JP2009019984A - Target observation radar device and target tracking method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of correction instead of correction of an observation prediction value by parallel movement. <P>SOLUTION: This target observation radar device includes an observation plan formation processing section for forming an observation prediction value according to a locus data of an observed target. The target observation radar device further includes an observation execution plan processing section that obtains two or more locus models according to consideration of an error value including a data error included in the locus data of the observed target and an instable element of the specific locus of the target, extracts locus data approximated to the observation data obtained by initially catching the target from the above locus data, and outputs the observation prediction value of the extracted locus data as the tracked observation data of the target. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a ground-based target observation radar apparatus and a target tracking method for detecting and tracking (hereinafter referred to as observation) an artificial object (hereinafter referred to as a target) such as an artificial satellite or space debris orbiting the earth orbit.

  Observation by a ground-mounted target observation radar device, a so-called primary radar device, has already stopped operation and has stopped responding to the interrogation signal transmitted from the secondary radar device, space debris without active response function ( Rocket boosters or fragments etc. scattered by collision, explosion, etc.) (Patent Documents 1 to 4).

  Objects to be observed by the primary radar device are classified into targets that have already been cataloged with their orbital values already known from past observations, and targets that are newly generated and have unknown orbits.

  A general observation system using a primary radar apparatus is shown in FIG. The primary role of the primary radar apparatus shown in FIG. 5 is to find an unknown target, track the target, and obtain a trajectory from the track. The primary radar apparatus shown in FIG. 5 includes a radar unit 1 that emits an antenna, a signal processing unit 2, a trajectory value conversion processing unit 3, a trajectory database 4, an initial acquisition plan processing unit 5, and a beam scanning data processing unit. 6.

  The primary radar apparatus shown in FIG. 5 generally does not have prediction information for the position and motion of the target. After detecting the target, the position change (vector) is obtained from the detected data, and the next radar hit The autonomous tracking is performed by controlling the beam direction of the antenna.

  In the case of a target orbiting the earth, as shown in FIG. 6, two or more radar stations 9 are distributed on the earth, and each radar station 9 is connected to each other by a network 10. By relaying the observation data of the target moving through the network 10 one after another, even if there is a change in the orbital value, the time interval is shortened, so the change is reduced and the target is not missed. The method is taken.

  For targets for which orbital values are already known and when and where to pass can be obtained by orbital calculation, observation forecast values are created in advance, and observations are made according to the observation forecast values. Can be raised. This type of radar apparatus is shown in FIG.

  The radar apparatus shown in FIG. 7 includes a radar unit 1 that emits radio waves from an antenna, a signal processing unit 2, an orbital value conversion processing unit 3, an orbital database 4, an observation plan creation processing unit 7, and a beam scanning data process. Part 6.

  The radar apparatus shown in FIG. 7 prepares a series of parameters (observation forecast values) starting with AOS and ending with LOS before starting observation, and performs initial acquisition and tracking accordingly. Even if the orbital stability is high to some extent, the error ΔT is not zero in actual observation, so that the forecast value must be corrected when the initial acquisition is completed. In this case, the forecast value is corrected by moving the observed forecast value on the time axis by ΔT to generate a new observed value.

The radar apparatus shown in FIG. 8 is an observation system for a target with low orbit stability. The radar unit 1 emits radio waves from an antenna, a signal processing unit 2, an orbital value conversion processing unit 3, an orbit database 4 and the like. , An observation plan creation processing unit 7, an observation parameter reconstruction processing unit 8, and a beam scanning data processing unit 6.
JP 2002-249100 A JP 2004-205525 A JP 2006-213089 A Japanese Patent No. 3001757

  However, in the case of the radar apparatus shown in FIG. 7, as shown in FIGS. 10A and 10B, when the absolute value t1 of the time deviation ΔT of the orbit is small, it can be approximated by parallel movement, but the absolute value t2 to some extent. If is large, it is practically impossible to generate a new observation value by moving the observation forecast value on the time axis by ΔT.

  The radar apparatus shown in FIG. 8 assumes a case where the trajectory stability is low because the target is on a low trajectory, and it is assumed that the parallel movement of ΔT is insufficient, and ΔT obtained by initial capture of the target is obtained. It is intended to obtain new observation forecast values by feeding back to the calculation used to generate the observation forecast values and restarting the calculation from the beginning.

  However, in the radar apparatus of FIG. 8, it is necessary to perform the recalculation process in real time from the end of the initial acquisition to the start of tracking, which is not realistic considering the burden on the system. There is a need for alternative equivalent strategies.

