JP2005024395A - Radar device and radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radar device capable of highly accurately correcting deterioration in an SAR image caused by antenna oscillation, and to provide a radar system. <P>SOLUTION: In the radar device, a reception signal obtained by an antenna section 110 is converted to reception data by a signal processing section 120. A detection section 140 detects the position of the antenna section 110. A recording device 130 allows the reception data momentarily outputted from the signal processing section 120 to correspond to movement information detected by the detection section 140 for recording on recording media M. A reader 210 reads data from the recording media M. An oscillation correction processing section 220 performs estimation processing using a fixed section smoother, based on the movement information, for estimating the flight route of the antenna section 110 for removing influence caused by variations in the flight route of the antenna section 110 from the reception data. An SAR processing section 230 creates picture data for changing a target into a picture by SAR processing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radar apparatus using a synthetic aperture radar that is mounted on a moving platform such as an aircraft or an artificial satellite and generates an image of a target by observation as it moves.
[0002]
[Prior art]
As is well known, in a synthetic aperture radar (SAR), when a platform is an aircraft or the like, an antenna is shaken as the body shakes. As a result, an error occurs in the received data, and the obtained SAR image deteriorates. For this reason, at the time of SAR signal processing, the position of the antenna to be shaken is estimated, and shake compensation processing (motion compensation) for correcting the deviation of the antenna position is performed (see, for example, Patent Document 1).
[0003]
However, since the conventional radar apparatus estimates the antenna position at the time of observation based on information acquired until the time of observation, there is a problem that the position estimation of the antenna is limited in the shake correction processing.
[0004]
[Patent Document 1]
JP 2001-194456 A.
[0005]
[Problems to be solved by the invention]
Conventionally, since the antenna position at the time of observation is estimated based on information acquired until the time of observation, there is a problem that the antenna estimation is limited in the shake correction processing.
[0006]
The present invention has been made to solve the above problem, and an object thereof is to provide a radar apparatus and a radar system capable of correcting the deterioration of the SAR image caused by the antenna fluctuation with higher accuracy.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention according to claim 1 is a radar apparatus using SAR, wherein antenna means for receiving radar echoes from a target from space, and signals received by the antenna means are received data. A signal processing means for converting to a position detecting means, a position detecting means for detecting the position of the antenna means, and a movement path of the antenna means based on the position information detected by the position detecting means, and the movement at each time point Prediction processing means for predicting a route based on position information at the previous and subsequent time points, and the influence of the movement of the antenna means on the received data obtained by the signal processing means based on the information on the movement route predicted by the prediction processing means Based on the correction data that corrects the image and the received data corrected by the correction data, the SAR processing is performed and the data for visualizing the target is displayed. And to constitute by comprising a SAR processing means for generating.
[0008]
The present invention according to claim 2 is the radar system using the SAR in which the data processing device visualizes the target based on the observation result of the observation device mounted on the moving body. Antenna means for receiving an echo from space, signal processing means for converting a signal received by the antenna means into reception data, position detection means for detecting the position of the antenna means, position information detected by the position detection means, Recording means for recording the received data obtained by the signal processing means on a storage medium, and the data processing device reads out the position information and the received data from the storage medium, and the position information read out by the reading means. Based on the position information at the time points before and after the movement route at each time point. And a correction processing unit that performs a process of correcting the influence of the movement of the antenna unit on the received data read by the reading unit based on the information on the movement path predicted by the prediction processing unit. SAR processing is performed based on the received data corrected by the means, and SAR processing means for generating data for visualizing the target is provided.
[0009]
Further, the present invention according to claim 3 is a radar system using a SAR in which a data processing device visualizes a target based on an observation result of an observation device mounted on a moving body. Antenna means for receiving an echo from space, signal processing means for converting a signal received by the antenna means into reception data, position detection means for detecting the position of the antenna means, position information detected by the position detection means, First data means for wirelessly transmitting data received by the signal processing means, and the data processing device receives position information and data received wirelessly from the first communication means. 2 and the position information received by the second communication means are used to predict the movement path of the antenna means at each time point. Prediction processing means for predicting the movement path based on position information at the previous and subsequent time points, and the influence of the movement of the antenna means on the received data read by the reading means based on the information of the movement path predicted by the prediction processing means And a SAR processing unit that performs SAR processing based on the reception data corrected by the correction unit and generates data for visualizing the target. .
