An underwater target motion parameter estimation method based on azimuth-radial velocity
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA SHIP SCIENTIFIC RESEARCH CENTER
- Filing Date
- 2026-04-30
- Publication Date
- 2026-08-07
AI Technical Summary
然而，对于静止观测站而言，如果仅依赖目标的方位信息无法确定目标的唯一轨迹，还需引入频率、多途到达时延等多维观测量进行联合估计，极大限制了现有目标运动分析方法的参数估计性能
1.引入目标径向速度信息，推导了目标径向速度与目标运动参数的变化关系，通过融合目标方位和目标径向速度信息，构建了目标参数估计模型，实现了距离及轨迹信息的估计。
Smart Images
Figure CN122525649A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of target motion analysis, and in particular to a method for estimating underwater target motion parameters based on azimuth-radial velocity. Background Technology
[0002] Underwater target parameter estimation is fundamental to underwater acoustic target tracking, surveillance, and localization, providing strong support for my country's maritime security, maritime management, and marine protection, and has become a major research hotspot in the field of underwater acoustic signal processing. Obtaining more comprehensive, accurate, and reliable target parameter information is of great guiding significance for safeguarding maritime rights and developing the marine economy. Most existing target motion analysis methods require prior knowledge of the target's initial state and seek a balance between robustness and accuracy through recursion and iteration to achieve better target motion parameter estimation performance. However, in practical applications, due to the complexity and variability of the marine environment, prior information such as the target's initial position, velocity, and direction of motion is often difficult to obtain and contains significant errors, which greatly limits the performance of the aforementioned methods.
[0003] As one of the most stable and reliable parameters of a sound source, azimuth information is widely used in target motion parameter estimation, leading to the development of underwater pure azimuth target motion analysis methods. However, for stationary observation stations, relying solely on the target's azimuth information is insufficient to determine the target's unique trajectory. Furthermore, multi-dimensional observations such as frequency and multipath arrival delay must be introduced for joint estimation, which significantly limits the parameter estimation performance of existing target motion analysis methods. Summary of the Invention
[0004] To address the aforementioned problems and technical requirements, the inventors propose a method for estimating underwater target motion parameters based on azimuth-radial velocity. The generalized Radon transform method effectively avoids the sensitivity to initial conditions and local convergence issues of existing target motion analysis methods, providing a new approach for target parameter estimation. The technical solution of this invention is as follows: A method for estimating underwater target motion parameters based on azimuth-radial velocity includes the following steps: Acquire the temporal azimuth history and temporal radial velocity history of an underwater target within a certain sampling period; Extract the azimuth information from the time-domain azimuth history, and determine the target based on the azimuth change pattern over time using the model; A generalized Radon transform is applied to the time-radial velocity history to obtain two-dimensional parameter estimates of the target velocity and heading angle. By combining the target with the model and orientation information, a unique solution for the heading angle estimation result is determined; The target's azimuth, velocity estimate, and unique heading angle estimate are combined to estimate the target's relative distance and trajectory.
[0005] A further technical solution is that the method also includes: A geometric model of the target's motion in the northeast is constructed with the location of the detection equipment as the origin. The geometric model of the target's motion is based on a left-handed coordinate system. x The positive axis points to due north in geodetic coordinates; Target heading angle For the target motion heading and x Clockwise deflection angle on the positive axis, target azimuth angle For the target relative to the detection equipment and x Clockwise deflection angle in the positive direction of the axis.
[0006] A further technical solution involves calculating the two-dimensional parameter estimation results of the target velocity and heading angle, including: Based on the relationship between target velocity and target radial velocity in the target motion geometry model, a formula for calculating the target radial velocity is derived. This formula is then substituted into the parameter estimation formula for the generalized Radon transform to obtain the time-varying radial velocity history curve. With heading angle The result of the two-dimensional spatial projection integral is a two-dimensional spatial matrix about the energy distribution. ; Two-dimensional space matrix The horizontal and vertical axes corresponding to the peak values represent the target velocity. With heading angle The two-dimensional parameter estimation results.
