JP5573256B2 - Synthetic aperture radar equipment - Google Patents

Synthetic aperture radar equipment Download PDF

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JP5573256B2
JP5573256B2 JP2010055530A JP2010055530A JP5573256B2 JP 5573256 B2 JP5573256 B2 JP 5573256B2 JP 2010055530 A JP2010055530 A JP 2010055530A JP 2010055530 A JP2010055530 A JP 2010055530A JP 5573256 B2 JP5573256 B2 JP 5573256B2
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秀樹 長谷川
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Mitsubishi Electric Corp
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この発明は、航空機や衛星等に搭載する合成開口レーダ(SAR:Synthetic Aperture Radar)装置に係り、特に、地表や海面を観測し、画像化する合成開口レーダ装置に関する。   The present invention relates to a synthetic aperture radar (SAR) device mounted on an aircraft, a satellite, or the like, and more particularly to a synthetic aperture radar device that observes and images the ground surface and the sea surface.

合成開口レーダは、航空機や衛星等の移動プラットフォームに搭載され、移動しつつ進行方向の側方に電波を送受信して地表や海面の観測を行うことにより、二次元の高分解能画像を得るレーダである(例えば、特許文献1参照)。また、バイスタティックレーダは、電波の送信アンテナと受信アンテナを異なる位置に設置するレーダである(例えば、非特許文献1参照)。これらを組み合わせたレーダは、バイスタティック合成開口レーダと呼ばれる。   Synthetic aperture radar is a radar that is mounted on a mobile platform such as an aircraft or satellite, and obtains a two-dimensional high-resolution image by transmitting and receiving radio waves to the side of the traveling direction while moving and observing the ground surface and sea surface. Yes (see, for example, Patent Document 1). The bistatic radar is a radar in which a radio wave transmission antenna and a reception antenna are installed at different positions (for example, see Non-Patent Document 1). A radar combining these is called a bistatic synthetic aperture radar.

特開2001−188084号公報JP 2001-1888084 A

Alvin S. Goh 他、“The Ingara Bistatic SAR Upgrade: First Results”、IEEE Radar Conference Sep. 2008Alvin S. Goh et al., “The Ingara Bistatic SAR Upgrade: First Results”, IEEE Radar Conference Sep. 2008

バイスタティック合成開口レーダ装置の運用形態として、送信アンテナを航空機あるいは衛星に搭載し、受信アンテナを地上に設置することがある。その際、別々に運用される送信側と受信側とで両者の時刻を同期させる。この時刻を同期させる手段としては、GPS受信機を用いる方法がある。精度の良いGPS受信機を用いることにより、数ns〜数十nsの時刻同期精度が期待できる。   As an operation mode of the bistatic synthetic aperture radar apparatus, there is a case where a transmitting antenna is mounted on an aircraft or a satellite and a receiving antenna is installed on the ground. At that time, the time of both is synchronized between the transmitting side and the receiving side which are operated separately. As a means for synchronizing the time, there is a method using a GPS receiver. By using a highly accurate GPS receiver, a time synchronization accuracy of several ns to several tens of ns can be expected.

ただし、GPS信号の受信状況があまり期待できない環境で運用する場合や、GPS衛星が老朽化した場合等、GPSの時刻精度が劣化してしまった場合には、上記時刻同期の精度が劣化する。この劣化は、合成開口レーダ画像に誤差を生じ、画像をぼけさせてしまうという問題があった。   However, when operating in an environment where the reception status of GPS signals cannot be expected so much, or when the GPS time accuracy has deteriorated, such as when the GPS satellite has become obsolete, the accuracy of the time synchronization is deteriorated. This deterioration has a problem of causing an error in the synthetic aperture radar image and blurring the image.