  An object of the present invention is to provide a target observation radar apparatus and a target tracking method that employ a correction method that replaces correction of an observation forecast value by parallel movement.

In order to achieve the above object, a target observation radar device according to the present invention is a target observation radar device for tracking observation of a target,
An observation plan creation processing unit that creates observation forecast values based on the trajectory data of the target;
A range of possible time lag is set in consideration of an error in the observation forecast value from the observation plan creation processing unit, and two or more trajectory models of the target are obtained within the range, and the target is initialized. And an observation execution plan processing unit that extracts the orbit model approximated to the captured observation data and outputs data based on the extracted orbit model as tracking observation data of the target.

  The present invention is not limited to the case where it is constructed as a target observation radar device as hardware. The present invention may be constructed as a target observation program as software or an eye tracking method.

A target observation program according to the present invention includes a computer constituting a target observation radar device that tracks and tracks a target,
A function to create observation forecast values based on the trajectory data of the target;
A function of setting a range of possible time lag in consideration of an error in the observation forecast value from the observation plan creation processing unit, and obtaining two or more trajectory models of the target within the range;
The trajectory model approximated to the observation data obtained by initially capturing the target is extracted, and a function of outputting data based on the extracted trajectory model as tracking observation data of the target is constructed.

A target tracking method according to the present invention is a target tracking method for tracking observation of a target,
Create observation forecast values based on the trajectory data of the target,
A range of possible time lags is set in consideration of errors in the observation forecast value, and two or more trajectory models of the target are determined within the range,
The trajectory model approximated to the observation data obtained by initially capturing the target is extracted, and the data based on the extracted trajectory model is output as tracking observation data of the target.

  According to the present invention, it is possible to improve the correction accuracy for a target with a large trajectory shift, and to increase the tracking duration time.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  For example, if the target is an artificial satellite that orbits the earth, the difference between the observed observation value of the target and the actual observation will be (1) mispredicted based on the errors included in the past observation data used for the prediction. (2) Fluctuations of various external factors that occurred within the time lapse from the time point of past observations to the present (for example, changes in atmospheric density in high airspace affected by solar activity, It is conceivable that the trajectory of the target slips due to the difference in mass.

  Case (1) is a random error that depends on the characteristics of the radar observation system, whereas case (2) is treated as an unpredictable variable at the time of observation. When the target is on a relatively low altitude trajectory, the trajectory fluctuates particularly greatly. Especially in order to reliably observe a target that is approaching (falling) into the atmosphere, an observation method that can cope with this fluctuation is used. It is necessary to devise. These orbital changes appear as altitude changes, and the angular velocity of the target around the earth changes, so that the time (AOS) that enters the field of view of the radar station changes. At the same time, it appears as a deviation in azimuth and a change in maximum elevation angle due to the rotation of the earth.

  FIG. 9 shows an example of the relationship between the azimuth and elevation angle at which a target whose trajectory has changed appears in the field of view of the radar station. In FIG. 9, when the target trajectory R1 indicated by the solid line is used as a reference, the target trajectory R2 indicated by the one-dot chain line is a case where the target appears earlier in the field of view of the radar station than the predicted time on the trajectory R1. The elevation angle is already in the vicinity of 40 degrees at time t = a (time shift ΔT is negative). The trajectory R3 of the target indicated by the two-dot chain line is a case where the target appears later in the field of view of the radar station than the predicted time on the trajectory R1 (time shift ΔT is positive), and is still at the time of t = a. Below 40 degrees.

  From the above relationship, only the time lag is noticeable near the time (AOS) when the target appears in the field of view of the radar station and the time (LOS) when the target disappears inside and outside the field of view of the radar station. In the high-elevation region, the azimuth, elevation angle, and time are greatly shifted.

  If the absolute value of the time shift ΔT is relatively small (for example, about 10 seconds or less), the time shift (correction) is performed by ΔT obtained by the initial acquisition with respect to the forecast value already obtained. Thus, an approximate value close to the true value can be obtained. However, when the absolute value is large as shown in FIGS. 10A and 10B, the approximation is not sufficient, and tracking is broken particularly near the high elevation angle, so further measures are required.

  As shown in FIG. 1, the target observation radar apparatus according to the embodiment of the present invention uses a system in which the beam directing direction can be electronically controlled by the phased array antenna shown in FIG. In this way, a system is constructed that enables continuous observation with only one station, such as capturing a target, for example, a target that appears in the field of view of the local station again, such as a satellite.