[0007] A further technical solution is that the parameter estimation formula for the generalized Radon transform is:
[0008] In the formula, The radial velocity history matrix over time. For the first Observation time The radial velocity of the target is in the direction from the target's location to the location of the detection equipment; N This represents the total number of observation points, and ; The target velocity is denoted by a direction along the target's trajectory. express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history.
[0009] Its further technical solution is to determine the target based on the change pattern of orientation over time through a model including: In the target motion geometry model, with the detection device as the central viewpoint, the target passage model is divided into left-side passage and right-side passage, where: When a target passes on the left, the azimuth angle increases with time; when a target passes on the right, the azimuth angle decreases with time.
[0010] Its further technical solution is that the mathematical relationship between the target azimuth angle and various motion parameters under the model on the left is as follows:
[0011] The mathematical relationship between the target azimuth and various motion parameters under the model on the right is as follows:
[0012] In the formula, express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history; It is the ratio of the target speed to the shortest distance traveled, and it is a positive value; The most recent passing time; This indicates the modulo operation.
[0013] Its further technical solution is to combine the target with the model and azimuth information to determine the unique solution of the heading angle estimation result, including: For two heading angle estimates that are 180° apart obtained by generalized Radon transform, the changes in azimuth angle of the target under different heading angles are given under the target passage model. Find the heading angle estimate that is consistent with the azimuth angle change over time, and use it as the unique solution for the heading angle estimation result.
[0014] Its further technical solution is that the relative distance to the target is Distance of the target relative to the detection device at the observation time In the target motion geometry model, its solution formula is:
[0015] In the formula, express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history; The target's speed estimate and unique heading angle estimate.
[0016] A further technical solution is that the target's trajectory is composed of the target's coordinate positions at each observation time. The target's coordinates in the northeast coordinate system at the time of observation The solution formula is:
[0017]
[0018] In the formula, express The estimated distance between the target and the detection equipment at the observation time; express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history; The target's speed estimate and unique heading angle estimate.
[0019] A further technical solution is that this method is applicable to the estimation of motion parameters of underwater targets traveling at a constant speed in a straight line, without the need to preset the initial motion state of the target.
[0020] The beneficial technical effects of this invention are: 1. By introducing target radial velocity information, the relationship between target radial velocity and target motion parameters was derived. By fusing target orientation and target radial velocity information, a target parameter estimation model was constructed, realizing the estimation of distance and trajectory information.
[0021] 2. By introducing the idea of generalized Radon transform, the target velocity and heading angle can be accurately estimated by performing an integral transform on the time radial velocity history, thus avoiding the problems of sensitivity to initial values and local convergence of traditional target parameter estimation methods.
[0022] 3. By using global integration, the global information of the image is mapped to the parameter domain in the form of energy integration. It is not sensitive to the local signal-to-noise ratio and outliers in the image, and can better extract the subtle features in the image, with good robustness and accuracy. Attached Figure Description
[0023] Figure 1 This is a flowchart of the underwater target motion parameter estimation method based on azimuth-radial velocity provided in this application; Figure 2 -(1) is a time-location history diagram of the target provided in this application; Figure 2 -(2) is the time radial velocity history diagram of the target provided in this application; Figure 3 This is a schematic diagram of the target motion geometry model provided in this application; Figure 4 The two-dimensional space matrix provided in this application is obtained by generalized Radon transformation. Schematic diagram; Figure 5 This is a schematic diagram of the target provided in this application; Figure 6 -(1) is the target on the left through the model provided in this application at the heading angle. The corresponding motion diagram; Figure 6 -(2) is the target on the left through the model provided in this application at the heading angle. The corresponding motion diagram; Figure 7 -(1) is a comparison diagram of the estimated target distance curve and the actual target distance curve calculated using the estimation method provided in this application; Figure 7 -(2) is a schematic diagram of the target's trajectory in the northeast coordinate system provided in this application. Detailed Implementation
[0024] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.
[0025] One embodiment of this application discloses a method for estimating underwater target motion parameters based on azimuth-radial velocity, referencing... Figure 1 As shown, the method includes the following steps: Step 1: Obtain the time-azimuth and time-radial velocity histories of the underwater target within a certain sampling period. In this step, beamforming and spectrum analysis are performed on the array signals collected by the detection equipment at different times to obtain the target's time within a certain sampling period. t -position Process and Time t Radial velocity The process, such as Figure 2 -(1) Figure 2 As shown in -(2).
