A ground precise positioning method based on fireproof monitoring video

Abstract

The application discloses a kind of ground accurate positioning method based on fire prevention monitoring video, comprising: S1: the pan-tilt for observing monitoring area is laid out;S2: the DEM data of monitoring area is acquired;S3: the attitude data generated when RTK unmanned aerial vehicle observation falls into specified position is determined by pan-tilt, and the pan-tilt attitude parameter calibration value is determined;S4: when fire occurs, pan-tilt is aimed at fire point, and the position of fire point is determined based on DEM data, pan-tilt attitude parameter calibration value, pan-tilt real-time PT value.The application is based on fire prevention monitoring video, realizes the accurate positioning of fire point, is not influenced by weather, illumination and other factors, with all-weather nature.The application can obtain the position of fire point within several seconds through the observation of real-time camera and the real-time calculation of fire point accurate positioning service, and the positioning speed is fast.

Description

Technical Field

[0001] This invention relates to the field of fire location, and in particular to a ground-based precise location method based on fire monitoring video. Background Technology

[0002] Fires are one of the most common, prominent, and devastating disasters in real life, directly impacting people's lives and property. Forest fires are particularly prone to occur in high-risk areas, making their monitoring and prevention especially crucial. In recent years, the global greenhouse effect has intensified, extreme weather events have become more frequent, and the frequency of fires has increased dramatically.

[0003] Due to the uncertainty of fire occurrence times, fire monitoring and location require 24 / 7 capability. For fire prevention, adhering to the principle of "nipping it in the bud and extinguishing it early," controlling the spread of fire as early as possible and reducing fire losses also necessitates timeliness. Precise fire location helps fire departments and emergency rescue teams accurately pinpoint the fire's location and take timely countermeasures to control the fire; therefore, fire prevention also requires precision. Given the wide scope and long duration of fire monitoring, how to conduct this work at a low cost is also a matter worthy of careful consideration. Addressing these characteristics and requirements of fire monitoring and location, this invention proposes a 24 / 7, low-cost, easy-to-operate, fast, and high-precision ground-based precise location method based on fire monitoring video.

[0004] Traditional fire location techniques are typically based on ground observation and data processing, including the following methods:

[0005] 1. Manual observation method: Professional personnel regularly patrol the area under their jurisdiction. Upon discovering a fire, they observe along the edge of the fire zone or surrounding high points, using telescopes, optical instruments, and other means to determine the location of the fire. This method not only requires a large amount of manpower and resources but also relies on manual observation and judgment, which involves subjective factors and is prone to location errors.

[0006] 2. Aerial observation method: This method utilizes aircraft such as helicopters and airplanes for aerial observation, determining the location of the fire through visual inspection or photography. However, this method is susceptible to factors such as weather, terrain, and lighting conditions, and is prone to blind spots or dead zones.

[0007] 3. Satellite Remote Sensing: This method utilizes satellite remote sensing technology to acquire the infrared spectral characteristics of the fire area. Combined with geographic information systems and other technologies, data analysis and processing are performed to determine the fire's location. However, satellite remote sensing data acquisition intervals are relatively long. For example, the sampling interval for images from the domestic Himawari-8 satellite is at least 10 minutes, making real-time data acquisition impossible and resulting in low positioning efficiency, which cannot meet the needs of rapid response. Furthermore, its positioning accuracy is low and cannot meet the requirements for high-precision positioning.

[0008] 4. Traditional ground-based positioning method for fire monitoring videos: This method uses 3D reconstruction technology to determine the object's position in 3D space based on its coordinates in the image coordinate system and the camera's intrinsic and extrinsic parameters. Then, based on the object's position in space, combined with map information and GPS positioning technology, the object is precisely located on the ground. This method utilizes multiple technologies, resulting in a complex technical system and high cost.

[0009] None of the aforementioned technologies can simultaneously meet the requirements of all-weather, low-cost, easy-to-operate, fast, and high-precision fire point location. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides an all-weather, low-cost, easy-to-operate, fast, and high-precision ground positioning method based on fire monitoring video.

