates abnormal fluctuation;
and the star clock fluctuation value fitting algorithm module is configured to calculate a star clock fluctuation value through a star clock fluctuation value fitting algorithm, and carry out error adjustment on the star clock according to the star clock fluctuation value.
Optionally, in the Beidou satellite clock autonomous health management system based on the inter-satellite link unidirectional measurement, the clock fluctuation monitoring algorithm includes:
and taking the one-way ranging value of the inter-satellite link, the local satellite/other satellite precise ephemeris and the local satellite/other satellite clock difference as input parameters, periodically performing epoch normalization on the one-way ranging value, calculating the difference value between the actual clock difference and the pre-noted clock difference, and judging that the satellite clock of the local satellite abnormally fluctuates if the difference value is greater than the satellite clock fluctuation judgment threshold value.
Optionally, in the Beidou satellite clock autonomous health management system based on the inter-satellite link unidirectional measurement, the satellite clock fluctuation value fitting algorithm includes:
and calculating an actual clock difference model of the satellite after the abnormal fluctuation of the clock by taking the one-way ranging value of the inter-satellite link, the local satellite/other satellite precise ephemeris and the local satellite/other satellite clock difference as input parameters, comparing the actual clock difference model with the pre-noted clock difference model to obtain a satellite clock fluctuation value, and adjusting the satellite clock error according to the satellite clock fluctuation value.
The invention also provides a management method of the Beidou satellite clock autonomous health management system based on the above one-way measurement of the inter-satellite link, which comprises the following steps:
step S1: injecting a starting instruction and a judgment threshold value into a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement;
step S2-1: starting a star clock fluctuation monitoring algorithm module;
step S2-2: the satellite clock fluctuation monitoring algorithm module monitors a satellite clock by using a one-way distance measurement value of an inter-satellite link;
step S3: judging whether the star clock generates abnormal fluctuation or not by the star clock fluctuation monitoring algorithm module;
step S4: if so, the satellite clock fluctuation monitoring algorithm module sets the satellite availability as 'unavailable' and gives an alarm to a user, otherwise, the step S2-2 is returned to, so that the purpose of monitoring the satellite clock by cyclically using the one-way ranging value of the link between the satellites is realized;
step S5-1: after the star clock fluctuation monitoring algorithm module gives an alarm to a user, a star clock fluctuation value fitting algorithm module is started;
step S5-2: the star clock fluctuation value fitting algorithm module calculates a star clock fluctuation value by using the one-way ranging value of the link between the stars;
step S6-1: the star clock fluctuation value fitting algorithm module automatically adjusts the star clock fluctuation error;
step S6-2: the star clock fluctuation monitoring algorithm module evaluates the adjustment effect by using a star clock fluctuation monitoring algorithm;
step S6-3: judging whether the adjustment meets the requirements or not by the star clock fluctuation monitoring algorithm module;
step S7: if so, the satellite clock fluctuation monitoring algorithm module sets the satellite availability to "available" and returns to step S2-1, otherwise returns to step S5-1.
Optionally, in the Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement, the method further includes:
the inter-satellite link terminal uses the time frequency maintained by the satellite clock as a reference, and solves the pseudo range value of the other satellite relative to the local satellite according to the arrival time of the inter-satellite link signal by capturing the inter-satellite link signal of the other satellite to be used as the one-way ranging value of the inter-satellite link;
the inter-satellite link terminal is accessed to the inter-satellite link network according to the plan to carry out normal work, and the one-way ranging values of a plurality of inter-satellite links are obtained;
injecting a star clock autonomous health management starting instruction into the ground, judging a star clock fluctuation threshold value, and judging the number of links by star clock fluctuation;
optionally, in the Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement,
the module for starting the star clock fluctuation monitoring algorithm comprises: each other satellite establishing an inter-satellite link with the satellite corresponds to one unidirectional ranging value storage unit, a series of storage units are arranged to store unidirectional ranging values of a plurality of inter-satellite links respectively, and the storage time of the unidirectional ranging values of the plurality of inter-satellite links is longer than the execution time of the whole Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement.