この発明は、係る課題を解決するためになされたものであり、送信アンテナと受信アンテナを異なる位置に設置する際、GPS受信機による送信側と受信側の時刻同期精度の劣化を抑えることのできる合成開口レーダ装置を得ることを目的とする。   The present invention has been made to solve such a problem, and when the transmitting antenna and the receiving antenna are installed at different positions, degradation of time synchronization accuracy between the transmitting side and the receiving side by the GPS receiver can be suppressed. An object is to obtain a synthetic aperture radar device.

この発明によれば、この発明に係る合成開口レーダ装置は、移動プラットフォームに搭載され、高周波パルス信号を空間に放射する送信用アンテナと、移動プラットフォームに搭載され、送信側時刻同期用信号を用いて時刻の同期を行い、同期した時刻にあわせて高周波パルス信号を生成し、上記送信用アンテナに出力する励振機及び信号処理器と、移動プラットフォームに搭載され、GPS衛星からのGPS信号を受信し、受信したGPS信号を元に上記送信側時刻同期用信号を生成し、上記励振機及び信号処理器に上記送信側時刻同期用信号を出力する送信側GPS受信機とを有した送信側レーダと、上記送信側レーダとは異なる位置に設けられ、上記送信用アンテナで送信されてターゲットで反射した高周波パルス信号を受信する第1の受信用アンテナと、上記送信側レーダとは異なる位置に配置され、上記送信用アンテナで送信され、ターゲットで反射した高周波パルス信号を受信し、上記第1の受信用アンテナに対して上記移動プラットフォームの移動方向に離間配置された第2の受信アンテナと、上記送信側レーダとは異なる位置に配置され、受信側時刻同期用信号を用いて時刻の同期を行い、同期した時刻にあわせて上記第1、第2の受信用アンテナからの高周波パルス信号を受信する受信機及び信号処理器と、上記送信側レーダとは異なる位置に配置され、GPS衛星からのGPS信号を受信し、受信したGPS信号を元に上記受信側時刻同期用信号を生成し、上記受信機及び信号処理器に上記受信側時刻同期用信号を出力する受信側GPS受信機とを有した受信側レーダと、を備え、上記受信機及び信号処理器は、上記第1、第2の受信用アンテナから受信した高周波パルス信号の位相差の観測値から、上記送信側時刻同期用信号と上記受信側時刻同期用信号との時刻同期誤差を求め、求めた時刻同期誤差によって上記第1、第2の受信用アンテナからの高周波パルス信号の位相補正を行い、合成開口処理を行うものである。 According to the present invention, a synthetic aperture radar device according to the present invention is mounted on a mobile platform and uses a transmission antenna that radiates a high-frequency pulse signal to space, and a mobile platform that uses a transmission-side time synchronization signal. Synchronize the time, generate a high-frequency pulse signal according to the synchronized time, output to the transmitting antenna and the signal processor, and mounted on the mobile platform, receive GPS signals from GPS satellites, A transmission-side radar having a transmission-side GPS receiver that generates the transmission-side time synchronization signal based on the received GPS signal and outputs the transmission-side time synchronization signal to the exciter and the signal processor; A first signal is provided at a position different from the transmission-side radar, and receives a high-frequency pulse signal transmitted from the transmission antenna and reflected by a target. A receiving antenna, and the transmitting side radar disposed at different positions are transmitted by the transmitting antenna, receiving a high-frequency pulse signal reflected by the target, the mobile platform with respect to the first receiving antenna The second receiving antennas spaced apart from each other in the moving direction and the transmitting radar are disposed at different positions, and time synchronization is performed using the receiving time synchronization signal, and the first time is synchronized with the synchronized time. The receiver and the signal processor that receive the high-frequency pulse signal from the second receiving antenna and the transmitter-side radar are disposed at different positions, receive the GPS signal from the GPS satellite, and receive the received GPS signal. A receiver having a reception side GPS receiver that originally generates the reception side time synchronization signal and outputs the reception side time synchronization signal to the receiver and a signal processor. A radar, and the receiver and the signal processor are configured to detect the transmission side time synchronization signal and the reception side based on the observation value of the phase difference between the high frequency pulse signals received from the first and second reception antennas. A time synchronization error with the time synchronization signal is obtained, and the phase correction of the high-frequency pulse signal from the first and second reception antennas is performed based on the obtained time synchronization error to perform a synthetic aperture process.

