SYSTEM AND METHOD FOR EVALUATION CENTROID RANGE-BEARING PROCESSING IN HIGH RESOLUTION COASTAL SURVEILLANCE RADAR

Abstract

The patent provides the system and the method of evaluation the centroid range-bearing processing in high resolution coastal surveillance radars to solve the problem of assessing the quality of centroid processing. The provided system includes blocks: Input data block, parameter calculation block, evaluation and export result block; The provided method includes steps: Loading input data, calculating parameters, evaluating and exporting results. The system and method provided in this invention solve the issue of the quality assessment of the radar system according to the battle-technical specification at the target centroid level.

Claims

1. The system to evaluate the target centroid range-bearing processing in high resolution coastal surveillance radars includes the following blocks: input data block loads data for evaluation, these data files are formatted as “*.csv” and include: a file “Data.csv” contains location (range, azimuth, time) of target centroids according to radar and AIS, data collection is manipulated via radar screen, first, select the target on the screen, then choose to record and export data to “Data.csv” file from radar system; a file “Constant.csv” contains the value of thresholds (constants) used for calculation in “Parameter calculation block 102”, Constants are γ.sub.i (first change threshold), γ.sub.2 (second change threshold), φ (time between two change points) and weights L.sub.i (i=1, . . . , 6) of each parameter in step 2, Parameters γ.sub.1, γ.sub.2 and φ will be selected by statistical method, The values L.sub.i can be chosen equally and equal to ⅙, or chosen according to the priority level, for example, if we pay much attention to the structural stability we can put the weight of the parameter “ratio of change points” higher than the weights of remaining parameters; the output of “Input data block” is given in following table TABLE-US-00004 Target Time Target Target Target state Target Target ID (s) range by azimuth by range by azimuth by radar radar AIS AIS (m) (degree) (m) (degree) where, target state takes value 1 if there are target detected hits and 0 if target is not detected (miss detection); parameter calculation block performs calculation of parameters (the ratio of break target hits, the ratio of miss detection, the ratio of reverse trend, the accuracy and the ratio of change points) for each target, the output of block is the a “csv” file with format given in table below: TABLE-US-00005 Target Ratio of Ratio of Ratio of Range Azimuth Ratio ID break miss reverse trend accuracy accuracy of target hits detection change points Evaluation and export result block performs the quality assessment of the centroid processing and exporting evaluation results in the form of a “csv” file in table, TABLE-US-00006 Ratio of Ratio of Ratio of Ratio of break miss reverse Range Azimuth change target hits detection trend accuracy accuracy points Mean . . . . . . . . . . . . . . . . . . Score

