Imaging satellite load and working mode decision-making method for silent target verification

Abstract

The invention provides an imaging satellite load and working mode decision-making method for silent target verification, and belongs to the technical field of earth observation satellite task planning and multi-satellite collaborative observation. The method comprises the following steps: firstly, predicting an escape area range of a target according to the silence moment and position of the target and the heading speed direction of the target, and calculating a top-crossing imaging satellite set in the escape area range in an escape time range; secondly, screening an imaging satellite set according to environment information such as day time and weather of a target predicted escape area; and finally, according to the breadth width constraint condition and the identification and discrimination capability constraint condition, determining a breadth width range and a resolution range, and determining specific satellite load parameters and working modes for imaging verification. The method can solve the load type and working mode optimization decision problem when the imaging reconnaissance satellite carries out silent target verification, and has the characteristics of advancement and practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of satellite mission planning and multi-satellite cooperative observation, and particularly relates to an imaging satellite payload and working mode decision method for silent target verification. BACKGROUND

[0002] In the cooperative observation of a large-scale heterogeneous constellation, an electronic observation satellite can discover target radiation source information in a wide range, thereby obtaining target positioning information, but the positioning accuracy is limited. Once the target is electromagnetically silent, an imaging satellite needs to relay to capture and track observation. Multi-satellite cooperative observation is a key means of future space-based earth observation. An imaging satellite can obtain clear and explicit appearance and activity information of a target, and has the advantages of high imaging resolution and high positioning accuracy.

[0003] According to the time and position of the silent target when it is discovered to be silent, the escape area range of the target is predicted. The imaging area of the imaging satellite needs to contain the escape area range in theory to capture the escape target. The amplitude length and amplitude width need to meet the escape area range prediction size constraint. Without loss of generality, the function relationship between the number of imaged points and the target size needs to meet the fixed capture recognition capability constraint to obtain clear imaging data and meet the practical value of target observation.

[0004] When a mobile target is electromagnetically silent, an imaging satellite needs to be used to relay observation of the target to track the behavior trend of the target. Currently, in the background of improving the cooperative detection capability of heterogeneous satellites, to complete the imaging payload and working mode decision for silent target verification, a strict calculation strategy needs to be followed.

[0005] At present, from the public literature, only a few documents study the selection of imaging satellite payload type and working mode parameter calculation for silent target verification. There is no related research on the selection of imaging reconnaissance satellite payload type and working mode parameters in the existing public literature materials. SUMMARY

[0006] Therefore, the present application provides an imaging satellite payload and working mode decision method for silent target verification. The method can constrain and optimize the imaging reconnaissance satellite payload and working mode parameters that meet the spatial and temporal constraints of silent target verification, and solve the optimization and decision problem of the payload type and working mode of the imaging reconnaissance satellite for silent target verification.

[0007] The technical scheme adopted by the present application is as follows:

[0008] The imaging satellite payload and working mode decision method for silent target verification comprises the following steps:

[0009] Step 1, according to the continuous situation information, determine the starting time of target silent escape , escape length , target position , escape speed , target length L, target width W, escape direction relative to satellite subsatellite point track direction angle , and weather environment information at position , wherein, cloud thickness, fog level, and sea wave level .

[0010] Step 2, determine the target escape area M as the area that the target can escape within time, calculate the over-the-horizon imaging satellite set of M area within to , including various optical satellites and SAR satellites .

[0011] Step 3, according to the weather environment information at the target position, screen the satellites in the over-the-horizon imaging satellite set .

[0012] Step 4, for the screened over-the-horizon imaging satellite set , according to the width and length constraints and the recognition and discrimination ability constraints, determine the width and length range and the resolution range, determine the specific satellite payload parameters and working mode for imaging verification.

[0013] Further, the specific way of step 2 is:

[0014] Step 201, according to the escape direction of the target relative to the satellite subsatellite point track angle and escape speed , determine the area range function of the target escape area M as a circle with the target position (x, y) as the center and as the radius;

[0015] Step 202, according to the target escape area M, satellite access calculation result, satellite-area coverage calculation result, obtain the over-the-horizon imaging satellite set of the target escape area M within , time interval .