Optionally, in the Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement, the method further includes:
the star clock fluctuation value fitting algorithm module automatically generates a star clock error adjusting instruction according to the star clock fluctuation value, and adjusts the star clock error to be consistent with the pre-noted clock error;
the star clock fluctuation monitoring algorithm module calls a star clock fluctuation monitoring algorithm to evaluate the star clock adjustment effect, if the difference value between the adjusted actual clock difference and the pre-noted clock difference is larger than the star clock fluctuation judgment threshold value, the adjustment is not in place, and the step S5-1 is returned to;
if the difference value between the adjusted actual clock difference and the pre-noted clock difference is smaller than the star clock fluctuation judgment threshold value, the star clock fluctuation monitoring algorithm module automatically sets the satellite availability identifier as 'available', returns to the step S2-1, and continues to monitor the star clock fluctuation.
Optionally, in the Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement, the clock fluctuation monitoring algorithm further includes:
the one-way ranging value of the inter-satellite link is as follows:
Ts＝Tsd+Tza+Ttd+Tzb+Trd，
wherein Tsd is the time delay of other satellite signal transmitting channel, Tza is the clock difference of other satellite, Ttd is the signal space propagation time delay, Tzb is the real-time clock difference of the satellite relative to some other satellite at the epoch reducing time, Trd is the time delay of the satellite signal receiving channel;
performing data preprocessing on the one-way ranging value of the inter-satellite link, wherein the data preprocessing comprises epoch reduction and wild value elimination at the ranging time;
calculating to obtain the real-time clock error Tzb of the satellite relative to other satellites at the epoch reducing time according to Tsd, Tza, Ttd and Trd;
and inputting the obtained Tzb into a comparison judgment logic module, comparing Tzb with the pre-noted clock difference, and judging whether the difference is smaller than a satellite clock fluctuation judgment threshold value.
Optionally, in the Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement, the satellite clock fluctuation value fitting algorithm further includes:
for the one-way ranging value of each inter-satellite link, calculating to obtain real-time clock errors Tzb of a plurality of satellites relative to other satellites at the epoch reducing time according to the respective Tsd, Tza, Ttd and Trd;
inputting a plurality of real-time clock differences Tzb into a clock difference model for fitting, and calculating a time difference element a0, a frequency difference element a1 and a frequency drift element a2 of the real-time clock differences through accumulative observation to obtain a real-time clock difference model;
and comparing the real-time clock difference model with the pre-noted clock difference model to obtain a star clock fluctuation value, generating a star clock error adjusting instruction, and adjusting the star clock to a state before fluctuation occurs.
In the Beidou satellite clock autonomous health management system based on the one-way measurement of the inter-satellite links, the one-way distance measurement value calculation module obtains the one-way distance measurement values of a plurality of satellites through the inter-satellite link measurement and stores the one-way distance measurement values, the clock fluctuation monitoring algorithm module monitors whether the clock generates abnormal fluctuation through the clock fluctuation monitoring algorithm, the clock fluctuation monitoring alarm module autonomously alarms a user if the clock fluctuation monitoring algorithm module monitors that the clock generates abnormal fluctuation, the clock fluctuation fitting algorithm module calculates the clock fluctuation value through the clock fluctuation value fitting algorithm and performs error adjustment on the clock according to the clock fluctuation value, a novel Beidou third-numbered satellite-borne atomic clock autonomous health management method is provided, and when the satellite encounters the abnormal fluctuation of the satellite-borne atomic clock, the satellite can automatically monitor and give alarm information, and then carrying out reduction fitting on the fluctuation value, and finally autonomously carrying out autonomous time reference recovery.
According to the method, the microwave inter-satellite link load of the Beidou third satellite is utilized to obtain the inter-satellite one-way measurement value, the health state of the satellite-borne atomic clock is automatically monitored, the user is automatically warned when abnormality occurs, an algorithm is started to carry out reduction fitting on the fluctuation value of the satellite-borne atomic clock, and finally, the autonomous time reference recovery is automatically carried out.
