CN115309028A - Spacecraft time reference stability measuring method and system - Google Patents

Spacecraft time reference stability measuring method and system Download PDF

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CN115309028A
CN115309028A CN202210854501.0A CN202210854501A CN115309028A CN 115309028 A CN115309028 A CN 115309028A CN 202210854501 A CN202210854501 A CN 202210854501A CN 115309028 A CN115309028 A CN 115309028A
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spacecraft
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王冲
沈亦纯
杨同智
周捷
张鑫鑫
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Shanghai Institute of Satellite Engineering
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    • G06F1/04—Generating or distributing clock signals or signals derived directly therefrom
    • G06F1/14—Time supervision arrangements, e.g. real time clock
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Abstract

The invention provides a method and a system for measuring the time reference stability of a spacecraft, comprising the following steps: step 1: a satellite-ground measurement and control link is established through a ground antenna, an up-down converter and a measurement and control baseband, and data receiving, processing and displaying are carried out through receiving software, analyzing software and displaying software; and 2, step: setting a ground time reference; and step 3: selecting a ground time code, and performing group telemetry frame on the time code of the measurement and control baseband and on-satellite telemetry, wherein the spacecraft time code in the telemetry frame corresponds to the measurement and control baseband time code; and 4, step 4: the time stability is calculated by comparing the absolute value of the difference between the telemetry frame synchronization pulse time code and the satellite time code to the average value. The invention utilizes ground equipment, test software and a worst difference method to enable a user to conveniently and quickly measure the short-term stability and the long-term stability of the spacecraft integrated electronic subsystem and calculate and compare data.

