High-speed and high-precision attitude measurement method of star sensor system

Abstract

The invention relates to a high-speed and high-precision attitude measurement method of a star sensor system. The star sensor system comprises at least three star sensors. The high-speed and high-precision attitude measurement method comprises the following steps: providing external synchronization signals with time intervals as set values for at least three star sensors; the at least three star sensors comprise a current star sensor which outputs attitude data at the current moment and other star sensors which do not output attitude data at the current moment. Acquiring attitude data output by the current star sensor at the current moment, and taking the attitude data as first attitude data; according to the attitude data output by each star sensor in the other star sensors last time, predicting the attitude data of each star sensor in the other star sensors at the current moment, taking the attitude data as second attitude data, and determining the comprehensive attitude data output by the star sensor system at the current moment according to the first attitude data and the second attitude data. Therefore, the attitude data updating rate and the attitude measurement precision of the star sensor system are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of navigation, and particularly relates to a high-speed and high-precision attitude measurement method for a star sensor system. Background Art

[0002] A star sensor takes stars as measurement objects and is a highly reliable autonomous attitude measurement instrument, which has been widely used in space payloads such as spacecraft. With the rapid development of aerospace technology, the maneuverability of spacecraft is increasing day by day, and the demand for obtaining high-speed and high-precision attitude data is very urgent. Therefore, higher requirements are put forward for the data update rate and attitude measurement accuracy of traditional star sensors.

[0003] The main method to improve the data update rate of a star sensor is to shorten the imaging time or data processing time of the star sensor. However, limited by the limiting detection magnitude of the star sensor and the algorithm complexity, this method has limited improvement in the data update rate of the star sensor and is difficult to achieve obvious effects.

[0004] Attitude measurement accuracy is one of the key indicators of a star sensor. Under the condition that the single-star measurement accuracy is determined, the attitude measurement accuracy is positively correlated with the number of available stars in the field of view of the star sensor. The more the number of available stars in the field of view, the higher the attitude measurement accuracy. However, the number of available stars in the field of view is restricted by system parameters such as the focal length, field of view, and aperture of the star sensor. Moreover, the more the number of available stars, the higher the complexity of the data processing algorithm, the longer the processing time required by the algorithm, and at the same time, it will affect the data update rate of the star sensor.

[0005] Therefore, improving the attitude data update rate and attitude measurement accuracy of a star sensor is an important key technology in the current research field of star sensors. Summary of the Invention

[0006] In view of this, the present invention aims to provide a high-speed and high-precision attitude measurement method for a star sensor system, which improves the attitude data update rate and attitude measurement accuracy of the star sensor system and realizes high-speed and high-precision attitude measurement.

[0007] To achieve the above object, the technical solution of the present invention is realized as follows:

[0008] A high-speed and high-precision attitude measurement method for a star sensor system, the star sensor system includes at least three star sensors; the high-speed and high-precision attitude measurement method includes:

[0009] Providing an external synchronization signal with a set value of time interval to at least three star sensors;

[0010] At least three star sensors include a current star sensor that outputs attitude data at the current moment and other star sensors that do not output attitude data at the current moment; obtain the attitude data output by the current star sensor at the current moment and use it as the first attitude data;

[0011] According to the attitude data output by each of the other star sensors last time, predict the current attitude data of each of the other star sensors at the current moment and use it as the second attitude data; and

[0012] According to the first attitude data and the second attitude data, determine the comprehensive attitude data output by the star sensor system at the current moment.

[0013] Further, the set value is where T is the attitude update period of the star sensor; N is the number of star sensors.

[0014] Further, according to the attitude data output by each of the other star sensors last time, predict the attitude data of each of the other star sensors at the current moment and use it as the second attitude data, including:

[0015] Predict the attitude data of one of the other star sensors at the current moment n through the following formula

[0016]

[0017] where is the attitude data output by this star sensor among the other star sensors last time; is the angular velocity vector from the moment m when this star sensor output attitude data last time to the current moment n.

[0018] Further, the angular velocity vector is obtained through an angular velocity sensor.

