JPS6311885A - Method for continuously observing specific area in earth observation - Google Patents
Method for continuously observing specific area in earth observationInfo
- Publication number
- JPS6311885A JPS6311885A JP61154734A JP15473486A JPS6311885A JP S6311885 A JPS6311885 A JP S6311885A JP 61154734 A JP61154734 A JP 61154734A JP 15473486 A JP15473486 A JP 15473486A JP S6311885 A JPS6311885 A JP S6311885A
- Authority
- JP
- Japan
- Prior art keywords
- specific area
- sar
- synthetic aperture
- antenna
- ground
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 10
- 230000001360 synchronised effect Effects 0.000 abstract description 8
- 238000009826 distribution Methods 0.000 abstract description 7
- 238000012876 topography Methods 0.000 abstract description 3
- 230000004304 visual acuity Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Landscapes
- Radar Systems Or Details Thereof (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
この発明は、パルス電波を用いた能動型地球観測におい
て、特定地域の常時観測を高分解能で可能とした観測方
法に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an observation method that enables constant observation of a specific area with high resolution in active earth observation using pulsed radio waves.
（従来の技術）
従来、パルス電波を用いた能動型地球観測としては、通
常のレーダを用いた実開口式（以下、「ＲＡＲＪと略称
する）と、合成開口手法を用いた合成開口レーダ（以下
、ｒｓＡＲＪと略称する）とがある。(Prior art) Conventionally, active earth observation using pulsed radio waves has been conducted using real aperture radar (hereinafter referred to as "RARJ") using ordinary radar, and synthetic aperture radar (hereinafter referred to as "RARJ") using synthetic aperture method. , rsARJ).
（発明が解決しようとする問題点）
人工衛星等の飛しよう体の大きさに比べてアンテナが比
較的小さく、分解能の高い従来のＳＡＲは、その基本原
理から一定速度で走行させることが必須であり、特定地
域の常時観測は困難であった。他方、ＲＡＲにおいては
、常時観測は可能であるが、分解能は悪くアンテナが大
きくなりすぎて実際的ではない。(Problem to be solved by the invention) Conventional SAR, which has a relatively small antenna and high resolution compared to the size of a flying object such as an artificial satellite, requires the antenna to travel at a constant speed due to its basic principle. Therefore, constant observation of specific areas was difficult. On the other hand, with RAR, constant observation is possible, but the resolution is poor and the antenna is too large to be practical.
このような理由から、地域観測において、パルス電波を
用いた能動型センサで特定地域を常時観測する観測方法
は、未だ何等提案されていない。For these reasons, in regional observation, no observation method has yet been proposed in which a specific area is constantly observed using an active sensor using pulsed radio waves.
（問題点を解決するだめの手段）
この発明は、前記問題点に鑑み、ＳＡＲで特定地域の常
時観測を可能とし、ＲＡＲと比べてはもちろん、従来の
走行型ＳＡＲより分解能を高くしたもので、パルス電波
を用いた能動型地球観測において特定地域の常時観測を
可能とするとともに、ＲＡ Ｒと比べて分解能を向上さ
せるようにしたもので、空中においてＳＡＲを特定地域
の地表に対して相対的に往復運動させ、該ＳＡＲの往復
運動中そのアンテナより一定間隔でパルス電波を発射し
、該パルス電波の送受信により中央で疎、左右両端で密
となる不等間隔合成開口アレイをデータ処理において等
価的に形成し、同時にデータ処理により特定地域の情報
を画像として形成しかつ出力するものである。これによ
り、アンテナは小さアンテナが大きくなるため、ＲＡＲ
で不可能であった高分解能を小型アンテナで可能にした
。(Means for Solving the Problems) In view of the above-mentioned problems, this invention enables constant observation of a specific area using SAR, and has higher resolution than conventional mobile SAR as well as compared to RAR. , which enables constant observation of a specific area in active earth observation using pulsed radio waves, and improves resolution compared to RAR, which allows SAR to be measured in the air relative to the ground surface in a specific area. During the reciprocating movement of the SAR, pulse radio waves are emitted from the antenna at regular intervals, and by transmitting and receiving the pulse radio waves, an unequally spaced synthetic aperture array that is sparse in the center and dense at both left and right ends is equivalent in data processing. At the same time, information on a specific area is formed as an image through data processing and output. This makes the antenna smaller and the antenna larger, so RAR
This made it possible to achieve high resolution with a small antenna, which was previously impossible.