[0011] This invention discloses a ground-based precise positioning method based on fire monitoring video, comprising:

[0012] S1: Deploy pan-tilt units for observation and monitoring of the area;

[0013] S2: Obtain DEM data for the monitored area;

[0014] S3: Determine the gimbal attitude parameter calibration value by using the attitude data generated when the gimbal observes the RTK drone falling into the designated location;

[0015] S4: When a fire is detected, the gimbal aims at the fire point and determines the location of the fire point based on DEM data, gimbal attitude parameter calibration values, and gimbal real-time PT values.

[0016] Further, step S1 includes:

[0017] The pan-tilt unit is installed on the fire tower and connected to the fire monitoring and command center via a private network or wide area network.

[0018] Further, step S2 includes:

[0019] DEM data used to describe the elevation information of the terrain surface has a horizontal resolution of within 12.5 meters and a vertical accuracy of within 5 meters.

[0020] Further, step S3 includes:

[0021] S301: The drone equipped with RTK moves to the gimbal and determines the coordinates of the gimbal in three-dimensional geodetic coordinates.

[0022] S302: Determine the three-dimensional station center coordinate system centered on the gimbal, and the coordinate system transformation relationship between the three-dimensional station center coordinate system and the three-dimensional geodetic coordinate system;

[0023] S303: Deploy space observation points so that the gimbal can observe all space observation points;

[0024] S304: Control the UAV to land at the space observation point and obtain the PT value of the UAV at each location when the gimbal observes the UAV;

[0025] S305: Establish a gimbal attitude parameter correction model and calculate the gimbal attitude parameter calibration values.

[0026] Further, step S3 01 specifically includes:

[0027] Control the RTK drone to fly to the same height as the gimbal, and obtain the altitude of the RTK drone, which is the gimbal elevation H; control the RTK drone to fly to the vertical top of the gimbal, and obtain the latitude and longitude of the RTK drone, which are the gimbal latitude B and gimbal longitude L.

[0028] Furthermore, step S303 specifically includes:

[0029] In the three-dimensional station-centered coordinate system, a spatial observation point is set up at 30-degree intervals on the same horizontal plane as the gimbal. Furthermore, a spatial observation point is set up at 60-degree intervals on horizontal planes with pitch angles of -3 degrees, -6 degrees, and 3 degrees, respectively. The initial horizontal angle is set to 0 degrees by default. The observation distance between the spatial observation point and the gimbal ranges from 100 to 300 meters.

[0030] Specifically, the specific observation distance and starting horizontal angle are determined based on DEM data to ensure that the gimbal can observe all spatial observation points. Furthermore, the observation distance should be selected as large as possible within the range to reduce the impact of UAV position jitter on pitch or azimuth calculations.

[0031] Further, step S304 specifically includes:

[0032] Based on the coordinate system transformation relationship, the coordinate information of the spatial observation point is converted from the three-dimensional station-centered coordinate system to the geodetic coordinate system supported by the RTK UAV. The RTK UAV then lands on the spatial observation point based on the transformed coordinates.

[0033] Control the gimbal to observe the RTK drone, ensuring that the center of the gimbal's view is aligned with the RTK drone, and obtain the PT value of the gimbal during observation.

[0034] Further, step S305 specifically includes:

[0035] Establish a gimbal attitude parameter correction model and calculate the gimbal attitude calibration parameters. θ, β, ω c , σ c);in, θ The elevation angle is the direction of maximum tilt of the gimbal's rotation surface. β The azimuth angle is the direction of maximum tilt of the gimbal's rotation plane. ω c This is the azimuth constant correction value for gimbal observation. σ c This is the constant correction value for the elevation angle observed by the gimbal;

[0036] The corrected model formula is:

[0037] (5-1)

[0038] (5-2)

[0039] (5-3)

[0040] (5-4)

[0041] (5-5)

[0042] (5-6)

[0043] in, ω 真 and σ 真 These are the actual PT values ​​of the observation points in the gimbal observation space, calculated from the coordinates of the observation points and the gimbal coordinates. ω 测 and σ 测 These are the PT values ​​directly obtained from the gimbal when the gimbal observes the RTK drone falling into the space observation point;

[0044] Combining Equation 5-1, substituting the observed values, and taking the result that minimizes the root mean square error of the model ( σ c , β , θ The value is used as the solution result; the formula for calculating the root mean square error is: (5-7)

[0045] Where Δ is the difference between the actual observed pitch angle and the pitch angle calculated by the model;

[0046] Similarly, combining Equation 5-2, substitute the observed values ​​and take the result that minimizes the root mean square error of the model. ω c The value is used as the solution result, where Δ is the difference between the actual observed azimuth angle and the azimuth angle calculated by the model.