[0016] Further, the specific way of step 3 is:

[0017] Step 301, if the solar elevation angle exceeds the observation requirement of the optical satellite, remove all optical satellites, otherwise execute step 302;

[0018] Step 302, for optical satellites Obtain the threshold for the thickest imageable cloud layer and the threshold for the largest imageable fog level. If the current cloud layer thickness and fog level of the target escape region M are both greater than those of the optical satellite... The corresponding threshold will then Remove, otherwise keep ;

[0019] Step 303, for SAR satellites Obtain the maximum imageable wave level threshold. If the current wave level of the target escape area M is greater than that of the SAR satellite... The maximum imageable wave class threshold will then be... Remove, otherwise keep .

[0020] Furthermore, step 4 is specifically implemented as follows:

[0021] Step 401: When the working mode is single-strip, determine the swath length of the imaging satellite to be selected. and width The constraints are:

[0022]

[0023] When the working mode is stitching, determine the swath length of the imaging satellite to be selected. and width The constraints are:

[0024]

[0025] Where n is the number of stripes;

[0026] Step 402, for optical satellites, based on the number of imageable points Constraints:

[0027]

[0028] Calculate the resolution of optical satellite payloads The range of constraint values;

[0029] in, H represents the number of imaging points for target identification, and H represents the flight altitude of the optical satellite. The lateral swing angle is The distance between the optical satellite and the imaging center;

[0030] Step 403, for SAR satellites, based on the number of imageable points Constraints:

[0031]

[0032] Calculate SAR satellite signal bandwidth The range of constraint values;

[0033] in, To identify the number of imaging points for the target, The incident angle of the radar beam during SAR satellite reconnaissance. The speed of light;

[0034] Step 404, based on the optical satellite payload resolution The range of constraint values ​​in the over-the-top imaging satellite ensemble Select optical satellites and their operating mode parameters that meet the constraints; based on the SAR satellite signal bandwidth The range of constraint values ​​in the over-the-top imaging satellite ensemble Select SAR satellites and their operating mode parameters that meet the constraints.

[0035] The present invention has the following beneficial effects:

[0036] 1. This invention can solve the problem of optimal decision-making on payload type and working mode when imaging reconnaissance satellites conduct silent target verification, and has the characteristics of being advanced and practical.

[0037] 2. This invention focuses on optimizing the payload and operating mode parameters of imaging based on constraints of weather conditions, meteorological conditions, swath length and width constraints of the target escape prediction area, and constraints of target identifiability imaging. It can perform precise calculations and decision optimization on the payload type and operating mode parameter constraints of optical imaging and SAR imaging satellites for the verification and identification of electromagnetically silent targets at sea, and has good applicability.

[0038] 3. In the application scenario of space-based information support for moving targets, based on the method in this invention, the set of identifiable and observable imaging satellites is first determined according to the target access calculation and the spatiotemporal constraints of the moving target. Then, the set of identifiable and observable imaging satellites is screened according to the weather and meteorological conditions of the target's predicted escape area, and satellites that do not meet the requirements are eliminated. Finally, according to the target escape area and the constraints of imaging swath length, swath width and resolution, the satellite payload and working mode parameters that meet the constraints are obtained for application in the mission planning and control of the satellite constellation system. Attached Figure Description

[0039] Figure 1 This diagram illustrates the spatiotemporal relationship between satellite imaging reconnaissance and target escape. Detailed Implementation

[0040] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0041] A method for determining the imaging satellite payload and operating mode for silent target verification, comprising the following steps:

[0042] (1) Target escape area prediction: Based on the constellation's continuous situational information, the target's silent state information is determined, starting from the target's last transmitted position. The silent state information includes the start time of the target's silent escape. ,Location Meteorological and environmental information of the vicinity of this location. .

[0043] like Figure 1 As shown, assuming the target escape time is... escape velocity is The target length is L, the target width is W, and the angle between the escape direction and the trajectory direction of the satellite's nadir point is . The escape zone M is the target. The area within which one can escape depends on their escape speed and direction.