The invention has the advantages that: the Beidou third satellite can automatically and continuously monitor the health state of the satellite clock through parameters such as the one-way distance measurement value of the inter-satellite link and the like, and can quickly give out user alarm information, the response is quick, and ground operation is not needed; after abnormal fluctuation of the Beidou third satellite occurs, the satellite can calculate the satellite clock fluctuation value through parameters such as the one-way ranging value of the inter-satellite link, the satellite-borne atomic clock error adjustment and the subsequent effect evaluation are automatically completed, the whole process is rapidly processed without ground station intervention, the fault handling time is greatly shortened, and the navigation service performance and the satellite intelligent level of the Beidou third satellite are greatly improved. A novel autonomous health management method for the Beidou satellite III clock is provided.
Drawings
FIG. 1 is a schematic flow chart of an autonomous health management method of a Beidou third satellite-borne atomic clock based on inter-satellite link unidirectional measurement according to an embodiment of the invention;
FIG. 2 is a schematic flow chart of a star clock fluctuation monitoring algorithm according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of a star clock fluctuation value fitting algorithm according to an embodiment of the present invention.
Detailed Description
The Beidou satellite clock autonomous health management system based on the inter-satellite link unidirectional measurement provided by the invention is further described in detail with reference to the attached drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.
Furthermore, features from different embodiments of the invention may be combined with each other, unless otherwise indicated. For example, a feature of the second embodiment may be substituted for a corresponding or functionally equivalent or similar feature of the first embodiment, and the resulting embodiments are likewise within the scope of the disclosure or recitation of the present application.
The invention provides an autonomous health management system of a Beidou satellite clock based on inter-satellite link unidirectional measurement, and aims to solve the problem that the conventional satellite-borne atomic clock cannot respond quickly after abnormal fluctuation.
In order to realize the thought, the invention provides a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement, which comprises: the one-way ranging value resolving module is configured to obtain one-way ranging values of a plurality of satellites through inter-satellite link measurement and store the one-way ranging values; the star clock fluctuation monitoring algorithm module is configured to monitor whether the star clock generates abnormal fluctuation or not through a star clock fluctuation monitoring algorithm; the satellite clock fluctuation monitoring and alarming module is configured to autonomously alarm a user if the satellite clock fluctuation monitoring algorithm module monitors that the satellite clock generates abnormal fluctuation; and the star clock fluctuation value fitting algorithm module is configured to calculate a star clock fluctuation value through a star clock fluctuation value fitting algorithm, and carry out error adjustment on the star clock according to the star clock fluctuation value.
The invention relates to the field of satellite navigation, satellite-borne atomic clocks (star clocks), satellite inter-satellite links and satellite autonomous health management in aerospace, in particular to a method for acquiring inter-satellite unidirectional measurement values by a satellite by using loads of the equipped microwave inter-satellite links after abnormal fluctuation of a Beidou No. three satellite time reference satellite-borne atomic clock or a satellite-borne time-frequency system, performing reduction fitting on the time reference fluctuation values and autonomously recovering time references.
An inter-satellite link system based on a time division space division multiplexing system in a China Beidou No. three global navigation positioning system is a special function, and the system realizes the two-way ranging and communication functions with other satellites through a microwave inter-satellite link terminal configured for each Beidou No. three satellite; and the communication ranging of the same satellite and a plurality of satellites is realized through the modes of signal receiving and transmitting time division switching and signal pointing space division multiplexing. The inter-satellite link works by taking the time frequency of the satellite-borne atomic clock as a reference, so that the inter-satellite link has sensitivity and correlation to the fluctuation of the satellite-borne atomic clock.
The invention aims to obtain an inter-satellite one-way measurement value by utilizing a microwave inter-satellite link load equipped by a Beidou third satellite, autonomously monitor the health state of a satellite-borne atomic clock, automatically alarm a user when an abnormality occurs, start an algorithm to carry out reduction fitting on a fluctuation value of the satellite-borne atomic clock, and finally autonomously recover the time reference.
In order to achieve the purpose, the invention provides an autonomous health management process of a Beidou three-satellite spaceborne atomic clock by utilizing intersatellite link unidirectional measurement, wherein (1) the satellite acquires unidirectional distance measurement values of a plurality of satellites through intersatellite link measurement, and a corresponding cache is opened up to store observation data; (2) the satellite monitors whether the satellite clock fluctuates or not by utilizing a satellite clock fluctuation monitoring algorithm; (3) if the satellite monitors that the star clock generates abnormal fluctuation, the satellite autonomously alarms a user, starts a star clock fluctuation value fitting algorithm and calculates a star clock fluctuation value; (4) and (3) the satellite adjusts the error of the satellite clock, the satellite clock fluctuation monitoring algorithm is used for evaluating the adjusted effect, if the satellite clock fluctuation monitoring algorithm meets the design requirement, the user is cancelled and quit after the alarm is cancelled, and if the satellite clock fluctuation monitoring algorithm does not meet the requirement, the two steps (3) and (4) are repeated.
