JP4966105B2 - Target angle measuring device - Google Patents

Description

  The present invention relates to a target angle measurement device used in a pulse radar device, and more particularly to a target angle measurement device that precisely measures a target angle detected by performing integration processing on a received radar pulse reflected wave.

  In order to obtain position information such as target distance and angle using pulse radar, for example, a reflected wave of a radar pulse transmitted while scanning a radar beam in a predetermined direction is received, and the received reflected wave is A target detection process for determining the presence of the target is performed. When the target is detected, distance information to the target is acquired based on the time difference between transmission and reception of the radar pulse, and target angle information is acquired based on the pointing direction of the radar beam at that time. Further, for target angle information, for example, angle measurement processing is performed by a method such as monopulse angle measurement, and based on the ratio of reflected waves received by each angle measurement beam having directivity characteristics called Σ beam and Δ beam, in advance The angle information is obtained by referring to the created angle measurement table.

  In this type of pulse radar apparatus, the reflected wave of the received radar pulse is often integrated over a plurality of continuous PRI (Pulse Repetition Intervals) so as to perform good target detection. The continuous number is, for example, several PRI to several tens PRI. The integration period over a plurality of PRIs is called CPI (Coherent Processing Interval) and is represented by an integral multiple of PRI. Then, the reflected wave integrated for each CPI is sent to the subsequent stage and used for various processes such as the target detection process and the angle measurement process described above.

As described above, an example of a radar apparatus that performs target detection and angle measurement processing using an integrated radar pulse reflected wave is disclosed (for example, see Patent Document 1). In the case disclosed in this patent document 1, the target angle measurement value is calculated by monopulse angle measurement processing that refers to the angle measurement table using the integrated received signal during angle measurement processing in the low elevation angle region. ing.
Japanese Patent Laying-Open No. 2005-233673 (7th page, FIG. 1)

  Incidentally, the angle measurement table used in the angle measurement process described above is created in advance as a static table based on the beam patterns of the Σ beam and Δ beam for angle measurement. Accordingly, in the angle measurement process using the angle measurement table, the angle information is calculated on the assumption that the directional relationship between the target and these angle measurement beams does not change during the process.

  However, since the target position is constantly changing during the CPI period, and the angle measuring beam is sequentially scanned for each pulse, the relationship between the target and the angle measuring beam is not necessarily constant throughout the CPI period. , Changes from moment to moment. For this reason, when the angle measurement process is performed by applying this angle measurement table to the signal integrated in the unit of the CPI period, the calculation result includes an error due to the change described above. Therefore, it has been desired to obtain angle measurement results with higher accuracy.

  The present invention has been made in consideration of the above-described circumstances, and has higher accuracy when performing angle measurement processing on a target detected by performing integration processing on a reflected wave received by a pulse radar device. An object of the present invention is to provide a target angle measuring device that acquires a result of angle measurement.

In order to achieve the above object, a target angle measuring apparatus according to a first aspect of the present invention is used in a pulse radar apparatus including a tracking process for tracking while predicting position information of a detected target, and applying a result of the tracking process. A target angle measuring device that precisely measures target angle information, and forms a Σ beam and a Δ beam as predetermined angle measuring beams, and also reflects reflected wave signals of radar pulses received by the respective beams. Angle measuring beam forming means for integrating a predetermined CPI (Coherent Processing Interval) in the direction and outputting a signal after integration of the Σ beam and Δ beam for each CPI period, and from these angle measuring beam forming means Based on the signal level, the target in the angle measuring beam integrated over the CPI period is detected, and when the target is detected, Target detection means for calculating Δ / Σ, which is a level ratio of the signal after integration of the Δ beam and Σ beam with respect to the target, as an error voltage, and a predicted position from the tracking processing for the target detected by the target detection means Based on the information, within the angle measuring beam of the target during the CPI period as seen from the own apparatus, due to the mutual change between the moving direction of the target during the CPI period and the scanning direction of the angle measuring beam. Angle change predicting means for predicting the angle change tendency at the angle, and the error voltage and the target angle measured in advance reflecting the angle change tendency in the target angle measurement beam during the CPI period A plurality of angle measurement tables for associating values, and selecting one of the plurality of angle measurement tables based on the prediction result from the angle change prediction means; And having a angle measuring means for Seihaka angle information of the target with reference to the corner table based on the error voltage from the target detector.