[0047] Further, step S4 includes:

[0048] When a fire occurs, the pan-tilt-zoom (PTZ) equipment in the fire prevention command center, equipped with a video monitoring terminal, can automatically identify the fire point, or the fire point can be identified manually.

[0049] After identifying the fire point, the center of the video frame can be automatically or manually aimed at the fire point, and the fire point precise positioning service can be informed that the pan-tilt device has observed a fire and needs to calculate the fire point location.

[0050] The fire point precise location service obtains the PT value of the pan-tilt unit that observes the fire in real time, and calculates its true PT value based on Equations 5-1 and 5-2;

[0051] The precise fire point location service uses real PT values ​​and DEM data, combined with the line-of-sight principle and trigonometric functions, to calculate the fire point location.

[0052] Furthermore, the method also includes:

[0053] S5: After obtaining the location of the fire, the fire command center notifies the relevant fire departments to carry out subsequent fire control work.

[0054] The present invention has at least the following beneficial effects:

[0055] (1) The present invention is based on the realization of fire monitoring video to accurately locate the fire point, which is not affected by weather, light and other factors, and has all-weather capability.

[0056] (2) In actual verification, under good observation conditions, the final positioning accuracy of the fire point 3 kilometers away from the gimbal is within 100m error, which shows that the invention has high precision.

[0057] (3) The present invention can obtain the location of the fire point within a few seconds through real-time camera observation and real-time calculation of the fire point precise positioning service, and the positioning speed is fast.

[0058] (4) After a fire occurs, the present invention only requires the user to control the center of the pan-tilt-zoom screen to aim at the fire point, and the location of the fire point can be obtained through the fire point precise positioning service. The operation is simple and convenient.

[0059] (5) The invention has low construction cost and long service life.

[0060] Other beneficial effects of the present invention will be described in detail in the Detailed Description of the Embodiments section. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a flowchart of the ground-based precise positioning method based on fire monitoring video disclosed in this invention.

[0063] Figure 2 This is a flowchart illustrating the technical implementation of the ground-based precise positioning method based on fire monitoring video disclosed in this invention.

[0064] Figure 3 This is a schematic diagram of P-value observation.

[0065] Figure 4 This is a schematic diagram of T-value observation.

[0066] Figure 5 This is a diagram illustrating the installation of the gimbal.

[0067] Figure 6 This is a diagram illustrating the network connection of a PTZ device.

[0068] Figure 7 This is a schematic diagram of the station-centered coordinate system.

[0069] Figure 8 A schematic diagram of the layout of space observation points.

[0070] Figure 9 A diagram showing the gimbal center aiming at the drone.

[0071] Figure 10 A diagram showing how to center the gimbal and aim it at the fire point.

[0072] Figure 11 Schematic diagram of the principle for precise fire point location service.

[0073] Figure 12 Calculation logic diagram for precise fire point location service. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0075] like Figure 1The method for precise ground positioning based on fire monitoring video, as shown, includes:

[0076] S1: Deploy pan-tilt units for observation and monitoring of the area;

[0077] S2: Obtain DEM data for the monitored area;

[0078] S3: Determine the gimbal attitude parameter calibration value by using the attitude data generated when the gimbal observes the RTK drone falling into the designated location;

[0079] S4: When a fire is detected, the gimbal aims at the fire point and determines the location of the fire point based on DEM data, gimbal attitude parameter calibration values, and gimbal real-time PT values. Example

[0080] like Figure 2 As shown, the technical implementation process of this invention mainly includes: the construction of basic engineering for PTZ (video surveillance) equipment connected to a private network or wide area network; aiming the center of the PTZ monitoring screen at the fire point (target point) and obtaining the PT value of the PTZ at this time; calibrating the attitude parameters of each PTZ based on a UAV with RTK, including measuring the geographic three-dimensional coordinates of the PTZ and calculating the calibration model parameters of the PTZ (azimuth angle, pitch angle); acquiring high-precision DEM data; transmitting the PTZ coordinates and real-time PT value to the fire point precise positioning service (server); and calculating the three-dimensional coordinates (B, L, H) of the fire point.

