1. A parameter integration setting method based on a multi-rotor unmanned aerial vehicle SAR imaging system comprises the following steps: the system comprises an unmanned aerial vehicle platform, an antenna servo control module and an imaging subsystem; the method is characterized by comprising the following steps:

step S1, setting input parameters, where the input parameters include: coordinates of the upper leftmost point and the lower rightmost point of the target region, a range-wise resolution, and imaging geometry parameters, the imaging geometry parameters including: slant distance, beam center ground wiping angle and relative working height;

step S2, determining flight parameters of the unmanned aerial vehicle platform in an imaging area, wherein the flight parameters comprise: scanning a course, ground speed and vertical speed, wherein the imaging area is a flight area of the imaging subsystem to image the target area;

step S3, determining the roll angle and the pitch angle of the antenna servo control module in the imaging area according to the position information of the starting point and the end point of the central line of the surveying and mapping belt;

and step S4, determining the azimuth resolution, the starting position and the closing position of the imaging subsystem in the imaging area according to the distance resolution and the node position information of the flight path of the unmanned aerial vehicle in the imaging area.

2. The method for integrally setting parameters based on the multi-rotor unmanned aerial vehicle SAR imaging system according to claim 1, wherein in the step S2, the method for determining the scanning route of the unmanned aerial vehicle platform in the imaging area specifically comprises:

step S201, according to the geometric relationship among the slant distance, the ground wiping angle of the beam center and the vertical angle of the beam, the width of a surveying and mapping belt is obtained, wherein the width of the surveying and mapping belt is the projection width of a sector formed by the vertical angle of the radar beam on the ground by the ground wiping angle;

s202, enabling the width of the surveying and mapping belt to be equal to the distance between scanning routes of an imaging area, and calculating the side length of a target area in the weft direction, the side length of the target area in the warp direction and the area of the target area;

step S203, based on the principle that the scanning areas are not overlapped and the number of times of turning the flight path is the least, determining the direction of the scanning flight path by comparing the width of the surveying and mapping belt with the side length of the weft direction and the side length of the warp direction;

step S204, determining node position information of the unmanned aerial vehicle in the scanning air route of the imaging area according to the air route direction determined in the step S203 and by combining the area of the target area, the width of the mapping belt and the projection distance, wherein the scanning air route comprises at least one air route, when the number of the scanning air route is larger than two, the air route is connected with the air route through a turning air route, each air route comprises a starting point and an end point, and the node position information is longitude and latitude coordinates and height of the starting point and the end point of each air route in the scanning air route.

3. The method for integrally setting parameters based on the multi-rotor unmanned aerial vehicle SAR imaging system according to claim 2, wherein in step S202, the distance difference is obtained according to the coordinates of the leftmost upper point and the rightmost lower point of the target region, the length of the side in the weft direction and the length of the side in the warp direction of the target region are obtained, and finally the two lengths of the sides are multiplied to obtain the area of the target region.

4. The integrated parameter setting method based on the SAR imaging system of the multi-rotor unmanned aerial vehicle according to claim 3, wherein the step S203 comprises:

if the width of the surveying and mapping belt is greater than the length of the side in the warp direction and greater than the length of the side in the weft direction, the direction of the scanning route is along the warp direction or along the weft direction, and the scanning starting point is the point which is closest to the flying point in the upper leftmost point or the lower rightmost point;

if the width of the surveying and mapping belt is larger than the length of the side in the warp direction and smaller than the length of the side in the weft direction, the direction of the scanning route is along the weft direction, and the scanning starting point is the point which is closest to the flying start point in the leftmost upper point or the rightmost lower point;

if the width of the surveying and mapping belt is smaller than the length of the side in the warp direction and larger than the length of the side in the weft direction, the direction of the scanning route is along the warp direction, and the scanning starting point is the point which is closest to the flying point in the leftmost upper point or the rightmost lower point;

if the width of the surveying and mapping belt is smaller than the length of the side in the warp direction and smaller than the length of the side in the weft direction, further judging, if the length of the side in the warp direction of the target area is smaller than the length of the side in the weft direction, the direction of the scanning route is along the weft direction, if the length of the side in the warp direction of the target area is larger than the length of the side in the weft direction, the direction of the scanning route is along the warp direction, and the scanning starting point is the point which is closest to the starting point in the upper leftmost point or the lower rightmost point.