（作 用）
この発明においては、ＳＡＲを空中において特定地域の
地表に対して相対的に往復運動させ、この往復運動中、
ＳＡＲのアンテナから一定間隔でパルス電波を発射する
とともに、地表からのエコー信号を受信する。これによ
り、特定地域の空間には中央で疎、左右両端で密となる
不等間隔合成開口アレイがデータ処理上で等価的に形成
される。(Function) In this invention, the SAR is moved in the air in a reciprocating manner relative to the ground surface in a specific area, and during this reciprocating movement,
The SAR antenna emits pulsed radio waves at regular intervals and receives echo signals from the ground. As a result, in the space of a specific area, an unequally spaced synthetic aperture array that is sparse at the center and dense at both left and right ends is equivalently formed in data processing.
この等価的な不等間隔合成開口アレイの単位時間内のエ
ネルギー分布は両端分布型となり、合成開口アンテナパ
ターン上のメインロープのビーム幅は、ＲＡＲのそれと
比べてはもちろん、ＳＡＲと比べても狭く、その分解能
が向上する。一方、受信されたエコー信号は、別途求め
た参照関数とともに相互相関処理され、これにより特定
地域の地形等の情報が画像として形成されかつ出力する
。The energy distribution within the unit time of this equivalent nonuniformly spaced synthetic aperture array becomes a double-ended distribution type, and the beam width of the main rope on the synthetic aperture antenna pattern is narrower than that of RAR, as well as compared to SAR. , its resolution is improved. On the other hand, the received echo signal is subjected to cross-correlation processing together with a separately determined reference function, whereby information such as the topography of a specific area is formed as an image and output.
（実施例）
以下、具体的実施例に基づいてこの発明の詳細な説明す
る。(Examples) Hereinafter, the present invention will be described in detail based on specific examples.
空中におけるＳＡＲの、特定地域の地表に対する相対的
な往復運動は、１例として地表に対し相対的に往復運動
を行なう同期軌道に、ＳＡＲを搭載した人工衛星を乗せ
ることにより行なわれ、同期軌道上の人工衛星が地表に
対して相対的に往復運動するため、人工衛星に搭載され
ているＳＡＲが空中において特定地域の地表に対し相対
的に往復運動する。For example, reciprocating motion of SAR in the air relative to the ground surface in a specific area is carried out by placing an artificial satellite equipped with SAR in a synchronous orbit that makes reciprocating motion relative to the ground surface. Since the artificial satellite makes a reciprocating motion relative to the ground surface, the SAR mounted on the artificial satellite makes a reciprocating motion in the air relative to the ground surface in a specific area.
同期軌道は、人工衛星の周期が地球の自転周期と一致す
る軌道で、人工衛星の軌道要素のうち、軌道傾斜角ｉお
よび離心率ｅの一方もしくは両方を変化させることによ
り得られる。第１図に示すように、軌道傾斜角ｉを変化
させた、軌道傾斜角ｉ＼０ （離心率ｅ＝０）の同期軌
道上の人工衛星１は、地球２の地軸Ｏと人工衛星１との
距離をＲＧとすると、地表から見ると南北方向に２・Ｒ
Ｇ・ｉの範囲で地表に対して相対的に往復移動する。A synchronous orbit is an orbit in which the period of the artificial satellite matches the rotation period of the earth, and is obtained by changing one or both of the orbital inclination angle i and eccentricity e among the orbital elements of the artificial satellite. As shown in Figure 1, an artificial satellite 1 on a synchronous orbit with an orbital inclination i\0 (eccentricity e = 0) whose orbital inclination angle i has been changed is aligned with the earth's axis O of the earth 2 and the artificial satellite 1. If the distance is RG, then 2・R in the north-south direction when viewed from the ground
It moves back and forth relative to the earth's surface within a range of G.i.
