Unmanned aerial vehicle height early warning and recovery method based on multi-source height
By using a multi-source altitude fusion algorithm to calculate the unmanned aerial vehicle (UAV) airport altitude in real time and provide audible and visual alarms, the problem of relying on operator experience for altitude judgment when UAVs are flying in mountainous areas has been solved, enabling safe early warning and efficient recovery of UAVs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN AISHENG TECH GRP
- Filing Date
- 2026-01-04
- Publication Date
- 2026-05-05
AI Technical Summary
When existing drones fly in mountainous or geographically confined areas, altitude judgment relies on operator experience and lacks clear warnings, increasing flight safety risks. Drone recovery route planning also relies on operator experience, making it prone to misoperation and requiring frequent adjustments.
The drone's altitude is calculated in real time using a multi-source altitude fusion algorithm. Combined with the altitude of terrain points, it provides audible and visual alarms and autonomously controls the drone to avoid danger and adaptively adjust the recovery route when the operator does not react.
It enables real-time early warning of drone flight altitude and safe recovery, reducing operator workload and improving flight safety and recovery accuracy.
Smart Images
Figure CN121979256A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of unmanned aerial vehicle (UAV) control technology, specifically to a method for UAV altitude warning and recovery based on multi-source altitude. Background Technology
[0002] Fixed-wing drones are widely used in civilian applications. During missions, they often fly in mountainous or geographically confined areas. In such situations, emergency maneuvers to avoid risks due to low flight altitude are typically performed by operators based on experience. Currently, terrain altitude is determined by operators observing contour maps, which is not clear or intuitive enough. Safety strategies lack geographically specific operational standards for drones, and there are insufficient and unclear warnings for operators when drones fly too low. If operators fail to detect and control the aircraft in time, the risk of drones crashing into mountains or flying too low increases, seriously threatening drone flight safety.
[0003] Unmanned aerial vehicle (UAV) systems typically employ runway takeoff and landing (LATCH) and parachute descent methods for UAV recovery. During parachute descent recovery, the attitude, altitude, speed, stopping point, and parachute deployment point of the UAV are controlled by planning the recovery route. Generally, the recovery route consists of eight points. Points 1-3 are primarily used to adjust the UAV, ensuring it reaches the stopping and parachute deployment points with optimal attitude, altitude, and speed. Point 4 is the stopping point; upon reaching point 4, the UAV shuts down its engine and glides forward without power. Point 5 is the parachute deployment point; upon reaching point 5 in a stopped state, the parachute opens, allowing the UAV to land. Points 6-8 are backup waypoints; if the UAV fails to meet the recovery conditions between points 1-3, it will not stop or deploy its parachute at points 4 and 5, but will exit the recovery state according to the planned route from points 6-8, and will be recovered again at a later time.
[0004] Currently, drone recovery route planning primarily involves operators inputting the air pressure and altitude of the route, selecting various waypoints on a map, and generating a recovery model based on the input wind speed, wind direction, and drone entry angle. This method relies heavily on operator experience and judgment, making it prone to errors. Furthermore, because real-time wind speed, wind direction, and drone entry angle frequently change, operators need to constantly modify the recovery route during the recovery phase, placing a significant operational burden on them. Summary of the Invention
[0005] To address the shortcomings of the aforementioned background technology, this invention provides a method for UAV altitude warning and recovery based on multi-source altitude. This method integrates the UAV's multi-source altitude and the altitude of the terrain point at its current location in real time to calculate the UAV's current field altitude. If the UAV's current field altitude falls within an alarm threshold or a danger threshold, an alarm is issued to the operator via the ground control vehicle's audio-visual system and a text alarm is displayed on the user interface. If the operator fails to take any evasive action, the method controls the UAV to avoid danger based on the current situation. Furthermore, based on the UAV's multi-source altitude and other telemetry parameters, the method integrates the UAV's multi-source altitude in real time to calculate the UAV's stopping point and parachute deployment point. Upon reaching the stopping point and parachute deployment point, the method executes stopping and parachute deployment commands accordingly.