  As shown in FIG. 1, the target observation radar apparatus according to the embodiment of the present invention includes a radar unit 1, a signal processing unit 2, a trajectory value conversion processing unit 3, a trajectory database 4, and a beam scanning data processing unit 6. In addition, an observation plan creation processing unit 11 and an observation execution plan processing unit 12 are included.

  As shown in FIG. 2, the radar unit 1 radiates a radio beam 14 from a radar station 13 toward a space through which a target passes, and a spot 14a of the radio beam 14 is set in a lateral sector search area ( The target is captured by scanning the space within the range of n) and the elevation sector search area (m) set in the vertical direction.

  In the example shown in FIG. 2, the radar unit 1 scans the spot 14a of the radio beam 14 in the horizontal direction at times t1, t2... T (n) within the direction sector search area (n), and then the direction. Return to the reference position (right end in FIG. 2) of the sector search area (n), shift the vertical direction of the elevation sector search area (m) by one step, and scan again from the time t (n + 1) in the horizontal direction. Search for (n) and elevation search area (m). The search volume for searching the azimuth sector search area (n) and the elevation search area (m) with the spot 14a of the radio wave beam 14 is (n * m).

  In FIG. 2, an arrow A indicates the movement trajectory of the target. ● indicates that the target is detected by the spot 14 a of the radio wave beam 14. ○ indicates that the target was not detected by the spot 14 a of the radio wave beam 14. The radar unit 1 shown in FIG. 2 is an example, and a device other than the search method shown in FIG. 2 may be used. In short, the radar unit 1 may be any system as long as it can capture a target.

  The signal processing unit 2 detects the target by identifying the reflected signal reflected by the target from the radio wave radiated from the radar unit 1 from the noise signal, and converts the position information of the target into the trajectory value conversion processing unit. 3 to send. The signal processing unit 2 uses the monopulse angle measurement function provided in the radar unit 1 to detect the movement trajectory and reference of the target detected within the range of the azimuth sector area (n) and the elevation angle area (m). A time shift ΔT with respect to the target movement trajectory is detected, and the data of the time shift is transmitted to the trajectory value conversion processing unit 3. The above-described processing of the signal processing unit 2 is general-purpose, and the processing does not have the characteristics of the embodiment of the present invention, and detailed description thereof is omitted. The signal processing unit 2 sequentially transmits correction data to the beam scanning data processing unit 6 when the target deviates from the center of the radio wave beam 14 of the radar unit 1 by a certain limit.

  The trajectory value conversion processing unit 3 converts the position information of the target received from the signal processing unit 2 into the trajectory data of the target captured by the radar unit 1 and uses the data as the trajectory data of the target actually observed. Transmit to the trajectory database 4. The orbital value conversion processing unit 3 transmits the time shift data (ΔT data in FIG. 1) received from the signal processing unit 2 to the observation execution plan processing unit 12 described later. The above-described processing of the trajectory value conversion processing unit 3 is general-purpose, and the processing does not have the characteristics of the embodiment of the present invention, and detailed description thereof is omitted.

  The trajectory database 4 sequentially stores and stores target trajectory data, which is actual observation data, received from the trajectory value conversion processing unit 3.

  The observation plan creation processing unit 11 reads data from the trajectory database 4 and creates an observation forecast value of the target trajectory for the next observation based on the observed target trajectory data.

  The observation plan creation processing unit 11 uses the trajectory data of the target obtained by past observations stored in the trajectory database 4 to determine the time when the target will reach the radar unit 1 in the future. Further, the azimuth angle, elevation angle, and distance of the target are calculated in advance at desired time intervals during the period in which the target passes through the field of view of the radar unit 1, and stored as observation forecast values.

  The observation execution plan processing unit 12 sets a range of possible time lag ΔT in consideration of an error in the observation forecast value from the observation plan creation processing unit 11, as shown in FIGS. 3 (a) and 3 (b). Within the set range, two or more trajectory models M1 to Mn of the target in the relationship between the elevation angle, the azimuth, and the time are obtained, and the trajectory data M1 to Mn approximated to the observation data obtained by initially capturing the target are extracted. Data based on the extracted trajectory models M1 to Mn is output as tracking observation data of the target.

  The observation execution plan processing unit 12 considers, for example, forecast value accuracy as the error included in the trajectory data of the target as the error to be considered for the observation forecast value, and as an unstable element of the trajectory unique to the target, for example Consider orbit stability. The observation execution plan processing unit 12 sets the maximum width of the forecast value error that is the difference between the actual trajectory of the target and the observed forecast value as the range of the time shift ΔT.

