JPS6237344B2 - - Google Patents
Info
- Publication number
- JPS6237344B2 JPS6237344B2 JP54009827A JP982779A JPS6237344B2 JP S6237344 B2 JPS6237344 B2 JP S6237344B2 JP 54009827 A JP54009827 A JP 54009827A JP 982779 A JP982779 A JP 982779A JP S6237344 B2 JPS6237344 B2 JP S6237344B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- noise source
- switch
- noise
- comparison
- 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.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K11/00—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
- G01K11/006—Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00 using measurement of the effect of a material on microwaves or longer electromagnetic waves, e.g. measuring temperature via microwaves emitted by the object
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radiation Pyrometers (AREA)
- Geophysics And Detection Of Objects (AREA)
Description
【発明の詳細な説明】
この発明は人工衛星等の飛翔体に搭載してリモ
ートセンシングを行うマイクロ波放射計のアンテ
ナ温度校正用低雑音源の改良に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a low noise source for calibrating the antenna temperature of a microwave radiometer mounted on a flying object such as an artificial satellite for remote sensing.
第１図は従来の人工衛星に搭載して地球表面の
物体から放射する電磁波を受信して地球環境のリ
モートセンシングを行うマイクロ波放射計の一例
である。図中１は受信アンテナ、２はスカイホー
ンと呼ばれるホーンアンテナ、３は標準雑音源、
４は比較雑音源、５は受信機および６，７，８は
それぞれＡ，Ｂ，Ｃである。一般に自然界の物体
からは電磁波が放射されており、放射の強度はそ
の物体の輝度温度と密接な関係がある。第１図の
受信アンテナ１で受信されるアンテナ温度ＴAは
受信アンテナ１を取りまく物体の輝度温度の分布
ＴB（Ω）と受信アンテナ１の利得関数Ｇ（Ω）
とを用いて
ＴA＝１／４π∫∫Ｇ ４〓（Ω）ＴB（Ω）ｄΩ……(1
)
で表される。ここでΩは立体角である。 FIG. 1 is an example of a conventional microwave radiometer mounted on an artificial satellite to receive electromagnetic waves emitted from objects on the earth's surface and perform remote sensing of the earth's environment. In the figure, 1 is a receiving antenna, 2 is a horn antenna called a skyhorn, 3 is a standard noise source,
4 is a comparison noise source, 5 is a receiver, and 6, 7, and 8 are A, B, and C, respectively. Generally, objects in the natural world emit electromagnetic waves, and the intensity of the radiation is closely related to the brightness temperature of the object. The antenna temperature T A received by the receiving antenna 1 in FIG .
Using TA = 1/4π∫∫ G 4 〓(Ω)T B (Ω)dΩ……(1
). Here Ω is the solid angle.
スイツチＡ６が側に接続されている場合、受
信されたアンテナ温度ＴAはスイツチＢ７に向か
う。スイツチＢ７はある瞬間には側に接続さ
れ、次の瞬間には側に接続される操作を数百Hz
で繰り返す。またスイツチＢ７の側には比較的
高温で一定温度ＴOの雑音を発生する比較雑音源
４が接続されており、このスイツチ切換操作に同
期する受信機５内の同期検波器を通して比較雑音
源４の温度ＴOとアンテナ温度ＴAとの差に比例す
る電圧Ｖが得られる。マイクロ波放射計の観測機
能を達成するためには、発生した電圧Ｖをもとに
アンテナ温度ＴAの値を知ることが必要条件であ
り、この値は次の手順を経ることによつて求める
ことができる。 If switch A6 is connected to the side, the received antenna temperature T A goes to switch B7. Switch B7 is connected to the side at one moment, and the operation at the next moment is several hundred Hz.
Repeat with Further, a comparison noise source 4 that generates noise at a relatively high temperature and a constant temperature T O is connected to the switch B7 side, and the comparison noise source 4 is transmitted through a synchronous detector in the receiver 5 that is synchronized with the switch switching operation. A voltage V proportional to the difference between the temperature T O and the antenna temperature T A is obtained. In order to achieve the observation function of a microwave radiometer, it is necessary to know the value of the antenna temperature T A based on the generated voltage V, and this value can be found by going through the following steps. be able to.
