JPS6238658B2 - - Google Patents
Info
- Publication number
- JPS6238658B2 JPS6238658B2 JP54009829A JP982979A JPS6238658B2 JP S6238658 B2 JPS6238658 B2 JP S6238658B2 JP 54009829 A JP54009829 A JP 54009829A JP 982979 A JP982979 A JP 982979A JP S6238658 B2 JPS6238658 B2 JP S6238658B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- noise source
- switch
- comparison
- antenna
- 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Dicke比較形マイクロ波放
射計の比較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 of the comparative noise source of a Dicke comparative microwave radiometer that is mounted on a flying object such as an artificial satellite and performs 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Dicke比較形マイクロ波
放射形の一例である。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はそれぞれスイツチ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〓4〓Ｇ（Ω）ＴB（Ω）ｄΩ…(1)
で表される。ここでΩは立体角である。 Figure 1 is an example of the Dicke Comparative Microwave Radiation System, which is mounted on a conventional artificial satellite and receives electromagnetic waves emitted from objects on the earth's surface for remote sensing of the earth's environment. In the figure, 1 is the receiving antenna, 2
3 is a standard noise source, 4 is a comparison noise source, 5 is a receiver, and 6, 7, and 8 are switches 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 . =1/4π〓 4 〓G(Ω)T B (Ω)dΩ…(1) It is expressed as follows. 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 , and if 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−Ｔ
２／Ｖ１−Ｖ２Ｖ…(2)
現実には受信機５には利得変動があり、この利
得変動はアンテナ温度校正上の誤差の一因とな
る。校正誤差△ＴGは受信機５の利得をＧ、利得
変動を△Ｇとすれば次式で表される。 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 reality, the receiver 5 has gain fluctuations, and this gain fluctuation is a cause of errors in antenna temperature calibration. The calibration error ΔT G is expressed by the following equation, where G is the gain of the receiver 5 and ΔG is the gain fluctuation.
△ＴG＝｜（ＴO−ＴA）△Ｇ／Ｇ｜ …(3)
したがつて△ＴGを小さくするためには比較雑
音源４の温度ＴOをアンテナ温度ＴAに近くなるよ
うにあらかじめ設定することが望ましい。しかし
アンテナ温度ＴAは観測対象物の輝度温度と不可
分の関係にあり、しかも広い範囲の輝度温度に対
して観測を可能ならしめるためにはＴOの値をＴO
−ＴA≒０となるような特定のアンテナ温度ＴAに
対して設定するのではなく、一般には観測アンテ
ナ温度の上限に近い値に設定される。この時、比
較雑音源４の温度は高温で一定（たとえば340±
0.2K）となるように設定されるため精密な温度
制御回路が必要となるばかりでなく、雑音源自身
も恒温槽に入れる等構成が複雑となる欠点があつ
た。なお、以上では便宜上スイツチ等RF回路の
損失は無いものと仮定して説明した。 △T G = | (T O - T A ) △G/G | ...(3) Therefore, in order to reduce △T G , the temperature T O of comparison noise source 4 should be made close to the antenna temperature T A It is desirable to set this in advance. However, the antenna temperature T A is inseparable from the brightness temperature of the object to be observed, and in order to enable observation over a wide range of brightness temperatures, the value of T O must be adjusted to
Rather than setting for a specific antenna temperature T A such that −T A ≈0, it is generally set to a value close to the upper limit of the observation antenna temperature. At this time, the temperature of comparison noise source 4 is constant at a high temperature (for example, 340±
0.2K), which not only required a precise temperature control circuit, but also had the disadvantage of complicating the configuration, as the noise source itself had to be placed in a thermostatic oven. Note that, for convenience, the explanation above has been made on the assumption that there is no loss in the RF circuit such as a switch.