Description

Spacecraft time reference stability measuring method and system
Technical Field
The invention relates to the technical field of time reference stability measurement, in particular to a method and a system for measuring the time reference stability of a spacecraft.
Background
The time reference represents an important performance index of the time stability of the integrated electronic subsystem of the spacecraft, the self stability of the integrated electronic subsystem is generally divided into long-term stability and short-term stability, the long-term stability and the short-term stability are stability under the condition of not intervening in the autonomous timing of the navigation spacecraft, and the self stability can reflect the performance index of the high-stability crystal oscillator of the integrated electronic subsystem. The time reference of the integrated electronic subsystem generally adopts a high-stability crystal oscillator with the frequency of 10MHz, a 48-bit counter is driven through multi-stage frequency division, and the minimum resolution of a clock is 0.1ms. The clock uses accumulated time, with the time starting point being (UTC) time.
Through the search of the prior art, the invention patent with application publication number CN108732597A discloses a method and a system for establishing a time reference of a multi-spacecraft navigation system, and the method and the system comprise: acquiring ground station GNSS observation data and satellite-borne GNSS observation data of a multi-spacecraft navigation system, and respectively constructing a corresponding ground station observation model and a corresponding satellite-borne GNSS observation model according to the ground station GNSS observation data and the satellite-borne GNSS observation data; performing combined precise orbit determination and time synchronization on a navigation spacecraft and a low orbit spacecraft in the multi-spacecraft navigation system according to the ground station observation model and the satellite-borne GNSS observation model to obtain clock errors of each spacecraft navigation system; constructing time scales of the multi-spacecraft navigation systems according to clock errors of the spacecraft navigation systems; and constraining the time scale to the system time of a certain spacecraft navigation system, and generating a uniform time reference of each spacecraft in the multi-spacecraft navigation system. However, the patent cannot measure the time reference stability of the spacecraft integrated electronic subsystem.
The invention patent with application publication No. CN111224733B discloses a "time calibration method, apparatus, calculation and storage medium", the system comprising: the system sends a first time calibration request to a server, first time synchronization information fed back by the server is to be received, and first time calibration is carried out on an internal RTC according to the first time synchronization information; and sending a second time calibration request to the server, waiting for receiving second time synchronization information fed back by the server, and performing second time calibration or performing first time calibration again on the internal RTC according to the current time of the internal RTC by the second time synchronization information. However, the patent cannot measure the time reference stability of the spacecraft integrated electronic subsystem.
The invention patent with application publication number CN112379120A discloses a method, a device, equipment and a storage medium for acquiring speed acquisition time, and the method and the system comprise: recording response receiving time when receiving time calibration response time fed back by the coding speed measuring unit based on the time calibration request; determining a speed measurement delay value according to the time calibration request, the time calibration response and the response receiving time; and when receiving the speed time information acquired by the decoding speed measuring unit, determining the speed acquisition time according to the speed time information and the speed measuring delay value. However, the patent cannot measure the time reference stability of the spacecraft integrated electronic subsystem.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a spacecraft time reference stability measuring method and system.
The spacecraft time reference stability measuring method provided by the invention comprises the following steps:
step 1: a satellite-ground measurement and control link is established through a ground antenna, an up-down converter and a measurement and control baseband, and data receiving, processing and displaying are carried out through receiving software, analyzing software and displaying software;
step 2: setting a ground time reference;
and 3, step 3: selecting a ground time code, and performing group telemetry frame on the time code of the measurement and control baseband and on-satellite telemetry, wherein the spacecraft time code in the telemetry frame corresponds to the measurement and control baseband time code;
and 4, step 4: the time stability is calculated by comparing the absolute value of the difference between the telemetry frame synchronization pulse time code and the satellite time code to the average value.
Preferably, the measurement and control baseband time reference setting is carried out, the time reference is set as an external reference in measurement and control baseband software, the time input hardware interface of the measurement and control baseband is connected with the time server, the measurement and control 10MHz external reference is connected with the rubidium clock, and the time server 10MHz external reference is connected with the rubidium clock.
Preferably, the frame synchronization pulse is output when the ground measurement and control baseband equipment completes telemetry frame synchronization, the time latched by the telemetry frame synchronization pulse of the baseband equipment is packaged in front of telemetry frame data, and the corresponding time code is displayed in ground comprehensive processing software.
Preferably, the preset long-term stability and the preset short-term stability are calculated by adopting a maximum value interpolation method.
Preferably, the time stability calculation includes:
calculate the time T of the star s And base band time T g Series of differences { T } n }，n＝0,1,2,…；
T n ＝T s -T g …………(1)
Find the mean value μ of the difference series:
Figure BDA0003755621710000021
find the difference sequence { T } n Standard deviation of }:
Figure BDA0003755621710000031
the spacecraft time reference stability measuring system provided by the invention comprises:
a module M1: a satellite-ground measurement and control link is established through a ground antenna, an up-down converter and a measurement and control baseband, and data receiving, processing and displaying are carried out through receiving software, analyzing software and displaying software;
a module M2: setting a ground time reference;
a module M3: selecting a ground time code, and performing group telemetry frame on the time code of the measurement and control baseband and on-satellite telemetry, wherein the spacecraft time code in the telemetry frame corresponds to the measurement and control baseband time code;
a module M4: the time stability is calculated by comparing the absolute value of the difference between the telemetry frame synchronization pulse time code and the satellite time code to the average value.
Preferably, the measurement and control baseband time reference setting is carried out, the time reference is set as an external reference in measurement and control baseband software, the time input hardware interface of the measurement and control baseband is connected with the time server, the measurement and control 10MHz external reference is connected with the rubidium clock, and the time server 10MHz external reference is connected with the rubidium clock.