5. The integrated parameter setting method based on the SAR imaging system of multi-rotor unmanned aerial vehicle according to claim 4, wherein in the step S204,

if the course direction determined in step S203 is the warp direction, the number of scanning courses is the area of the target area divided by the area swept by the single scanning course and rounded upward, wherein the area swept by the single scanning course is specifically the width of the mapping belt multiplied by the length of the warp direction side;

when i is an even number, the latitude of the starting point of the flight line is the latitude of the scanning starting point, the latitude of the end point is the latitude of the scanning end point, and when i is an odd number, the latitude of the starting point of the flight line is the latitude of the scanning end point, and the latitude of the end point is the latitude of the scanning starting point.

6. The integrated parameter setting method based on the SAR imaging system of multi-rotor unmanned aerial vehicle according to claim 5, wherein in the step S204,

if the course direction determined in step S203 is the weft direction, the number of scanning courses is the area of the target area divided by the area swept by the single scanning course and rounded upward, wherein the area swept by the single scanning course is specifically the width of the mapping belt multiplied by the side length in the weft direction;

when i is an even number, the longitude of the starting point of the flight path is the longitude of the scanning starting point, and the longitude of the ending point is the longitude of the scanning ending point, and when i is an odd number, the longitude of the starting point of the flight path is the longitude of the scanning ending point, and the longitude of the ending point is the longitude of the scanning starting point.

7. The method for integrally setting parameters based on the SAR imaging system of the multi-rotor unmanned aerial vehicle is characterized in that in the scanning routes, a starting point and an end point in each route are determined by the latitude and the longitude of a target area scanning starting point, the projection distance of the slant distance and the width of a mapping strip.

8. The method for integrally setting parameters based on the multi-rotor unmanned aerial vehicle SAR imaging system according to claim 7, wherein in step S3, when the unmanned aerial vehicle platform is on a certain route of the imaging area, the roll angle of the antenna servo control module on the certain route is determined according to the starting point height, the ending point height and the projection distance between the starting point and the ending point of the centerline of the mapping strip corresponding to the certain route, and the maximum value of the roll angle is the maximum limit value of the antenna servo control module.

Background

Synthetic Aperture Radar (SAR) is used as a high-resolution microwave imaging Radar, not only can realize two-dimensional high-resolution imaging of a target, but also has the advantages of all-time, all-weather, multi-polarization, interference resistance and the like, and has good military application prospect. In recent years, with the development of science and technology, the miniaturization of the SAR system gradually becomes a research hotspot, and the miniature SAR system is emphasized in various application fields by the advantages of small system volume, light weight, flexible platform adaptation, low manufacturing cost and the like. However, in order to accurately acquire a high-quality image of a target area by using a miniature SAR, in addition to the performance of the SAR system itself, the cooperation of the SAR system with an antenna servo control system and a motion platform is also important. In particular, non-ideal motions of the moving platform, such as a non-constant velocity of the platform along the flight path, a non-0 velocity of the platform along the radar line of sight, and angular motions of the platform in pitch, roll, and yaw, all have a severe impact on imaging quality, as described in, for example, references [ song victory, terrorism, liu epi. The first two points mainly affect the phase error of the echo signal, and the last point causes the amplitude modulation of the echo doppler signal. Generally, the SAR antenna can realize self-stabilization by means of an antenna servo control system, so that the negative influence caused by angular motion can be basically eliminated. And the uniform motion of the platform along the course direction and the speed of the radar in the sight line direction of 0 are the main constraint conditions of the platform motion.