[0006] The first objective of this invention is to provide a method for early warning and recovery of unmanned aerial vehicles (UAVs) based on multi-source altitude, comprising: During flight, the drone collects real-time data on its current position, weight, real-time wind speed, the angle between wind direction and drone speed, and altitude. The drone's altitude data includes barometric altitude, satellite altitude, and radio altitude. Load the regional map elevation data in TIFF format and obtain the elevation of terrain points; Record 20 consecutive frames of drone altitude data, obtain the measurement variances of barometric altitude, satellite altitude, and radio altitude, and calculate the corresponding confidence levels for each. The confidence scores are normalized to obtain the barometric altitude fusion weight, satellite altitude fusion weight, and radio altitude fusion weight. The three altitudes are adaptively weighted and fused based on the fusion weights corresponding to each altitude to obtain the drone altitude. The current field altitude of the drone is then calculated by combining the altitude of the terrain points. By continuously recording 20 consecutive frames of drone altitude data and updating the variances of the three altitude measurements in real time, the fusion weights are corrected in real time. The system presets alarm and danger thresholds for drone airport height. When the drone's current airport height reaches the alarm threshold, the ground control vehicle issues an alarm to the operator via an audio-visual system and displays a text alarm on the operation interface. When the drone's current airport height reaches the danger threshold, the ground control vehicle issues a danger warning to the operator via an audio-visual system. If the operator fails to perform risk avoidance operations within the preset time, the system will automatically send avoidance instructions to the drone, including climb instructions and left and right hovering instructions.
[0007] In one embodiment, the normalization process employs linear normalization to make the sum of the barometric altitude fusion weight, satellite altitude fusion weight, and radio altitude fusion weight equal to 1.
[0008] In one embodiment, the confidence level is calculated using the following formula:
[0009] In the formula, For the first i The variance of altitude source measurements includes the variance of atmospheric pressure measurements. Satellite height measurement variance Variance of radio height measurement ; For real-time deviation; , All are adjustment coefficients; For the first i The confidence levels corresponding to altitude sources include high confidence levels for air pressure. High confidence level of satellites High confidence level of radio .
[0010] In one embodiment, the current field altitude of the UAV is calculated using the following formula:
[0011] In the formula, The current field height of the drone; The altitude of the terrain point at the current latitude and longitude of the drone; The altitude of the drone is calculated using the following formula: ,in, For the first i The height of the altitude source; For the first i The fusion weights corresponding to altitude sources include barometric altitude fusion weights. Satellite high fusion weight Radio high integration weight .
[0012] In one embodiment, the fusion weights corresponding to each height are calculated using the following formula:
[0013] In the formula, For the first i The fusion weights corresponding to the high-level sources; For the first i The confidence level corresponding to the height source; n is the number of height sources.
[0014] In one embodiment, the fusion weights are corrected in real time by continuously recording 20 consecutive frames of UAV altitude data and updating the variances of the three altitude measurements in real time, including: When the airspeed of the drone is greater than 54 km / h, if the deviation of a certain frame of altitude data is greater than 100m, then the altitude data has a sudden change, and the fusion weight of the corresponding altitude source is reduced; if the deviation of 20 consecutive frames of altitude data is less than 100m, the fusion weight of the corresponding altitude source is reduced; if the altitude data does not change for 20 consecutive frames, or remains at 0, then the altitude source data is invalid, its fusion weight is adjusted to 0, and the altitude data is discarded.
[0015] In one embodiment, the alarm threshold range is 200m < <300m; danger threshold range is ≤200m.
[0016] In one embodiment, after the system autonomously sends evasion commands to the drone, it also includes drone recovery, specifically including: Before the drone is recovered, the operator plans the landing point and parachute deployment point at the field altitude. After the drone arrives at the recovery point, the parachute descent time is calculated based on the drone's own weight using a parachute recovery model. At the same time, the drone's speed and altitude are automatically controlled to the preset values. The ground speed of the drone is calculated by combining the real-time site wind speed, wind direction and the angle between the drone speed and the drone speed, and the coordinates of the drone parking point and parachute opening point are corrected based on the ground speed. Once the drone reaches the preset key node, it stops adjusting the parking point and parachute deployment point, maintaining the current speed and altitude; when the drone reaches the parking point, it executes the parking command; when the drone reaches the parachute deployment point, it executes the parachute deployment command.