The embodiment of the invention provides a satellite clock fluctuation monitoring algorithm, which takes an inter-satellite link one-way ranging value, a local satellite/other satellite precise ephemeris and a local satellite/other satellite clock difference as input parameters, periodically carries out epoch normalization on the ranging value, calculates an actual clock difference and compares the actual clock difference with a pre-noted clock difference, and judges that the satellite clock fluctuates if the difference value of the two is greater than a certain threshold value.
The embodiment of the invention provides a star clock fluctuation value fitting algorithm which is started after the star clock fluctuation occurs, calculates the actual clock difference of a satellite after the star clock fluctuation by taking an inter-satellite link one-way ranging value, a local satellite/other satellite precise ephemeris and other star clock difference as input parameters, compares the actual clock difference with a pre-noted clock difference, automatically generates a star clock adjusting instruction and adjusts the error of a satellite-borne atomic clock.
The invention has the advantages that: the Beidou third satellite can automatically and continuously monitor the health state of the satellite clock through parameters such as the one-way distance measurement value of the inter-satellite link and the like, and can quickly give out user alarm information, the response is quick, and ground operation is not needed; after abnormal fluctuation of the Beidou third satellite occurs, the satellite can calculate the satellite clock fluctuation value through parameters such as the one-way ranging value of the inter-satellite link, the satellite-borne atomic clock error adjustment and the subsequent effect evaluation are automatically completed, the whole process is rapidly processed without ground station intervention, the fault handling time is greatly shortened, and the navigation service performance and the satellite intelligent level of the Beidou third satellite are greatly improved. A novel autonomous health management method for the Beidou satellite III clock is provided.
The inter-satellite link terminal of the Beidou third satellite strictly takes the time frequency (Beidou time) maintained by the satellite-borne atomic clock as a reference, the pseudo range value (one-way measurement value) of the other satellite relative to the satellite is calculated according to the signal arrival time by capturing inter-satellite link signals of other satellites, and the inter-satellite link ranging value has strong sensitivity and correlation to the fluctuation of the satellite-borne atomic clock because the signal arrival time is calculated according to the time maintained by the satellite-borne atomic clock strictly. Based on the facts, the Beidou third satellite can monitor the fluctuation of the satellite-borne atomic clock by using the inter-satellite link one-way measurement value, and carry out reduction fitting on the fluctuation value.
As shown in FIG. 1, the autonomous health management process of the Beidou third satellite space-borne atomic clock based on the inter-satellite link unidirectional measurement mainly comprises the following steps:
s1, after the satellite finishes the clock error measurement and the inter-satellite link is accessed to the inter-satellite link network to normally work according to the plan, the ground injects a 'clock autonomous health management starting' instruction, injects a clock fluctuation judgment threshold value delta T (the value is that the subsequent clock fluctuation value fitting algorithm is started when the satellite autonomously monitors that the clock fluctuation exceeds delta T), and injects a 'clock fluctuation judgment link number' instruction (considering that the other clock fluctuation can also cause the inter-satellite link ranging value fluctuation, therefore, a plurality of links need to be monitored for comprehensive judgment);
s2-1, the satellite starts a satellite clock fluctuation monitoring algorithm, corresponding cache storage one-way ranging values are developed for each satellite establishing an inter-satellite link with the satellite, and the storage time of the ranging values needs to be longer than the time of the satellite completing the whole satellite clock autonomous health management process;
s2-2, the satellite clock fluctuation monitoring algorithm takes the inter-satellite link one-way ranging value, the local satellite/other satellite precise ephemeris and the local satellite/other satellite clock difference as input parameters, carries out epoch normalization on the ranging value periodically, calculates the actual clock difference and compares the actual clock difference with the pre-noted clock difference;