この発明に係る合成開口レーダ装置は、GPS受信機による送信側レーダと受信側レーダの時刻同期誤差による、合成開口レーダ画像の劣化を抑えることができる。   The synthetic aperture radar apparatus according to the present invention can suppress deterioration of the synthetic aperture radar image due to the time synchronization error between the transmission side radar and the reception side radar by the GPS receiver.

この発明に係る実施の形態1による合成開口レーダ装置の構成を示す図である。It is a figure which shows the structure of the synthetic aperture radar apparatus by Embodiment 1 which concerns on this invention. この発明に係る実施の形態1による合成開口レーダ装置の信号処理の流れを示す図である。It is a figure which shows the flow of the signal processing of the synthetic aperture radar apparatus by Embodiment 1 which concerns on this invention.

実施の形態1.
図1は、この発明に係る実施の形態1による合成開口レーダ装置の構成を示す図である。図において、実施の形態1の合成開口レーダ装置は、航空機や衛星等の移動プラットフォームに搭載された送信用アンテナ1と、上記移動プラットフォームに搭載された励振機及び信号処理器2と、上記移動プラットフォームに搭載されたGPS受信機3からなる送信側レーダと、地上に設けられた第1の受信用アンテナ5と、地上に設けられた第2の受信用アンテナ6と、地上に設けられた受信機及び信号処理器7と、地上に設けられたGPS受信機8からなる受信側レーダによって構成されて、バイスタティック合成開口レーダを構成する。第1の受信用アンテナ5と第2の受信用アンテナ6は、一定距離だけ離して設置される。
Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of a synthetic aperture radar apparatus according to Embodiment 1 of the present invention. In the figure, the synthetic aperture radar apparatus according to the first embodiment includes a transmission antenna 1 mounted on a mobile platform such as an aircraft or a satellite, an exciter and signal processor 2 mounted on the mobile platform, and the mobile platform. A transmission-side radar comprising a GPS receiver 3 mounted on the ground, a first receiving antenna 5 provided on the ground, a second receiving antenna 6 provided on the ground, and a receiver provided on the ground And a signal processing unit 7 and a receiving-side radar including a GPS receiver 8 provided on the ground to form a bistatic synthetic aperture radar. The first receiving antenna 5 and the second receiving antenna 6 are set apart by a certain distance.

励振機及び信号処理器2は、高周波パルス信号を生成する。送信用アンテナ1は、励振機及び信号処理器2により生成された高周波パルス信号を空間に放射する。励振機及び信号処理器2は、GPS受信機3からの時刻同期用の信号(送信側時刻同期用信号)を用いて地上の受信側との時刻の同期を行う。励振機及び信号処理器2は、当該送信側時刻同期用信号により同期した時刻にあわせて高周波パルス信号を生成し、送信用アンテナ1に出力する。GPS受信機3は、GPS衛星4からのGPS信号を受信し、このGPS信号を元に時刻同期用の信号を励振機及び信号処理器2に出力する。GPS衛星4は、地球の周りを周回し、位置及び時刻の情報を送信する。   The exciter and signal processor 2 generates a high frequency pulse signal. The transmitting antenna 1 radiates a high-frequency pulse signal generated by the exciter and the signal processor 2 into space. The exciter and signal processor 2 synchronizes the time with the reception side on the ground by using a signal for time synchronization (transmission side time synchronization signal) from the GPS receiver 3. The exciter and signal processor 2 generates a high-frequency pulse signal in synchronization with the time synchronized by the transmission side time synchronization signal, and outputs the high frequency pulse signal to the transmission antenna 1. The GPS receiver 3 receives a GPS signal from the GPS satellite 4 and outputs a signal for time synchronization to the exciter and the signal processor 2 based on the GPS signal. The GPS satellite 4 orbits the earth and transmits position and time information.