まずスイツチＡ６の接続を側から側に切り
換える。スイツチＣ８が側の時にスカイホーン
２からのアンテナ温度T1が、そして側の時に
標準雑音源３の雑音温度T2が受信機５に導か
れ、それぞれ比較雑音源４との温度差に比例する
電圧V1およびV2が受信機５内で発生する。ここ
でスカイホーン２は常に宇宙の冷たい空間に向け
られているとすれば、その輝度温度は周波数の関
数として既知の量であり、同時にスカイホーン２
自身の利得関数も既知であるため、これらをもと
に受信機５の入力温度T1を知ることができる。
一方、標準雑音源３の雑音温度も標準雑音源３に
温度センサを取り付け、それをモニタすることに
よつて受信機５の入力温度T2を知ることができ
る。なおT1＜T2＜ＴO，V1＞Ｖ＞V2の関係があり
T1，T2，V1，V2およびＶがわかるとアンテナ温
度ＴAは次式から求まる。 First, switch the connection of switch A6 from side to side. When the switch C8 is on the side, the antenna temperature T1 from the skyhorn 2 is guided to the receiver 5, and when it is on the side, the noise temperature T2 of the standard noise source 3 is guided to the receiver 5, and each is proportional to the temperature difference with the comparison noise source 4. Voltages V 1 and V 2 are generated within the receiver 5. If Skyhorn 2 is always pointed toward the cold space of space, its brightness temperature is a known quantity as a function of frequency, and at the same time Skyhorn 2
Since its own gain function is also known, the input temperature T 1 of the receiver 5 can be known based on these.
On the other hand, by attaching a temperature sensor to the standard noise source 3 and monitoring the noise temperature of the standard noise source 3, the input temperature T2 of the receiver 5 can be determined. Note that there is a relationship of T 1 <T 2 <T O , V 1 >V>V 2
When T 1 , T 2 , V 1 , V 2 and V are known, the antenna temperature T A can be found from the following equation.
ＴA＝Ｖ１Ｔ２−Ｖ２Ｔ１／Ｖ１−Ｖ２＋Ｔ１−Ｔ２
／Ｖ１−Ｖ２Ｖ……(2)
以上では説明の便宜上スイツチ等RF回路の損
失は無いものと仮定している。 T A =V 1 T 2 −V 2 T 1 /V 1 −V 2 +T 1 −T 2
/V 1 −V 2 V (2) In the above, for convenience of explanation, it is assumed that there is no loss in the RF circuit such as a switch.
以上の説明からも明らかなようにスカイホーン
２と標準雑音源３はアンテナ温度ＴAの校正のた
めに用いられる校正用雑音源である。標準雑音源
３は衛星の構体内にあり、校正用雑音源として常
時使用可能であるが、スカイホーン２については
それが校正用雑音源（今の場合低雑音源）となり
得るためにはスカイホーン２の利得関数およびス
カイホーン２を取りまく周囲の輝度温度分布を正
確に知る必要がある。普通スカイホーン２は衛星
構体上の太陽等に対して陰の面に取り付けられ、
そのメインビームは宇宙の冷たい空間に向けられ
るようになつている。この場合スカイホーン２の
サイドローブは衛星構体の陰の面の輝度温度を補
足するため、スカイホーン２を低雑音源とするた
めには、その陰の面の輝度温度分布を正確に知る
必要がある。しかし、輝度温度分布を正確に知る
ことは衛星の形状、構体の使用材料、衛星の軌道
等を考慮した複雑な熱解析が要求されるため、簡
単には低雑音源としての特性が把握できない欠点
があつた。 As is clear from the above explanation, the skyhorn 2 and the standard noise source 3 are calibration noise sources used to calibrate the antenna temperature T A. The standard noise source 3 is located inside the satellite body and can be used at all times as a calibration noise source, but for the skyhorn 2, in order for it to be a calibration noise source (low noise source in this case), the skyhorn is required. It is necessary to accurately know the gain function of 2 and the brightness temperature distribution in the surroundings of the skyhorn 2. Normally, Skyhorn 2 is attached to the surface of the satellite structure that is in the shade from the sun, etc.
Its main beam is directed toward the cold space of space. In this case, the sidelobes of skyhorn 2 supplement the brightness temperature of the shadow surface of the satellite structure, so in order to make skyhorn 2 a low noise source, it is necessary to accurately know the brightness temperature distribution of the shadow surface. be. However, accurately knowing the brightness temperature distribution requires complex thermal analysis that takes into account the shape of the satellite, the materials used for its structure, the orbit of the satellite, etc., so the characteristics of a low noise source cannot be easily determined. It was hot.
そこでこの発明においてはダミーロードと温度
センサとを用いることによつて上述の従来の欠点
を除去するようにしたものである。以下図面によ
りこの発明の一実施例について説明する。 Therefore, the present invention uses a dummy load and a temperature sensor to eliminate the above-mentioned drawbacks of the conventional technology. An embodiment of the present invention will be described below with reference to the drawings.
第２図において、１は受信アンテナ、３は標準
雑音源、４は比較雑音源、５は受信機、６，７，
８はそれぞれスイツチＡ，Ｂ，Ｃおよび９はダミ
ーロードである。この発明においてはダミーロー
ド９は衛星構体の外側の面に取り付けられ、取り
付けられた面は太陽等に対して長期間にわたつて
陰になつているものとする。またダミーロード９
には温度センサを取り付け、更にダミーロード９
の整合は十分とれているものとする。一般に整合
のとれたダミーロードの等価雑音温度はそのダミ
ーロードの物理的温度に等しいことが知られてい
る。したがつてダミーロード９に取り付けた温度
センサによつてダミーロード９の物理的温度をモ
ニタしさえすれば常に正確な低雑音特性が把握で
きる。 In FIG. 2, 1 is a receiving antenna, 3 is a standard noise source, 4 is a comparison noise source, 5 is a receiver, 6, 7,
8 are switches A, B, and C, and 9 is a dummy load. In this invention, the dummy load 9 is attached to the outer surface of the satellite structure, and the attached surface remains in the shadow from the sun etc. for a long period of time. Also dummy load 9
A temperature sensor is attached to the dummy load 9.