[0019] Further, according to the first attitude data and the second attitude data, determine the comprehensive attitude data output by the star sensor system at the current moment, including:

[0020] Determine the comprehensive attitude data output by the star sensor system at the current moment n through the following formula

[0021]

[0022] where k 1 and k 2 are weight coefficients and satisfy k 1 > k 2 ,k 1 +(N - 1)k 2 = 1; is the first attitude data; Z 1 is the installation matrix from the current star sensor to the set star sensor; Z 2 is the installation matrix from the first star sensor among other star sensors to the set star sensor; is the predicted attitude data of the first star sensor among other star sensors; Z a is the installation matrix from the ath star sensor among other star sensors to the set star sensor; is the predicted attitude data of the ath star sensor among other star sensors.

[0023] Furthermore, the installation matrix from any one of at least three star sensors to the set star sensor is obtained by calibrating the installation angle.

[0024] Compared with the prior art, the present invention can achieve the following beneficial effects: The high-speed and high-precision attitude measurement method of the star sensor system provided by the embodiments of the present invention improves the attitude data update rate and attitude measurement accuracy of the star sensor system, and realizes high-speed and high-precision attitude measurement. Among them, an external synchronization signal with a set time interval is provided to at least three star sensors, so that the attitude update rate of the star sensor system is increased by at least three times. At the same time, since the comprehensive attitude data output by the star sensor system is obtained by fusing and calculating the attitude data of at least three star sensors, it is equivalent to that the available star quantity of the star sensor system is increased by at least three times, so that the attitude measurement accuracy of the star sensor system is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0026] Figure 1 is the structural schematic diagram of the star sensor system described in the embodiments of the present invention;

[0027] Figure 2 is the working timing schematic diagram of the star sensor system described in the embodiments of the present invention;

[0028] Figure 3 is the flowchart of the high-speed and high-precision attitude measurement method of the star sensor system described in the embodiments of the present invention.

[0029] Description of the reference numerals:

[0030] 10. Star sensor system; 11. Star sensor; 12. Data processor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention. Similar elements in different embodiments are labeled with related similar element numbers. In the following embodiments, many detailed descriptions are provided to enable a better understanding of the present invention. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, or methods. In some cases, some operations related to the present invention are not shown or described in the specification, which is to avoid the core part of the present invention being overwhelmed by excessive descriptions. For those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the descriptions in the specification and the general technical knowledge in the art.

[0032] It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other to form various embodiments. At the same time, the steps or actions in the method description can also be adjusted in the order that is obvious to those skilled in the art. Therefore, the various sequences in the specification and drawings are only for clearly describing a certain embodiment and do not mean that they are the necessary sequences, unless it is stated that a certain sequence must be followed.

[0033] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0034] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0035] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0036] See Figure 1 、 Figure 2 and Figure 3 As shown in

[0037] Step S1: Provide an external synchronization signal with a set value of time interval to at least three star sensors 11. The external synchronization signal is a time synchronization pulse signal provided by the data processor 12 to at least three star sensors 11 to ensure that the time interval of attitude update of at least three star sensors 11 is the set value. In one embodiment, the set value is where T is the attitude update period of the star sensor 11, and the attitude update period is the time interval for the star sensor 11 to update the attitude data each time. N is the number of star sensors 11. In this embodiment, the star sensor system 10 includes three star sensors 11, and the set value is Taking Figure 1 and Figure 2 the embodiment shown as an example, the data processor 12 provides an external synchronization signal with a time interval of to the three star sensors 11. Among them, after the star sensor A performs attitude update calculation , the star sensor B starts to perform attitude update calculation. After the star sensor B performs attitude update calculation After that, the star sensor C starts to perform attitude update calculation. The above is a working cycle of the star sensor system 10, and the star sensor system 10 may include multiple working cycles. At least three star sensors 11 include the current star sensor that outputs attitude data at the current moment and other star sensors that do not output attitude data at the current moment. The number of current star sensors may be one, and the number of other star sensors may be two, three or more.

[0038] In one embodiment, the star sensor 11 outputs attitude data through attitude update calculation, and the attitude update calculation includes:

[0039] Capture a starry sky image through the optical system of the star sensor 11, image it on the target surface of the image sensor of the star sensor 11, and identify the star points in the starry sky image through star point extraction.

[0040] Perform centroid positioning on each star point in the starry sky image to determine the observation information of each star point; the observation information includes the position of the star point on the target surface of the image sensor and the brightness information of the star point.

[0041] Compare and match the observation information of the star points with the pre-stored star catalog, find the corresponding navigation stars of the star points in the star catalog, and output attitude data through calculation.