第1の受信用アンテナ5は、送信用アンテナ1から送信され、ターゲットで反射した高周波パルス信号を受信する。第2の受信用アンテナ6は、第1の受信用アンテナ5と同じく送信用アンテナ1から送信され、ターゲットで反射した高周波パルス信号を受信する。GPS受信機8は、GPS衛星からの信号を受信し、この信号を元に時刻同期用の信号(受信側時刻同期用信号)を受信機及び信号処理器7に出力する。受信機及び信号処理器7は、GPS受信機8からのGPS信号を用いて航空機あるいは衛星の送信側との時刻の同期を行う。また、受信機及び信号処理器7は、当該同期した時刻にあわせて、第1、第の受信用アンテナ5,6で受けた高周波パルス信号をそれぞれ受信するとともに、当該2つのアンテナで受信した各々の高周波パルス信号を用いて時刻の誤差を求め、フォーカスしたSAR画像を得るためのSAR信号処理を行う。   The first receiving antenna 5 receives the high-frequency pulse signal transmitted from the transmitting antenna 1 and reflected by the target. The second receiving antenna 6 is transmitted from the transmitting antenna 1 similarly to the first receiving antenna 5 and receives a high-frequency pulse signal reflected by the target. The GPS receiver 8 receives a signal from a GPS satellite and outputs a time synchronization signal (reception side time synchronization signal) to the receiver and the signal processor 7 based on this signal. The receiver and signal processor 7 uses the GPS signal from the GPS receiver 8 to synchronize the time with the transmitting side of the aircraft or satellite. In addition, the receiver and the signal processor 7 receive the high-frequency pulse signals received by the first and second receiving antennas 5 and 6 in accordance with the synchronized time, respectively, and each received by the two antennas. The time error is obtained using the high-frequency pulse signal and SAR signal processing for obtaining a focused SAR image is performed.

次に、受信機及び信号処理器7において、フォーカスしたSAR画像を得るためのSAR信号処理について説明する。第1の受信用アンテナ5と第2の受信用アンテナ6は、合成開口レーダ装置の送信側レーダを搭載した移動プラットフォームの移動方向と平行になるように、互いに離れて設置される。ここでは第1、第2の受信用アンテナ5、6の移動プラットフォームに対する移動方向の設置位置を各々x1、x2とする。好ましくは、第1の受信用アンテナ5と第2の受信用アンテナ6は、移動プラットフォームの移動軌道上の真下にあると良い。なお、第1、第2の受信用アンテナ5、6が移動プラットフォームの移動軌道と平行になるように、第1、第2の受信用アンテナ5、6の設置位置を予め調整しておくと良い。   Next, SAR signal processing for obtaining a focused SAR image in the receiver and signal processor 7 will be described. The first receiving antenna 5 and the second receiving antenna 6 are installed apart from each other so as to be parallel to the moving direction of the moving platform on which the transmitting-side radar of the synthetic aperture radar apparatus is mounted. Here, the installation positions of the first and second receiving antennas 5 and 6 in the moving direction with respect to the moving platform are x1 and x2, respectively. Preferably, the first receiving antenna 5 and the second receiving antenna 6 are located directly below the moving trajectory of the moving platform. It should be noted that the installation positions of the first and second receiving antennas 5 and 6 are preferably adjusted in advance so that the first and second receiving antennas 5 and 6 are parallel to the movement trajectory of the moving platform. .

受信機及び信号処理器7は、第1,第2の受信用アンテナ5,6を介してそれぞれ得られた受信信号について、各々SAR画像再生処理を行う。ここで、第1,第2の受信用アンテナ5,6を介してそれぞれ得られる同じターゲットからの現在時刻tにおける受信信号位相φ1、φ2は、次式で表される。   The receiver and the signal processor 7 perform SAR image reproduction processing on the received signals respectively obtained via the first and second receiving antennas 5 and 6. Here, the received signal phases φ1 and φ2 at the current time t from the same target obtained via the first and second receiving antennas 5 and 6 are expressed by the following equations.