[0017] A second objective of this invention is to provide a system for a multi-source altitude-based drone altitude warning and recovery method, comprising: The data acquisition module is used to collect real-time data on the drone's current position, weight, real-time site wind speed, the angle between wind direction and drone speed, and altitude during flight. The drone's altitude data includes barometric altitude, satellite altitude, and radio altitude. It also loads regional map elevation data in TIFF format to obtain terrain point altitudes. The data processing module records 20 consecutive frames of UAV altitude data, acquires the measurement variances of barometric altitude, satellite altitude, and radio altitude, and calculates the corresponding confidence scores for each. The confidence scores are then normalized to obtain barometric altitude fusion weights, satellite altitude fusion weights, and radio altitude fusion weights. Based on these fusion weights, the three altitudes are adaptively weighted and fused to obtain the UAV altitude. The current field altitude of the UAV is calculated by combining this with the terrain point altitude. The fusion weights are then continuously corrected in real-time by recording 20 consecutive frames of UAV altitude data and updating the measurement variances of the three altitudes. The altitude warning module is used to preset the drone airport altitude alarm threshold and danger threshold. When the drone's current airport altitude reaches the alarm threshold, the ground control vehicle issues an alarm prompt to the operator through an audio-visual system and displays a text alarm on the operation interface. When the drone's current airport altitude reaches the danger threshold, the ground control vehicle issues a danger warning to the operator through an audio-visual system. If the operator does not perform risk avoidance operations within a preset time, the system will automatically send avoidance commands to the drone. The avoidance commands include climb commands and left and right hover commands.
[0018] A third objective of this invention is to provide a system for a multi-source altitude-based drone altitude warning and recovery method, comprising: The drone recovery module is used by the operator to plan the drone's landing point and parachute deployment altitude before recovery. After the drone arrives at the recovery starting point, the module calculates the descent time based on the drone's weight using a parachute recovery model, and automatically controls the drone's speed and altitude to preset values. It also calculates the drone's ground speed by combining real-time wind speed, wind direction, and the angle between the drone's speed and the ground speed, and adjusts the drone's parking and parachute deployment coordinates based on this ground speed. When the drone reaches a preset key node, the module stops adjusting the parking and parachute deployment points, maintaining the current speed and altitude. When the drone reaches the parking point, a parking command is executed; when the drone reaches the parachute deployment point, a parachute deployment command is executed.
[0019] The present invention has at least the following beneficial effects: This invention provides a method for drone altitude warning and recovery based on multi-source altitude. The method calculates the drone's real-time field altitude using multi-source altitude data, and judges it based on a field altitude alarm threshold and a danger threshold. When the drone's altitude falls within the threshold range, the system promptly alerts the operator to avoid danger, and the operator takes immediate countermeasures. If the operator fails to take action within a certain time, the system can autonomously send avoidance commands to the drone.
[0020] Based on real-time field altitude, during the drone recovery phase, the drone's altitude and speed are controlled, and the recovery stopping point and parachute deployment point are adjusted in real time. When the drone reaches the stopping point and parachute deployment point, it executes the stopping and parachute deployment commands.
[0021] The present invention has the following advantages: Real-time performance: It can correct the parking point and umbrella opening point in real time, improving the safety of recycling; Cross-platform compatibility: The system's calculations are based solely on inputs from UAV telemetry data and commercial elevation data, making it applicable to other UAV platforms that use parachute recovery. Fault tolerance: In response to the possibility of data anomalies or invalid data in the height data received by the system, the system can eliminate the impact through an adaptive weighted fusion algorithm, which has a high fault tolerance rate and can ensure the accuracy of multi-source height fusion data; Autonomy: When the operator fails to react in time to a high-danger warning, the system can autonomously control the drone to avoid danger. Attached Figure Description
[0022] Figure 1 A flowchart of the high-altitude early warning method; Figure 2 The flowchart shows the method for calculating drone fusion weights based on altitude. Figure 3 A flowchart for multi-source high-level data fusion; Figure 4 This is a flowchart for the recovery process of drones based on altitude. Detailed Implementation
[0023] In order to illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description is provided in conjunction with the embodiments.