[0081] The present invention will now be described in detail step by step:

[0082] Step 1

[0083] The basic engineering construction for PTZ devices connected to private networks or wide area networks includes the selection of PTZ devices, the selection of the number and location of PTZ devices, network cabling, network equipment selection, and the installation and debugging of PTZ devices.

[0084] like Figure 5 As shown, the pan-tilt unit (PTZ) is typically installed on top of a fire tower. Its lens can rotate 360 ​​degrees horizontally and 180 degrees vertically, ensuring observation of ground targets. The PTZ has built-in attitude sensing capabilities, allowing it to acquire the two angle values ​​mentioned above, commonly referred to in this field as PT values. The P value starts at 0 degrees north on a horizontal plane and increases clockwise, ranging from [0, 360]. The T value starts at 0 degrees horizontally on a vertical plane and increases upwards and decreases downwards, ranging from [-90, 90]. See also... Figure 3 The diagram showing the observation of the P-value and Figure 4 The diagram illustrating the T-value observation.

[0085] Pan-tilt units (PTZ) are typically installed on top of fire-resistant towers, 20-35 meters above the ground. In China, Hikvision and Dahua are the most common manufacturers. Thermal infrared (TII) type equipment is recommended because infrared thermal radiation has a stronger ability to penetrate fog, haze, rain, and snow than visible light, and its observation effect is almost unaffected under adverse weather conditions. The installation of the PTI should ensure that its horizontal rotation plane is as level as possible.

[0086] Fire suppression towers are typically evenly distributed throughout the monitoring area to ensure comprehensive coverage of the entire area. The placement of these towers should ideally be at a high vantage point within the area. This not only increases the effective field of view of a single pan-tilt unit but also improves the accuracy of fire location calculations.

[0087] The PTZ (pan-tilt-zoom) device connects to the fire prevention monitoring and command center via a private network or wide area network. The fire prevention monitoring and command center can then obtain real-time monitoring images and PTZ device parameter information through this network. (See also...) Figure 6 The diagram shows the network access of the PTZ device.

[0088] The PTZ cameras connected to the network need to be debugged so that end users in the network can obtain their monitoring screens and PT values ​​in real time and confirm their operational stability.

[0089] Step Two

[0090] Acquisition of high-precision DEM data. DEM data, short for Digital Elevation Model, is a type of digital terrain model data that describes the elevation information of the Earth's surface. DEM data consists of a series of grid cells, each containing an elevation value. The elevation value H of each geographic point (B, L) within the data range can be obtained from the DEM data. DEM data is typically collected from data sources such as radar, laser scanning, and satellite mapping. The high precision required in this embodiment not only requires high horizontal resolution (ideally within 12.5m) but also high vertical accuracy (ideally within 5m error). High-precision DEM data can be obtained and authorized from relevant surveying and mapping departments. Regarding the coordinate system, the geographic coordinate system of the DEM data needs to be supported by an RTK drone. If not, the DEM data needs to be converted to a geographic coordinate system supported by the RTK drone.

[0091] Step 3

[0092] This involves calibrating gimbal attitude parameters using a drone equipped with RTK (Real-Time Kinematic) technology. An RTK drone is a high-precision GPS positioning device capable of centimeter-level positioning accuracy. By flying the RTK drone to a specific point in space, its 3D geodetic coordinates (B, L, H) can be obtained in real-time via a companion app or handheld device. Alternatively, the 3D geodetic coordinates (B, L, H) can be preset to guide the RTK drone to that location.

