阅读说明：本技术 一种适用于小型飞行器光电系统高效扫描方法 (Efficient scanning method suitable for photoelectric system of small aircraft ) 是由 袁屹杰 伊兴国 董期林 赵创社 周根东 王马强 王毅 于 2021-09-08 设计创作，主要内容包括：本发明属于机载光电系统地面搜索侦察技术领域,具体涉及一种适用于小型飞行器光电系统高效扫描方法,实现在低空、小俯仰角应用场景下高效扫描同时避免漏扫,既能提高搜索效率又能保证侦察品质。该方法首先依据飞行器在扫描起始时刻的飞行状态,计算出一套优化的扫描参数,完成扫描过程；其次,采用基于地理坐标点的指向控制方法,使地面上扫描条带平直,在飞行航迹两侧形成一定幅宽的规则区域,最大限度利用探测器的探测能力。最后,建立警示及退出机制,保证扫描数据的有效性和可靠性。本发明可以实现在低空、小俯仰角的应用场景下全覆盖、高效地扫描飞行航迹周围区域,具有隐蔽性好,扫描范围大,效率高的特点,降低了对飞行器飞行控制要求。(The invention belongs to the technical field of ground search and reconnaissance of airborne photoelectric systems, and particularly relates to a high-efficiency scanning method suitable for a photoelectric system of a small aircraft, which can realize high-efficiency scanning in low-altitude and small-pitch angle application scenes and avoid missing scanning, thereby improving the search efficiency and ensuring the reconnaissance quality. Firstly, calculating a set of optimized scanning parameters according to the flight state of an aircraft at the scanning starting moment to finish the scanning process; secondly, a pointing control method based on geographic coordinate points is adopted, so that a scanning strip on the ground is straight, regular areas with certain widths are formed on two sides of a flight track, and the detection capability of a detector is utilized to the maximum extent. And finally, establishing a warning and quitting mechanism to ensure the validity and reliability of the scanning data. The invention can realize full coverage and high-efficiency scanning of the area around the flight track in the application scene of low altitude and small pitch angle, has the characteristics of good concealment, large scanning range and high efficiency, and reduces the requirement on the flight control of the aircraft.)

1. An efficient scanning method for a photovoltaic system of a small aircraft is characterized by comprising the following steps:

step 1: calculating a set of optimized scanning parameters according to the flight state of the aircraft at the scanning starting moment, wherein the scanning parameters are bound when a scanning mode is started, and the position of a visual axis pointing to a scanning point is adjusted in real time in the flight process by combining attitude information to finish the scanning process;

step 2: by adopting a pointing control method based on geographic coordinate points, the scanning strip on the ground is straight, regular areas with certain widths are formed on two sides of the flight path, and the detection capability of the detector is utilized to the maximum extent.

2. The method for scanning the optoelectronic system of a small aircraft with high efficiency as set forth in claim 1, wherein the scanning parameters are calculated in step 1, and under the limitation of the visual range of the detector, the scanning width, the initial pitch angle and the position parameters of each scanning point are calculated by using an optimization algorithm according to the height, the speed and the preset scanning conditions of the aircraft, and finally the coordinate sequence of the scanning point position is generated.

3. The method for scanning the photovoltaic system of a small aircraft with high efficiency as set forth in claim 2, wherein the step 1 comprises:

step 11: setting calculation conditions including flight states, detector parameters and preset scanning conditions; the flight state comprises the flight height and the speed of the aircraft; the detector parameters comprise visual range and visual field; the preset scanning conditions comprise scanning frequency and overlapping rate;

step 12: calculating an optimal value of a scanning parameter; the optimal values of the scanning parameters comprise an initial pitch angle, a maximum roll angle and a stepping amplitude;

step 13: calculating a mapping area of the monoscopic field on the ground;

step 14: calculating the overlapping area of the transverse and longitudinal fields of view;

step 15: calculating the transverse step amount and the longitudinal step amount of scanning;

step 16: and generating a scanning point position coordinate sequence.