なお、第１図において、３は赤道面、Ｎは牝、Ｓは南で
ある。また、第２図（Ａ）、（Ｂ）に示すように、離心
率ｅを変化させた、離心率ｅζ０ （傾斜軌道角ｉ；０
）の同期軌道上の人工衛星１は、地表から見ると東西方
向に４・ＲＧｓｅの範囲で地表に対して相対的に往復移
動する。なお、第２図（Ａ） 、 （Ｂ）において、
Ｅは東、Ｗは西であり、また第２図（Ｂ）において、Ｐ
は軌道傾斜角ｉ＝０、離心率ｅ ＝ Ｏとした場合の人
工衛星１の静止位置を示している。In addition, in FIG. 1, 3 is the equatorial plane, N is female, and S is south. In addition, as shown in Fig. 2 (A) and (B), eccentricity eζ0 (inclined orbit angle i; 0
) The artificial satellite 1 on the synchronous orbit moves back and forth relative to the earth's surface in the east-west direction within a range of 4·RGse when viewed from the earth's surface. In addition, in Fig. 2 (A) and (B),
E is east, W is west, and in Figure 2 (B), P
indicates the stationary position of the artificial satellite 1 when the orbital inclination angle i=0 and the eccentricity e=0.
したがって、観測目的に応じて軌道傾斜角ｉおよび離心
率ｅを適宜変化させた同期軌道に人工衛星１を乗せると
、この人工衛星１に搭載されたＳＡＲは、空中において
特定地域の地表に対して相対的に往復運動を行なう。Therefore, if the artificial satellite 1 is placed in a synchronous orbit with the orbital inclination i and eccentricity e changed appropriately according to the observation purpose, the SAR on board this artificial satellite 1 will be Performs a relative reciprocating motion.
ＳＡＲの前記往復運動を振子と同じく単振動とすると、
瞬時の速度Ｖは中央で最大、左右両端でＯとなる、いわ
ゆる余弦関数（ｃ ｏ ｓ関数）となり、ｖ＝ｖｏ＊ｃ
ｏｓ（Ｊ・ｔ （ただし、ｔ：パルス電波の発射時刻
、 ＣＩＪ ”” ２７［−７＊ τ：捩振動周期）で
求められ、パルス電波の発射間隔Ｔｏを一定とすると、
等価的に形成される合成開口アレイアンテナの仮想的に
並んだ各アンテナの間隔ｄは、その各アンテナの位置を
座標図として説明する第３図に示すように、ｄ＝ｙ＊’
ｌ’０となる。その絶′対値はｄ＝ｌｄｎ−ｄｎ＋１１
（ただし、ｎ：自然数）である。したがって、前記
間隔ｄの瞬時の存在位置間隔は、第４図に示すように、
中央で疎、左右両端で密となり、データ処理上等価的に
形成される合成開口アレイアンテナは、不等間隔合成開
口アレイを形成する。Assuming that the reciprocating motion of the SAR is a simple harmonic motion like a pendulum,
The instantaneous velocity V is maximum at the center and O at both left and right ends, which is a so-called cosine function (cos function), and v=vo*c
os(J・t (where t: emission time of pulse radio waves, CIJ "" 27[-7* τ: torsional vibration period), and assuming the emission interval To of pulse radio waves is constant,
The interval d between each virtually lined-up antenna of an equivalently formed synthetic aperture array antenna is d=y*' as shown in FIG. 3, which explains the position of each antenna as a coordinate diagram.
It becomes l'0. Its absolute value is d=ldn-dn+11
(However, n: natural number). Therefore, the instantaneous existing position interval of the interval d is as shown in FIG.
A synthetic aperture array antenna that is sparse at the center and dense at both left and right ends and equivalently formed in terms of data processing forms an unequally spaced synthetic aperture array.
前記不等間隔合成開口アレイの単位時間内のエネルギー
分布は、第５図に示すように、両端分布型となる。この
両端分布型のアレイは、均一分布型に比ベサイドロープ
４のレベルは悪くなるが、メインローブ５のビーム幅Ｗ
ｄは狭くなり （第６図参照）、この結果得られる分解
能は向上する。The energy distribution within a unit time of the non-uniformly spaced synthetic aperture array has a two-end distribution type, as shown in FIG. In this double-ended distribution type array, the level of the side rope 4 is worse than that of the uniform distribution type, but the beam width W of the main lobe 5 is
d becomes narrower (see Figure 6) and the resulting resolution improves.