s3, if the difference obtained in the above steps is smaller than a set value delta T, the state of the satellite clock is considered to be in accordance with expectation, the step S2-2 is repeated, if the difference is larger than the delta T, the satellite clock fluctuation of the satellite is judged to occur, the step S4 is carried out, generally, the satellite clock fluctuation value related by the method is smaller than the uncertainty capturing capacity of the inter-satellite link time of the Beidou third satellite, and the satellite keeps the inter-satellite link ranging communication normal;
s4, after the satellite judges that the satellite clock fluctuation occurs, the satellite availability identification is automatically set to be unavailable, and warning information is sent to a user in a downlink navigation signal; starting a star clock fluctuation value fitting algorithm S5-1;
s5-2, the satellite starts a satellite clock fluctuation value fitting algorithm, the inter-satellite link one-way ranging value, the local satellite/other satellite precise ephemeris and the other satellite clock difference are used as input parameters, the actual clock difference of the local satellite after the satellite clock fluctuation is calculated and compared with the pre-noted clock difference, and the satellite clock fluctuation value is obtained;
s6-1, automatically generating a satellite clock adjusting instruction by the satellite according to the satellite clock fluctuation value obtained in the step S5-2, and adjusting the satellite-borne atomic clock error to be adjusted back to be consistent with the pre-noted clock error;
s6-2, the satellite calls a satellite clock fluctuation monitoring algorithm to evaluate the satellite clock adjustment effect;
s6-3, if the difference between the adjusted actual clock difference and the pre-injection clock difference is larger than delta T, the adjustment is not in place, and the steps S5-1 to S6-2 are repeated;
s7, if the difference is less than delta T, automatically setting the satellite availability identification as 'available', and going to step S2-1 to continue monitoring the satellite clock fluctuation.
As shown in fig. 2, the main working flow of the star clock fluctuation monitoring algorithm of the present invention is as follows:
the load time sharing of the inter-satellite link of the satellite and the chain establishment of different satellites obtain a one-way ranging value Ts (pseudo-range value), the ranging value comprises other satellite signal transmitting channel time delay Tsd, other satellite clock difference Tza, signal space propagation time delay Ttd, local satellite clock difference Tzb and local satellite signal receiving channel time delay Trd,
Ts＝Tsd+Tza+Ttd+Tzb+Trd，
generally, Tsd and Trd are regarded as device performance constants, Tza is an accurate value, and Ttd is an accurate value that can be estimated by precision ephemeris of both parties, so that variation of the satellite clock difference Tzb caused by satellite clock fluctuation directly causes variation of one-way ranging values; performing data preprocessing on the input one-way ranging value, including epoch reduction, wild value elimination and the like at the ranging time;
calculating accurate values of Tsd, Tza, Ttd and Trd in Ts by using an algorithm and deducting the accurate values to obtain a real-time clock error Tzb of the satellite relative to a certain satellite at the epoch reducing time;
inputting the obtained real-time clock difference into a comparison decision logic module, comparing the real-time clock difference with a pre-noted theoretical clock difference by the module, judging whether the error is smaller than a satellite clock fluctuation judgment threshold value delta T, if so, judging that the satellite clock does not fluctuate, skipping to the step 1) to continue monitoring, and if not, judging that the satellite clock fluctuates, and starting a satellite clock fluctuation value fitting algorithm. ③ noteworthy: in order to prevent misjudgment caused by other satellite abnormalities, the comparison judgment logic module needs to synthesize a plurality of link results and judge by combining satellite telemetering quantity, and the specific number is set by a 'satellite clock fluctuation judgment link number' instruction.
As shown in fig. 3, the star clock fluctuation value fitting algorithm of the present invention has the following main working processes:
processing the unidirectional measured values of the links between the satellites by adopting the same method as the star clock fluctuation monitoring algorithm shown in the figure 2 to obtain real-time clock difference data of a plurality of links;
inputting real-time clock difference data into a clock difference model for fitting, and calculating clock difference element time difference a0, frequency difference a1 and frequency drift a2 in an accumulative observation mode to form a real-time clock difference model;
and comparing the obtained real-time clock error model with the pre-noted clock error model to obtain a satellite clock fluctuation value, further generating a satellite clock error adjusting instruction, and adjusting the satellite-borne atomic clock to a state before fluctuation.