[0042] Step S2: Obtain the attitude data output by the current star sensor at the current moment and use it as the first attitude data. Among them, the attitude data output by the current star sensor at the current moment is used as the first attitude data.

[0043] Step S3: According to the attitude data output by each of the other star sensors last time, predict the attitude data of each of the other star sensors at the current moment and use it as the second attitude data.

[0044] In one embodiment, step S3 includes: predicting the attitude data of one of the other star sensors at the current moment n through the following formula

[0045]

[0046] Among them, is the attitude data output by this star sensor among the other star sensors last time. is the angular velocity vector from the moment m when this star sensor output attitude data last time to the current moment n. In one embodiment, the angular velocity vector is obtained through an angular velocity sensor.

[0047] In this embodiment, at the current moment n is t kWhen the star sensor A is the current star sensor, and the star sensors B and C are other star sensors, at this time, the star sensor A outputs attitude data The star sensors B and C do not output attitude data at the current moment. Therefore, according to the attitude data output by the star sensor B last time and the attitude data output by the star sensor C last time Predict the attitude data of the star sensor B at the current moment and the attitude data of the star sensor C at the current moment And use them as the second attitude data, that is

[0048]

[0049] Among them, is the angular velocity vector from the moment when the star sensor B output attitude data last time to the current moment t k ; is the angular velocity vector from the moment when the star sensor C output attitude data last time to the current moment t k ;

[0050] Similarly, when the current moment n is t k+1 the star sensor B is the current star sensor, and the star sensors A and C are other star sensors. At this time, the star sensor B outputs attitude data The star sensors A and C do not output attitude data at the current moment. Therefore, according to the attitude data output by the star sensor A last time and the attitude data output by the star sensor C last time Predict the attitude data of the star sensor A at the current moment and the attitude data of the star sensor C at the current moment And use them as the second attitude data, that is

[0051]

[0052] Among them, is the angular velocity vector from the moment when the star sensor A output attitude data last time to the current moment t k+1 ; is the angular velocity vector from the moment when the star sensor C output attitude data last time to the current moment t k+1 ;

[0053] When the current moment n is t k+2 the star sensor C is the current star sensor, and the star sensors A and B are other star sensors. At this time, the star sensor C outputs attitude data Star sensor A and star sensor B do not output attitude data at the current moment. Therefore, according to the attitude data output by star sensor A last time and the attitude data output by star sensor B last time predict the attitude data of star sensor A at the current moment and the attitude data of star sensor B at the current moment and use them as the second attitude data, that is

[0054]

[0055] wherein, is the angular velocity vector from the moment when star sensor A output attitude data last time to the current moment t k+1 ; is the angular velocity vector from the moment when star sensor B output attitude data last time to the current moment t k+1 ;

[0056] Step S4: Determine the comprehensive attitude data output by the star sensor system 10 at the current moment according to the first attitude data and the second attitude data.

[0057] In one embodiment, the comprehensive attitude data output by the star sensor system 10 at the current moment n is determined by the following formula

[0058]

[0059] where k 1 and k 2 are weight coefficients, and satisfy k 1 > k 2 , k 1 +(N - 1)k 2 = 1. is the first attitude data. Z 1 is the installation matrix from the current star sensor to the set star sensor. Z 2 is the installation matrix from the first star sensor among other star sensors to the set star sensor. is the attitude data of the first star sensor among other star sensors obtained by prediction. Z a is the installation matrix from the a-th star sensor among other star sensors to the set star sensor. is the attitude data of the a-th star sensor among other star sensors obtained by prediction. Among them, any one of at least three star sensors can be selected as the set star sensor. In one embodiment, the installation matrix from any star sensor among at least three star sensors to the set star sensor is obtained by calibrating the installation angle.

[0060] In this embodiment, the star sensor system 10 includes three star sensors 11, then k 1 +2k 2 = 1, and star sensor A is used as the set star sensor.

[0061] At the current moment n being t k o'clock, star sensor A is the current star sensor, and star sensors B and C are other star sensors. Star sensor A outputs attitude data The attitude data of star sensor B predicted among other star sensors The attitude data of star sensor C predicted among other star sensors At this time, Z 1 is 1, Z 2 is Z 3 is And based on the attitude data Attitude data Attitude data To determine the comprehensive attitude data output by the star sensor system 10 at the current moment t k Namely That is

[0062]

[0063] Wherein, is the installation matrix from star sensor B to star sensor A. is the installation matrix from star sensor C to star sensor A.