Preferably, the frame synchronization pulse is output when the ground measurement and control baseband equipment completes telemetry frame synchronization, the time latched by the telemetry frame synchronization pulse of the baseband equipment is packaged in front of telemetry frame data, and the corresponding time code is displayed in ground comprehensive processing software.
Preferably, the preset long-term stability and the preset short-term stability are calculated by adopting a maximum value interpolation method.
Preferably, the time stability calculation includes:
calculate the time T of the star s And base band time T g Difference sequence of { T } n }，n＝0,1,2,…；
T n ＝T s -T g …………(1)
Find the mean μ of the difference series:
Figure BDA0003755621710000032
find the sequence of differences T n Standard deviation of }:
Figure BDA0003755621710000033
compared with the prior art, the invention has the following beneficial effects:
the invention provides a method for measuring the time reference stability of a spacecraft integrated electronic subsystem, which utilizes ground equipment, test software and a worst difference method to enable a user to conveniently and quickly measure the short-term stability and the long-term stability of the spacecraft integrated electronic subsystem and calculate and compare data.
Drawings
Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:
FIG. 1 is a flow chart of the test of the present invention;
FIG. 2 is a schematic diagram of the system of the present invention;
FIG. 3 is a short term time stability analysis graph of the present invention;
FIG. 4 is a graph of the long term stability analysis of the present invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.
Example (b):
as shown in fig. 1 and fig. 2, the invention provides a spacecraft time reference stability measurement method, which comprises the following steps:
establishing satellite-ground measurement and control link
A satellite-ground measurement and control link is established through equipment and software such as a ground antenna, an up-down converter, a measurement and control baseband, forwarding software, server software, display terminal software and the like.
(II) ground time reference setting
1) Setting the measurement and control baseband equipment as an external reference, and using a GPS time server as a time reference of the measurement and control baseband equipment;
2) And connecting the 10MHz external reference of the measurement and control baseband and the time server with a rubidium clock.
(III) ground time code selection
When the ground measurement and control baseband equipment completes telemetering frame synchronization, the frame synchronization pulse is output, and the telemetering frame synchronization pulse of the baseband equipment is transmittedTime T of latching g Encapsulated in front of the telemetry frame data, this time code is displayed at the surface integrated processing software.
(IV) calculation of time stability
The time stability is calculated by adopting a worst value difference method, namely the stability of the time stability is judged by comparing the absolute value of the difference value with the average value.
1) Calculate the time T of the star s And base band time T g Series of differences { T } n }，n＝0,1,2,…；
T n ＝T s -T g …………(1)
Wherein, T s Is star hour, T g Telemetry of the encapsulation time for baseband;
2) Find the mean μ of the difference series:
Figure BDA0003755621710000051
3) Find the difference sequence { T } n Standard deviation of }:
Figure BDA0003755621710000052
(V) calculation of the stability
1) Short term time stability calculation
Calculating the difference value between the spacecraft time and the ground time, and calculating the short-term stability of the TO TO TO +20min time period according TO a formula (3), wherein n =1200;
the calculation result of the 20min time stability is shown in FIG. 3.
2) Long term time stability calculation
Calculating the difference value between the spacecraft time and the ground time, and calculating the long-term stability of the TO TO TO +24h time period according TO a formula (3), wherein n =86400;
the results of the calculation of the 24h time stability are shown in fig. 4.
The invention provides a method for testing the time reference stability of an integrated electronic subsystem, which enables a user to conveniently and quickly establish and modify rules, can measure and calculate the time reference stability of the integrated electronic subsystem according to the method, and can analyze and judge the calculation result.
The spacecraft time reference stability measuring system provided by the invention comprises: a module M1: a satellite-ground measurement and control link is established through a ground antenna, an up-down converter and a measurement and control baseband, and data receiving, processing and displaying are carried out through receiving software, analyzing software and display software; a module M2: setting a ground time reference; a module M3: selecting a ground time code, and performing group telemetry frame on the time code of the measurement and control baseband and on-satellite telemetry, wherein the spacecraft time code in the telemetry frame corresponds to the measurement and control baseband time code; a module M4: the time stability is calculated by comparing the absolute value of the difference between the telemetry frame synchronization pulse time code and the satellite time code to the average value.
And setting a measurement and control baseband time reference, setting the time reference as an external reference in measurement and control baseband software, inputting the time of the measurement and control baseband into a hardware interface to be connected with a time server, connecting the measurement and control 10MHz external reference to a rubidium clock, and connecting the time server 10MHz external reference to the rubidium clock. And outputting frame synchronization pulses while the ground measurement and control baseband equipment completes telemetry frame synchronization, packaging the time latched by the telemetry frame synchronization pulses of the baseband equipment in front of telemetry frame data, and displaying corresponding time codes in ground comprehensive processing software. And calculating the preset long-term stability and the preset short-term stability by adopting a maximum interpolation method. The time stability calculation includes: calculate the time T of the star s And base band time T g Difference sequence of { T } n }，n＝0,1,2,…；T n ＝T s -T g \8230; (1); find the mean μ of the difference series:
Figure BDA0003755621710000053
find the sequence of differences T n Standard deviation of }:
Figure BDA0003755621710000061
those skilled in the art will appreciate that, in addition to implementing the systems, apparatus, and various modules thereof provided by the present invention in purely computer readable program code, the same procedures can be implemented entirely by logically programming method steps such that the systems, apparatus, and various modules thereof are provided in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system, the device and the modules thereof provided by the present invention can be considered as a hardware component, and the modules included in the system, the device and the modules thereof for implementing various programs can also be considered as structures in the hardware component; modules for performing various functions may also be considered to be both software programs for performing the methods and structures within hardware components.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims (10)