[0024] The purpose of this invention is to provide early warnings about drone altitude based on the current terrain using multi-source drone altitude data, and to autonomously control and avoid dangerous situations. It also addresses the issues of adaptive generation and recovery control of drone recovery routes. This invention relies on a Ground Control Station (GCS) software system, which uses the altitude of the recovery site and surrounding ground to avoid potential risks affecting flight safety. The software system uses a multi-source drone altitude fusion algorithm to calculate the current drone altitude in real time. When the drone altitude is abnormal or the surrounding terrain altitude changes drastically, it can issue a warning to the operator. If the operator fails to take effective avoidance measures, the software system can autonomously control the drone to avoid danger and adjust the drone recovery route. During the recovery phase, the software system uses real-time wind speed and direction, and the drone's weight at the recovery site to correct the drone's stopping point and parachute deployment point, and controls the drone for complete final recovery.
[0025] This invention provides a method for UAV altitude warning and recovery based on multi-source altitude. The entire process uses "field altitude" as the core decision indicator, employing a closed-loop logic of "multi-source altitude fusion → dynamic weight correction → graded warning and avoidance → precise recovery control." This solves the error problem of single altitude measurement and achieves safe warning and efficient recovery of UAVs at low altitudes through dual guarantees of "human intervention + autonomous control." The key lies in the progressive development of "data real-time performance → model dynamism → decision accuracy → graded response." The core of the UAV altitude warning and recovery method provided by this invention is "multi-source data acquisition - adaptive fusion modeling - real-time threshold warning - intelligent avoidance - precise recovery," proceeding in layers according to two core scenarios: "dynamic monitoring during flight" and "precise control during recovery," with each step interconnected and data closed-loop correction.
[0026] Unmanned aerial vehicles (UAVs) are aircraft capable of autonomous or remote-controlled flight, with the ability to acquire images and transmit data back. In the military field, they are typically used to carry out reconnaissance, strike, and other missions.
[0027] Ground Control Vehicle (GCS): A ground platform or vehicle used for monitoring and controlling drones, which can receive telemetry data from drones via a radio data link.
[0028] Radio data link: A dedicated communication link that enables two-way information transmission between UAVs and ground control vehicles via radio waves.
[0029] To achieve the above objectives, the present invention provides a method for UAV altitude warning and recovery based on multi-source altitude, comprising: During flight, the S1 drone collects real-time data on its current position, weight, real-time wind speed, the angle between wind direction and drone speed, and altitude. The altitude data includes barometric altitude, satellite altitude, and radio altitude. S2 loads the regional map elevation data in TIFF format and obtains the elevation of terrain points. The S3 records 20 consecutive frames of drone altitude data, obtains the measurement variances of barometric altitude, satellite altitude, and radio altitude, and calculates the corresponding confidence levels for each. The confidence level is calculated using the following formula:
[0030] In the formula, For the first i The variance of altitude source measurements includes the variance of atmospheric pressure measurements. Satellite height measurement variance Variance of radio height measurement ; For real-time deviation; , All are adjustment coefficients; For the first i The confidence levels corresponding to altitude sources include high confidence levels for air pressure. High confidence level of satellites High confidence level of radio .
[0031] S4 normalizes the confidence level to obtain the barometric height fusion weight, satellite height fusion weight, and radio height fusion weight. The normalization process uses linear normalization to make the sum of the barometric altitude fusion weight, satellite altitude fusion weight, and radio altitude fusion weight equal to 1.
[0032] The fusion weights corresponding to each height are calculated using the following formula:
[0033] In the formula, For the first i The fusion weights corresponding to the high-level sources; For the first i The confidence level corresponding to the height source; n is the number of height sources.
[0034] S5 performs adaptive weighted fusion of the three altitudes based on the fusion weights corresponding to each altitude to obtain the UAV altitude, and calculates the current field altitude of the UAV by combining the altitude of the terrain points; The current field altitude of the drone is calculated using the following formula:
[0035] In the formula, The current field height of the drone; The altitude of the terrain point at the current latitude and longitude of the drone; The altitude of the drone is calculated using the following formula: ,in, For the first i The height of the altitude source; For the first i The fusion weights corresponding to altitude sources include barometric altitude fusion weights. Satellite high fusion weight Radio high integration weight .