なお、第４図および第５図における符号Ｘは、仮想的に
並ぶ各アンテナの位置の進行方向を示し、またｔはパル
ス電波の発射時刻を示している。Note that the symbol X in FIGS. 4 and 5 indicates the advancing direction of the positions of the virtual antennas, and t indicates the emission time of the pulse radio wave.
前記のように、メインロープ５のビーム幅Ｗｄが狭いパ
ルス電波の地表からのエコー信号６は、通常のパルスレ
ーダと同様の方法により受信され、かつ記録されるもの
で、その詳細な説明は省略する０
そして、前記エコー信号６は、速度（相対的）、パルス
電波の繰返周波数、軌道情報等を考慮して求められた参
照関数とともに相互相関演算処理される。この処理され
たデータは、画像７として形成されかつ出力される（第
７図参照）。したがって、この画像７は、特定地域の地
形等の情報を常時出力することになり、この画像７の観
察により特定地域の常時観測が可能となる。As mentioned above, the echo signal 6 from the earth's surface of pulsed radio waves with a narrow beam width Wd of the main rope 5 is received and recorded in the same manner as a normal pulse radar, and a detailed explanation thereof will be omitted. Then, the echo signal 6 is subjected to a cross-correlation calculation process together with a reference function obtained by taking into account the speed (relative), the repetition frequency of pulse radio waves, orbit information, etc. This processed data is formed and output as an image 7 (see Figure 7). Therefore, this image 7 always outputs information such as the topography of a specific area, and by observing this image 7, it becomes possible to constantly observe the specific area.
以上のように、この実施例においては、同期軌道上の人
工衛星にＳＡＲを搭載し、ＳＡＲを空中において特定地
域の地表に対し相対的に往復運動させたものであるから
、特定地域の常時観測が可能となる。なお、ＳＡＲを空
中において特定地域の地表に対して相対的に往復運動さ
せる方法は、前記実施例のように、同期軌道上の人工衛
星に搭載する方法に限定されるものではなく、ＳＡＲが
空中において特定地域の地表に対して相対的に往復運動
する方法であればどのような方法でもよく、たとえばＳ
ＡＲを航空機に搭載し、この航空機を特定地域の上空に
おいて旋回させたり、往復させることも可能である。As described above, in this embodiment, the SAR is mounted on an artificial satellite on a synchronous orbit, and the SAR is moved in the air in a reciprocating manner relative to the ground surface in a specific area, so that constant observation of the specific area is possible. becomes possible. Note that the method of making SAR reciprocate in the air relative to the ground surface in a specific area is not limited to the method of mounting it on a satellite in a synchronous orbit as in the above embodiment; Any method may be used as long as it makes a reciprocating motion relative to the ground surface in a specific area, for example, S
It is also possible to mount an AR on an aircraft and make the aircraft circle or reciprocate over a specific area.
（発明の効果）
以上のように、この発明によれば、ＳＡＲが空中におい
て、特定地域の地表に対して相対的に往復運動するもの
であるから、特定地域の常時観測が可能となる。また、
ＳＡＲの往復運動により、特定地域の空間には不等間隔
合成開口アレイがデータ処理によって等価的に形成され
るものであるから、結果的に合成開口アンテナパターン
上のメインロープのビーム幅が狭くなって分解能が向上
する０(Effects of the Invention) As described above, according to the present invention, since the SAR reciprocates in the air relative to the ground surface in a specific area, constant observation of the specific area is possible. Also,
Due to the reciprocating motion of SAR, an unequally spaced synthetic aperture array is equivalently formed in the space of a specific area by data processing, and as a result, the beam width of the main rope on the synthetic aperture antenna pattern becomes narrower. The resolution is improved0
図面は、この発明の一実施例を示すもので、第軌道を表
わす説明図、第２図（Ｂ）は地球の地表から見たときの
人工衛星の相対的軌跡を表わす説明図、第３図はパルス
電波を一定間隔で発射したときの等価的に形成される合
成開口アレイアンテナの仮想的に並んだ各アンテナの位
置を説明する座標図、第４図は等価的に形成される合成
開口アレイアンテナの仮想的に並んだ各アンテナの間隔
を示す説明図、第５図は不等間隔合成開口アレイの単位
時間内のエネルギー分布の説明図、第６図は合成開口ア
ンテナパターンの説明図、第７図はエコー信号の処理系
統を示すブロック図である。
１・・・人工衛星、２・・・地球、３・・・赤道面、４
・・・サイドローブ、５・・・メインロープ、６・・・
エコー信号、７・・・画像、ＴＯ・・・パルス電波の発
射間隔、ｄ・・・仮想的に並んだ各アンテナの間隔、ｔ
・・・パルス電波の発射時刻、Ｘ・・・仮想的に並ぶ各
アンテナの位置の進行方向、Ｗｄ・・・メインロープの