[0010]
In the radar apparatus and the radar system configured as described above, when the movement path of the antenna unit is predicted based on the position information of the antenna unit, the movement path at each time point is predicted based on the position information at the previous and subsequent time points. Based on the predicted movement path information, the influence on the reception data due to the movement of the antenna means is corrected.
[0011]
Therefore, according to the radar apparatus having the above configuration, the information on the moving path of the antenna means can be obtained with higher accuracy than in the case of estimating the antenna position at the time of observation based on the information acquired until the time of observation. Degradation of the SAR image due to fluctuation can be corrected with higher accuracy.
[0012]
According to a fourth aspect of the present invention, there is provided information acquisition means for acquiring observation data observed by a radar by an observation apparatus mounted on a moving body, position information of an antenna when the observation apparatus performs radar observation, and the information acquisition means. Predicting the movement path of the antenna based on the acquired position information, and a prediction processing means for predicting the movement path at each time point based on the position information at the previous and subsequent time points, and Based on the predicted movement path information, correction means for correcting the influence of the movement of the antenna means on the observation data, and SAR processing is performed based on the received data corrected by the correction means, and the target is set. SAR processing means for generating data to be visualized is provided.
[0013]
In the radar apparatus having the above configuration, when the movement path of the antenna unit is predicted based on the position information of the antenna unit, the movement path at each time point is predicted based on the position information at the time points before and after the prediction. Based on the information of the movement path, the influence on the reception data due to the movement of the antenna means is corrected.
[0014]
Therefore, according to the radar apparatus having the above configuration, the antenna movement path information can be obtained with higher accuracy than in the case of estimating the antenna position at the time of observation based on the information acquired until the time of observation. It is possible to correct the deterioration of the SAR image due to the higher accuracy.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of a radar system according to an embodiment of the present invention. This radar system includes an upper part 100 mounted on a flying object such as an aircraft or an artificial satellite, and an off-line processing unit 200 installed on the earth or the like (or an aircraft if the upper part 100 is mounted on an artificial satellite). With.
[0016]
The upper part 100 includes an antenna unit 110, a signal processing unit 120, a recording device 130, and a detection unit 140.
The antenna unit 110 transmits a radar signal in the observation direction, receives a radar echo from the target from the space, and outputs it as a received signal to the signal processing unit 120. The signal processing unit 120 converts the received signal into received data and outputs the received data to the recording device 130. The detection unit 140 includes a GPS (Global Positioning System) receiver, an acceleration sensor, and the like, detects the position of the antenna unit 110, and outputs this to the recording device 130 as movement information. The recording device 130 records information on a recording medium M such as a semiconductor or a magneto-optical disk. The recording device 130 receives reception data output from the signal processing unit 120 every moment, and the detection unit 140 correspondingly processes the received data. The detected movement information is associated and recorded on the recording medium M.
[0017]
The offline processing unit 200 includes a reading device 210, a shake correction processing unit 220, and a SAR processing unit 230.
The reading device 210 reads information recorded on the recording medium M, reads the received data and the movement information, and outputs them to the shake correction processing unit 220.
[0018]
As shown in FIG. 2, the shake correction processing unit 220 performs a prediction process for predicting the flight path L <b> 1 of the antenna unit 110 based on the movement information. In FIG. 2, the flight path L0 is an actual (true) flight path. In this prediction processing, the observation data is smoothed using a fixed section smoother to predict the flight position at a certain point in time, based on the movement information before and after that.
Then, the fluctuation correction processing unit 220 corrects the received data observed at the corresponding position by using the result of the prediction process to remove the influence due to the variation in the flight path of the antenna unit 110, and the corrected received data is subjected to SAR. The data is output to the processing unit 230.
The SAR processing unit 230 performs SAR processing based on the reception data corrected by the fluctuation correction processing unit 220 and creates video data to be visualized as a target.
[0019]
Next, the operation of the radar system configured as described above will be described.