1. A spacecraft time reference stability measurement method is characterized by comprising the following steps:
step 1: a satellite-ground measurement and control link is established through a ground antenna, an up-down converter and a measurement and control baseband, and data receiving, processing and displaying are carried out through receiving software, analyzing software and displaying software;
step 2: setting a ground time reference;
and step 3: selecting a ground time code, and performing group telemetry frame on the time code of the measurement and control baseband and on-satellite telemetry, wherein the spacecraft time code in the telemetry frame corresponds to the measurement and control baseband time code;
and 4, step 4: the time stability is calculated by comparing the absolute value of the difference between the telemetry frame synchronization pulse time code and the satellite time code to the average value.
2. A spacecraft time reference stability measurement method according to claim 1, wherein a measurement and control baseband time reference setting is performed, the time reference is set as an external reference in measurement and control baseband software, the time of the measurement and control baseband is input to a hardware interface and is connected to a time server, the measurement and control 10MHz external reference is connected to a rubidium clock, and the time server 10MHz external reference is connected to the rubidium clock.
3. A spacecraft time reference stability measurement method according to claim 1, wherein frame synchronization pulses are output while telemetry frame synchronization is completed by ground measurement and control baseband equipment, the time latched by the baseband equipment telemetry frame synchronization pulses is packaged in front of telemetry frame data, and corresponding time codes are displayed in ground comprehensive processing software.
4. A spacecraft time referenced stability measurement method according to claim 1, wherein the predetermined long term stability and the predetermined short term stability are calculated using a maximum interpolation method.
5. A spacecraft time reference stability measurement method according to claim 1, wherein time stability calculation comprises:
calculate the time T of the star s And base band time T g Difference sequence of { T } n }，n＝0,1,2,…；
T n ＝T s -T g ………… (1)
Find the mean μ of the difference series:
Figure FDA0003755621700000011
find the sequence of differences T n Standard deviation of }:
Figure FDA0003755621700000012
6. a spacecraft time reference stability measurement system, comprising:
a module M1: a satellite-ground measurement and control link is established through a ground antenna, an up-down converter and a measurement and control baseband, and data receiving, processing and displaying are carried out through receiving software, analyzing software and displaying software;
a module M2: setting a ground time reference;
a module M3: selecting a ground time code, and performing group telemetry frame on the time code of the measurement and control baseband and on-satellite telemetry, wherein the spacecraft time code in the telemetry frame corresponds to the measurement and control baseband time code;
a module M4: the time stability is calculated by comparing the absolute value of the difference between the telemetry frame synchronization pulse time code and the satellite time code to the average value.
7. A spacecraft time-referenced stability measurement system according to claim 6, wherein a measurement and control baseband time-referenced reference setting is performed, the time-referenced setting is set as an external reference in measurement and control baseband software, the time of the measurement and control baseband is input to a hardware interface and is connected to a time server, the measurement and control 10MHz external reference is connected to a rubidium clock, and the time server 10MHz external reference is connected to the rubidium clock.
8. A spacecraft time reference stability measurement system according to claim 6, wherein the frame synchronization pulse is output when the ground measurement and control baseband device completes telemetry frame synchronization, the time latched by the baseband device telemetry frame synchronization pulse is packaged in front of telemetry frame data, and the corresponding time code is displayed in ground comprehensive processing software.
9. A spacecraft time referenced stability measurement system according to claim 6, wherein the preset long term stability and the preset short term stability calculations are performed using a most-valued interpolation method.
10. A spacecraft time reference stability measurement system according to claim 6, wherein the time stability calculation comprises:
calculate the time of the star T s And base band time T g Difference sequence of { T } n }，n＝0,1,2,…；
T n ＝T s -T g ………… (1)
Find the mean value μ of the difference series:
Figure FDA0003755621700000021
find the sequence of differences T n Standard deviation of }:
Figure FDA0003755621700000022
CN202210854501.0A 2022-07-20 2022-07-20 Spacecraft time reference stability measuring method and system Pending CN115309028A (en)

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