  The observation execution plan processing unit 12 uses an observation forecast value corresponding to the extracted orbit model as data based on the orbit model. The observation execution plan processing unit 12 calculates an observation prediction value for each of the extracted orbital models M1 to Mn, that is, observation parameters such as AOS (see FIG. 9), azimuth angle, elevation angle, distance, and line-of-sight velocity for the observation time, Records and saves these observation forecast values. The process for calculating the observation forecast value for each orbit model is general-purpose, and since the process has no features in the embodiment of the present invention, detailed description thereof is omitted.

  The beam scanning data processing unit 6 converts the tracking observation data of the target output from the observation execution plan processing unit 12 into a control signal for controlling the radio beam 14 and transmits the control signal to the radar unit 1. .

  In the above description, the hardware target observation radar device is constructed. However, the signal processing unit 2, the orbital value conversion processing unit 3, the orbital database 4, the observation plan creation processing unit 11, and the observation execution plan processing unit 12 are used. It may be constructed as a program as software that causes a computer to execute the function.

  Next, a case where tracking observation of a target is performed using the target observation radar apparatus according to the embodiment of the present invention shown in FIG. 1 will be described with reference to FIG.

  The observation plan processing unit 11 extracts all target data passing through the field of view of the radar unit 1 within the observation period from the stored data in the orbit database 4 and, for each extracted target, the observation parameters (observation) AOS with respect to time, azimuth angle, elevation angle, distance, line-of-sight speed, etc.), that is, observation forecast values are generated (step S1 in FIG. 4).

  When the observation execution plan processing unit 12 receives the observation forecast value from the observation plan processing unit 11, a range of a possible time shift ΔT in consideration of errors (predicted value accuracy, orbit stability, etc.) in the observation forecast value. And two or more trajectory models M1 to Mn of the target in the relationship between the elevation angle, the azimuth, and the time are obtained within the set range as shown in FIGS. 3A and 3B (step S2 in FIG. 4). ).

  Specifically, the observation execution plan processing unit 12 subdivides (quantizes) the interval of ± ΔT within the set range, and discretely sets different forecast value errors (time shift ΔT). As shown in 3 (a) and (b), two or more orbital models M1 to Mn having different forecast value errors (time shift ΔT) are obtained.

  The observation execution plan processing unit 12 calculates observation forecast values (observation parameters) for the orbital models M1 to Mn, and stores and stores the calculation results (step S3 in FIG. 4).

  The processing by the observation plan creation processing unit 11 and the observation execution plan processing unit 12 described above is executed as preprocessing for performing tracking observation of the target.

  When a command for executing tracking observation of a target is received from the outside, the observation execution plan processing unit 12 performs tracking observation of the target immediately before the observation time at which the commanded target appears in the field of view of the radar unit 1. Data (observation forecast value) is transmitted to the beam scanning data processing unit 6.

  The beam scanning data processing unit 6 converts the tracking observation data of the target output from the observation execution plan processing unit 12 into a control signal for controlling the radio beam 14 and transmits the control signal to the radar unit 1. .

  When the radar unit 1 receives the control signal, the radar unit 1 emits a radio wave beam 14 to the range of the azimuth sector area and the elevation sector area, and monitors the passage of the target passing through the area. When the radar unit 1 starts tracking observation and detects a reflected signal reflected by a radio wave beam at the target in the initial acquisition of the target, whether the target that has received the reflected signal is an object for tracking observation. If it is determined whether or not it is recognized (identified), the initial capture of the target is terminated (step S4 in FIG. 4).

  The trajectory value conversion processing unit 3 calculates a prediction value error (time shift; ΔT data) between the actual trajectory of the target and the observed predicted value based on the data obtained during the initial acquisition period of the target by the radar unit 1. The prediction value error (time shift; ΔT data) is obtained and transmitted to the observation execution plan processing unit 12 (step S5 in FIG. 4).

  When the observation execution plan processing unit 12 receives the prediction value error (time lag; ΔT data) data from the orbital value conversion processing unit 3, the observation execution plan processing unit 12 is one of the orbital data M1 to Mn approximated to the observation data that initially captured the target. The observation forecast values (observation parameters) corresponding to the extracted orbit data M1 to Mn stored are transmitted to the beam scanning data processing unit 6 as tracking observation data of the target (step S6 in FIG. 4). ).

  Thereafter, tracking of the target is performed based on the extracted orbit data M1 to Mn.

  In the process of performing tracking observation of the target, if the accuracy of the quantization of the orbit model is incomplete and the target deviates from the center of the radio wave beam by a certain limit, the signal processing unit 1 scans the correction data sequentially by beam scanning. The data is transmitted to the data processing unit 6. When receiving the sequential correction data, the beam scanning data processing unit 6 controls the radiation direction of the radio wave beam 14 so as to track the target at the center of the radio beam.