For example, in order to acquire a ground image of the target area, the flying body equipped with the upper part 100 flies over the target area. When the search is started, the radar signal is sequentially transmitted in the observation direction from the antenna unit 110, and the antenna unit 110 receives the radar echo from the target from the space and outputs it as a received signal to the signal processing unit 120. The reception signal output from the antenna unit 110 every moment is converted into reception data by the signal processing unit 120 and output to the recording device 130.
[0020]
On the other hand, the detection unit 140 detects the position of the antenna unit 110 by a GPS receiver, an acceleration sensor, or the like. This information is output to the recording device 130 as movement information.
In the recording device 130, the reception data output every moment from the signal processing unit 120 and the movement information detected every moment by the detection unit 140 are associated with each other and recorded on the recording medium M.
[0021]
When the observation is finished and the flying object returns to the ground, the recording medium M is set in the reading device 210. The reading device 210 reads received data and movement information from the recording medium M, and outputs them to the shake correction processing unit 220.
[0022]
On the other hand, the fluctuation correction processing unit 220 performs a prediction process using a fixed section smoother, and predicts the flight path L1 of the antenna unit 110 based on the movement information. Then, the fluctuation correction processing unit 220 performs correction for removing the influence of the variation in the flight path of the antenna unit 110 on the reception data observed at the corresponding position, using the prediction processing result.
[0023]
The corrected received data is output to the SAR processing unit 230, and the SAR processing unit 230 performs the SAR process to create video data that visualizes the target. This video data is visualized by an image processing device (not shown) and displayed to the operator.
[0024]
As described above, in the radar system configured as described above, information on the flight path L1 of the antenna unit 110 used to correct the influence of the antenna fluctuation on the received data is obtained using the fixed section smoother. .
[0025]
Therefore, according to the radar system having the above-described configuration, the flight path information of the antenna unit 110 can be obtained with higher accuracy than in the conventional case where the antenna position at the time of observation is estimated based on the information acquired until the time of observation. As a result, the deterioration of the SAR image caused by the antenna fluctuation can be corrected with higher accuracy.
[0026]
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. Further, for example, a configuration in which some components are deleted from all the components shown in the embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.
[0027]
For example, in the above embodiment, data is exchanged between the upper unit 100 and the offline processing unit 200 via the recording medium M, but instead, for example, the upper unit 100 and the offline processing unit 200 are offline. Data transmission may be performed with the processing unit 200 by wireless communication. An example of such a configuration is shown in FIG.
[0028]
In the configuration shown in FIG. 3, in the upper part 100, the recording device 130 receives received data output from the signal processing unit 120 and movement information detected by the detection unit 140 corresponding to the received data. The data is output to the communication unit 150 in association with it. On the other hand, the communication unit 150 transmits data given from the recording device 130 by a wireless signal.
[0029]
On the other hand, in the offline processing unit 200, the communication unit 240 extracts data received from the wireless signal transmitted from the communication unit 150, and outputs the data to the fluctuation correction processing unit 220.
Even with such a configuration, it is possible to correct the deterioration of the SAR image caused by the antenna fluctuation with higher accuracy.
[0030]
Further, the aircraft upper part 100 and the offline processing unit 200 may be integrated, and both may be provided on the flying object. An example of such a configuration is shown in FIG.
In the configuration shown in FIG. 4, the recording apparatus 130 associates the received data output from the signal processing unit 120 with the movement information detected by the detection unit 140 in correspondence with the received data. The result is output to the shake correction processing unit 220.
Even with such a configuration, it is possible to correct the deterioration in the accuracy of the SAR image due to the fluctuation of the antenna with high accuracy.
[0031]
In the above embodiment, the fluctuation correction processing unit 220 has been described as performing the prediction process by smoothing the observation data using the fixed interval smoother. However, smoothing processing using other filters or other methods may be used. However, if the method of predicting the flight position at a certain point in time is predicted based on the movement information before and after that, the same effect can be achieved by applying instead.
In addition, it goes without saying that the present invention can be similarly implemented even if various modifications are made without departing from the gist of the present invention.
[0032]
【The invention's effect】
As described above, in the present invention, when the movement path of the antenna unit is predicted based on the position information of the antenna unit, the movement path at each time point is predicted based on the position information at the previous and subsequent time points. Based on the predicted movement path information, the influence on the reception data due to the movement of the antenna means is corrected.