In the prior art, the problems of SAR imaging indexes and imaging parameter optimization design of high maneuvering platforms, small and above aircraft platforms, and airship platforms are mainly discussed, for example, in the invention patent with the application number of 202010963255.3, the performances of a moving platform and SAR are considered, and a setting method of system parameters is discussed according to imaging constraint conditions.

And many rotor unmanned aerial vehicle platform is different from above-mentioned motion platform, has its distinctive characteristics: the aircraft can take off and land vertically, turn on the spot, have slower flying speed and equal performance in all directions during level flying. The prior art can not solve many rotor unmanned aerial vehicle's miniature SAR imaging system's parameter setting problem well.

In order to ensure the imaging quality, a flight line needs to be designed according to the constraint condition of platform motion, and the scanning efficiency of a target area is improved by utilizing the characteristics of the multi-rotor unmanned aerial vehicle and the imaging geometry. Various parameters of the subsystem (module) and the platform need to be calculated respectively according to the imaging task and need to be set by utilizing various software platforms, the process efficiency is low, and the system deployment speed is reduced.

Disclosure of Invention

In view of this, the invention aims to provide a parameter integrated setting method based on an unmanned aerial vehicle SAR imaging system, and the method can drive the working parameter setting task of each subsystem according to a small amount of input parameters, so that the accuracy and efficiency of the unmanned aerial vehicle SAR imaging system for imaging a target area are improved, and the system deployment speed can be greatly improved.

In order to achieve the above purpose, the invention provides the following technical scheme:

a parameter integration setting method based on a multi-rotor unmanned aerial vehicle SAR imaging system comprises the following steps: the system comprises an unmanned aerial vehicle platform, an antenna servo control module and an imaging subsystem; the method comprises the following steps:

step S1, setting input parameters, where the input parameters include: coordinates of the upper leftmost point and the lower rightmost point of the target region, a range-wise resolution, and imaging geometry parameters, the imaging geometry parameters including: slant distance, beam center ground wiping angle and relative working height; only the parameters input in step S1 are needed to drive the subsequent steps;

step S2, determining flight parameters of the unmanned aerial vehicle platform in an imaging area, wherein the flight parameters comprise: scanning a course, ground speed and vertical speed, wherein the imaging area is a flight area of the imaging subsystem to image the target area;

step S3, determining the roll angle and the pitch angle of the antenna servo control module in the imaging area according to the position information of the starting point and the end point of the central line of the surveying and mapping belt;

and step S4, determining the azimuth resolution, the starting position and the closing position of the imaging subsystem in the imaging area according to the distance resolution and the node position information of the flight path of the unmanned aerial vehicle in the imaging area.

Further, in step S2, the method for determining the scanning path of the drone platform in the imaging area specifically includes:

step S201, according to the geometric relationship among the slant distance, the ground wiping angle of the beam center and the vertical angle of the beam, the width of a surveying and mapping belt is obtained, wherein the width of the surveying and mapping belt is the projection width of a sector formed by the vertical angle of the radar beam on the ground by the ground wiping angle;

s202, enabling the width of the surveying and mapping belt to be equal to the distance between scanning routes of an imaging area, and calculating the side length of a target area in the weft direction, the side length of the target area in the warp direction and the area of the target area;

step S203, based on the principle that the scanning areas are not overlapped and the number of times of turning the flight path is the least, determining the direction of the scanning flight path by comparing the width of the surveying and mapping belt with the side length of the weft direction and the side length of the warp direction;

step S204, determining node position information of the unmanned aerial vehicle in the scanning air route of the imaging area according to the air route direction determined in the step S203 and by combining the area of the target area, the width of the mapping belt and the projection distance, wherein the scanning air route comprises at least one air route, when the number of the scanning air route is larger than two, the air route is connected with the air route through a turning air route, each air route comprises a starting point and an end point, and the node position information is longitude and latitude coordinates and height of the starting point and the end point of each air route in the scanning air route.