[0064] Similarly, at the current moment n being t k+1 o'clock, star sensor B is the current star sensor, and star sensors A and C are other star sensors. Star sensor B outputs attitude data The attitude data of star sensor A predicted among other star sensors The attitude data of star sensor C predicted among other star sensors At this time, Z 1 is Z 2 is 1, Z 3 is And based on the attitude data Attitude data Attitude data To determine the comprehensive attitude data output by the star sensor system 10 at the current moment Namely

[0065]

[0066] At the current moment n being t k+2When the star sensor C is the current star sensor, and the star sensors A and B are other star sensors. The star sensor C outputs attitude data The predicted attitude data of the star sensor A among other star sensors The predicted attitude data of the star sensor B among other star sensors At this time, Z 1 is Z 2 is 1, Z 3 is And based on the attitude data Attitude data Attitude data To determine the comprehensive attitude data output by the star sensor system 10 at the current moment That is

[0067]

[0068] The high-speed and high-precision attitude measurement method of the star sensor system provided by the embodiment of the present invention realizes the improvement of the attitude update rate and attitude measurement accuracy of the star sensor system 10, and realizes high-speed and high-precision attitude measurement. Among them, an external synchronization signal with a set time interval is provided to at least three star sensors 11, so that the attitude update rate of the star sensor system 10 is increased by at least three times. At the same time, since the comprehensive attitude data output by the star sensor system 10 is obtained through the fusion calculation of the attitude data of at least three star sensors 11, it is equivalent to that the available star quantity of the star sensor system 10 is increased by at least three times, so that the attitude measurement accuracy of the star sensor system 10 is greatly improved.

[0069] It should be understood that various forms of the processes shown above can be used, reordering, adding or deleting steps. For example, the steps recorded in the present disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in the present disclosure can be achieved, which are not limited herein.

[0070] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A high-speed, high-precision attitude measurement method for a star sensor system, characterized in that: The star sensor system includes at least three star sensors; the high-speed, high-precision attitude measurement method includes: Providing an external synchronization signal with a set time interval to the at least three star sensors; The at least three star sensors include a current star sensor that outputs attitude data at the current moment and other star sensors that do not output attitude data at the current moment; acquiring the attitude data output by the current star sensor at the current moment and using it as the first attitude data; Predicting the attitude data of each of the other star sensors at the current moment according to the attitude data outputted last time by each of the other star sensors, and using the attitude data as the second attitude data; and The comprehensive attitude data output by the star sensor system at the current moment is determined according to the first attitude data and the second attitude data.

2. The high-speed, high-precision attitude measurement method of a star sensor system according to claim 1, characterized in that: The setting value is Wherein, T is the attitude update period of the star sensor; N is the number of the star sensors.

3. The high-speed, high-precision attitude measurement method of a star sensor system according to claim 1, characterized in that: The step of predicting the attitude data of each of the other star sensors at the current moment according to the attitude data outputted last time by each of the other star sensors as the second attitude data comprises: The attitude data of one of the other star sensors at the current time n is predicted by the following formula: in, The attitude data last outputted by the star sensor among the other star sensors; is the angular velocity vector from the time m when the star sensor last outputted attitude data to the current time n.

4. The high-speed, high-precision attitude measurement method of a star sensor system according to claim 3, characterized in that: The angular velocity vector is obtained by an angular velocity sensor.

5. The high-speed, high-precision attitude measurement method of a star sensor system according to claim 1, characterized in that: The step of determining the comprehensive attitude data output by the star sensor system at the current moment according to the first attitude data and the second attitude data includes: The comprehensive attitude data output by the star sensor system at the current time n is determined by the following formula: Wherein, k1 and k2 are weight coefficients, and satisfy k1>k2, k1+(N-1)k2=1; is the first posture data; Z1 is the installation matrix from the current star sensor to the set star sensor; Z2 is the installation matrix from the first star sensor among the other star sensors to the set star sensor; is the predicted attitude data of the first star sensor among the other star sensors; a An installation matrix from the ath star sensor among the other star sensors to the set star sensor; is the predicted attitude data of the ath star sensor among the other star sensors.

6. The high-speed, high-precision attitude measurement method of a star sensor system according to claim 5, characterized in that: The installation matrix from any one of the at least three star sensors to the set star sensor is obtained by calibrating the installation angle.

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