ビーム幅。The drawings show an embodiment of the present invention; FIG. 2(B) is an explanatory diagram showing the orbit, FIG. 4 is a coordinate diagram illustrating the positions of virtually lined up antennas of a synthetic aperture array antenna that is formed equivalently when pulsed radio waves are emitted at regular intervals. Figure 4 is a synthetic aperture array that is formed equivalently. FIG. 5 is an explanatory diagram showing the spacing between each antenna that is virtually lined up. FIG. FIG. 7 is a block diagram showing an echo signal processing system. 1...Artificial satellite, 2...Earth, 3...Equatorial plane, 4
...Side lobe, 5...Main rope, 6...
Echo signal, 7... Image, TO... Pulse radio wave emission interval, d... Interval between virtual antennas, t
...The emission time of the pulse radio wave,
Claims (1)
相対的に往復運動させ、該合成開口レーダの往復運動中
そのアンテナより一定間隔でパルス電波を発射し、該パ
ルス電波の送受信により中央で疎、左右両端で密となる
不等間隔合成開口アレイをデータ処理において等価的に
形成し、同時にデータ処理により特定地域の情報を画像
として形成しかつ出力することを特徴とする、地球観測
における特定地域の常時観測方法。A synthetic aperture radar is moved in the air in a reciprocating manner relative to the ground surface in a specific area, and during the reciprocating movement of the synthetic aperture radar, pulsed radio waves are emitted from its antenna at regular intervals. A method for detecting a specific area in earth observation, which is characterized in that an unevenly spaced synthetic aperture array that is dense at both left and right ends is equivalently formed in data processing, and at the same time, information on a specific area is formed and output as an image through data processing. Constant observation method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61154734A JPS6311885A (en) | 1986-07-01 | 1986-07-01 | Method for continuously observing specific area in earth observation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61154734A JPS6311885A (en) | 1986-07-01 | 1986-07-01 | Method for continuously observing specific area in earth observation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6311885A true JPS6311885A (en) | 1988-01-19 |
| JPH055312B2 JPH055312B2 (en) | 1993-01-22 |
Family
ID=15590766
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61154734A Granted JPS6311885A (en) | 1986-07-01 | 1986-07-01 | Method for continuously observing specific area in earth observation |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6311885A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004309178A (en) * | 2003-04-02 | 2004-11-04 | Oyo Corp | Ground surface variation measuring method using synthetic aperture radar |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4991787A (en) * | 1972-12-30 | 1974-09-02 | ||
| JPS60170775A (en) * | 1984-02-15 | 1985-09-04 | Natl Space Dev Agency Japan<Nasda> | Synthetic aperture radar |
| JPS6135382A (en) * | 1984-07-28 | 1986-02-19 | Natl Space Dev Agency Japan<Nasda> | Synthetic aperture radar |
-
1986
- 1986-07-01 JP JP61154734A patent/JPS6311885A/en active Granted
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4991787A (en) * | 1972-12-30 | 1974-09-02 | ||
| JPS60170775A (en) * | 1984-02-15 | 1985-09-04 | Natl Space Dev Agency Japan<Nasda> | Synthetic aperture radar |
| JPS6135382A (en) * | 1984-07-28 | 1986-02-19 | Natl Space Dev Agency Japan<Nasda> | Synthetic aperture radar |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004309178A (en) * | 2003-04-02 | 2004-11-04 | Oyo Corp | Ground surface variation measuring method using synthetic aperture radar |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH055312B2 (en) | 1993-01-22 |
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