Further, in the step S202, according to the coordinate of the leftmost upper point and the coordinate of the rightmost lower point of the target region, the distance difference is obtained to obtain the length of the side in the weft direction and the length of the side in the warp direction of the target region, and finally the two lengths of the sides are multiplied to obtain the area of the target region.

Further, the step S203 includes:

if the width of the surveying and mapping belt is greater than the length of the side in the warp direction and greater than the length of the side in the weft direction, the direction of the scanning route is along the warp direction or along the weft direction, and the scanning starting point is the point which is closest to the flying point in the upper leftmost point or the lower rightmost point;

if the width of the surveying and mapping belt is larger than the length of the side in the warp direction and smaller than the length of the side in the weft direction, the direction of the scanning route is along the weft direction, and the scanning starting point is the point which is closest to the flying start point in the leftmost upper point or the rightmost lower point;

if the width of the surveying and mapping belt is smaller than the length of the side in the warp direction and larger than the length of the side in the weft direction, the direction of the scanning route is along the warp direction, and the scanning starting point is the point which is closest to the flying point in the leftmost upper point or the rightmost lower point;

if the width of the surveying and mapping belt is smaller than the length of the side in the warp direction and smaller than the length of the side in the weft direction, further judging, if the length of the side in the warp direction of the target area is smaller than the length of the side in the weft direction, the direction of the scanning route is along the weft direction, if the length of the side in the warp direction of the target area is larger than the length of the side in the weft direction, the direction of the scanning route is along the warp direction, and a scanning starting point is a point which is closest to a flying point in the upper leftmost point or the lower rightmost point;

further, in the step S204,

if the course direction determined in step S203 is the warp direction, the number of scanning courses is the area of the target area divided by the area swept by the single scanning course and rounded upward, wherein the area swept by the single scanning course is specifically the width of the mapping belt multiplied by the length of the warp direction side;

when i is an even number, the latitude of the starting point of the flight line is the latitude of the scanning starting point, the latitude of the end point is the latitude of the scanning end point, and when i is an odd number, the latitude of the starting point of the flight line is the latitude of the scanning end point, and the latitude of the end point is the latitude of the scanning starting point.

Further, in the step S204,

if the course direction determined in step S203 is the weft direction, the number of scanning courses is the area of the target area divided by the area swept by the single scanning course and rounded upward, wherein the area swept by the single scanning course is specifically the width of the mapping belt multiplied by the side length in the weft direction;

when i is an even number, the longitude of the starting point of the flight path is the longitude of the scanning starting point, and the longitude of the ending point is the longitude of the scanning ending point, and when i is an odd number, the longitude of the starting point of the flight path is the longitude of the scanning ending point, and the longitude of the ending point is the longitude of the scanning starting point.

Further, in the scanning routes, the starting point and the end point of each route are determined by the latitude and the longitude of the scanning starting point of the target area, the projection distance of the slant distance and the width of the mapping strip.

Further, in step S3, when the unmanned aerial vehicle platform is located on a certain route in the imaging area, the roll angle of the antenna servo control module on the certain route is determined according to the height of the starting point and the height of the ending point of the center line of the surveying strip corresponding to the certain route, and the projection distance between the starting point and the ending point, and the maximum value of the roll angle is the maximum limit value of the antenna servo control module.

The invention has the beneficial effects that:

compared with the prior art, the method can autonomously drive the working parameter setting task of each subsystem according to a small amount of input parameters, improves the accuracy and efficiency of the unmanned aerial vehicle SAR system in imaging the target area, and can greatly improve the deployment speed of the system.

Drawings

Fig. 1 is a schematic diagram of the SAR imaging of the unmanned aerial vehicle in this embodiment 1.