Figure 0005573256
Figure 0005573256
Figure 0005573256
Figure 0005573256

式(1)、(2)において、λは送信用アンテナ1から放射される既知の送信電波の波長(レーダ波長)、vは移動プラットフォームの移動速度、Δtは上記送信側時刻同期用信号と受信側時刻同期用信号との時刻同期誤差、AzはSAR画像におけるターゲットのアジマス方向の位置、Rtは送信側レーダの移動軌道とターゲットの間の距離(レンジ)、Rrは受信側レーダの移動軌道とターゲットの間の距離(レンジ)、cは送信用アンテナ1から放射される送信電波の搬送波速度(光速)である。また、受信位相φ1,φ2の観測値は、第1,第2の受信用アンテナ5,6からの受信信号を位相検波することによって計測される(例えば、IQ分離した受信信号の実部と虚部の逆正接(arctangent)を得ることで求められる)。移動速度vは移動プラットフォームに搭載された速度センサによって計測される。   In equations (1) and (2), λ is the wavelength of the known transmission radio wave (radar wavelength) radiated from the transmitting antenna 1, v is the moving speed of the mobile platform, and Δt is the above-mentioned transmission side time synchronization signal and reception Time synchronization error with the side time synchronization signal, Az is the position in the azimuth direction of the target in the SAR image, Rt is the distance (range) between the moving trajectory of the transmitting radar and the target, Rr is the moving trajectory of the receiving radar The distance (range) between the targets, c is the carrier velocity (light velocity) of the transmission radio wave radiated from the transmitting antenna 1. In addition, the observation values of the reception phases φ1 and φ2 are measured by phase detection of the reception signals from the first and second reception antennas 5 and 6 (for example, the real part and the imaginary part of the reception signal separated by IQ). Obtained by obtaining the arctangent of the part). The moving speed v is measured by a speed sensor mounted on the moving platform.

この式(1)、(2)の右辺において、Δt以外の変数t(例えばt=0)、λ、v、x1、x2は既知であり、Az、Rt、RrはSAR画像を求めるターゲットの位置から得ることができる。また、左辺のφ1−φ2の観測値は、SAR画像を得るために第1,第2の受信用アンテナ5,6を介してそれぞれ得られた各受信信号φ1,φ2の観測値の差分から求めることができる。   On the right side of the equations (1) and (2), variables t other than Δt (for example, t = 0), λ, v, x1, and x2 are known, and Az, Rt, and Rr are target positions for obtaining the SAR image. Can be obtained from Further, the observation value of φ1 to φ2 on the left side is obtained from the difference between the observation values of the reception signals φ1 and φ2 obtained through the first and second reception antennas 5 and 6 in order to obtain the SAR image. be able to.

このため、第1,第2の受信用アンテナ5,6を介してそれぞれ得られた受信信号について、各々SAR画像再生処理を行った後、式(1)、(2)を用いてΔtの関数となるφ1−φ2の位相差分を求め、求めたΔtの関数となる位相差分について、φ1−φ2の観測値を代入することで、時刻同期誤差Δtの値を解くことができる。
求めた時刻同期誤差Δtを用いて、第1,第2の受信用アンテナ5,6を介してそれぞれ得られた受信信号の位相を補正し、位相の補正された受信信号について再度SAR画像再生処理を行うことにより、フォーカスさせたSAR画像を得ることが可能となる。
For this reason, the SAR image reproduction process is performed on the received signals obtained via the first and second receiving antennas 5 and 6, respectively, and then the function of Δt using the equations (1) and (2). By substituting the observed value of φ1-φ2 for the phase difference that is a function of the obtained Δt, the value of the time synchronization error Δt can be solved.
Using the obtained time synchronization error Δt, the phase of the received signal obtained via the first and second receiving antennas 5 and 6 is corrected, and the SAR image reproduction process is performed again on the received signal whose phase has been corrected. By performing the above, it is possible to obtain a focused SAR image.