It is assumed that there is sufficient consistency. It is generally known that the equivalent noise temperature of a matched dummy load is equal to the physical temperature of the dummy load. Therefore, as long as the physical temperature of the dummy load 9 is monitored by the temperature sensor attached to the dummy load 9, accurate low-noise characteristics can always be grasped.
以上では人工衛星を例にとつて説明したが、他
の飛翔体であつても差し支えない。 Although the above explanation uses an artificial satellite as an example, other flying objects may also be used.
以上述べたようにこの発明によれば、簡単にし
てしかも正確な低雑音特性が常時把握できるた
め、アンテナ温度の校正が正確に行なえる効果を
有する。 As described above, according to the present invention, the low noise characteristics can be easily and accurately grasped at all times, so that the antenna temperature can be calibrated accurately.
第１図は従来のマイクロ波放射計の説明図、第
２図はこの発明の一実施例を示す図であり、図
中、１は受信アンテナ、２はスカイホーン、３は
標準雑音源、４は比較雑音源、５は受信機、６，
７，８はそれぞれスイツチおよび９はダミーロー
ドである。図中、同一部分または相当部分には同
一記号を付して示してある。
FIG. 1 is an explanatory diagram of a conventional microwave radiometer, and FIG. 2 is a diagram showing an embodiment of the present invention. In the figure, 1 is a receiving antenna, 2 is a skyhorn, 3 is a standard noise source, and 4 is the comparison noise source, 5 is the receiver, 6,
7 and 8 are switches, and 9 is a dummy load. In the figures, the same or equivalent parts are indicated by the same symbols.
Claims (1)
と、一定温度T0の雑音を発生する比較雑音源
と、温度T1の雑音を発生する温度校正用低雑音
源と、温度T2（T1＜T2）の雑音を発生する標準雑
音源と、上記受信アンテナで受信された雑音アン
テナ温度ＴAと上記比較雑音源の温度T0との差に
比例する電圧、上記温度校正用低雑音源の温度
T1と上記比較雑音源の温度T0との差に比例する
電圧、および上記標準雑音源の温度T2と上記比
較雑音源の温度T0との差に比例する電圧を得る
受信機と、上記受信アンテナの受信出力と上記温
度校正用低雑音源あるいは上記標準雑音源の出力
とを切換えるスイツチと、このスイツチと上記受
信機との間に接続され、上記スイツチからの出力
と上記比較雑音源の出力とを切換えて上記受信機
に与えるスイツチとから構成され、人工衛星等の
飛翔体に搭載して使用されるマイクロ波放射計に
おいて、上記温度校正用低雑音源としてダミーロ
ードを用いたことを特徴とするマイクロ波放射
計。1. A receiving antenna that receives electromagnetic waves from an object, a comparison noise source that generates noise at a constant temperature T 0 , a low noise source for temperature calibration that generates noise at a temperature T 1 , and a temperature T 2 (T 1 < T 2 ) A standard noise source that generates the noise, a voltage proportional to the difference between the noise antenna temperature T A received by the receiving antenna and the temperature T 0 of the comparison noise source, and the temperature of the low noise source for temperature calibration.
a receiver that obtains a voltage proportional to the difference between T 1 and the temperature T 0 of the comparison noise source, and a voltage proportional to the difference between the temperature T 2 of the standard noise source and the temperature T 0 of the comparison noise source; A switch is connected between the receiving output of the receiving antenna and the output of the low noise source for temperature calibration or the standard noise source, and the switch is connected between the switch and the receiver, and the switch is connected between the output of the receiving antenna and the output of the low noise source for temperature calibration or the standard noise source. A dummy load is used as a low-noise source for temperature calibration in a microwave radiometer that is used onboard a flying object such as an artificial satellite, and is comprised of a switch that switches between the output of A microwave radiometer featuring:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP982779A JPS55101825A (en) | 1979-01-31 | 1979-01-31 | Microwave radiometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP982779A JPS55101825A (en) | 1979-01-31 | 1979-01-31 | Microwave radiometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55101825A JPS55101825A (en) | 1980-08-04 |
| JPS6237344B2 true JPS6237344B2 (en) | 1987-08-12 |
Family
ID=11730958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP982779A Granted JPS55101825A (en) | 1979-01-31 | 1979-01-31 | Microwave radiometer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55101825A (en) |
-
1979
- 1979-01-31 JP JP982779A patent/JPS55101825A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55101825A (en) | 1980-08-04 |
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