4. The method according to claim 3, wherein in step 2, the ground area scanning control is performed, the current scanning point position is obtained according to real-time data provided by a gyroscope, an encoder and an inertial navigation system device and in combination with the scanning parameters in step 1, and the calculation result is used for controlling a servo mechanism, so that the visual axis of the sensor points to the current scanning point, and continuous scanning is realized by means of the maneuverability of the aircraft.

5. The method for scanning the photovoltaic system of a small aircraft with high efficiency as set forth in claim 4, wherein the step 2 comprises:

step 21: starting a scanning task;

step 22: establishing a coordinate system, taking the current aircraft position as the origin of the coordinate system, adopting a northeast coordinate system as a navigation coordinate system, and adopting a front right lower coordinate system as a carrier coordinate system;

step 23: binding matched scanning parameters and a scanning point position coordinate sequence according to the detector parameters, the flight state and preset scanning conditions;

step 24: acquiring attitude information in real time;

step 25: calculating the position of the aircraft under the north east coordinate system at the current moment;

step 26: calculating the position of a scanning point under a northeast coordinate system at the current moment, and establishing a current scanning point vector;

step 27: converting the scanning point vector into an aircraft carrier coordinate system through attitude sensor data; the attitude sensor data comprises course data, pitching data and rolling data;

step 28: calculating the angles of an outer bracket and an inner bracket of the photoelectric system, namely resolving the azimuth angle and the pitch angle of the photoelectric pod, thereby obtaining the angle of the visual axis which is required to rotate towards the current scanning point;

step 29: outputting a servo control instruction, controlling servo output, and adjusting the azimuth and the pitching mechanism to enable the visual axis to point to the current scanning point.

6. The method for scanning the photovoltaic system of a small aircraft with high efficiency as set forth in claim 5, wherein the step 2 further comprises:

step 210: judging a scanning mode alarm condition and a scanning mode exit condition; when the scanning mode alarm condition is met, sending out scanning alarm information; if the scan mode exit condition is met, the scan mode is exited, otherwise step 24 is repeated.

7. The method according to claim 5, wherein in step 210, an alarm mechanism is established to alarm the cumulative error due to the mismatching of the flight status and the scanning parameters, and report the current scanning status in time, and exit the scanning mode in case of serious conditions, so as to ensure the validity and reliability of the scanning data.

8. The method according to claim 6, wherein in step 210, the status of the aircraft is monitored in real time, and when the change in flight status does not meet the set parameters, i.e. meets the scan mode alarm condition, the scan alarm message is given, and when the change in flight status is severe, i.e. meets the scan mode exit condition, the scan mode exits.

9. The method for efficient scanning of photovoltaic systems for small aircraft according to claim 6, wherein said step 210 comprises:

step 2101: calculating an actual initial pitch angle according to the actual flight state;

step 2102: taking mechanical limit as a scan mode exit condition;

step 2103: taking the minimum roll angle scanning distance limit as a first scanning mode warning condition;

step 2104: taking the maximum roll angle scanning distance limit as a second scanning mode warning condition;

step 2105: using the limit of the transverse scanning overlapping rate as a third scanning mode alarm condition;

step 2106: and limiting the longitudinal scanning overlapping rate as a fourth scanning mode alarm condition.

10. The method for scanning photovoltaic systems of small aircraft with high efficiency as claimed in claim 1, wherein the scanning method is executed in the CPU of the photovoltaic system.

Technical Field

The invention belongs to the technical field of ground search and reconnaissance of airborne photoelectric systems, and particularly relates to a high-efficiency scanning method suitable for a photoelectric system of a small aircraft.