Further, the target angle measuring apparatus of the second invention is used in a pulse radar apparatus including a tracking process for tracking while predicting the position information of the detected target. The target angle information is obtained while applying the result of the tracking process. A target angle measuring apparatus for precise measurement, which forms a Σ beam and a Δ beam as predetermined angle measuring beams, and outputs a reflected wave signal of a radar pulse received by each beam to a predetermined CPI ( Coherent processing interval), and angle measuring beam forming means for outputting a signal after integration of the Σ beam and Δ beam for each CPI period, and based on the level of the signal from these angle measuring beam forming means A target in the angle measuring beam integrated over the CPI period is detected, and if a target is detected, the target for the target is detected. Based on target detection means for calculating Δ / Σ, which is the level ratio of the signal after integration of Δ beam and Σ beam, as an error voltage, and predicted position information from the tracking process for the target detected by the target detection means. The angle change of the target in the angle measuring beam during the CPI period as seen from its own apparatus due to the mutual change between the moving direction of the target and the scanning direction of the angle measuring beam during the CPI period. The angle change prediction means for predicting the tendency of the angle and the angle measurement table that associates the error voltage with the target angle measurement value set in advance are corrected based on the prediction result from the angle change prediction means, and after this correction Angle measuring means for accurately measuring the angle information of the target based on the error voltage from the target detecting means with reference to the angle measuring table.

  According to the present invention, a target angle at which a more accurate angle measurement result can be obtained when angle measurement is performed on a target detected by performing integration processing on a reflected wave received by a pulse radar device. A measuring device can be obtained.

  Hereinafter, the best mode for carrying out a target angle measuring apparatus according to the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram showing a first embodiment of a target angle measuring apparatus according to the present invention. The target angle measurement apparatus illustrated in FIG. 1 is connected to, for example, a pulse radar apparatus including a tracking process for tracking while predicting position information of a detected target, and includes an angle measurement beam forming unit 11 and a target detection processing unit. 12, an angle measurement processing unit 13, an angle measurement table group 14, and an angle measurement table selection unit 15.

  The angle measurement beam forming unit 11 forms a Σ beam and a Δ beam as angle measurement beams by using a technique such as DBF (Digital Beam Forming), and scans in a predetermined direction, and receives the formed beams. The reflected wave of the radar pulse is integrated for a predetermined CPI period, and the integrated signal is sent to the target detection processing unit 12 together with the CPI number as its CPI identification information in each CPI unit. In addition, the CPI identification information and the beam management information including the formed beam directing direction are sent to the angle measurement table selection unit 15. The relationship between the beam to be formed, its scan and CPI is modeled and illustrated in FIG. In the example shown in FIG. 2, the case of the Σ beam formed when the angle is measured while scanning in the azimuth direction is taken, and the CPI period is 8 times the PRI. That is, the reflected wave for each of the eight consecutive transmission pulses is received and integrated by each Σ beam, and is output together with the CPI number for each CPI. The Δ beam is similarly processed and output.

  The target detection processing unit 12 determines whether or not a target is present based on the level of the signal after integration from the angle measurement beam forming unit 11. For the target determination, for example, a technique for determining a signal level based on an appropriate signal-to-noise threshold value can be applied. When the target is detected, Δ / Σ, which is the level ratio of each signal after integration of Δ beam and Σ beam, is calculated as the detected error voltage of the target, and the calculation result is measured together with the CPI identification information. Send to the corner processing unit 13. The angle measurement processing unit 13 refers to one angle measurement table selected by the angle measurement table selection unit 15 from the angle measurement table group 14 to be described later based on the error voltage Δ / Σ from the target detection processing unit 12. The target angle measurement value is calculated.

  The angle measurement table group 14 includes a plurality of angle measurement tables 141 to 14n set in advance. Each angle measurement table is set with a table value that associates the error voltage Δ / Σ with the angle measurement value, and is referred to when the angle measurement processing unit 13 calculates the target angle measurement value. Since the detected target is moved even during the CPI period, and the relationship between the target and the angle beam is not necessarily constant throughout the CPI period, the table values of the plurality of angle measurement tables 141 to 14n are the CPI period. Different values are set to reflect the tendency of movement in the target angle beam. 3 and 4 are diagrams for explaining a difference in table values among the plurality of angle measurement tables.