[0026] Step 2: Extract the azimuth information from the time-series data and determine the target's passage model based on the changing pattern of azimuth over time. In this step, the target's passage model is divided into two cases: passing to the left and passing to the right, which will be described in detail later.
[0027] Step 3: Perform a generalized Radon transform on the time-radial velocity history to obtain the two-dimensional parameter estimates of the target velocity and heading angle, denoted as... .
[0028] Step 4: Combine the target via model and bearing information to determine the unique solution of the heading angle estimation result.
[0029] Step 5: Combine the target's azimuth, velocity estimate, and unique heading angle estimate to estimate the target's relative distance and trajectory.
[0030] In this embodiment, since the radial velocity of the target reflects the rate of change of the relative distance between the detection device and the target, it also contains rich information on the target's motion parameters. Compared with frequency and multipath arrival delay information, the change in radial velocity per unit time is more significant, and it is easier to extract at low signal-to-noise ratios. Therefore, parameter estimation based on target radial velocity information has great development potential.
[0031] In one possible implementation, before using the generalized Radon transform for estimation, a target motion geometry model needs to be constructed first. That is, the above method also includes step 0: establishing a motion geometry model of a target traveling at a constant speed in a straight line.
[0032] like Figure 3 As shown, a northeast coordinate system is constructed with the location of the detection equipment as the origin, using a left-handed coordinate system, i.e. x The positive axis points to true north in geodetic coordinates. Target heading angle. For the target motion heading and x The clockwise deflection angle of the positive axis (due north), i.e., the angle of north-east; The azimuth angle of the target relative to the detection device (origin) is defined as the angle between the line connecting the target to the origin and... x Clockwise deflection angle in the positive direction of the axis; The target velocity is denoted by a direction along the target's trajectory. Let be the radial velocity of the target, and its direction be from the target's location to the location of the detection equipment. Assume the target is located at [location missing] at the two observation times. A , B Point, the interval between two observation times is Then in the triangle oAB middle, A , B Distance line segment between points AB It can be represented as Based on this, line segments oB That is, the distance between the target and the detection device. It can be obtained using the Law of Sines: (1) In the formula, For the goal A , B The azimuth angle between two points, that is, the difference in azimuth angles of the target at two observation times; For the goal A Target speed at point radial velocity of the target The angle between them, therefore the target speed It can be further expressed as Based on this mathematical relationship and and , Based on the angular relationship in the motion model, the formula for calculating the target radial velocity can be derived, that is, for the first... Observation time ( (integer), the radial velocity of the target It can be represented as: (2) In the formula, express The azimuth angle of the target at the observation time can be obtained from, for example... Figure 2 It was extracted from the time and location history shown in -(1).
[0033] In one possible implementation, step 3 specifically includes the following: combining the mathematical relationship derived from formula (2), applying the idea of the generalized Radon transform to, for example... Figure 2 In the target motion parameter feature extraction of the time radial velocity history map shown in -(2), the parameter estimation formula of the generalized Radon transform is obtained as follows: (3) In the formula, This is the time-radial velocity history matrix; N ( (and are integers) represents the total number of observation points; It can be obtained by solving formula (2).
[0034] The calculation expressed by the above formula is essentially taking the time-radial velocity history matrix. The amplitude values of the radial velocity at each moment are accumulated to obtain the time-radial velocity history curve at the target velocity. With heading angle The result of the two-dimensional spatial projection integral is a two-dimensional spatial matrix about the energy distribution. ,like Figure 4 As shown. The accumulated amplitude value is only valid if and only if the theoretical radial velocity history curve obtained by solving formula (2) matches the actual time-radial velocity history curve. The maximum value in the two-dimensional space matrix. The horizontal and vertical axes corresponding to the peak value (maximum value) are the target velocity. With heading angle The two-dimensional parameter estimation results.