[0036] S6 continuously records 20 consecutive frames of drone altitude data and updates the variances of the three altitude measurements in real time to correct the fusion weights in real time. By continuously recording 20 consecutive frames of drone altitude data and updating the variances of the three altitude measurements in real time, the fusion weights are corrected in real time, including: When the airspeed of the drone is greater than 54 km / h, if the deviation of a certain frame of altitude data is greater than 100m, then the altitude data has a sudden change, and the fusion weight of the corresponding altitude source is reduced; if the deviation of 20 consecutive frames of altitude data is less than 100m, but the data is unstable and fluctuates too much, the fusion weight of the corresponding altitude source is reduced; if 20 consecutive frames of altitude data have no change, or are continuously 0, then the altitude source data is invalid, its fusion weight is adjusted to 0, and the altitude data is discarded.
[0037] The S7 has preset alarm and danger thresholds for drone altitude. When the drone's current altitude reaches the alarm threshold, the ground control vehicle issues an alarm to the operator via an audio-visual system and displays a text alarm on the operating interface; when the drone's current altitude reaches the danger threshold, the ground control vehicle issues a danger warning to the operator via an audio-visual system. The alarm threshold range is 200m < <300m; danger threshold range is ≤200m.
[0038] If the operator fails to perform risk avoidance operations within a preset time, the system will automatically send avoidance instructions to the drone. The avoidance instructions include climb instructions and left and right hovering instructions. After the S9 system autonomously sends evasion commands to the drone, it also includes drone recovery, specifically including: Before the drone is recovered, the operator plans the landing point and parachute deployment point at the field altitude. After the drone arrives at the recovery point, the parachute descent time is calculated based on the drone's own weight using a parachute recovery model. At the same time, the drone's speed and altitude are automatically controlled to the preset values. The ground speed of the drone is calculated by combining the real-time site wind speed, wind direction and the angle between the drone speed and the drone speed, and the coordinates of the drone parking point and parachute opening point are corrected based on the ground speed. Once the drone reaches the preset key node, it stops adjusting the parking point and parachute deployment point, maintaining the current speed and altitude; when the drone reaches the parking point, it executes the parking command; when the drone reaches the parachute deployment point, it executes the parachute deployment command.
[0039] To illustrate the UAV altitude warning and recovery method based on multi-source altitude provided by the present invention, the accompanying drawings are provided for illustrative purposes.
[0040] A method for drone altitude warning and recovery based on multi-source altitude, the specific steps of which are as follows: See Figure 1 As shown, the high-altitude early warning methods include: Step 1: During flight, the drone's current position is collected in real time. and air pressure altitude Satellite altitude Radio altitude Self-respect Real-time site wind speed Angle between wind direction and drone speed ; Step 2: Load the regional map elevation data in TIFF format and obtain the elevation of terrain points. ; See Figure 2 As shown, the calculation of the drone fusion weights based on altitude is as follows: Step 3: Record 20 consecutive frames of the three drone altitudes and obtain the measurement variances of the three altitudes, including the air pressure measurement variance. Satellite height measurement variance Variance of radio height measurement Calculate the corresponding confidence level. , , ; Formula 1 in: The variance of the measurements for each height source is given. For real-time deviation, and This is the adjustment coefficient.
[0041] Step 4: To avoid distortion of the fusion result due to a sudden change in a certain height value, the confidence score is normalized to obtain the fusion weight. , ,
[0042] Formula 2 Step 5: Refer to Figure 2 The three altitudes are adaptively weighted and fused to obtain the drone altitude. And calculate the current field height of the drone. ; Formula 3 in: The height of each altitude source.
[0043] Formula 4 See Figure 3 As shown, the multi-source high-resolution data fusion process is as follows: Step 6: Record the three drone altitudes for 20 consecutive frames, then return to steps 3 and 4, and calculate the measurement variance based on the real-time data. , , For fusion weights , , Make real-time corrections.