Background

In the search and reconnaissance application of the current airborne photoelectric pod to the ground, the mobility of a carrier is mainly utilized to carry out real-time scanning on a lower area or a front lower area, the photoelectric system is limited by the layout of a small aircraft, the photoelectric system is integrated in a transverse suspension mode, and the photoelectric system adopts rolling scanning and utilizes a platform flight path to realize area reconnaissance, so that the search and reconnaissance working mode is high in efficiency. Considering that the flying height and the speed of the platform are limited, the low-altitude and small-pitch roll scanning mode is favorable for the safety of the system. At present, the application of a roll scanning mode is mainly high-altitude and long-distance reconnaissance, a large pitch angle and over-the-top reconnaissance mode are usually adopted, and under the application, the pitch angle only needs to compensate course displacement. However, in the small aircraft reconnaissance application, the pitch angle is small, when the previous scanning method is used, the scanning area on the ground scanned by the rotation in the rolling direction can be obviously deformed to form an arc-shaped strip, the scanning points at two ends extend forwards, the distance from the aircraft is greatly increased, the visual axis distance is greatly changed, the effective search width based on a certain visual level (such as based on a detection level, an identification level and the like) is greatly limited, and the actual effective scanning area is narrowed, as shown in fig. 1. Meanwhile, in the high-altitude and long-distance reconnaissance application, the requirement on the scanning efficiency is relatively low due to the large coverage area, but in the reconnaissance application of a small aircraft, due to the low flying speed, the low height and the small coverage area of the field of view, the establishment of a set of optimized scanning parameters is particularly important for improving the scanning efficiency. On the other hand, the flight state of the small aircraft is easily influenced by the external environment, in order to ensure the search scouting quality (maximum search width and certain overlap rate), a direction control method based on geographic coordinate points is adopted for scouting, but in actual search scouting, the quality is still influenced by a platform, when the flight state of the aircraft changes and scanning is still carried out according to the preset scanning parameters, an accumulated error can be generated on a scanning pitch angle, the error exceeds a certain limit, the scanning overlap area is too large or too small, the scanning overlap rate cannot meet the requirement, and even a scanning mechanism reaches mechanical limit.

Disclosure of Invention

Technical problem to be solved

The technical problem to be solved by the invention is as follows: aiming at a photoelectric system loaded in a transverse suspension mode of a small aircraft, how to provide a scanning method for ground region reconnaissance is required, the method can realize high-efficiency scanning in an application scene with a small pitch angle, meanwhile, missing scanning is avoided, the searching efficiency can be improved, and the reconnaissance quality can be ensured.

(II) technical scheme

In order to solve the technical problem, the invention provides an efficient scanning method for an optoelectronic system of a small aircraft, which comprises the following steps:

step 1: calculating a set of optimized scanning parameters according to the flight state of the aircraft at the scanning starting moment, wherein the scanning parameters are bound when a scanning mode is started, and the position of a visual axis pointing to a scanning point is adjusted in real time in the flight process by combining attitude information to finish the scanning process;

step 2: by adopting a pointing control method based on geographic coordinate points, the scanning strip on the ground is straight, regular areas with certain widths are formed on two sides of the flight path, and the detection capability of the detector is utilized to the maximum extent.

And (2) calculating scanning parameters in the step (1), calculating the scanning width, the initial pitch angle and position parameters of each scanning point by using an optimization algorithm according to the height, the speed and the preset scanning condition of the aircraft under the limitation of the visual range of the detector, and finally generating a position coordinate sequence of the scanning point.

Wherein the step 1 comprises:

step 11: setting calculation conditions including flight states, detector parameters and preset scanning conditions; the flight state comprises the flight height and the speed of the aircraft; the detector parameters comprise visual range and visual field; the preset scanning conditions comprise scanning frequency and overlapping rate;

step 12: calculating an optimal value of a scanning parameter; the optimal values of the scanning parameters comprise an initial pitch angle, a maximum roll angle and a stepping amplitude;

step 13: calculating a mapping area of the monoscopic field on the ground;

step 14: calculating the overlapping area of the transverse and longitudinal fields of view;

step 15: calculating the transverse step amount and the longitudinal step amount of scanning;

step 16: and generating a scanning point position coordinate sequence.

And 2, performing ground area scanning control, obtaining the position of the current scanning point according to real-time data provided by a gyroscope, an encoder and an inertial navigation system device and in combination with the scanning parameters in the step 1, resolving, wherein the resolving result is used for controlling a servo mechanism, so that the visual axis of the sensor points to the current scanning point, and realizing continuous scanning by means of the maneuverability of an aircraft.