[0093] The specific steps for calibrating gimbal attitude parameters include:

[0094] a. Determine the three-dimensional coordinates (B, L, H) of the gimbal. Fly the RTK drone to the same height as the gimbal and obtain its altitude H. Fly the drone to the vertical top of the gimbal and obtain its B and L coordinates. To ensure high-precision positioning of the fire point, the measurement accuracy of B and L needs to be within decimeters, and the measurement accuracy of H needs to be within centimeters.

[0095] b. Establish a three-dimensional station-centered coordinate system (ENU) with the pan-tilt unit as the center, and establish the transformation relationship between this station-centered coordinate system (ENU) and the geodetic coordinate system (BLH) to facilitate subsequent calculations. The transformation formula is a general formula and will not be elaborated here. See the schematic diagram of the station-centered coordinate system. Figure 7 .

[0096] c. Spatial observation point setup for establishing the gimbal PT value calibration model. Subsequently, the UAV will be launched sequentially at these observation points, and the gimbal will be used for observation. In the three-dimensional station-centered coordinate system (ENU), observation points will be set up at 30-degree intervals on the same horizontal plane as the gimbal. Additionally, observation points will be set up at 60-degree intervals on horizontal planes with pitch angles of -3 degrees, -6 degrees, and 3 degrees. The initial horizontal angle is set to 0 degrees by default, but this value can be adjusted flexibly to ensure that the observation points are above the ground and that the line of sight is unobstructed. The angles set here represent the true PT value, and the true P value is set to... ω 真 The actual T value is σ 真 The distance between the observation point and the gimbal is called the observation distance, which is planned within the range of 100-300m. While ensuring the observation point is above the ground and the line of sight is unobstructed, the observation distance should be as close to 300m as possible. This ensures easy adjustment of the gimbal image to locate the drone and reduces the impact of drone positional jitter caused by external factors such as wind on pitch or azimuth angle calculations. The selection of the observation distance and the horizontal starting angle of the observation point can be achieved using the acquired DEM data, considering the unobstructed line of sight to ensure that all planned points can be observed. The point layout is as follows... Figure 8 As shown, for easy viewing, Figure 8 The image only shows the placement points in the 0-degree and 3-degree pitch directions. After placement, the points need to be converted to the geodetic coordinate system supported by the RTK drone to facilitate drone landing.

[0097] d. Obtain the PT value of the gimbal observation at each spatial observation point. Sequentially land the UAV at each planned spatial observation point, and control the gimbal to center the view on the UAV (see...). Figure 9 Simultaneously, the PT value is acquired in real time from the PT device. PT control can be achieved using the PT device's accompanying terminal, or by developing a custom terminal program based on the PT device manufacturer's SDK. Here, the P value is set to... ω 测 The value of T is σ 测 .

[0098] e. Establish a gimbal attitude parameter correction model and calculate the gimbal attitude calibration parameters. θ, β, ω c , σ c ).in θ The elevation angle is the direction of maximum tilt of the gimbal's rotation surface. β The azimuth angle is the direction of maximum tilt of the plane of rotation. ω c This is the azimuth constant correction value for gimbal observation. σ c This is the constant correction value for the pitch angle observed by the gimbal.

[0099] The corrected model formula is:

[0100] (5-1)

[0101] (5-2)

[0102] in:

[0103] (5-3)

[0104] (5-4)

[0105] (5-5)

[0106] (5-6)

[0107] Combining Equation 5-1, substituting the observed values, and taking the result that minimizes the root mean square error of the model ( σ c , β , θThe value is used as the solution result. The formula for calculating the root mean square error is:

[0108] (5-7)

[0109] Where Δ is the difference between the actual observed pitch angle and the pitch angle calculated by the model.

[0110] Using the same method, and combining Equation 5-2, substitute the observed values ​​and take the result with the minimum root mean square error of the model. ω c The value is used as the solution result. Here, Δ refers to the difference between the actual observed azimuth angle value and the azimuth angle value calculated by the model.

[0111] Step Four

[0112] The fire point location (B, L, H) values ​​are calculated in real time based on the fire point precise location service.