[0044] When the UAV's airspeed exceeds 54 km / h, if the deviation of a certain frame of altitude data is greater than 100m, it is considered that the altitude data has a sudden change. Then, according to steps 3 and 4, as well as equations 2 and 3, the weight is calculated, and the corresponding altitude source weight is reduced. If the deviation of 20 consecutive frames of altitude data is less than 100m, but the data is unstable and fluctuates too much, then according to steps 3 and 4, as well as equations 2 and 3, the weight is calculated, and the corresponding altitude source weight is reduced. If 20 consecutive frames of altitude data do not change or remain at 0, then the altitude source data is considered invalid, its weight is reduced to 0, and the altitude data is removed. It should be noted that the instability and excessive fluctuation of the data are reflected by the real-time deviation of the data in steps 3 and 4, and equations 2 and 3, indicating whether the fluctuation of 20 consecutive frames of data is too large. Step 7: Based on the current field altitude of the drone When judging 200m < When the drone's current altitude is below 300m, and the drone's current altitude is at the alarm threshold, the system will invoke the interfaces of the ground control vehicle's voice output equipment (such as speakers) and lighting equipment (such as alarm lights) to issue a voice alarm, such as "Please note that the drone's altitude is too low; please take immediate precautions." Simultaneously, the lighting equipment will flash yellow, and the current drone altitude will be displayed in flashing yellow text on the operating interface. When the system determines When the altitude is ≤300m, the system calls upon the interfaces of the ground control vehicle's voice output equipment (such as speakers) and lighting equipment (such as alarm lights) to issue a voice alarm, such as "Please note that the drone altitude is too low. Please take immediate evasive action." At the same time, the lighting equipment keeps flashing red lights, and the current drone airport altitude is displayed in red text on the operation interface. .
[0045] Step 7: When the system determines the real-time drone airport altitude When the distance is ≤200m, the system starts timing. If the operator does not take risk avoidance actions within a certain time when the timer reaches 10s, the system will automatically send avoidance instructions to the drone, including climbing, left and right turning, etc. See Figure 4 As shown, the drone recovery process based on altitude is as follows: Step 8: Before the drone is recovered, the operator plans the drone's landing point. High point of parachute opening ; Step 10: The drone arrives at recovery point 1, based on the drone's own weight. High point of parachute opening Parachute descent time was calculated using a parachute recovery model. At the same time, the speed of the drone is automatically controlled to be field height is ; Formula 5 In the formula, For the recovery parachute model, the descent time of the drone, that is, the time from parachute opening to landing, is calculated based on the recovery parachute model, the opening height, and the drone's own weight. Different recovery parachute models will have different results.
[0046] Step 11: Combine with real-time site wind speed Angle between wind direction and drone speed Obtain the ground speed of the drone And finally calculate the drone parking point. Umbrella opening point ; Formula 6 Formula 7 Formula 8 Formula 9 Formula 10 In the formula, For the ground speed of the drone; This is the drone's current speed; Real-time site wind speed; For the time of the parachute drop; The angle between wind direction and drone speed; The coordinates of the drone's landing point; Coordinates of the drone parking point; Provide the coordinates of the drone's parachute deployment point; As a scalar, is The vector magnitude.
[0047] Step 12: When the drone reaches point 3, the system stops adjusting the stopping point and parachute deployment point, and continues to control the drone's speed. field height is When the drone reaches the parking point, it executes the parking command; when it reaches the parachute deployment point, it executes the parachute deployment command.