[0035] Depend on Figure 4 As shown, a two-dimensional plane There are two peak highlights, namely the heading angle. exist There are two sets of solutions. This is because in equation (2) Therefore, the target velocity is calculated using equation (2). At that time, heading angle exist Within the range of values, there will be two solutions that differ by 180°. By reading the horizontal and vertical coordinates corresponding to the maximum peak brightness in the two-dimensional plane, we can obtain... , Therefore, it is necessary to further utilize the target's time-location history to determine the unique solution for the target's heading angle.
[0036] In one possible implementation, step 2 specifically includes the following: Figure 3 In the target motion geometry model shown, with the detection device as the central viewpoint, the target passage model is divided into two cases: passing on the left and passing on the right, as shown below. Figure 5 As shown in the figure, This is the shortest passing distance to the target, and also the shortest distance between the target's trajectory and the detection equipment; The most recent transit time is the time corresponding to the target's most recent transit distance from the measurement time.
[0037] When the target is a model passing through on the left, the target azimuth angle The mathematical relationship with each motion parameter is as follows: (4) When the target is a model passing to the right, the target azimuth angle is... The mathematical relationship with each motion parameter is as follows: (5) In the formula, For target speed Distance to the nearest pass The ratio is positive; This indicates a modulo operation to prevent the target azimuth angle from being greater than 360° or less than 0°.
[0038] From equations (4) and (5), it can be seen that, without considering the 0° and 360° angle jumps, when the target passes to the left of the detection point, the target's azimuth angle increases with time; when the target passes to the right of the detection point, the target's azimuth angle decreases with time. Therefore, the specific passing pattern of the target can be determined based on the change law of the target's azimuth over time according to the time-location history. In this embodiment, from... Figure 2 As shown in (1), without considering the angle jumps of 0° and 360°, the azimuth of the target increases with time, thus proving that the target satisfies the left-hand pass model.
[0039] In one possible implementation, step 4 specifically includes the following: For two heading angle estimates that differ by 180° obtained through the generalized Radon transform, the azimuth angle changes corresponding to the target at different heading angles are given under the target passage model. Then, the heading angle estimate that is consistent with the azimuth angle change in the time-location history is found as the unique solution of the heading angle estimation result.
[0040] In this embodiment, Figure 6 -(1) Figure 6 -(2) The left-hand side shows the target in the model. Schematic diagrams of motion corresponding to two heading angles. When the target heading angle is... At that time, the target azimuth angle It increases over time, and after passing through a 360° angle, it undergoes a jump, and... Figure 2 -(1) The time and position history are consistent; while when the target heading angle is At that time, the target azimuth angle It starts to change from the range of (0, 60°), and... Figure 2 -(1) starts from [240, 360°) and then reverses, which fails to satisfy the above conditions. Therefore, the estimated heading angle of the target can be determined as follows: .
[0041] In one possible implementation, step 5 specifically includes the following: the relative distance to the target is... Distance of the target relative to the detection device at the observation time From equation (1), we can see that The solution formula is:
[0042] In the formula, The target's speed estimate and unique heading angle estimate are obtained from steps 3 and 4; The azimuth angle of the target at the observation time This can be obtained by reading the target time and location history map.
[0043] Based on this, The target's coordinates in the northeast coordinate system at the time of observation The solution formula is:
[0044] In the formula, express The estimated distance of the target relative to the detection device at the observation time (i.e., the time immediately following the initial observation time) is calculated using formula (6); express The azimuth angle corresponding to the target at the observation time is extracted from the target's time azimuth history. Combined with the target motion parameters obtained in steps 1 to 4, the position coordinate information of the target at different times in the northeast coordinate system can be obtained by using the trajectory calculation formula (7), and then the target's motion trajectory can be calculated.
[0045] Figure 7 -(1) Figure 7 -(2) The estimated distance curves and actual trajectory information of the target at different times are given respectively. Figure 7 -(2) The pentagram in the diagram indicates the location of the detection equipment, and the arrow indicates the target's trajectory. Figure 7 -(1) It can be seen that the target estimated distance curve (as shown by the dotted line) calculated by equation (6) is in perfect agreement with the true distance curve (as shown by the solid line). Compared with existing target motion analysis methods, the method proposed in this application does not require a given initial state of the target and does not require recursive calculations. It can achieve accurate estimation of the target distance with just one integral transformation. Therefore, from the perspective of practical application, the generalized Radon transform is undoubtedly a very reasonable solution.