[0113] The fire point precise positioning service is deployed on the server. It can combine DEM data, gimbal attitude calibration parameter values, and real-time PT values ​​obtained from the gimbal to calculate the fire point location, providing users with a real-time online interface capability to calculate the fire point location observed by each gimbal device.

[0114] When a fire occurs, the pan-tilt-zoom (PTZ) equipment and video monitoring terminal in the fire prevention command center can automatically or manually identify the fire point. After identifying the fire point, the video feed can be automatically or manually centered on the fire point (see [link to relevant documentation]). Figure 10 The system notifies the PT (Potential Dynamics) device that it has detected a fire and needs to calculate the fire's location. The PT service obtains the PT value of the PT device in real time and calculates its true PT value using equations 5-1 and 5-2. The PT service then uses the true PT value and DEM (Digital Elevation Model) data, combined with the line-of-sight principle and trigonometric functions, to calculate the fire's location.

[0115] See Figure 11 and Figure 12 The calculation logic for precise fire point location service includes:

[0116] (1) The distance increment step in the observation direction is 1 / 2 of the resolution of the DEM data, and is set as dS.

[0117] (2) The elevation error threshold is set to dH and initialized to 1m.

[0118] (3) Make an observation ray from the gimbal S, and gradually increase the observation distance dS.

[0119] (4) Judgment: If the observation radius of the gimbal exceeds the range, proceed to (5); otherwise, proceed to (6).

[0120] (5) Increase the dH value by 2 and return to (2).

[0121] (6) Calculate the target point L(B,L,H) using trigonometric functions, based on the actual PT value.

[0122] (7) Calculate the elevation h corresponding to point P(B,L) from the DEM, based on the DEM data of the monitored area.

[0123] (8) Determine whether the absolute value of the difference between H and h is less than dH. If yes, proceed to (9); otherwise, return to (3).

[0124] (9) The values ​​of B, L, and h are the required values.

[0125] Once the fire command center receives the fire location calculated by the precise fire location service, it notifies the fire department and other relevant responsible departments to carry out subsequent fire control work.

[0126] Using the method disclosed in this embodiment, gimbal device attitude parameter calibration is performed based on an RTK-equipped UAV. Practical verification shows that the calibrated gimbal device's three-dimensional coordinate accuracy is at the centimeter level, the pitch angle error is within 0.2 degrees, and the azimuth angle error is within 0.5 degrees, thus ensuring the accuracy of the final fire point location. This embodiment uses real-time video for fire point location, ensuring the timeliness of the location.

[0127] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A ground-based precise positioning method based on fire monitoring video, characterized in that, include: S1: Deploy pan-tilt units for observation and monitoring of the area; S2: Obtain DEM data for the monitored area; S3: Determine the gimbal attitude parameter calibration value by using the attitude data generated when the gimbal observes the RTK drone falling into the designated location; Step S3 includes: S301: The UAV with RTK moves to the gimbal and determines the coordinates of the gimbal in the three-dimensional geodetic coordinate system. S302: Determine the three-dimensional station center coordinate system centered on the gimbal, and the coordinate system transformation relationship between the gimbal three-dimensional coordinate system and the three-dimensional geodetic coordinate system; S303: Deploy space observation points so that the gimbal can observe all space observation points; S304: Control the UAV to land at the space observation point and obtain the PT value of the UAV at each location when the gimbal observes the UAV; S305: Establish a gimbal attitude parameter correction model and calculate the gimbal attitude parameter calibration values; Step S305 specifically includes: Establish a gimbal attitude parameter correction model and solve for the gimbal attitude calibration parameters. θ, β, ω c , σ c );in, θ The elevation angle is the direction of maximum tilt of the gimbal's rotation surface. β The azimuth angle is the direction of maximum tilt of the gimbal's rotation plane. ω c This is the azimuth constant correction value for gimbal observation. σ c This is the constant correction value for the elevation angle observed by the gimbal; The corrected model formula is: (5-1) (5-2) (5-3) (5-4) (5-5) (5-6) in, ω 真 and σ 真 These are the actual PT values ​​of the observation points in the gimbal observation space, calculated from the coordinates of the observation points and the gimbal coordinates. ω 测 and σ 测 These are the PT values ​​directly obtained from the gimbal when the gimbal observes the RTK drone falling into the space observation point; Combining Equation 5-1, substituting the observed values, and taking the result that minimizes the root mean square error of the model ( σ c , β , θ The value is used as the solution result; the formula for calculating the root mean square error is: (5-7) Where Δ is the difference between the actual observed pitch angle and the pitch angle calculated by the model; Similarly, combining Equation 5-2, substitute the observed values ​​and take the result that minimizes the root mean square error of the model. ω c The value is used as the solution result, where Δ is the difference between the actual observed azimuth angle value and the azimuth angle value calculated by the model. S4: When a fire is detected, the gimbal aims at the fire point and determines the location of the fire point based on DEM data, gimbal attitude parameter calibration values, and gimbal real-time PT values.