Wherein the step 2 comprises:

step 21: starting a scanning task;

step 22: establishing a coordinate system, taking the current aircraft position as the origin of the coordinate system, adopting a northeast coordinate system as a navigation coordinate system, and adopting a front right lower coordinate system as a carrier coordinate system;

step 23: binding matched scanning parameters and a scanning point position coordinate sequence according to the detector parameters, the flight state and preset scanning conditions;

step 24: acquiring attitude information in real time;

step 25: calculating the position of the aircraft under the north east coordinate system at the current moment;

step 26: calculating the position of a scanning point under a northeast coordinate system at the current moment, and establishing a current scanning point vector;

step 27: converting the scanning point vector into an aircraft carrier coordinate system through attitude sensor data; the attitude sensor data comprises course data, pitching data and rolling data;

step 28: calculating the angles of an outer bracket and an inner bracket of the photoelectric system, namely resolving the azimuth angle and the pitch angle of the photoelectric pod, thereby obtaining the angle of the visual axis which is required to rotate towards the current scanning point;

step 29: outputting a servo control instruction, controlling servo output, and adjusting the azimuth and the pitching mechanism to enable the visual axis to point to the current scanning point.

Wherein, the step 2 further comprises:

step 210: judging a scanning mode alarm condition and a scanning mode exit condition; when the scanning mode alarm condition is met, sending out scanning alarm information; if the scan mode exit condition is met, the scan mode is exited, otherwise step 24 is repeated.

In step 210, an alarm mechanism is established to alarm the cumulative error exceeding caused by the mismatching of the flight status and the scanning parameters, the current scanning status is reported in time, and the scanning mode is exited when the situation is serious, so as to ensure the validity and reliability of the scanning data.

In step 210, the aircraft state is monitored in real time, when the change of the aircraft state does not meet the set parameters, that is, when the aircraft state meets the scan mode alarm condition, the scan mode alarm information is given, and when the aircraft state is serious, that is, when the aircraft state meets the scan mode exit condition, the aircraft state exits the scan mode.

Wherein the step 210 comprises:

step 2101: calculating an actual initial pitch angle according to the actual flight state;

step 2102: taking mechanical limit as a scan mode exit condition;

step 2103: taking the minimum roll angle scanning distance limit as a first scanning mode warning condition;

step 2104: taking the maximum roll angle scanning distance limit as a second scanning mode warning condition;

step 2105: using the limit of the transverse scanning overlapping rate as a third scanning mode alarm condition;

step 2106: and limiting the longitudinal scanning overlapping rate as a fourth scanning mode alarm condition.

Wherein the scanning method is operated in a CPU of the optoelectronic system.

(III) advantageous effects

Compared with the prior art, the invention provides the high-efficiency scanning method suitable for the photoelectric system of the small aircraft, and the method provides optimized scanning parameter calculation, ensures the highest scanning efficiency under a certain overlapping rate and improves the reconnaissance efficiency to the maximum extent; the scanning control is provided, the detection capability of the detector is utilized to the maximum extent, and the combined scanning of a plurality of aircraft cluster operations is facilitated; the method provides a scanning mode exit mechanism, and ensures the scanning effectiveness and reliability.

The technical scheme of the invention can realize full coverage and high-efficiency scanning of the area around the flight track in the application scene of low altitude and small pitch angle, has the characteristics of good concealment, large scanning range and high efficiency, reduces the flight control requirement on the aircraft, and has good application prospect in the background that the intelligent and cluster battle mode is more and more emphasized. Meanwhile, the device can be further expanded and applied to the existing high-altitude and long-distance reconnaissance equipment so as to enrich the application mode of the equipment.

Drawings

Fig. 1 is a schematic view of an uncompensated scan operation.

Fig. 2 is a schematic view of the effect of scan compensation.

Fig. 3 is a schematic diagram of an application carrier and related components according to the present invention.

Fig. 4 is a schematic arrangement diagram of scanning points in one scanning cycle.

Fig. 5 is a schematic view of the scanned width.

FIG. 6 is a schematic view of the longitudinal length of a scanned monoscopic field.

Detailed Description

In order to make the objects, contents, and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.