Fig. 2 is a schematic view of scanning of the flight path and the target area of the unmanned aerial vehicle in the imaging area in the embodiment 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Referring to fig. 1 and fig. 2, the present embodiment provides a parameter integration setting method based on an unmanned aerial vehicle SAR imaging system, where the unmanned aerial vehicle SAR imaging system includes: the system comprises an unmanned aerial vehicle platform, an antenna servo control module and an imaging subsystem; specifically, the unmanned aerial vehicle platform is an aerial vehicle used for carrying an imaging subsystem and an antenna servo control module; the antenna servo control module is a subsystem for controlling and stabilizing an antenna in an imaging subsystem to point to a target area, and the imaging subsystem is a subsystem for imaging a ground object target by using electromagnetic waves. The types of parameters involved in the method include three types, the first type is fixed parameters, and the parameters are determined by the inherent performances of the subsystem (module) and the platform, and are known and unadjustable; the second type is input parameters, and the parameters are set by a user according to the requirements of the imaging task; the third type is a calculation parameter, and the calculation parameter is obtained by calculation according to the setting method provided by the implementation.

The setting method specifically comprises the following steps:

step S1, setting input parameters, where the input parameters include:

upper left coordinate T of target area₁(lon, lat, h) and lower right coordinate T₂(lon, lat, h), wherein lon, lat, h respectively denote longitude, latitude and altitude;

distance direction resolution rho_r；

Imaging geometric parameters:SR，H_wwherein, in the step (A),expressed as the beam center scrub angle, SR as the slant distance, H_wExpressed as relative working height;

the three imaging geometric parameters have corresponding value ranges, specifically:

slope SR ∈ [ SR_{w_min}，SR_{w_max}]Wherein SR_{w_min}Is the minimum range of SAR imaging and is a fixed parameter, SR_{w_max}Is the maximum working distance of SAR imaging, and is also fixedDetermining parameters;

relative working height H_w∈[h_{w_min}，h_{w_max}]Wherein h is_{w_min}Is the lowest height at which the SAR can form an ideal image and is a fixed parameter, h_{w_max}＝min(h_{carrier_max}，SR_{w_max}) Practical lifting limit h of loader_{carrier_max}And SR_{w_max}Small value of h_{carrier_max}Also fixed parameters;

beam center ground wiping angleWherein

Specifically, in this embodiment, in order to facilitate and rapidly deploy the method, the three imaging geometric parameters have two setting modes, specifically: the identification rate priority method and the priority parameter self-selection method are characterized in that the former can complete the imaging geometric parameter setting under the optimal identification rate target by setting 1 parameter, and the latter can flexibly set the imaging geometric parameters by selecting different combinations.

More specifically, the method for prioritizing the recognition rate includes:

firstly, the center of the wave beam is fixed to wipe the groundRelating to SAR image features of the target to a particular in the data setThe target recognition rate can reach an optimal value, and then H is determined_w∈[h_{w_min}，h_{w_max}]Passing through the center of the beam to wipe the groundAnd determining the relative working height H of a particular value_wCalculating the slope distance SR, wherein the expression is as follows:

more specifically, the method for selecting the priority parameter is to determine another parameter by determining two imaging geometry parameters of the three imaging geometry parameters, and specifically includes:

preferential selection of beam center scrub angleAnd relative working height H_wAnd then determining the slope distance SR or,

preferential selection of beam center scrub angleAnd the slope distance SR, and then the relative working height H is determined_wAlternatively, the first and second electrodes may be,

preference for relative working height H_wAnd the slant distance SR, and then the central ground wiping angle of the wave beam is determined

More specifically, the present invention relates to a method for producing,

1. when in useH_wPreferably, the first step is to take precedence,(tunable), H_w∈[h_{w_min}，h_{w_max}](can be adjusted),(displaying the current value and the variable value interval);

2. when in useThe SR takes precedence over the SR,(tunable), SR ∈ [ SR ∈ ]_{w_min}，SR_{w_max}](can be adjusted),(displaying the current value and the variable value interval);

3. when SR, H_wPreferably, SR ∈ [ SR ∈ ]_{w_min}，SR_{w_max}](tunable), H_w∈[h_{w_min}，h_{w_max}](can be adjusted),(display the current value and the variable value interval).