[0033]
Therefore, according to the present invention, the information on the movement path of the antenna means can be obtained with higher accuracy than in the case of estimating the antenna position at the time of observation based on the information acquired until the time of observation. It is possible to provide a radar apparatus and a radar system that can correct the deterioration of the SAR image to be performed with higher accuracy.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing a configuration of an embodiment of a radar system according to the present invention.
FIG. 2 is a diagram for explaining prediction processing performed by a fluctuation correction processing unit of the radar system shown in FIG. 1;
FIG. 3 is a circuit block diagram showing another configuration of the radar system according to the present invention.
FIG. 4 is a circuit block diagram showing another configuration of the radar system according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Upper part, 110 ... Antenna part, 120 ... Signal processing part, 130 ... Recording apparatus, 140 ... Detection part, 150 ... Communication part, 200 ... Offline processing part, 210 ... Reading apparatus, 220 ... Shake correction processing part, 230 ... Processing unit, 240 ... Communication unit, L0 ... Flight path, L1 ... Flight path, M ... Recording medium.

Claims (4)

In a radar apparatus using SAR (Synthetic Aperture Radar),
Antenna means for receiving radar echoes from the target from space;
Signal processing means for converting a signal received by the antenna means into received data;
Position detecting means for detecting the position of the antenna means;
Prediction processing means for predicting the movement path of the antenna means based on the position information detected by the position detection means, and predicting the movement path at each time point based on the position information at the previous and subsequent time points When,
Based on the information on the movement path predicted by the prediction processing unit, a correction unit that performs processing for correcting the influence of the movement of the antenna unit on the reception data obtained by the signal processing unit;
A radar apparatus comprising: SAR processing means for performing SAR processing based on the reception data corrected by the correction means and generating data for visualizing a target. In a radar system using a SAR (Synthetic Aperture Radar) in which a data processing device visualizes a target based on an observation result of an observation device mounted on a moving object,
The observation device is
Antenna means for receiving radar echoes from the target from space;
Signal processing means for converting a signal received by the antenna means into received data;
Position detecting means for detecting the position of the antenna means;
A recording means for recording the position information detected by the position detecting means and the received data obtained by the signal processing means on a storage medium;
The data processing device includes:
Read means for reading the position information and the received data from the storage medium;
Prediction processing means for predicting the movement path of the antenna means based on the position information read by the reading means, and predicting the movement path at each time point based on the position information at the previous and subsequent time points; ,
Correction means for performing a process of correcting the influence of the movement of the antenna means on the received data read by the reading means based on the information of the movement path predicted by the prediction processing means;
A radar system comprising: SAR processing means for performing SAR processing based on the reception data corrected by the correction means and generating data for visualizing a target. In a radar system using a SAR (Synthetic Aperture Radar) in which a data processing device visualizes a target based on an observation result of an observation device mounted on a moving object,
The observation device is
Antenna means for receiving radar echoes from the target from space;
Signal processing means for converting a signal received by the antenna means into received data;
Position detecting means for detecting the position of the antenna means;
A first communication unit that wirelessly transmits the position information detected by the position detection unit and the received data obtained by the signal processing unit;
The data processing device includes:
Second communication means for receiving the position information and the received data wirelessly transmitted from the first communication means;
Predicting the movement path of the antenna means based on the position information received by the second communication means, and predicting the movement path at each time point based on the position information at the time points before and after Processing means;
Correction means for performing a process of correcting the influence of the movement of the antenna means on the received data read by the reading means based on the information of the movement path predicted by the prediction processing means;
A radar system comprising: SAR processing means for performing SAR processing based on the reception data corrected by the correction means and generating data for visualizing a target. Observation data that the observation device mounted on the moving body performs radar observation, and information acquisition means for acquiring the position information of the antenna when the observation device performs radar observation;
Prediction processing means for predicting the movement path of the antenna based on the position information acquired by the information acquisition means, and predicting the movement path at each time point based on the position information at the previous and subsequent time points; ,
Correction means for performing processing for correcting the influence of the movement of the antenna means on the observation data based on the information of the movement path predicted by the prediction processing means;
A radar apparatus comprising: SAR processing means for performing SAR processing based on the reception data corrected by the correction means and generating data for visualizing a target.

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