In order to solve the technical problem, the invention provides an efficient scanning method for an optoelectronic system of a small aircraft, which comprises the following steps:

step 1: calculating a set of optimized scanning parameters according to the flight state of the aircraft at the scanning starting moment, wherein the scanning parameters are bound when a scanning mode is started, and the position of a visual axis pointing to a scanning point is adjusted in real time in the flight process by combining attitude information to finish the scanning process;

step 2: by adopting the pointing control method based on the geographic coordinate point, the scanning strip on the ground is straight, and a regular area with a certain width is formed on two sides of the flight path, as shown in fig. 2, the detection capability of the detector is utilized to the maximum extent, and the combined scanning of the cluster operation of a plurality of aircrafts is facilitated.

And (2) calculating scanning parameters in the step (1), calculating the scanning width, the initial pitch angle and position parameters of each scanning point by using an optimization algorithm according to the height, the speed and the preset scanning condition of the aircraft under the limitation of the visual range of the detector, and finally generating a position coordinate sequence of the scanning point.

Wherein the step 1 comprises:

step 11: setting calculation conditions including flight states, detector parameters and preset scanning conditions; the flight state comprises the flight height and the speed of the aircraft; the detector parameters comprise visual range and visual field; the preset scanning conditions comprise scanning frequency and overlapping rate;

step 12: calculating an optimal value of a scanning parameter; the optimal values of the scanning parameters comprise an initial pitch angle, a maximum roll angle and a stepping amplitude;

step 13: calculating a mapping area of the monoscopic field on the ground;

step 14: calculating the overlapping area of the transverse and longitudinal fields of view;

step 15: calculating the transverse step amount and the longitudinal step amount of scanning;

step 16: and generating a scanning point position coordinate sequence.

And 2, performing ground area scanning control, obtaining the position of the current scanning point according to real-time data provided by a gyroscope, an encoder and an inertial navigation system device and in combination with the scanning parameters in the step 1, resolving, wherein the resolving result is used for controlling a servo mechanism, so that the visual axis of the sensor points to the current scanning point, and realizing continuous scanning by means of the maneuverability of an aircraft.

Wherein the step 2 comprises:

step 21: starting a scanning task;

step 22: establishing a coordinate system, taking the current aircraft position as the origin of the coordinate system, adopting a northeast coordinate system as a navigation coordinate system, and adopting a front right lower coordinate system as a carrier coordinate system;

step 23: binding matched scanning parameters and a scanning point position coordinate sequence according to the detector parameters, the flight state and preset scanning conditions;

step 24: acquiring attitude information in real time;

step 25: calculating the position of the aircraft under the north east coordinate system at the current moment;

step 26: calculating the position of a scanning point under a northeast coordinate system at the current moment, and establishing a current scanning point vector;

step 27: converting the scanning point vector into an aircraft carrier coordinate system through attitude sensor data; the attitude sensor data comprises course data, pitching data and rolling data;

step 28: calculating the angles of an outer bracket and an inner bracket of the photoelectric system, namely resolving the azimuth angle and the pitch angle of the photoelectric pod, thereby obtaining the angle of the visual axis which is required to rotate towards the current scanning point;

step 29: outputting a servo control instruction, controlling servo output, and adjusting the azimuth and the pitching mechanism to enable the visual axis to point to the current scanning point.

Wherein, the step 2 further comprises:

step 210: judging a scanning mode alarm condition and a scanning mode exit condition; when the scanning mode alarm condition is met, sending out scanning alarm information; if the scan mode exit condition is met, the scan mode is exited, otherwise step 24 is repeated.

In step 210, an alarm mechanism is established to alarm the cumulative error exceeding caused by the mismatching of the flight status and the scanning parameters, the current scanning status is reported in time, and the scanning mode is exited when the situation is serious, so as to ensure the validity and reliability of the scanning data.

In step 210, the aircraft state is monitored in real time, when the change of the aircraft state does not meet the set parameters, that is, when the aircraft state meets the scan mode alarm condition, the scan mode alarm information is given, and when the aircraft state is serious, that is, when the aircraft state meets the scan mode exit condition, the aircraft state exits the scan mode.