この発明においては比較雑音源にホーンアンテ
ナを用い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。 In this invention, a horn antenna is used as a comparison noise source to eliminate the above-mentioned drawbacks of the conventional method. 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、２はスカ
イホーン、３は標準雑音源、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
ホーンアンテナから成る比較雑音源である。比較
雑音源９のホーンアンテナはスカイホーン２と同
様、太陽、月等の影響を受けないような衛星構体
面に取り付けられ、常に宇宙の冷たい空間側にあ
るものとする。この場合、スイツチＡ６の切換操
作によつて比較雑音源９の温度ＴOとアンテナ温
度ＴAとの差によつて受信機５内部で発生する電
圧をＶとする。同様にＴOとスカイホーン２の温
度T1との差によつて発生する電圧をV1、ＴOと標
準雑音源３の温度T2との差によつて発生する電
圧をV2とし、ＴO＜T1＜T2であればV1＜Ｖ＜V2
となるからアンテナ温度ＴAは次式から求まる。 In Fig. 2, 1 is a receiving antenna, 2 is a skyhorn, 3 is a standard noise source, 5 is a receiver, 6,
7 and 8 are comparative noise sources consisting of switches A, B, and C, respectively, and 9 a horn antenna. Like the skyhorn 2, the horn antenna of the comparison noise source 9 is attached to the surface of the satellite structure that is not affected by the sun, the moon, etc., and is always located on the cold space side of space. In this case, by operating the switch A6, the voltage generated inside the receiver 5 due to the difference between the temperature T O of the comparison noise source 9 and the antenna temperature T A is set to V. Similarly, the voltage generated due to the difference between T O and the temperature T 1 of the skyhorn 2 is V 1 , the voltage generated due to the difference between T O and the temperature T 2 of the standard noise source 3 is V 2 , If T O < T 1 < T 2 then V 1 < V < V 2
Therefore, the antenna temperature T A can be found from the following equation.
ＴA＝Ｖ２Ｔ１−Ｖ１Ｔ２／Ｖ２−Ｖ１＋Ｔ２−Ｔ
１／Ｖ２−Ｖ１Ｖ…(4)
この場合でも受信機５の利得変動による校正誤
差△ＴGが問題となる。ここで比較雑音源９の温
度ＴOはアンテナ温度の観測範囲の下限に設定す
るものとする。こうすることによつて校正誤差△
ＴGの値は比較雑音源の温度ＴOを従来のように高
温に設定した場合でも、この発明のように低温に
設定した場合でも互いに同程度とすることができ
る。また、この発明の比較雑音源９にはホーンア
ンテナを用いていることからその構造は簡単であ
り、しかもホーンアンテナは衛星構体上の宇宙の
冷たい空間側に取り付けられていることから容易
に低雑音源とすることができる。 T A =V 2 T 1 −V 1 T 2 /V 2 −V 1 +T 2 −T
1 /V 2 −V 1 V (4) Even in this case, the calibration error ΔT G due to the gain fluctuation of the receiver 5 poses a problem. Here, it is assumed that the temperature T O of the comparison noise source 9 is set at the lower limit of the antenna temperature observation range. By doing this, the calibration error △
The value of T G can be made to be approximately the same whether the temperature T O of the comparison noise source is set to a high temperature as in the conventional case or a low temperature as in the present invention. In addition, since a horn antenna is used as the comparison noise source 9 of the present invention, its structure is simple, and since the horn antenna is attached to the cold space side of space on the satellite structure, it is easy to generate low noise. It can be used as a source.
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な構成
で比較雑音源が得られる効果を有する。 As described above, according to the present invention, a comparison noise source can be obtained with a simple configuration.
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はホーンアン
テナである。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, respectively, and 9 is a horn antenna. In the drawings, 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の雑音を発生するスカイホーンと、
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、上記スカイホーンの温度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スカイホーン
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、上記比較
雑音源としてホーンアンテナ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 skyhorn that generates noise at a temperature T 1 ,
A voltage proportional to the difference between a standard noise source that generates noise at a temperature T 2 (T 1 < T 2 ) and the noise antenna temperature T A received by the receiving antenna and the temperature T 0 of the comparison noise source, the above Obtain a voltage proportional to the difference between the temperature T 1 of the skyhorn 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. receiver and
a switch for switching between the receiving output of the receiving antenna and the output of the skyphone or the standard noise source; and a switch connected between the switch and the receiver to switch between the output from the switch and the output of the comparison noise source. A microwave radiation meter comprising a switch and a switch to be applied to the receiver and used on board a flying object such as an artificial satellite, characterized in that a horn antenna is used as the comparison noise source. Total.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP982979A JPS55101827A (en) | 1979-01-31 | 1979-01-31 | Microwave radiometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP982979A JPS55101827A (en) | 1979-01-31 | 1979-01-31 | Microwave radiometer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55101827A JPS55101827A (en) | 1980-08-04 |
| JPS6238658B2 true JPS6238658B2 (en) | 1987-08-19 |
Family
ID=11731010
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP982979A Granted JPS55101827A (en) | 1979-01-31 | 1979-01-31 | Microwave radiometer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55101827A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105372610B (en) * | 2015-10-27 | 2017-12-29 | 中国科学院国家空间科学中心 | A kind of device and method for 4 points of calibrations of microwave radiometer |
-
1979
- 1979-01-31 JP JP982979A patent/JPS55101827A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55101827A (en) | 1980-08-04 |
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