2. A method to evaluate the target centroid range-bearing processing in high resolution coastal surveillance radars includes the following steps: Step 1: Loading the input data; at this step, two data sets (Data.csv and Constant.csv described above) are loaded to system and will be used for the parameter calculation block; the output of step 1 is the data of each target shown as in table below, TABLE-US-00007 Target Time Target Target Target state Target Target ID (s) range by azimuth by range by azimuth by radar radar AIS AIS (m) (degree) (m) (degree) Step 2: calculating parameters; input: location information of target centroids as given in table in step 1; constants are entered in step 1, where ID is the target identification number, Each target has only one ID to distinguish targets together, “Target state” is the logic value of 0 or 1 (value 0 corresponding when there is not target centroid—miss detection and value 1 when the target centroid appears on the radar screen); output: parameters (the ratio of break target hits, the ratio of miss detection, the ratio of reverse trend, the accuracy and the ratio of change points) realization: the ratio of break target hits is calculated by: $\mathrm{Ratio}\mathrm{of}\mathrm{break}\mathrm{target}\mathrm{hits}=\frac{\mathrm{All}\mathrm{target}\mathrm{centroids}}{\mathrm{Number}\mathrm{of}\mathrm{all}\mathrm{scans}}-1$ the ratio of miss detection: $\mathrm{Ratio}\mathrm{of}\mathrm{miss}\mathrm{detection}=1-\frac{Nu\mathrm{mber}\mathrm{of}\mathrm{times}\mathrm{with}\mathrm{target}\mathrm{centroid}}{\mathrm{Number}\mathrm{of}\mathrm{all}\mathrm{scans}}$ the ratio of reverse trend: $\mathrm{Ratio}\mathrm{of}\mathrm{reverse}\mathrm{trend}=\frac{N\mathrm{umber}\mathrm{of}\mathrm{times}\mathrm{the}\mathrm{target}\mathrm{centroid}\mathrm{goes}\mathrm{against}\mathrm{the}\mathrm{trend}}{N\mathrm{umber}\mathrm{of}\mathrm{all}\mathrm{scans}}$ accuracy: By range: $\mathrm{Range}\mathrm{accuracy}=\sqrt{\frac{.Math.{\left(\mathrm{Range}\mathrm{by}\mathrm{radar}-\mathrm{Range}\mathrm{by}\mathrm{AIS}\right)}^2}{N}}$ By azimuth: $\mathrm{Azimuth}\mathrm{accuracy}=\sqrt{\frac{.Math.{\left(\mathrm{Azimuth}\mathrm{by}\mathrm{radar}-\mathrm{Azimuth}\mathrm{by}\mathrm{AIS}\right)}^2}{N}}$ Where, N is the total number of times target centroid appears in radar and AIS data; The ratio of change points: determine the ratio of changing points based on location series (range, azimuth) of target centroids, Assuming the input data series of a target {(r.sub.i, θ.sub.i)}.sub.i=1.sup.N, to calculate the ratio of changing points we perform: calculating the distances:
d.sub.i=dist((r.sub.i+1,θ.sub.i+1),(r.sub.i,θ.sub.i)),i=1 . . . N−1 where, dist is the distance function
dist((r.sub.i+1,θ.sub.i+1),(r.sub.i,θ.sub.i))=√{square root over (r.sub.i+1.sup.2+r.sub.i.sup.2−2r.sub.i+1r.sub.i cos(θ.sub.i+1−θ.sub.i))} determining the points (r.sub.i, θ.sub.i) such that: d.sub.i>γ.sub.i, parameter γ.sub.i is chosen in step 1, for each point (r.sub.i, θ.sub.i) satisfying condition d.sub.i>γ.sub.i: determining the value (r, θ).sub.left which is the mean value of all points in the time duration φ before the point (r.sub.i, θ.sub.i), determining the value (r, θ).sub.right which is the mean value of all points in the time duration φ after the point (r.sub.i, θ.sub.i), Value φ is chosen in step 1, if
dist((r,θ).sub.left,(r,θ).sub.right)>γ.sub.2 then point (r.sub.i, θ.sub.i) is called “a possible change point” and denoted by (r.sub.i*, θ.sub.i*), Value γ.sub.2 is chosen in step 1; arrange the possible change points {(r.sub.i*, θ.sub.i*)} by in descending order of dist((r, θ).sub.left, (r, θ).sub.right), if the time difference between the point (r.sub.i*, θ.sub.i*) and (r.sub.i−1*, θ.sub.i−1*) is greater or equal φ, then (r.sub.i*, θ.sub.i*) is a change point; the ratio of change points is determined by: $\mathrm{Ratio}\mathrm{of}\mathrm{change}\mathrm{points}=\frac{\mathrm{Number}\mathrm{of}\mathrm{change}\mathrm{points}}{N};$ Step 3: evaluating and exporting results; input: parameters evaluated for each target in table: TABLE-US-00008 Target Ratio of Ratio of Ratio of Range Azimuth Ratio ID break miss reverse trend accuracy accuracy of target hits detection change points Output: evaluation results in table TABLE-US-00009 Ratio of Ratio of Ratio of Ratio of break miss reverse Range Azimuth change target hits detection trend accuracy accuracy points Mean . . . . . . . . . . . . . . . . . . Score realization: find the average values of all parameters by number of targets: $\mathrm{Average}\mathrm{ratio}\mathrm{break}\mathrm{target}\mathrm{hits}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{break}\mathrm{target}\mathrm{hits}\mathrm{of}k-\mathrm{th}\mathrm{target}$ $\mathrm{Average}\mathrm{ratio}\mathrm{of}\mathrm{miss}\mathrm{detection}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{miss}\mathrm{detection}\mathrm{of}k-\mathrm{th}\mathrm{target}$ $\mathrm{Average}\mathrm{ratio}\mathrm{of}\mathrm{reverse}\mathrm{trend}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{reverse}\mathrm{trend}\mathrm{of}k-\mathrm{th}\mathrm{target}$ $\mathrm{Average}\mathrm{accuracy}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Accuracy}\mathrm{of}k-\mathrm{th}\mathrm{target}$ $\mathrm{Average}\mathrm{ratio}\mathrm{of}\mathrm{change}\mathrm{points}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{change}\mathrm{points}\mathrm{of}k-\mathrm{th}\mathrm{target}$ where, N is the total number of targets in the output of step 2; evaluation result is estimated by: $\mathrm{Evaluation}\mathrm{result}=\underset{i=1}{\overset{6}{.Math.}}{L}_i*\left(i-\mathrm{th}\mathrm{parameter}\right)$ where, L.sub.i is the weight of i-th parameter; The evaluation result is exported in a “csv” file.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0011] Drawing 1: Scheme of radar data processing;