Step S2, determining flight parameters of the unmanned aerial vehicle platform in the approach section, the separation section and the imaging area, wherein the flight parameters comprise: three-dimensional course, ground speed and vertical speed;

specifically, the approach section refers to a flight phase from a departure point to a first starting point of an imaging area of the unmanned aerial vehicle, the departure section refers to a flight phase from a last end point of the imaging area to a descent point, and the imaging area refers to a flight area of the SAR subsystem for imaging the target area.

The key point in this step is that flight parameters of the unmanned aerial vehicle platform in the imaging area need to be determined, and it needs to be explained that the planning principle of the flight line of the unmanned aerial vehicle platform in the early imaging area is as follows: the scanning starting point of the target area is closest to the flying starting point and the turning times of the flight path are the least. The imaging area course planning needs to fully utilize the width of a mapping strip to improve the efficiency of imaging a target area, specifically referring to fig. 1 and 2, the SAR beam is directed perpendicular to the course of a carrier, and the width S _ W of the mapping strip is the vertical angle theta of the radar beam_VFan face formed to wipe floor cornerThe projected width on the ground.

Specifically, step S2 includes: step S201, according to the slant range SR and the beam center ground wiping angleAngle theta perpendicular to the beam_VThe geometrical relationship between the (fixed parameters) and,and solving the width S _ W of the mapping belt, wherein the expression is as follows:

step S202, in order to ensure that the scanning areas are not overlapped, the width of the mapping strip is equal to the distance between the scanning air lines of the imaging area (the distance between the scanning air lines of the imaging area is also the distance between the scanning air lines of the imaging area), and the scanning air lines of the imaging area are arranged according to the T₁And T₂Calculating the target region (T in FIG. 2)₁And T₂Area in between) and the longitude direction side length T _ lon of the latitude direction, and the area of the target area:

T_S＝T_lat·T_lon；

step S203, based on the principle that the scanning areas are not overlapped and the turning times of the flight path are minimum, determining the direction of the scanning flight path and the starting point of the scanning area by comparing the width of the surveying and mapping belt with the side length in the weft direction and the side length in the warp direction;

specifically, determining the direction of the scan path includes four situations:

1. if S _ W > T _ lon and S _ W > T _ lat (the width of the mapping belt is larger than any side of the target area), the scanning of the whole target area can be completed by executing a single scanning route along any side. In this case, the starting point T is scanned according to the target area_sThe principle of being closest to the flying point,

from the lower flying point P_homeTo determine the start point and end point of the target area scan, i.e. the start point T of the target area scan_sIs T₁And T₂Middle distance flying point P_homeCloser point, and in addition, target area scanning end point T_eIs T₁And T₂Middle distance flying point P_homeA remote point. Then scan the course direction along(l ═ lat, lon) direction in whichlat and Ion denote the weft direction and the warp direction respectively,

2. if S _ W > T _ lon and S _ W < T _ lat, scanning the flight path direction along the weft (lat) direction;

3. if S _ W is less than T _ lon and S _ W is more than T _ lat, scanning the flight path direction along the meridian (lon) direction;

4. if S _ W is less than T _ lon and S _ W is less than T _ lat, continuously judging that if T _ lon is less than T _ lat, the scanning route direction is along the weft (lat) direction; if T _ lon > T _ lat, scanning the route direction along the meridian (lon) direction;

step S204, determining node position information of a flight route of the unmanned aerial vehicle in the imaging area according to the route direction determined in the step S203 and by combining the area of the target area, the width of the surveying and mapping belt and the projection distance, wherein the node comprises a starting point and an end point;

specifically, it is known that: slope distance SR, beam center ground wiping angleAnd the height H of SAR relative to the target area_w(input parameters), projection distance(derived parameter), T_sIs the starting point of the scanning area (estimated parameter), and the scanning route interval is S _ W (estimated parameter), as shown in fig. 2.