Wherein the step 210 comprises:

step 2101: calculating an actual initial pitch angle according to the actual flight state;

step 2102: taking mechanical limit as a scan mode exit condition;

step 2103: taking the minimum roll angle scanning distance limit as a first scanning mode warning condition;

step 2104: taking the maximum roll angle scanning distance limit as a second scanning mode warning condition;

step 2105: using the limit of the transverse scanning overlapping rate as a third scanning mode alarm condition;

step 2106: and limiting the longitudinal scanning overlapping rate as a fourth scanning mode alarm condition.

Wherein the scanning method is operated in a CPU of the optoelectronic system.

Example 1

The scanning method described in this embodiment is run in software in the "solution and control unit" of the optoelectronic pod shown in fig. 3. Meanwhile, the support of various components such as a secondary power supply, a communication unit, a servo mechanism, a gyroscope, an encoder, an infrared sensor, an inertial navigation system and the like is required. The present invention may be embodied in various forms without being limited to the embodiments, and modifications, alterations, substitutions, etc. based on the present invention are intended to be included within the scope of the present invention.

In the first step of the method, scanning parameter calculation is performed, and finally, a scanning point position coordinate sequence of a scanning cycle is generated, as shown in table 1. The scanning cycle starts from an initial scanning point p (0) and is completed by one scanning band and two scanning half-bands, and the scanning points are arranged as shown in fig. 4. A complete scanning process is completed by sequentially connecting a plurality of scanning cycles until the scanning exit condition is met. The calculation specifically comprises the following steps:

11. setting calculation conditions including flight state (height, speed), detector parameters (visual range, visual field) and preset scanning conditions (scanning frequency and overlapping rate).

In the present embodiment, the sensor field of view is 5.4 ° × 4.3 ° (a is 5.4, b is 4.3), the viewing distance L is 4000m, the flying height h is 1500m, the velocity v is 50m/s, the scanning frequency f is 1Hz (period T is 1s), the overlap ratio p is not less than 30%, and the initial roll angle α is equal to or greater than the initial roll angle α₀＝0。

12. And calculating the optimal values of the scanning parameters (initial pitch angle, maximum roll angle and stepping amplitude). In this embodiment, a genetic algorithm is used to find the optimal value at the initial pitch angle β₀∈[10 40]Maximum roll angle α_max∈[0 50]The number of steps n ∈ [ 115 ]]When in use, a population is randomly generated, the population size is 300, a mutation operator is 0.1, a crossover operator is 0.9, the iteration times are 200, the line-of-sight condition and the overlapping rate condition are taken as fitness, and the fitness is calculated to obtain the following results: initial pitch angle beta₀Scan maximum roll angle α 22.02431_max41.35739, the number of transverse stepping n is 5 (no intermediate scanning point), and the scanning width 2Y_max2640.893m, maximum viewing distance L_scanmax4000m, roll scan overlap ratio p_roll0.3 course scan overlap ratio p_course＝0.319188。

13. And calculating the mapping area of the monoscopic field on the ground. Calculated by the following formula:

flight distance of the aircraft when scanning a strip: x ═ n × 2+1 × T × v ═ 5 × 2+1 × 50 ═ 550 m.

Flight compensation distance at maximum roll angle: x is the number of_half＝n×T×v＝5×1×50＝250m

The first scanning point sight distance is projected on the ground:

scan width (single side): y is_max＝h×tanα_max＝1500×tan41.35739＝1320.5m

Maximum roll angle scan distance, as shown in fig. 5:

minimum roll angle scan distance:

a single view field area map may be obtained,

transverse width: w_view＝L_scanmin×tana＝4000×tan5.4＝378.1m

Longitudinal length, as shown in fig. 6:

14. the field of view overlap regions in the lateral and longitudinal directions are calculated.