[0012] Drawing 2: Provided system in invention;

[0013] Drawing 3: Example of a change point of a series of radar target azimuths (degree) over consecutive scans.

DETAILED INVENTION DESCRIPTION

[0014] According to the first implementation plan, the invention provides the system to assess the centroid processing for high resolution coastal surveillance radars. This is an independent system with the radar data processing system and includes three sub-blocks corresponding to three functions. Specifically:

[0015] Function 1: loading the input data (following called “Input data block 101”).

[0016] Function 2: parameter calculating (following called “Parameter calculation block 102”).

[0017] Function 3: evaluating and exporting results (following called “Evaluation and export result block 103”).

[0018] The output of Input data block 101 will be used as the input of Parameter calculation block 102. Similarly, the output of Parameter calculation block 102 will be used as the input of Evaluation and export result block 103.

[0019] The Input data block 101: The purpose of the block is to load the input data files collected through the radar system to serve the evaluation. These data files are formatted as “*.csv” and include:

[0020] A file “Data.csv” contains location (range, azimuth, time) of target centroids according to radar and AIS. Data collection is manipulated via radar screen. First, select a target on the screen. Then, choose to record and export data to “Data.csv” file from radar system.

[0021] A file “Constant.csv” contains the value of thresholds (constants) used for calculation in “Parameter calculation block 102”. Constants are γ.sub.1 (first change threshold), γ.sub.2 (second change threshold), φ (time between two change points) and weights L.sub.i (i=1, . . . , 6) of each parameter in step 2. Parameters γ.sub.1, γ.sub.2 and φ will be selected by statistical method. The values L.sub.i can be chosen equally and equal to ⅙, or can be chosen according to the priority level. For example, if we pay much attention to the structural stability we can put the weight of the parameter “ratio of change points” higher than the weights of remaining parameters.

[0022] The output of block 101 is given in Table 1

TABLE-US-00001 TABLE 1 Target Time Target Target Target state Target Target ID (s) range by azimuth by range by azimuth by radar radar AIS AIS (m) (degree) (m) (degree)

[0023] Where, target state takes value 1 if there are target detected hits and 0 if target is not detected (miss detection).

[0024] Parameter calculation block 102 performs calculation of parameters (the ratio of break target hits, the ratio of miss detection, the ratio of reverse trend, the accuracy and the ratio of change points) for each target. The output of block 102 is saved in a “csv” file with format given in Table 2.