1. When the scanning route is along the meridian (lon),

number of scanning linesi∈(0，1…N-1)

The number N of the scanning route is the area of the target area divided by the area swept by the single scanning route and rounded up

Wherein the area swept by the single scan path is: s _ S is S _ W · T _ lon, i denotes the ith lane

When i is an even number:

latitude of origin i of the course: t is_s(lat)；

Latitude of route end i:T_e(lat)；

the machine head points at: pointing to the lane ending point i.

When i is an odd number:

latitude of origin i of the course: t is_e(lat)；

Latitude of route end i: t is_s(lat)；

The machine head points at: pointing to the starting point i of the flight path.

The longitude of the starting point i and the ending point i of the route is given by:

T_s(lon)±(R_c-S _ W/2+ i S _ W) (S-shaped scan)

When P is present_home(lon)＞T_s(lon), then take "+", when P is_home(lon)＜＝T_s(lon), then take "-";

specifically, the longitude of the starting point i and the ending point i of the route: the longitude of the scanning starting point of the target area, the projection distance of the skew distance and the width of the surveying strip are determined together.

The height of the air route: h_w+ (height of starting point i of swath centerline + height of ending point i of swath centerline)/2.

2. The scanning line being in the direction of the weft (lat)

Number of scanning linesi∈(0，1…N-1)

The number N of the scanning route is the area of the target area divided by the area swept by the single scanning route and rounded up

Wherein the area swept by the single scan path is: s _ S is S _ W · T _ lat, i denotes the ith lane

The latitude of the starting point i and the ending point i of the route is obtained by the following formula:

T_s(lat)±(R_c-S _ W/2+ i · S _ W) (sigmoid scan);

when P is present_home(lat)＞T_s(lat), then take "+"; when P is present_home(lat)＜＝T_s(lat), then take "-";

specifically, the latitude of the starting point i and the ending point i of the route: the latitude of the scanning starting point of the target area, the projection distance of the slant distance and the width of the mapping strip are determined together;

when i is an even number:

longitude of the origin i of the flight: t is_s(lon)；

Longitude of airline destination i: t is_e(lon)；

The machine head points at: pointing to a route terminal i;

when i is an odd number:

longitude of the origin i of the flight: t is_e(lon)；

Longitude of airline destination i: t is_s(lon)；

The machine head points at: pointing to the starting point i of the flight path.

Height of the flight path: h_w+ (height of swath centerline start point i + height of swath centerline end point i)/2;

imaging area carrier horizontal speed: rho_r-＞V_{work_H}。

S205, determining the flight path parameters of the unmanned aerial vehicle platform in the approach section;

the method specifically comprises the following steps:

according to known parameters: origin of flight point longitude and latitude P_home(lon, lat) (platform auto acquire), imaging region first start and height T_s(h)；

Determining an inflection point: p_turning(lon, lat, h), wherein,

turning point height: p_turning(h)＝T_s(h)*0.5；

Turning point meridian, latitude: p_turning(lon，lat)＝P_home(lon，lat)

S206, separating the section route parameters;

the parameters are the same as the parameters of the route of the approach segment, wherein the fixed parameters of the segment comprise:

vertical speed of approach section: v_{approach_V}；

Horizontal speed of approach section: v_{approach_H}；

Vertical speed of disengagement section: v_{disengage_V}；

Disengagement sectionHorizontal velocity: v_{disengage_H}＝V_{approach_H}。

Step S3, determining the roll angle and the pitch angle of the antenna servo control module according to the position information of the starting point and the end point of the central line of the surveying and mapping belt;

specifically, the position information of the start point and the end point of the center line of the swath is obtained by the following method:

1. when the centerline of the swath is along the warp (lon) direction;

number of scanning lines

i belongs to (0, 1 … N-1) (N is the number of strips of the center line of the surveying and mapping belt)

When i is an even number:

latitude of starting point i of center line of swath: t is_s(lat)

Latitude of the center line terminal point i of the mapping band: t is_e(lat)

When i is an odd number:

latitude of starting point i of center line of swath: t is_e(lat)

Latitude of the center line terminal point i of the mapping band: t is_s(lat)

The longitude of the starting point i and the ending point i of the center line of the swath is given by:

T_s(lon) ± (-S _ W/2+ i. S _ W) (S-shaped scanning)

When P is present_home(lon)＞＝T_s(lon), then take "+", when P is_home(lon)＜＝T_s(lon), then take "-";

specifically, the longitude of the starting point i and the ending point i of the center line of the swath: the longitude of the scanning starting point of the target area, the projection distance of the skew distance and the width of the mapping strip are determined together;

height of starting point i and ending point i of center line of surveying and mapping band: map acquisition (altitude).

2. When the swathe centerline is in the weft (lat) direction;

number of central lines of surveying and mapping belt

i belongs to (0, 1 … N-1) (N is the number of strips of the center line of the surveying and mapping belt)

Latitude of starting point i and ending point i of the center line of the mapping strip: t is_s(lat) + - (-S _ W/2+ i. S _ W) (S-shaped scanning)

When P is present_home(lat)＞T_s(lat), then get "+".

When P is present_home(lat)＜＝T_s(lat), then get "-".

I.e. latitude of starting point i and ending point i of the swath centerline: the latitude of the scanning starting point of the target area, the projection distance of the slant distance and the width of the mapping strip are jointly determined

When i is an even number:

longitude of swath centerline origin: t is_s(lon)

Longitude of swath centerline endpoint: t is_e(lon)

When i is an odd number:

longitude of the origin of the flight path: t is_e(lon)

Longitude of airline destination: t is_s(lon)

Height of starting point i and ending point i of center line of surveying and mapping band: map acquisition (altitude)

More specifically, the antenna servo control module controls the roll angle and the pitch angle of the holder so as to control the SAR beam to point to a target area, when the SAR beam approaches the section and leaves the section, the SAR subsystem does not work, and for reducing wind resistance and ensuring the landing and taking-off postures to be stable, so roll is 0 degrees, pitch is 0 degrees, namely the holder keeps the initial position.

When in the imaging zone, the roll angle roll is determined by the height of the start and end points of the swath centerline and the projected distance between them. If the absolute value of the roll is greater than the maximum limit value max _ roll of the antenna servo control module, the value of the roll max _ roll is taken, and the sign of the value remains unchanged.

When in the imaging area, roll ═ arctan [ (start point i (h) -end point i (h))/Distance (start point i (lat, lon), end point i (lat, lon)) ], and if abs (roll) > (max _ roll (fixed parameter), then roll ═ max _ roll.

The pitch is obtained by resolving an algorithm in an antenna servo control module, and input parameters required by the algorithm are longitude, latitude and height of a starting point i and an ending point i of a central line of the surveying and mapping band.

And step S4, determining the azimuth resolution, the starting position and the closing position of the imaging subsystem in the imaging area according to the distance resolution and the node position information of the flight path of the unmanned aerial vehicle in the imaging area.

Specifically, the parameters are known: distance resolution ρ r (input parameter), imaging area scanning course starting point i and ending point i (estimated parameter), estimated parameter: azimuthal resolution ρ_aStarting position P_{SAR_on}And a shutdown position P_{SAR_off}(ii) a The method comprises the following specific steps:

ρ_a＝ρ_r

P_{SAR_on}starting point i of scanning route

P_{SAR_off}Scanning route end point i

The invention is not described in detail, but is well known to those skilled in the art.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.