In summary, the above embodiments have described in detail different configurations of the Beidou satellite clock autonomous health management system based on the inter-satellite link unidirectional measurement, and of course, the present invention includes but is not limited to the configurations listed in the above embodiments, and any content that is transformed based on the configurations provided by the above embodiments belongs to the protection scope of the present invention. One skilled in the art can take the contents of the above embodiments to take a counter-measure.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.
Claims (9)
1. The utility model provides a big dipper satellite clock is health management system independently based on link one-way measurement between the satellite which characterized in that includes:
the one-way ranging value resolving module is configured to obtain one-way ranging values of a plurality of satellites through inter-satellite link measurement and store the one-way ranging values;
the star clock fluctuation monitoring algorithm module is configured to monitor whether the star clock generates abnormal fluctuation or not through a star clock fluctuation monitoring algorithm;
the satellite clock fluctuation monitoring and alarming module is configured to autonomously alarm a user if the satellite clock fluctuation monitoring algorithm module monitors that the satellite clock generates abnormal fluctuation;
and the star clock fluctuation value fitting algorithm module is configured to calculate a star clock fluctuation value through a star clock fluctuation value fitting algorithm, and carry out error adjustment on the star clock according to the star clock fluctuation value.
2. The Beidou satellite clock autonomous health management system based on one-way measurement of inter-satellite links as set forth in claim 1, wherein the clock fluctuation monitoring algorithm comprises:
and taking the one-way ranging value of the inter-satellite link, the local satellite/other satellite precise ephemeris and the local satellite/other satellite clock difference as input parameters, periodically performing epoch normalization on the one-way ranging value, calculating the difference value between the actual clock difference and the pre-noted clock difference, and judging that the satellite clock of the local satellite abnormally fluctuates if the difference value is greater than the satellite clock fluctuation judgment threshold value.
3. The Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement as set forth in claim 1, wherein the clock fluctuation value fitting algorithm comprises:
and calculating an actual clock difference model of the satellite after the abnormal fluctuation of the clock by taking the one-way ranging value of the inter-satellite link, the local satellite/other satellite precise ephemeris and the local satellite/other satellite clock difference as input parameters, comparing the actual clock difference model with the pre-noted clock difference model to obtain a satellite clock fluctuation value, and adjusting the satellite clock error according to the satellite clock fluctuation value.
4. The management method of the Beidou satellite clock autonomous health management system based on the one-way measurement of the inter-satellite links as set forth in claim 1, is characterized by comprising the following steps:
step S1: injecting a starting instruction and a judgment threshold value into a Beidou satellite clock autonomous health management system based on inter-satellite link unidirectional measurement;
step S2-1: starting a star clock fluctuation monitoring algorithm module;
step S2-2: the satellite clock fluctuation monitoring algorithm module monitors a satellite clock by using a one-way distance measurement value of an inter-satellite link;
step S3: judging whether the star clock generates abnormal fluctuation or not by the star clock fluctuation monitoring algorithm module;
step S4: if so, the satellite clock fluctuation monitoring algorithm module sets the satellite availability as 'unavailable' and gives an alarm to a user, otherwise, the step S2-2 is returned to, so that the purpose of monitoring the satellite clock by cyclically using the one-way ranging value of the link between the satellites is realized;
step S5-1: after the star clock fluctuation monitoring algorithm module gives an alarm to a user, a star clock fluctuation value fitting algorithm module is started;
step S5-2: the star clock fluctuation value fitting algorithm module calculates a star clock fluctuation value by using the one-way ranging value of the link between the stars;
step S6-1: the star clock fluctuation value fitting algorithm module automatically adjusts the star clock fluctuation error;
step S6-2: the star clock fluctuation monitoring algorithm module evaluates the adjustment effect by using a star clock fluctuation monitoring algorithm;
step S6-3: judging whether the adjustment meets the requirements or not by the star clock fluctuation monitoring algorithm module;
step S7: if so, the satellite clock fluctuation monitoring algorithm module sets the satellite availability to "available" and returns to step S2-1, otherwise returns to step S5-1.