TABLE-US-00002 TABLE 2 Target Ratio of Ratio of Ratio of Range Azimuth Ratio ID break miss reverse trend accuracy accuracy of target hits detection change points

[0025] Evaluation and export result block 103 performs the quality assessment of the centroid processing and exporting results in the form of a “csv” file in Table 3.

TABLE-US-00003 TABLE 3 Ratio of Ratio of Ratio of Ratio of break miss reverse Range Azimuth change target hits detection trend accuracy accuracy points Mean . . . . . . . . . . . . . . . . . . Score

[0026] According to the second implementation plan, the invention provides the method of assessing the centroid processing for high resolution coastal surveillance radars. The method includes the following steps:

[0027] Step 1: Loading the input data;

[0028] At this step, two data sets (Data.csv and Constant.csv described above) are loaded to system and will be used for the parameter calculation block 102.

[0029] The output of step 1 is the data of each target shown as in Table 1 above.

[0030] Step 2: Calculating parameters;

[0031] Input: location information of centroids of target hits as given in Table 1; Constants are entered in step 1, where ID is the target identification number. Each target has only one ID to distinguish targets together. “Target state” is the logic value of 0 or 1 (value 0 corresponding when there is not target centroid—miss detection and value 1 when the target centroid appears on the radar screen).

[0032] Output: parameters (the ratio of break target hits, the ratio of miss detection, the ratio of reverse trend, the accuracy and the ratio of change points)

[0033] Realization: [0034] The ratio of break target hits is calculated by:

[00001]$\mathrm{Ratio}\mathrm{of}\mathrm{break}\mathrm{target}\mathrm{hits}=\frac{\mathrm{All}\mathrm{target}\mathrm{centroids}}{N\mathrm{umber}\mathrm{of}\mathrm{all}\mathrm{scans}}-1$ [0035] The ratio of miss detection:

[00002]$\mathrm{Ratio}\mathrm{of}\mathrm{miss}\mathrm{detection}=1-\frac{N\mathrm{umber}\mathrm{of}\mathrm{times}\mathrm{with}\mathrm{target}\mathrm{centroid}}{\mathrm{Number}\mathrm{of}\mathrm{all}\mathrm{scans}}$ [0036] The ratio of reverse trend:

[00003]$\mathrm{Ratio}\mathrm{of}\mathrm{reverse}\mathrm{trend}=\frac{N\mathrm{umber}\mathrm{of}\mathrm{times}\mathrm{the}\mathrm{target}\mathrm{centroid}\mathrm{goes}\mathrm{against}\mathrm{the}\mathrm{trend}}{N\mathrm{umber}\mathrm{of}\mathrm{all}\mathrm{scans}}$ [0037] Accuracy: [0038] By range:

[00004]$\mathrm{Range}\mathrm{accuracy}=\sqrt{\frac{.Math.{\left(\mathrm{Range}\mathrm{by}\mathrm{radar}-\mathrm{Range}\mathrm{by}\mathrm{AIS}\right)}^2}{N}}$ [0039] By azimuth:

[00005]$\mathrm{Azimuth}\mathrm{accuracy}=\sqrt{\frac{.Math.{\left(\mathrm{Azimuth}\mathrm{by}\mathrm{radar}-\mathrm{Azimuth}\mathrm{by}\mathrm{AIS}\right)}^2}{N}}$ [0040] Where, N is the total number of times target centroid appears in radar and AIS data. [0041] The ratio of change points: determine the ratio of changing points based on location series (range, azimuth) of target centroids. Assuming the input data series of a target {(r.sub.i, θ.sub.i)}.sub.i=1.sup.N. To calculate the ratio of changing points we perform: [0042] Calculating the distances:

d.sub.i=dist((r.sub.i+1,θ.sub.i+1),(r.sub.i,θ.sub.i)),i=1 . . . N−1 [0043] Where, dist is the distance function