[0048] This invention provides a system for a multi-source altitude-based drone altitude warning and recovery method, comprising: The data acquisition module is used to collect real-time data on the drone's current position, weight, real-time site wind speed, the angle between wind direction and drone speed, and altitude during flight. The drone's altitude data includes barometric altitude, satellite altitude, and radio altitude. It also loads regional map elevation data in TIFF format to obtain terrain point altitudes. The data processing module records 20 consecutive frames of UAV altitude data, acquires the measurement variances of barometric altitude, satellite altitude, and radio altitude, and calculates the corresponding confidence scores for each. The confidence scores are then normalized to obtain barometric altitude fusion weights, satellite altitude fusion weights, and radio altitude fusion weights. Based on these fusion weights, the three altitudes are adaptively weighted and fused to obtain the UAV altitude. The current field altitude of the UAV is calculated by combining this with the terrain point altitude. The fusion weights are then continuously corrected in real-time by recording 20 consecutive frames of UAV altitude data and updating the measurement variances of the three altitudes. The altitude warning module is used to preset the airport altitude alarm threshold and danger threshold. When the current airport altitude of the drone reaches the alarm threshold, the ground control vehicle issues an alarm prompt to the operator through the sound and light system and displays a text alarm on the operation interface. When the current airport altitude of the drone reaches the danger threshold, the ground control vehicle issues a danger prompt to the operator through the sound and light system. If the operator does not perform risk avoidance operations within a preset time, the system will automatically send avoidance commands to the drone. The avoidance commands include climb commands and left and right hover commands. The drone recovery module is used by the operator to plan the drone's landing point and parachute deployment altitude before recovery. After the drone arrives at the recovery starting point, the module calculates the descent time based on the drone's weight using a parachute recovery model, and automatically controls the drone's speed and altitude to preset values. It also calculates the drone's ground speed by combining real-time wind speed, wind direction, and the angle between the drone's speed and the ground speed, and adjusts the drone's parking and parachute deployment coordinates based on this ground speed. When the drone reaches a preset key node, the module stops adjusting the parking and parachute deployment points, maintaining the current speed and altitude. When the drone reaches the parking point, a parking command is executed; when the drone reaches the parachute deployment point, a parachute deployment command is executed.
[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for early warning and recovery of unmanned aerial vehicles (UAVs) based on multi-source altitude, characterized in that, include: During flight, the drone collects real-time data on its current position, weight, real-time wind speed, the angle between wind direction and drone speed, and altitude. The drone's altitude data includes barometric altitude, satellite altitude, and radio altitude. Load the regional map elevation data in TIFF format and obtain the elevation of terrain points; Record 20 consecutive frames of drone altitude data, obtain the measurement variances of barometric altitude, satellite altitude, and radio altitude, and calculate the corresponding confidence levels for each. The confidence scores are normalized to obtain the barometric altitude fusion weight, satellite altitude fusion weight, and radio altitude fusion weight. The three altitudes are adaptively weighted and fused based on the fusion weights corresponding to each altitude to obtain the drone altitude. The current field altitude of the drone is then calculated by combining the altitude of the terrain points. By continuously recording 20 consecutive frames of drone altitude data and updating the variances of the three altitude measurements in real time, the fusion weights are corrected in real time. The system presets alarm and danger thresholds for drone airport height. When the drone's current airport height reaches the alarm threshold, the ground control vehicle issues an alarm to the operator via an audio-visual system and displays a text alarm on the operation interface. When the drone's current airport height reaches the danger threshold, the ground control vehicle issues a danger warning to the operator via an audio-visual system. If the operator fails to perform risk avoidance operations within the preset time, the system will automatically send avoidance instructions to the drone, including climb instructions and left and right hovering instructions.
2. The UAV altitude early warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, The normalization process uses linear normalization to make the sum of the barometric altitude fusion weight, satellite altitude fusion weight, and radio altitude fusion weight equal to 1.
3. The UAV altitude warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, The confidence level is calculated using the following formula: In the formula, For the first i The variance of altitude source measurements includes the variance of atmospheric pressure measurements. Satellite height measurement variance Variance of radio height measurement ; For real-time deviation; , All are adjustment coefficients; For the first i The confidence levels corresponding to altitude sources include high confidence levels for air pressure. High confidence level of satellites High confidence level of radio .
4. The UAV altitude warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, The current field altitude of the drone is calculated using the following formula: In the formula, The current field height of the drone; The altitude of the terrain point at the current latitude and longitude of the drone; The altitude of the drone is calculated using the following formula: ,in, For the first i The height of the altitude source; For the first i The fusion weights corresponding to altitude sources include barometric altitude fusion weights. Satellite high fusion weight Radio high integration weight .