Width of one band transverse overlap:

W_{overlap_total}＝W_view×2×n-2×Y_max＝378.1×2×5-2×1320.5＝1140m

single field overlap width:

single field overlap length: l is_overlap＝L_view-x＝807.86-550＝257.86m

15. And calculating the transverse step amount and the longitudinal step amount of the scanning.

Scanning point lateral stepping amount: w_step＝W_view-W_overlap＝378.1-114＝264.1m

Scanning point longitudinal stepping amount: l is_step＝L_view-L_overlap＝x＝550m

16. And generating a scanning point position coordinate sequence.

The intermediate scanning point is used as the first scanning point, and the position coordinate is set as (p)_{table_x}＝0,p_{table_y}0), the scanning point arrangement shown in fig. 4 is followed, and the position coordinate sequence of each scanning point shown in table 1 can be obtained.

TABLE 1 sequence Listing of position coordinates of each scan point in one scan cycle

Secondly, carrying out ground area scanning control, comprising the following steps:

21. starting a scanning task: during the flight of the aircraft, the photoelectric pod is not in the scanning mode by default, and after an external system gives an instruction for entering the scanning mode, the photoelectric pod enters the scanning mode, and the moment is defined as t₀Let t be₀＝0。

22. Establishing a coordinate system: in the embodiment, the current time aircraft position is taken as the origin of coordinates, a north (x) east (y) ground (z) coordinate system is taken as a navigation coordinate system, and a front (x) right (y) bottom (z) coordinate system is taken as a carrier coordinate system.

23. And (5) parameter binding. According to preset input conditions: the sensor visual range, visual field, flying height, speed, scanning frequency and overlapping rate are bound with matched scanning parameters, including initial pitch angle beta₀Scanning the maximum roll angle alpha_maxThe number n of transverse stepping steps (no middle scanning point is included), and the position coordinate sequence of each scanning point. In the present embodiment, the sensor field of view is 5.4 ° × 4.3 ° (a is 5.4, b is 4.3), the viewing distance L is 4000m, the flying height h is 1500m, the velocity v is 50m/s, the scanning frequency f is 1Hz (period T is 1s), the overlap ratio p is not less than 30%, and the initial roll angle α is equal to or greater than the initial roll angle α₀Under this condition, the scan parameter calculation performed in the first step according to the present invention yields: initial pitch angle beta₀Scan max of 22.02431Roll angle alpha_max41.35739, the number of transverse steps n is 5 (no intermediate scanning points), and the position coordinate sequence table of each scanning point. The distribution of the scanning points is shown in fig. 4, wherein x is the longitudinal direction of the aircraft, and y is the transverse direction of the aircraft.

24. And acquiring the state information of the aircraft in real time, wherein in the embodiment, the attitude information is provided by an inertial navigation system of the aircraft in real time. The specific information includes: flight speed v, altitude h, course anglePitch angle θ, roll angle γ.

25. The aircraft position is calculated. At time t, the aircraft is located in the northeast coordinate system as follows:

26. and calculating the position of the scanning point. At time t, the position of the scanning point on the course of the aircraft can be obtained by looking up the table (as shown in Table 1)

The position of the current scanning point is:

wherein:

n: the number of scan cycles that have already been scanned,

L_step: the point is scanned by the amount of longitudinal stepping.

After course correction, the position of the scanning point in the coordinate system of northeast is obtained as follows:

the scanning point vector at the current moment is as follows:

27. and converting the scanning point vector into an aircraft carrier coordinate system:

28. and resolving the azimuth angle and the pitch angle of the photoelectric pod, namely the angle of the visual axis which is required to rotate towards the current scanning point.

29. Outputting a servo control instruction, and adjusting the azimuth and the pitching mechanism to enable the visual axis to point to the current scanning point.

210. Whether the condition is satisfied is judged according to the scanning mode warning condition and the scanning mode exit condition provided in the third step of the invention. If the condition of exiting the scanning mode is met, the scanning process is ended, a servo zero-returning instruction is given, and the azimuth and the pitching mechanism are adjusted to return to the initial position (alpha)₀＝0,β₀22.02431). If the scanning exit condition is not met, the step 24 is skipped to continue scanning, and when the alarm condition is met, alarm information is reported.