5. The Beidou satellite clock autonomous health management method based on one-way measurement of inter-satellite links as set forth in claim 4, further comprising:
the inter-satellite link terminal uses the time frequency maintained by the satellite clock as a reference, and solves the pseudo range value of the other satellite relative to the local satellite according to the arrival time of the inter-satellite link signal by capturing the inter-satellite link signal of the other satellite to be used as the one-way ranging value of the inter-satellite link;
the inter-satellite link terminal is accessed to the inter-satellite link network according to the plan to carry out normal work, and the one-way ranging values of a plurality of inter-satellite links are obtained;
the method comprises the steps of injecting a start instruction of autonomous health management of the star clock into the ground, judging a threshold value of the fluctuation of the star clock and judging the number of links of the fluctuation of the star clock.
6. The Beidou satellite clock autonomous health management method based on inter-satellite link unidirectional measurement as set forth in claim 5,
the module for starting the star clock fluctuation monitoring algorithm comprises: each other satellite establishing an inter-satellite link with the satellite corresponds to one unidirectional ranging value storage unit, a series of storage units are arranged to store unidirectional ranging values of a plurality of inter-satellite links respectively, and the storage time of the unidirectional ranging values of the plurality of inter-satellite links is longer than the execution time of the whole Beidou satellite clock autonomous health management method based on the inter-satellite link unidirectional measurement.
7. The Beidou satellite clock autonomous health management method based on one-way measurement of inter-satellite links as set forth in claim 4, further comprising:
the star clock fluctuation value fitting algorithm module automatically generates a star clock error adjusting instruction according to the star clock fluctuation value, and adjusts the star clock error to be consistent with the pre-noted clock error;
the star clock fluctuation monitoring algorithm module calls a star clock fluctuation monitoring algorithm to evaluate the star clock adjustment effect, if the difference value between the adjusted actual clock difference and the pre-noted clock difference is larger than the star clock fluctuation judgment threshold value, the adjustment is not in place, and the step S5-1 is returned to;
if the difference value between the adjusted actual clock difference and the pre-noted clock difference is smaller than the star clock fluctuation judgment threshold value, the star clock fluctuation monitoring algorithm module automatically sets the satellite availability identifier as 'available', returns to the step S2-1, and continues to monitor the star clock fluctuation.
8. The Beidou satellite clock autonomous health management method based on one-way measurement of inter-satellite links according to claim 7, wherein the clock fluctuation monitoring algorithm further comprises:
the one-way ranging value of the inter-satellite link is as follows:
Ts＝Tsd+Tza+Ttd+Tzb+Trd，
wherein Tsd is the time delay of other satellite signal transmitting channel, Tza is the clock difference of other satellite, Ttd is the signal space propagation time delay, Tzb is the real-time clock difference of the satellite relative to some other satellite at the epoch reducing time, Trd is the time delay of the satellite signal receiving channel;
performing data preprocessing on the one-way ranging value of the inter-satellite link, wherein the data preprocessing comprises epoch reduction and wild value elimination at the ranging time;
calculating to obtain the real-time clock error Tzb of the satellite relative to other satellites at the epoch reducing time according to Tsd, Tza, Ttd and Trd;
and inputting the obtained Tzb into a comparison judgment logic module, comparing Tzb with the pre-noted clock difference, and judging whether the difference is smaller than a satellite clock fluctuation judgment threshold value.
9. The Beidou satellite clock autonomous health management method based on inter-satellite link unidirectional measurement as set forth in claim 8, wherein the clock fluctuation value fitting algorithm further comprises:
for the one-way ranging value of each inter-satellite link, calculating to obtain real-time clock errors Tzb of a plurality of satellites relative to other satellites at the epoch reducing time according to the respective Tsd, Tza, Ttd and Trd;
inputting a plurality of real-time clock differences Tzb into a clock difference model for fitting, and calculating a time difference element a0, a frequency difference element a1 and a frequency drift element a2 of the real-time clock differences through accumulative observation to obtain a real-time clock difference model;
and comparing the real-time clock difference model with the pre-noted clock difference model to obtain a star clock fluctuation value, generating a star clock error adjusting instruction, and adjusting the star clock to a state before fluctuation occurs.
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