dist((r.sub.i+1,θ.sub.i+1),(r.sub.i,θ.sub.i))=√{square root over (r.sub.i+1.sup.2+r.sub.i.sup.2−2r.sub.i+1r.sub.i cos(θ.sub.i+1−θ.sub.i))} [0044] Determining the points (r.sub.i, θ.sub.i) such that: d.sub.i>γ.sub.i. Parameter γ.sub.i is chosen in step 1. [0045] For each point (r.sub.i, θ.sub.i) satisfying condition d.sub.i>γ.sub.i: [0046] Determining the value (r, θ).sub.left which is the mean value of all points in the time duration φ before the point (r.sub.i, θ.sub.i). [0047] Determining the value (r, θ).sub.right which is the mean value of all points in the time duration φ after the point (r.sub.i, θ.sub.i). Value φ is chosen in step 1. [0048] If

dist((r,θ).sub.left,(r,θ).sub.right)>γ.sub.2 [0049] then the point (r.sub.i, θ.sub.i) is called “a possible change point” and denoted by (r.sub.i*, θ.sub.i*). Value γ.sub.2 is chosen in step 1.

{(r.sub.i*,θ.sub.i*)}dist((r,θ).sub.left,(r,θ).sub.right)(r.sub.i*,θ.sub.i*)(r.sub.i−1*,θ.sub.i−1*)φ(r.sub.i*,θ.sub.i*) [0050] Arrange the possible change points by in descending order of

{(r.sub.i*,θ.sub.i*)}dist((r,θ).sub.left,(r,θ).sub.right)(r.sub.i*,θ.sub.i*)(r.sub.i−1*,θ.sub.i−1*)φ(r.sub.i*,θ.sub.i*).

If the time difference between the point and is greater or equal, then is a change point (Drawing 3).

[0051] The ratio of change points is determined by:

[00006]$\mathrm{Ratio}\mathrm{of}\mathrm{change}\mathrm{points}=\frac{\mathrm{Number}\mathrm{of}\mathrm{change}\mathrm{points}}{N}.$

Step 3: Evaluating and Exporting Results;

[0052] Input: parameters evaluated for each target in table 2.

[0053] Output: evaluation results in table 3.

[0054] Realization: [0055] Find the average values of all parameters by number of targets:

[00007]$\mathrm{Average}\mathrm{ratio}\mathrm{break}\mathrm{target}\mathrm{hits}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{break}\mathrm{target}\mathrm{hits}\mathrm{of}k-\mathrm{th}\mathrm{target}$$\mathrm{Average}\mathrm{ratio}\mathrm{of}\mathrm{miss}\mathrm{detection}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{miss}\mathrm{detection}\mathrm{of}k-\mathrm{th}\mathrm{target}$$\mathrm{Average}\mathrm{ratio}\mathrm{of}\mathrm{reverse}\mathrm{trend}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{reverse}\mathrm{trend}\mathrm{of}k-\mathrm{th}\mathrm{target}$$\mathrm{Average}\mathrm{accuracy}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Accuracy}\mathrm{of}k-\mathrm{th}\mathrm{target}$$\mathrm{Average}\mathrm{ratio}\mathrm{of}\mathrm{change}\mathrm{points}=\frac{1}{N}\underset{k=1}{\overset{N}{.Math.}}\mathrm{Ratio}\mathrm{of}\mathrm{change}\mathrm{points}\mathrm{of}k-\mathrm{th}\mathrm{target}$

[0056] where, N is the total number of targets in the output of step 2. [0057] Evaluation result is estimated by:

[00008]$\mathrm{Evaluation}\mathrm{result}=\underset{i=1}{\overset{6}{.Math.}}{L}_i*\left(i-\mathrm{th}\mathrm{parameter}\right)$ [0058] where, L.sub.i is the weight of i-th parameter.
The evaluation result is exported as a “csv” file (Table 3).

[0059] While preferred embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.