  FIG. 3 shows an example in which the tendency of the target angle change in the azimuth angle measuring Σ beam corresponding to the CPI period is modeled into six patterns as an example. An example of a table value in each of the six types of patterns is shown as a graph using a curve. In the case of FIG. 3, the following six types of angle change tendencies within the beam are shown: the left end of the beam in FIG. 3 (a), the left center of the beam in FIG. 3 (b), and the The left side of the center of the beam, the right side of the center of the beam in FIG. 3D, the center of the right side of the beam in FIG. 3E, and the right end of the beam in FIG. An angle measurement table is provided corresponding to each of these patterns, and each angle measurement table has different table values corresponding to, for example, curves shown in association with each pattern in FIG. Set in advance. In this example, the angle value associated with the error voltage Δ / Σ is an error angle from the angle beam center. As described above, in the case where the target angle change tendency is six types as in the example of FIG. 3, the angle measurement table group 14 is composed of six types of angle measurement tables 141 to 146 corresponding to each. .

  The angle measurement table selection unit 15 receives predicted position information of a target as a tracking processing result from a pulse radar device or the like, and measures the angle of the target during the CPI period with respect to the target detected by the target detection processing unit 12. The angle change tendency in the beam is predicted, and based on the prediction result, one of the angle measurement tables 141 to 14n in the angle measurement table group 14 is selected and delivered to the angle measurement processing unit 13. . That is, as a result of the tracking process, for example, the predicted position information of the target pinpoint after a predetermined time has been continuously transmitted from the pulse radar device or the like. The tendency of the angle change in the angle measurement beam is predicted so as to draw a wake from the information, and an appropriate angle measurement table is selected.

  Next, the operation of the target angle measuring apparatus of the present embodiment configured as described above will be described with reference to the flowcharts of FIGS. 1 to 4 and FIG. FIG. 5 is a flowchart for explaining the operation of the first embodiment of the target angle measuring apparatus according to the present invention.

  First, the angle measurement table group 14 including a plurality of angle measurement tables is set in advance. In setting, for example, the tendency of the angle change in the target angle measuring beam during the CPI period is modeled into patterns as shown in FIGS. 3A to 3F, and the angle measurement to be formed for each of them is modeled. A table value is set based on the beam characteristics and the like (ST501).

  When a reflected wave of a radar pulse transmitted by a predetermined PRI from a pulse radar device or the like is received and sequentially sent to the angle measuring beam forming unit 11 (ST502), the angle measuring beam forming unit 11 uses a technique such as DBF. Are used to form a Σ beam and a Δ beam for angle measurement (ST503), and the reception results of these beams are integrated for a predetermined CPI period. As a result, the reflected waves for a plurality of radar pulses continuous within the CPI period are integrated, and the result is sent to the target detection processing unit 12 (ST504). The target detection unit 12 detects a target with respect to the integrated reflected wave by a method such as level determination using an appropriate threshold (ST505), and when a target is detected (Y in ST506) ) To calculate an error voltage Δ / Σ for the target. The calculated error voltage Δ / Σ is sent to the angle measurement processing unit 13 (ST507).

  On the other hand, in order to select the angle measurement table necessary for the angle measurement process in the angle measurement processing unit 13 from the angle measurement table group 14, the angle detection table selection unit 15 detects the angle detection table in the target detection processing unit 12. For a target, the CPI predicts the tendency of the angle change in the target's angle beam during the period. For this prediction, for example, the target detection processing unit 12 uses the beam management information and CPI identification information from the angle measurement beam forming unit 11 and the target detection processing unit 12 for the tracking processing result from a pulse radar device or the like. Correspondence with the detected target is performed, and the tendency is predicted by drawing a wake from the predicted position information (ST508). Then, an angle measurement table that is determined to be optimal is selected by comparing the similarity between the prediction of the tendency and the pattern modeled in step ST501. The selected angle measurement table is delivered to the angle measurement processing unit 13 (ST509).