なお、SAR画像再生処理の詳細については、例えば、「W.G.Carra et al. ,'Spotlight Synthetic Aperture Radar -Signal Processing Algorithm-',Artech House,London,1995 p.95-132」や、非特許文献2に記載されるので、ここでは説明を割愛する。   For details of the SAR image reproduction processing, for example, “WG Carra et al., 'Spotlight Synthetic Aperture Radar -Signal Processing Algorithm-', Artech House, London, 1995 p.95-132”, Non-Patent Document 2 The description is omitted here.

次に、実施の形態1による合成開口レーダ装置の信号処理動作の流れについて更に説明する。図2は、実施の形態1による合成開口レーダ装置の受信機及び信号処理器で実施される信号処理の流れを示す図である。   Next, the flow of the signal processing operation of the synthetic aperture radar device according to the first embodiment will be further described. FIG. 2 is a diagram illustrating a flow of signal processing performed by the receiver and the signal processor of the synthetic aperture radar apparatus according to the first embodiment.

図において、ステップS1では、第1の受信用アンテナ5で得られた受信信号のRAWデータ(生データ)に対し、SAR画像再生処理を行い、SAR画像1を得る。同じく、第2の受信用アンテナ6で得られた受信信号のRAWデータ(生データ)に対し、SAR画像再生処理を行い、SAR画像2を得る。
この時点では、SAR画像1、2は、時刻同期の誤差によって、画像がフォーカスしていないアンフォーカス状態となっている。
In the figure, in step S1, SAR image reproduction processing is performed on the RAW data (raw data) of the received signal obtained by the first receiving antenna 5 to obtain the SAR image 1. Similarly, the SAR image reproduction process is performed on the RAW data (raw data) of the received signal obtained by the second receiving antenna 6 to obtain the SAR image 2.
At this time, the SAR images 1 and 2 are in an unfocused state where the image is not focused due to a time synchronization error.

次に、ステップS2では、得られたSAR画像1,2により、同じターゲットからの位相差φ1−φ2を算出する。
ステップS3では、式(1)、式(2)を用いて、時間差Δtを算出する。
Next, in step S2, the phase difference φ1-φ2 from the same target is calculated from the obtained SAR images 1 and 2.
In step S3, the time difference Δt is calculated using equations (1) and (2).

ステップS4では、算出したΔt及び第1の受信アンテナ5のRAWデータを用いて、再度SAR画像再生処理を行い、フォーカスしたSAR画像1を得る。   In step S4, the SAR image reproduction process is performed again using the calculated Δt and the RAW data of the first receiving antenna 5, and the focused SAR image 1 is obtained.

ここで、第1の受信アンテナ5のRAWデータのかわりに、第2の受信アンテナ6のRAWデータを用いても良い。   Here, the RAW data of the second receiving antenna 6 may be used instead of the RAW data of the first receiving antenna 5.