[0044] (2) Based on the angle between the target's escape direction and the satellite's nadir point track. and target escape speed The function that determines the range of the target escape region M is... The relevant linear function, that is, with position With the center as the center, The circular area, specifically its location and included angle. related;

[0045] Based on the escape area M, the time from target detection escape is calculated using general satellite access calculation and satellite-region coverage calculation tools. Start to Overhead imaging satellite set in region M within the range This includes various types of optical satellites and SAR satellites;

[0046] (3) Based on the meteorological environment information at the target location, analyze the over-the-top imaging satellite array. The satellites in the selection process are screened; including:

[0047] (301) Based on the weather conditions at the target location, determine whether to remove the optical satellites in the imaging satellite set S. If the solar elevation angle is less than the threshold, remove them; otherwise, do not remove them.

[0048] (302) Based on meteorological and environmental information within the estimated escape area and escape duration range. Satellites were screened based on the thickest imageable cloud layer and the highest imageable fog level, removing optical satellites that did not meet the criteria; SAR satellites were also removed based on the highest imageable sea wave level; meteorological and environmental information was also provided. It is a spatiotemporally dependent function variable. For cloud thickness, It's a fog level. The wave rating is based on optical satellite data. The thresholds for the thickest imageable cloud layer and the maximum imageable fog level are used. If the current cloud thickness and fog level in region M are greater than the thresholds, then data is collected from the satellite set. Remove from Otherwise, retain; based on SAR satellite The maximum imageable wave level threshold is used. If the current wave level in region M is greater than the threshold, then the image is captured from the satellite set. Remove from Otherwise, keep it;

[0049] (4) For the selected imaging satellite set Based on the constraints of swath width and length and the constraints of recognition and discrimination capabilities, the swath width and length range and the resolution range are determined, and the payload parameters and operating modes of the specific satellites to be used for imaging verification are determined; the specific method is as follows:

[0050] (401) When the working mode is single strip, the swath length and swath width of the imaging satellite to be selected must satisfy the requirement that the rectangular area formed by the swath length and swath width includes the rectangular area where the expected position of the target and the starting silent position are diagonally opposite. Therefore, the following inequality must be satisfied:

[0051]

[0052] When the working mode is stitching, the swath length of the imaging satellite to be selected and width The following inequalities must be satisfied:

[0053]

[0054] Where n is the number of stripes.

[0055] (402) The resolution of the imaging satellite to be selected must meet the target recognition capability, that is... , This represents the number of imaging points assuming the target is an equivalent rectangle. Number of imaging points to identify the target;

[0056] Assuming the reconnaissance target is an equivalent rectangle, the number of points in its image can be estimated as follows:

[0057]

[0058] Let the physical size of the target be (rice), (meters), calculate the corresponding number of pixels according to the following formula:

[0059]

[0060]

[0061] Side swing angle Below, the ground resolution of optical imaging for:

[0062]

[0063] The optical star's flight altitude is (Unit: meters), the ground resolution for imaging the nadir point is... (meters), the side swing angle during imaging is (Unit: degrees), the lateral swing angle can be calculated using the following formula. Distance of the optical satellite from the center of the target (imaging center) :

[0064]

[0065] in, The radius of the local Earth reference ellipsoid at the nadir point is calculated as follows:

[0066]

[0067] In the formula:

[0068] The geocentric latitude of the satellite's nadir point. , This refers to the geodetic latitude of the sub-satellite point.

[0069] , where is the average equatorial radius of the reference ellipsoid;

[0070] , where is the polar radius of the reference ellipsoid;

[0071] Based on the above formula, for an optical satellite, the number of images that can be captured is:

[0072]

[0073] in, The number of imaging points for target identification can be obtained by looking up a table, and the final optical satellite payload resolution can be calculated. Constraint value range;

[0074] (403) The resolution of the imaging satellite to be selected must meet the target recognition capability, that is... , This represents the number of imaging points assuming the target is an equivalent rectangle. Number of imaging points to identify the target;

[0075] Assuming the reconnaissance target is an equivalent rectangle, the number of points in its image can be estimated as follows:

[0076]

[0077] Let the physical size of the target be (rice), (meters), calculate the corresponding number of pixels according to the following formula:

[0078]

[0079]

[0080] Let the bandwidth of the SAR payload be The incident angle of the radar beam during SAR detection is The speed of light is Therefore, the range resolution of SAR imaging can be calculated using the following formula:

[0081]

[0082] Based on the above formula, for SAR satellites, the number of images that can be captured is:

[0083]

[0084] in, The number of imaging points for target identification can be obtained by looking up a table; finally, the SAR satellite signal bandwidth is calculated. The range of constraint values;

[0085] (404) Based on the resolution of the optical satellite payload The range of constraint values, within the over-the-top imaging satellite ensemble Select optical satellites and their operating mode parameters that meet the constraints, based on the SAR satellite signal bandwidth. The range of constraint values ​​in the over-the-top imaging satellite ensemble Select SAR satellites and their operating mode parameters that meet the constraints.