  Then, the angle measurement processing unit 13 calculates an angle measurement value by referring to the angle measurement table from the angle measurement table selection unit 13 based on the error voltage calculated in step ST507. In the calculation, the angle from the center of the angle measurement beam obtained by referring to the angle measurement table and the pointing angle information of the angle measurement beam based on the CPI identification information and beam management information of the angle measurement beam are calculated. ,Get results. The angle value calculated in this way is sent to a subsequent device for display of target information or for use in tracking processing as a precise measurement value of target angle information (ST510). Thereafter, until the end of the operation is instructed, the steps from ST502 described above are repeated as the scanning in a predetermined direction is successively continued (ST511).

  As described above, in this embodiment, when the angle measurement process is performed on the target detected by performing the CPI period integration process on the received reflected wave of the radar pulse, the target measurement during the CPI period is performed. A plurality of angle measurement tables in which table values are set in advance reflecting the angle change tendency in the angle beam are prepared, and the angle change tendency in the angle measurement beam during the detected target CPI period is predicted. At the same time, based on the result, an appropriate angle measurement table is selected from a plurality of angle measurement tables and applied to calculate the angle measurement value. Thereby, the angle measurement error resulting from the angle change between the target and the angle measurement beam during the CPI period can be reduced, and the angle measurement result of the target with higher accuracy can be acquired.

  FIG. 6 is a block diagram showing a second embodiment of the target angle measuring apparatus according to the present invention. FIG. 7 is a flowchart for explaining the operation of the second embodiment of the target angle measuring apparatus. In the second embodiment, the same parts as those in the first embodiment shown in FIGS. 1 to 5 are denoted by the same reference numerals, and the description thereof is omitted. The second embodiment is different from the first embodiment in that the angle measurement table to be referred to in the angle measurement processing is provided, and in the first embodiment, a plurality of angle measurement tables are provided in advance as the angle measurement table group. While one angle measurement table is selected based on the prediction result of the angle change within the target angle measurement beam, in the second embodiment, one angle measurement table set in advance is selected as the target angle measurement table. This is a point applied to the angle measurement process while correcting based on the prediction result of the angle change in the angle measurement beam. Only the differences will be described below with reference to FIGS. 1 to 5 and FIGS. 6 to 8.

  As illustrated in FIG. 6, the target angle measurement apparatus includes an angle measurement beam forming unit 11, a target detection processing unit 12, an angle measurement processing unit 13, an angle measurement table 61, and an angle measurement table correction unit 62. Yes. In the angle measurement table 61, a table value for associating the error voltage Δ / Σ from the target detection processing unit 12 with the angle measurement value is set. As this table value, for example, a value in a known situation is set in advance by modeling a case where the target angle does not change in the angle measuring beam during the CPI period as shown in FIG. The

  The angle measurement table correction unit 62 predicts the tendency of the angle change in the angle measurement beam during the target CPI period detected by the target detection processing unit 12 by the same method as the angle measurement table selection unit 15, and The table value of the angle measurement table 61 is corrected based on this prediction result. In calculating the correction value, for example, as shown in FIG. 8A, a correction value calculation formula using a target angle change range θ as a prediction result viewed from the angle measurement beam center as a parameter is expressed in several orders. A method of calculating a correction value for the set value of the angle measurement table 61 illustrated in FIG. 8B by using this calculation formula can be applied.

  Next, the operation of this target angle measuring apparatus will be described with reference to the flowchart of FIG. First, the table value of the angle measurement table 61 is set. As the set value, for example, a value in a known situation obtained by modeling a predetermined situation is set (ST701). After starting to receive the reflected wave of the radar pulse, the error voltage Δ / Σ is calculated with respect to the target detected by integrating the reflected wave over the CPI period as in the case of the first embodiment (ST502 to ST507). Subsequently, the angle measurement table correction unit 62 predicts the tendency of the angle change in the target angle measurement beam during the CPI period by the same method as the angle measurement table selection unit 15, and the angle change range θ. Is obtained (ST508).

  Further, the angle measurement table correction unit 62 calculates a correction value from the prediction result by using a correction value calculation formula or the like, corrects the angle measurement table 61, and sends it to the angle measurement processing unit 13 (ST709). Then, the angle measurement processing unit 13 refers to the corrected angle measurement table and calculates a target angle measurement value based on the error voltage Δ / Σ calculated in step ST507 (ST510).