以上説明した通り、実施の形態1による合成開口レーダ装置は、移動プラットフォームに搭載され、高周波パルス信号を空間に放射する送信用アンテナと、移動プラットフォームに搭載され、送信側時刻同期用信号を用いて時刻の同期を行い、同期した時刻にあわせて高周波パルス信号を生成し、上記送信用アンテナに出力する励振機及び信号処理器と、移動プラットフォームに搭載され、GPS衛星からのGPS信号を受信し、受信したGPS信号を元に上記送信側時刻同期用信号を生成し、上記励振機及び信号処理器に上記送信側時刻同期用信号を出力する送信側GPS受信機とを有した送信側レーダと、上記送信側レーダとは異なる位置に設けられ、上記送信用アンテナで送信されてターゲットで反射した高周波パルス信号を受信する第1の受信用アンテナと、上記送信側レーダとは異なる位置に配置され、上記送信用アンテナで送信され、ターゲットで反射した高周波パルス信号を受信し、上記第1の受信用アンテナに対して上記移動プラットフォームの移動方向に離間配置された第2の受信アンテナと、上記送信側レーダとは異なる位置に配置され、受信側時刻同期用信号を用いて時刻の同期を行い、同期した時刻にあわせて上記第1、第2の受信用アンテナからの高周波パルス信号を受信する受信機及び信号処理器と、上記送信側レーダとは異なる位置に配置され、GPS衛星からのGPS信号を受信し、受信したGPS信号を元に上記受信側時刻同期用信号を生成し、上記受信機及び信号処理器に上記受信側時刻同期用信号を出力する受信側GPS受信機と有した受信側レーダと、を備え、上記受信機及び信号処理器は、上記第1、第2の受信用アンテナから受信した高周波パルス信号の位相差の観測値から、上記送信側時刻同期用信号と上記受信側時刻同期用信号との時刻同期誤差を求め、求めた時刻同期誤差によって上記第1、第2の受信用アンテナからの高周波パルス信号の位相補正を行い、合成開口処理を行うように構成する。これによって、GPS受信機による送信側レーダと受信側レーダの時刻同期誤差による、合成開口レーダ画像の劣化を抑えることができる。
なお、実施の形態1による合成開口レーダ装置は、GPS衛星の精度が期待できない場所でも利用可能であるため、汎用性が高い。
As described above, the synthetic aperture radar apparatus according to the first embodiment is mounted on a mobile platform, and is mounted on the mobile platform and radiates a high-frequency pulse signal to the space. Synchronize the time, generate a high-frequency pulse signal according to the synchronized time, output to the transmitting antenna and the signal processor, and mounted on the mobile platform, receive GPS signals from GPS satellites, A transmission-side radar having a transmission-side GPS receiver that generates the transmission-side time synchronization signal based on the received GPS signal and outputs the transmission-side time synchronization signal to the exciter and the signal processor; A high-frequency pulse signal transmitted from the transmitting antenna and reflected by the target is received at a position different from the transmitting radar. 1 of a receiving antenna, is disposed at a position different from the above-mentioned transmitting side radar, is transmitted by the transmitting antenna, receiving a high-frequency pulse signal reflected by the target, the mobile relative to the first receiving antenna The second receiving antennas spaced apart in the moving direction of the platform and the transmitting radar are arranged at different positions, and the time is synchronized using the receiving time synchronization signal. A receiver and a signal processor that receive high-frequency pulse signals from the first and second receiving antennas, and a GPS signal that is disposed at a position different from the transmission-side radar, receives GPS signals from GPS satellites, and receives GPS signals The receiver side synchronization receiver generates the reception side time synchronization signal based on the signal and outputs the reception side time synchronization signal to the receiver and the signal processor. A radar on the transmission side, wherein the receiver and the signal processor are configured to receive the signal for time synchronization on the transmission side and the reception on the basis of the observed value of the phase difference between the high frequency pulse signals received from the first and second reception antennas. A time synchronization error with respect to the side time synchronization signal is obtained, and the phase of the high-frequency pulse signal from the first and second receiving antennas is corrected based on the obtained time synchronization error to perform a synthetic aperture process. Thereby, it is possible to suppress the deterioration of the synthetic aperture radar image due to the time synchronization error between the transmission side radar and the reception side radar by the GPS receiver.
The synthetic aperture radar apparatus according to the first embodiment is highly versatile because it can be used in places where the accuracy of GPS satellites cannot be expected.

1 送信用アンテナ、2 励振機及び信号処理器、3 GPS受信機、4 GPS衛星、5 第1の受信用アンテナ、6 第2の受信用アンテナ、7 受信機及び信号処理器、8 GPS受信機、9 受信機及び信号処理器。   DESCRIPTION OF SYMBOLS 1 Transmitting antenna, 2 Exciter and signal processor, 3 GPS receiver, 4 GPS satellite, 5 First receiving antenna, 6 Second receiving antenna, 7 Receiver and signal processor, 8 GPS receiver , 9 Receiver and signal processor.