[0086] This invention focuses on optimizing the payload and operating mode parameters of imaging based on constraints of weather conditions, meteorological conditions, swath length and width constraints of the target escape prediction area, and constraints of target identifiability imaging. It can perform precise calculations and decision optimization on the payload type and operating mode parameter constraints of optical imaging and SAR imaging satellites for the verification and identification of electromagnetically silent targets at sea, and has good applicability.

Claims

1. A method for determining the imaging satellite payload and operating mode for silent target verification, characterized in that, Includes the following steps: Step 1: Determine the start time of the target's silent escape based on continuous situational information. Escape duration Target location Escape velocity Target length L, target width W, and the angle between the escape direction and the trajectory direction of the satellite's nadir point. and location Meteorological and environmental information ,in, For cloud thickness, It's a fog level. Wave rating; Step 2, determine the target escape area M as the target's location. The area that can be escaped within a certain time, calculated from arrive Overhead imaging satellite set in region M within the range This includes various types of optical satellites and SAR satellites; Step 3: Based on the meteorological and environmental information at the target location, analyze the over-the-top imaging satellite array. The satellites in the selection were screened; Step 4, for the filtered over-the-top imaging satellite set Based on the constraints of swath width and length and the constraints of recognition and discrimination capabilities, the range of swath width and length and the range of resolution are determined, and the specific satellite payload parameters and working modes for imaging verification are determined.

2. The imaging satellite payload and operating mode decision-making method for silent target verification according to claim 1, characterized in that, The specific method for step 2 is as follows: Step 201: Based on the angle between the target's escape direction and the satellite's nadir point track... and escape velocity The function for determining the range of the target escape region M is a circle centered at the target position (x, y). A circle with radius 1; Step 202, based on the target escape area M, satellite access calculation results, and satellite-region coverage calculation results, obtain the data in […]. , The set of over-the-head imaging satellites for the target escape region M within the time interval. .

3. The imaging satellite payload and operating mode decision-making method for silent target verification according to claim 1, characterized in that, The specific method for step 3 is as follows: Step 301: If the solar elevation angle exceeds the observation requirements of the optical satellite, remove all optical satellites; otherwise, proceed to step 302. Step 302, for optical satellites Obtain the threshold for the thickest imageable cloud layer and the threshold for the largest imageable fog level. If the current cloud layer thickness and fog level of the target escape region M are both greater than those of the optical satellite... The corresponding threshold will then Remove, otherwise keep ; Step 303, for SAR satellites Obtain the maximum imageable wave level threshold. If the current wave level of the target escape area M is greater than that of the SAR satellite... The maximum imageable wave class threshold will then be... Remove, otherwise keep .

4. The imaging satellite payload and operating mode decision-making method for silent target verification according to claim 1, characterized in that, The specific method for step 4 is as follows: Step 401: When the working mode is single-strip, determine the swath length of the imaging satellite to be selected. and width The constraints are: When the working mode is stitching, determine the swath length of the imaging satellite to be selected. and width The constraints are: Where n is the number of stripes; Step 402, for optical satellites, based on the number of imageable points Constraints: Calculate the resolution of optical satellite payloads The range of constraint values; in, H represents the number of imaging points for target identification, and H represents the flight altitude of the optical satellite. The lateral swing angle is The distance between the optical satellite and the imaging center; Step 403, for SAR satellites, based on the number of imageable points Constraints: Calculate SAR satellite signal bandwidth The range of constraint values; in, To identify the number of imaging points for the target, The incident angle of the radar beam during SAR satellite reconnaissance. The speed of light; Step 404, based on the optical satellite payload resolution The range of constraint values ​​in the over-the-top imaging satellite ensemble Select optical satellites and their operating mode parameters that meet the constraints; based on the SAR satellite signal bandwidth The range of constraint values ​​in the over-the-top imaging satellite ensemble Select SAR satellites and their operating mode parameters that meet the constraints.

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