And thirdly, monitoring the state of the aircraft in real time by the scanning method, judging alarm and exit conditions, giving alarm information when the change of the flight state does not accord with set parameters, and exiting the scanning mode when the change of the flight state is serious. The method specifically comprises the following steps:

2101. the actual initial pitch angle is calculated in the actual flight situation. In this embodiment, the sensor field of view is 5.4 ° × 4.3 ° (a is 5.4 and b is 4.3), and the viewing distance L is4000m, 1500m for flying height h, 50m/s for speed v, 1Hz for scanning frequency f (period T1 s), 30% or more for overlap ratio p, and initial roll angle α₀0. The efficient scanning parameter calculation method provided by the invention can be known as follows: initial pitch angle beta₀Scan maximum roll angle α 22.02431_max41.35739, the number of transverse stepping n is 5 (no intermediate scanning point), and the scanning width 2Y_max2640.893m, maximum viewing distance L_scanmax4000m, roll scan overlap ratio p_roll0.3 course scan overlap ratio p_course0.319188. Assuming that the actual flying speed is v 'and the actual flying height is h'.

The first scanning point sight distance is projected on the ground:

the first scan point apparent distance after N scan cycles is projected on the ground as:

X′_max＝X_max+N×2x-N×(4n+2)×v′

＝3708.1+N×2×550-N×(4×5+2)×v′

＝3708.1+(1100-22v′)×N

obtaining an actual initial pitch angle:

2102. mechanical limit is used as a scan mode exit condition: is beta'₀Approaching mechanical limit (beta) of the photoelectric pod in pitch_limit1,β_limit2) When it is time to ensure that the scanning mode can be exited, i.e. it is required to satisfyWherein: delta delta₁、Δδ₂The engineering experience error value can be added according to actual conditions.

2103. Taking the minimum roll angle scanning distance limit as a first scanning mode warning condition: when beta is₀' failure to satisfy stripsPieceWhen, the minimum roll angle scan distance is illustrated:if the visual distance of the sensor is exceeded, effective detection of the target cannot be guaranteed, and scanning warning information should be given.

2104. And taking the maximum roll angle scanning distance limit as a second scanning mode alarm condition:

distance of actual flight compensation at maximum roll angle: x'_half＝n×T×v′＝5v′

Actual scan maximum roll angle:

actual scan width (single side): y is_m′_ax＝h′×tanα′_max＝Y_max＝1320.5m

Distance limit by maximum roll angle scan:

the actual first scan point apparent distance projection on the ground can be obtained:

the actual initial pitch angle is thus obtained:

when beta is₀When this condition cannot be satisfied, the maximum roll angle scan distance is described: l'_scanmax>L, beyond the sensor's apparent distance, effective detection of the target cannot be guaranteed and a sweep should be givenAnd (5) tracing alarm information.

2105. And taking the transverse scanning overlapping rate limit as a third scanning mode alarm condition:

actual minimum roll angle scan distance:

monoscopic ground area maps the actual lateral width: w'_view＝L′_scanmin×tana＝L′_scanmin×tan5.4

Actual transverse overlap width of a strip:

W′_{overlap_total}＝W′_view×2×n-2×Y′_max＝W′_view×2×5-2×1320.5＝L′_scanmin×tan5.4×10-2641

actual overlap width of single field of view:

the actual lateral scan overlap ratio is:

then, in order to ensure a certain overlap ratio (p is more than or equal to 30% in this embodiment), the scanning efficiency can be ensured while avoiding missing scanning, and the following conditions are required: p + delta₅≤p′_WI.e. 0.3+ Δ δ in this embodiment₅≤p′_WWhen the limit condition is exceeded, scanning alarm information should be given.

2106. And taking the longitudinal scanning overlapping rate limit as a fourth scanning mode alarm condition:

distance actually flown by the aircraft when scanning a strip: x ' (n × 2+1) × T × v ' ═ 11v '

Monoscopic ground area maps actual longitudinal length:

the actual longitudinal scan overlap ratio is:

then, in order to ensure a certain overlap ratio (p is more than or equal to 30% in this embodiment), the scanning efficiency can be ensured while avoiding missing scanning, and the following conditions are required: p + delta₆≤p′_LI.e. 0.3+ Δ δ in this embodiment₆≤p′_LWhen the limit condition is exceeded, scanning alarm information should be given.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.