Claims (1)

移動プラットフォームに搭載され、高周波パルス信号を空間に放射する送信用アンテナと、
移動プラットフォームに搭載され、送信側時刻同期用信号を用いて時刻の同期を行い、同期した時刻にあわせて高周波パルス信号を生成し、上記送信用アンテナに出力する励振機及び信号処理器と、
移動プラットフォームに搭載され、GPS衛星からのGPS信号を受信し、受信したGPS信号を元に上記送信側時刻同期用信号を生成し、上記励振機及び信号処理器に上記送信側時刻同期用信号を出力する送信側GPS受信機と、
を有した送信側レーダと、
上記送信側レーダとは異なる位置に設けられ、上記送信用アンテナで送信されてターゲットで反射した高周波パルス信号を受信する第1の受信用アンテナと、
上記送信側レーダとは異なる位置に配置され、上記送信用アンテナで送信され、ターゲットで反射した高周波パルス信号を受信し、上記第1の受信用アンテナに対して上記移動プラットフォームの移動方向に離間配置された第2の受信アンテナと、
上記送信側レーダとは異なる位置に配置され、受信側時刻同期用信号を用いて時刻の同期を行い、同期した時刻にあわせて上記第1、第2の受信用アンテナからの高周波パルス信号を受信する受信機及び信号処理器と、
上記送信側レーダとは異なる位置に配置され、GPS衛星からのGPS信号を受信し、受信したGPS信号を元に上記受信側時刻同期用信号を生成し、上記受信機及び信号処理器に上記受信側時刻同期用信号を出力する受信側GPS受信機と、
を有した受信側レーダと、
を備え、
上記受信機及び信号処理器は、上記第1、第2の受信用アンテナから受信した高周波パルス信号の位相差の観測値から、上記送信側時刻同期用信号と上記受信側時刻同期用信号との時刻同期誤差を求め、求めた時刻同期誤差によって上記第1、第2の受信用アンテナからの高周波パルス信号の位相補正を行い、合成開口処理を行うことを特徴とした合成開口レーダ装置。
A transmission antenna mounted on a mobile platform that radiates high-frequency pulse signals into space,
An exciter and a signal processor that are mounted on a mobile platform, synchronize time using a signal for time synchronization on the transmission side, generate a high-frequency pulse signal in accordance with the synchronized time, and output to the antenna for transmission;
Mounted on a mobile platform, receives a GPS signal from a GPS satellite, generates the transmission side time synchronization signal based on the received GPS signal, and transmits the transmission side time synchronization signal to the exciter and the signal processor. A transmitting GPS receiver for output;
A transmitter radar having
A first receiving antenna that is provided at a position different from the transmitting radar and receives a high-frequency pulse signal transmitted from the transmitting antenna and reflected by a target;
Arranged at a position different from the transmission-side radar, receives a high-frequency pulse signal transmitted from the transmission antenna and reflected by the target, and is separated from the first reception antenna in the moving direction of the mobile platform A second receiving antenna,
Arranged at a position different from the transmission side radar, synchronizes the time using the reception side time synchronization signal, and receives the high frequency pulse signals from the first and second reception antennas according to the synchronized time. A receiver and a signal processor,
Arranged at a position different from the transmitting radar, receives GPS signals from GPS satellites, generates the receiving time synchronization signal based on the received GPS signals, and receives the signals to the receiver and signal processor. A receiving GPS receiver that outputs a side time synchronization signal;
A receiving radar having
With
The receiver and the signal processor, based on the observed value of the phase difference between the high-frequency pulse signals received from the first and second receiving antennas, determine whether the transmission time synchronization signal and the reception time synchronization signal are A synthetic aperture radar apparatus characterized by obtaining a time synchronization error, performing phase correction of the high frequency pulse signal from the first and second receiving antennas according to the obtained time synchronization error, and performing a synthetic aperture process.
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