  As described above, in this embodiment, when the angle measurement process is performed on the target detected by performing the CPI period integration process on the reflected wave of the received radar pulse, during the detected target CPI period. The angle change value in the angle measurement beam is predicted, and the angle measurement value is calculated while correcting the table value of the angle measurement table set in advance based on the result. Therefore, similarly to the first embodiment, in this embodiment, the angle measurement error due to the angle change between the target and the angle beam during the CPI period can be reduced, and the angle measurement result with higher accuracy can be obtained. Can be obtained.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The block diagram which shows the 1st Example of the target angle measuring apparatus which concerns on this invention. The figure which models and illustrates the relationship between the angle measuring beam to form, its scanning, and CPI. The figure which models and illustrates the tendency of the angle change of the target in the period of CPI. FIG. 4 is a diagram illustrating an example of a table value in each pattern of FIG. 3 in a graph. The flowchart for demonstrating operation | movement of the 1st Example of the target angle measuring apparatus which concerns on this invention. The block diagram which shows the 2nd Example of the target angle measuring apparatus which concerns on this invention. The flowchart for demonstrating operation | movement of the 2nd Example of the target angle measuring apparatus which concerns on this invention. The figure for demonstrating the correction value of an angle measurement table.

Explanation of symbols

11 Angle measurement beam forming unit 12 Target detection processing unit 13 Angle measurement processing unit 14 Angle measurement table group 15 Angle measurement table selection unit 61 Angle measurement table 62 Angle measurement table correction unit

Claims (2)

A target angle measurement device that is used in a pulse radar device including a tracking process that tracks while predicting position information of a detected target, and that precisely measures target angle information while applying the result of the tracking process,
A Σ beam and a Δ beam as predetermined angle measuring beams are formed, and the reflected wave signal of the radar pulse received by each beam is integrated in the scanning direction for a predetermined CPI (Coherent Processing Interval) period, and this CPI Angle measuring beam forming means for outputting a signal after integration of the Σ beam and Δ beam for each period;
Based on the level of the signals from the angle beam forming means, a target in the angle beam that has been integrated for the CPI period is detected. If a target is detected, the integration of the Δ beam and the Σ beam with respect to the target is detected. Target detection means for calculating Δ / Σ, which is the level ratio of the subsequent signal, as an error voltage;
Based on the predicted position information from the tracking process with respect to the target detected by the target detecting means , the own apparatus is based on the mutual change between the moving direction of the target and the scanning direction of the angle beam during the CPI period. Angle change predicting means for predicting a tendency of angle change in the angle measuring beam of the target during the CPI period viewed from
A plurality of angle measurement tables that correlate the error voltage and the target angle measurement value, which are set in advance to reflect the tendency of the angle change in the target angle measurement beam during the CPI period; Based on the prediction result from the change prediction means, one of these angle measurement tables is selected, and the target angle information based on the error voltage from the target detection means with reference to the selected angle measurement table A target angle measuring device comprising angle measuring means for precisely measuring the angle. A target angle measurement device that is used in a pulse radar device including a tracking process that tracks while predicting position information of a detected target, and that precisely measures target angle information while applying the result of the tracking process,
A Σ beam and a Δ beam as predetermined angle measuring beams are formed, and the reflected wave signal of the radar pulse received by each beam is integrated in the scanning direction for a predetermined CPI (Coherent Processing Interval) period, and this CPI Angle measuring beam forming means for outputting a signal after integration of the Σ beam and Δ beam for each period;
Based on the level of the signals from the angle beam forming means, a target in the angle beam that has been integrated for the CPI period is detected. If a target is detected, the integration of the Δ beam and the Σ beam with respect to the target is detected. Target detection means for calculating Δ / Σ, which is the level ratio of the subsequent signal, as an error voltage;
Based on the predicted position information from the tracking process with respect to the target detected by the target detecting means , the own apparatus is based on the mutual change between the moving direction of the target and the scanning direction of the angle beam during the CPI period. Angle change predicting means for predicting a tendency of angle change in the angle measuring beam of the target during the CPI period viewed from
A preset angle measurement table that associates the error voltage with the target angle measurement value is corrected based on the prediction result from the angle change prediction means, and the target detection is performed with reference to the corrected angle measurement table. A target angle measuring device comprising angle measuring means for precisely measuring the target angle information based on an error voltage from the means.

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