2. The ground-based precise positioning method based on fire monitoring video according to claim 1, characterized in that, Step S1 includes: The pan-tilt unit is installed on the fire tower and connected to the fire monitoring and command center via a private network or wide area network.

3. The ground-based precise positioning method based on fire monitoring video according to claim 1, characterized in that, Step S2 includes: DEM data used to describe the elevation information of the terrain surface has a horizontal resolution of within 12.5 meters and a vertical accuracy of within 5 meters.

4. The ground-based precise positioning method based on fire monitoring video according to claim 1, characterized in that, Step S301 specifically includes: Control the RTK drone to fly to the same height as the gimbal, and obtain the altitude of the RTK drone, which is the gimbal elevation H; control the RTK drone to fly to the vertical top of the gimbal, and obtain the latitude and longitude of the RTK drone, which are the gimbal latitude B and gimbal longitude L.

5. The ground-based precise positioning method based on fire monitoring video according to claim 4, characterized in that, Step S303 specifically includes: In the three-dimensional station-centered coordinate system, a spatial observation point is set up at 30-degree intervals on the same horizontal plane as the gimbal. Furthermore, a spatial observation point is set up at 60-degree intervals on horizontal planes with pitch angles of -3 degrees, -6 degrees, and 3 degrees, respectively. The initial horizontal angle is set to 0 degrees by default. The observation distance between the spatial observation point and the gimbal ranges from 100 to 300 meters. Specifically, the specific observation distance and starting horizontal angle are determined based on DEM data to ensure that the gimbal can observe all spatial observation points. Furthermore, the observation distance should be selected as large as possible within the range to reduce the impact of UAV position jitter on pitch or azimuth calculations.

6. The ground-based precise positioning method based on fire monitoring video according to claim 5, characterized in that, Step S304 specifically includes: Based on the coordinate system transformation relationship, the coordinate information of the spatial observation point is converted from the three-dimensional station-centered coordinate system to the geodetic coordinate system supported by the RTK UAV. The RTK UAV then lands on the spatial observation point based on the transformed coordinates. Control the gimbal to observe the RTK drone, ensuring that the center of the gimbal's view is aligned with the RTK drone, and obtain the PT value of the gimbal during observation.

7. The ground-based precise positioning method based on fire monitoring video according to claim 1, characterized in that, Step S4 includes: When a fire occurs, the pan-tilt-zoom (PTZ) equipment in the fire prevention command center, equipped with a video monitoring terminal, can automatically identify the fire point, or the fire point can be identified manually. After identifying the fire point, the center of the video frame can be automatically or manually aimed at the fire point, and the fire point precise positioning service can be informed that the pan-tilt device has observed a fire and needs to calculate the fire point location. The fire point precise location service obtains the PT value of the pan-tilt unit that observes the fire in real time, and calculates its true PT value based on Equations 5-1 and 5-2; The precise fire point location service uses real PT values ​​and DEM data, combined with the line-of-sight principle and trigonometric functions, to calculate the fire point location.

8. The ground-based precise positioning method based on fire monitoring video according to claim 1, characterized in that, The method also includes: S5: After obtaining the location of the fire, the fire command center notifies the relevant fire departments to carry out subsequent fire control work.

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