5. The UAV altitude warning and recovery method based on multi-source altitude as described in claim 4, characterized in that, The fusion weights corresponding to each height are calculated using the following formula: In the formula, For the first i The fusion weights corresponding to the high-level sources; For the first i The confidence level corresponding to the height source; n is the number of height sources.
6. The UAV altitude warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, By continuously recording 20 consecutive frames of drone altitude data and updating the variances of the three altitude measurements in real time, the fusion weights are corrected in real time, including: When the airspeed of the drone is greater than 54 km / h, if the deviation of a certain frame of altitude data is greater than 100m, then the altitude data has a sudden change, and the fusion weight of the corresponding altitude source is reduced; if the deviation of 20 consecutive frames of altitude data is less than 100m, the fusion weight of the corresponding altitude source is reduced; if the altitude data does not change for 20 consecutive frames, or remains at 0, then the altitude source data is invalid, its fusion weight is adjusted to 0, and the altitude data is discarded.
7. The UAV altitude warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, The alarm threshold range is 200m < <300m; danger threshold range is ≤200m.
8. The UAV altitude warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, After the system autonomously sends evasion commands to the drone, it also includes drone recovery, specifically including: Before the drone is recovered, the operator plans the landing point and parachute deployment point at the field altitude. After the drone arrives at the recovery point, the parachute descent time is calculated based on the drone's own weight using a parachute recovery model. At the same time, the drone's speed and altitude are automatically controlled to the preset values. The ground speed of the drone is calculated by combining the real-time site wind speed, wind direction and the angle between the drone speed and the drone speed, and the coordinates of the drone parking point and parachute opening point are corrected based on the ground speed. Once the drone reaches the preset key node, it stops adjusting the parking point and parachute deployment point, maintaining the current speed and altitude; when the drone reaches the parking point, it executes the parking command; when the drone reaches the parachute deployment point, it executes the parachute deployment command.
9. A system for the UAV altitude warning and recovery method based on multi-source altitude as described in claim 1, characterized in that, include: The data acquisition module is used to collect real-time data on the drone's current position, weight, real-time site wind speed, the angle between wind direction and drone speed, and altitude during flight. The drone's altitude data includes barometric altitude, satellite altitude, and radio altitude. It also loads regional map elevation data in TIFF format to obtain terrain point altitudes. The data processing module records 20 consecutive frames of UAV altitude data, acquires the measurement variances of barometric altitude, satellite altitude, and radio altitude, and calculates the corresponding confidence scores for each. The confidence scores are then normalized to obtain barometric altitude fusion weights, satellite altitude fusion weights, and radio altitude fusion weights. Based on these fusion weights, the three altitudes are adaptively weighted and fused to obtain the UAV altitude. The current field altitude of the UAV is calculated by combining this with the terrain point altitude. The fusion weights are then continuously corrected in real-time by recording 20 consecutive frames of UAV altitude data and updating the measurement variances of the three altitudes. The altitude warning module is used to preset the drone airport altitude alarm threshold and danger threshold. When the drone's current airport altitude reaches the alarm threshold, the ground control vehicle issues an alarm prompt to the operator through an audio-visual system and displays a text alarm on the operation interface. When the drone's current airport altitude reaches the danger threshold, the ground control vehicle issues a danger warning to the operator through an audio-visual system. If the operator does not perform risk avoidance operations within a preset time, the system will automatically send avoidance commands to the drone. The avoidance commands include climb commands and left and right hover commands.
10. A system for the UAV altitude warning and recovery method based on multi-source altitude as described in claim 8, characterized in that, include: The drone recovery module is used by the operator to plan the drone's landing point and parachute deployment point altitude before recovery. After the drone arrives at the recovery starting point, the module calculates the parachute descent time based on the drone's weight using a parachute recovery model, and automatically controls the drone's speed and altitude to preset values. It also calculates the drone's ground speed by combining real-time wind speed, wind direction, and the angle between the drone's speed and ground speed, and corrects the drone's parking point and parachute deployment point coordinates based on this ground speed. When the drone reaches a preset key node, the module stops adjusting the parking point and parachute deployment point, maintaining the current speed and altitude. When the drone arrives at the parking spot, it executes the parking command; When the drone reaches the parachute deployment point, it executes the parachute deployment command.