[0046] The above descriptions are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.
Claims
1. A method for estimating underwater target motion parameters based on azimuth-radial velocity, characterized in that, The method includes: Acquire the temporal azimuth history and temporal radial velocity history of an underwater target within a certain sampling period; Extract the azimuth information from the time-location history, and determine the target through the model based on the azimuth change pattern over time; A generalized Radon transform is performed on the aforementioned time-radial velocity history to obtain two-dimensional parameter estimation results for the target velocity and heading angle; By combining the target with the model and azimuth information, a unique solution for the heading angle estimation result is determined; The target's azimuth, velocity estimate, and unique heading angle estimate are combined to estimate the target's relative distance and trajectory.
2. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 1, characterized in that, The method further includes: A geometric model of the target's motion is constructed with the location of the detection equipment as the origin. This geometric model uses a left-handed coordinate system. x The positive axis points to due north in geodetic coordinates; Target heading angle For the target motion heading and the said x Clockwise deflection angle on the positive axis, target azimuth angle For the target relative to the detection device and the x Clockwise deflection angle in the positive direction of the axis.
3. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 2, characterized in that, The calculation method for the two-dimensional parameter estimation results of the target velocity and heading angle includes: Based on the relationship between target velocity and target radial velocity in the target motion geometry model, a formula for calculating the target radial velocity is derived. This formula is then substituted into the parameter estimation formula of the generalized Radon transform to obtain the time-varying radial velocity history curve at the target velocity. With heading angle The result of the two-dimensional spatial projection integral is a two-dimensional spatial matrix about the energy distribution. ; The two-dimensional space matrix The horizontal and vertical coordinates corresponding to the peak value are the target velocity. With heading angle The two-dimensional parameter estimation results.
4. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 3, characterized in that, The parameter estimation formula for the generalized Radon transform is as follows: In the formula, The radial velocity history matrix over time. For the first Observation time The radial velocity of the target is in the direction from the target's location to the location of the detection device; N This represents the total number of observation points, and ; The target velocity is oriented along the heading of the target motion. express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history.
5. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 2, characterized in that, The model for determining the target based on the change in orientation over time includes: In the target motion geometry model, with the detection device as the central viewpoint, the target passage model is divided into left-side passage and right-side passage, wherein: When a target passes on the left, the azimuth angle increases with time; when a target passes on the right, the azimuth angle decreases with time.
6. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 5, characterized in that, The mathematical relationship between the target azimuth angle and various motion parameters under the model on the left is as follows: The mathematical relationship between the target azimuth and various motion parameters under the model on the right is as follows: In the formula, express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history; It is the ratio of the target speed to the shortest distance traveled, and it is a positive value; The most recent passing time; This indicates the modulo operation.
7. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 1, characterized in that, Combining the target with the model and bearing information, the unique solution for determining the heading angle estimation result includes: For two heading angle estimates that are 180° apart obtained by the generalized Radon transform, the changes in the azimuth angle of the target under different heading angles are given under the target passage model. Find the heading angle estimate that is consistent with the azimuth angle change in the stated time azimuth history, and use it as the unique solution for the heading angle estimation result.
8. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 2, characterized in that, The relative distance of the target is Distance of the target relative to the detection device at the observation time The solution formula in the target motion geometry model is: In the formula, express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history; The target's speed estimate and unique heading angle estimate.
9. The underwater target motion parameter estimation method based on azimuth-radial velocity according to claim 2, characterized in that, The target's trajectory is composed of the target's coordinate positions at each observation time. The target's coordinates in the northeast coordinate system at the time of observation The solution formula is: In the formula, express The estimated distance of the target relative to the detection device at the observation time; express The azimuth angle of the target at the observation time is extracted from the target's time azimuth history; The target's speed estimate and unique heading angle estimate.
10. The underwater target motion parameter estimation method based on azimuth-radial velocity according to any one of claims 1-9, characterized in that, The method is applicable to the estimation of motion parameters of underwater targets traveling at a constant speed in a straight line, without the need to preset the initial motion state of the target.