  When the tracking observation of the target is completed, the series of observation data obtained by the tracking observation is converted into the trajectory value of the target by the trajectory value conversion processing unit 3, and the converted data is stored in the trajectory database 4. It is registered as a new trajectory value of the object (step S7 in FIG. 4).

  As described above, according to the embodiment of the present invention, in the method of tracking the target according to the observation forecast value, the correction method by the parallel movement of the time shift ΔT is obtained by correcting the shift of the actual target trajectory by this method. As compared with the above, it is possible to improve the correction accuracy in the vicinity of a high elevation angle and to increase the tracking duration time for a target having a large trajectory deviation (large forecast value error). For this reason, the amount of data obtained in one pass is increased, and the trajectory determination accuracy can be improved.

  When a new orbit model is set after the time lag ΔT is obtained and compared with the method of calculating the observation forecast value, instead of executing those calculations, an appropriate orbit model is prepared from the prepared orbit models. And selecting the observation forecast value that has already been calculated, the processing time can be shortened, and the mode can be shifted to the tracking mode without delay from the end of the initial acquisition of the target.

  According to the present invention, the device is optimal as a device for detecting and tracking an artificial object such as an artificial satellite or space debris orbiting the earth orbit.

It is a block diagram which shows the structure of the target observation radar apparatus which concerns on embodiment of this invention. It is a figure which shows an example of the radar part used in embodiment of this invention. It is a figure which shows the example of the trajectory model which made T the variable in the relationship between an elevation angle, an azimuth | direction, and time. It is a flowchart explaining the case where the tracking observation of a target is performed using the target observation radar apparatus which concerns on embodiment of this invention. It is a block diagram which shows the related target observation radar apparatus. It is a block diagram which shows the related target observation radar apparatus. It is a block diagram which shows the related target observation radar apparatus. It is a block diagram which shows the related target observation radar apparatus. It is a characteristic view which shows the relationship between a target azimuth | direction and an elevation angle. It is a characteristic view explaining the problem of a related technique.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radar part 2 Signal processing part 3 Orbital value conversion processing part 4 Orbital database 6 Beam scanning data processing part 11 Observation plan preparation processing part 12 Observation execution plan processing part

Claims (9)

A target observation radar device for tracking observation of a target,
An observation plan creation processing unit that creates observation forecast values based on the trajectory data of the target;
A range of possible time lag is set in consideration of an error in the observation forecast value from the observation plan creation processing unit, and two or more trajectory models of the target are obtained within the range, and the target is initialized. An observation execution plan processing unit that extracts the orbit model approximated to the captured observation data and outputs data based on the extracted orbit model as tracking observation data of a target; . The observation execution plan processing unit
The target observation radar apparatus according to claim 1, wherein an error included in the trajectory data of the target and an unstable element of the target specific trajectory are considered as the error. The observation execution plan processing unit
The target observation radar apparatus according to claim 1, wherein a maximum width of a prediction value error, which is a difference between an actual trajectory of a target and an observation prediction value, is set as the time lag range. The observation execution plan processing unit
The target observation radar apparatus according to claim 1, wherein an observation forecast value corresponding to the extracted orbit model is used as data based on the orbit model. In the computer that constitutes the target observation radar device that tracks the target,
A function to create observation forecast values based on the trajectory data of the target;
A function of setting a range of possible time lag in consideration of an error in the observation forecast value from the observation plan creation processing unit, and obtaining two or more trajectory models of the target within the range;
A function for extracting the trajectory model approximated to the observation data obtained by initially capturing the target, and executing a function of outputting data based on the extracted trajectory model as tracking observation data of the target. program. A target tracking method for tracking a target,
Create observation forecast values based on the trajectory data of the target,
A range of possible time lags is set in consideration of errors in the observation forecast value, and two or more trajectory models of the target are determined within the range,
A target tracking method, wherein the trajectory model approximated to observation data obtained by initially capturing the target is extracted, and data based on the extracted trajectory model is output as tracking observation data of the target. The target tracking method according to claim 6, wherein an error included in the trajectory data of the target and an unstable element of the target specific trajectory are considered as the error. The target tracking method according to claim 6, wherein a maximum width of a forecast value error that is a difference between an actual trajectory of a target and an observed forecast value is set as the range of the time lag. The target tracking method according to claim 6, wherein an observation forecast value corresponding to the extracted orbit model is used as data based on the orbit model.

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