CN111947790A - Internal and external calibration system and internal and external calibration method for satellite-borne microwave radiometer - Google Patents
Internal and external calibration system and internal and external calibration method for satellite-borne microwave radiometer Download PDFInfo
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Abstract
The invention belongs to the technical field of satellite-borne microwave radiometer calibration, and particularly relates to an internal and external calibration system of a satellite-borne microwave radiometer, which comprises the following components: the device comprises a microwave radiometer, an internal noise injection module, a GPS occultation signal receiving module, an external occultation module, a periodic self-calibration module and an on-satellite calibration processing module; the microwave radiometer is used for carrying out real-time nonlinear calibration on the calibration reference source by taking seconds as a unit to obtain an initial observation brightness temperature value of the observation target; the external occultation module is used for realizing occultation events according to the received periodic self-calibration temperature occultation signals taking the month as a unit to obtain an external calibration correction value; the periodic self-calibration module is used for switching to a periodic calibration observation mode through the program-controlled lifting mechanism and carrying out periodic observation on the matched load by taking the day as a unit to obtain an internal calibration correction amount; and the on-satellite calibration processing module is used for carrying out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target to obtain a corrected observation target brightness temperature value.
Description
Technical Field
The invention belongs to the technical field of satellite-borne microwave radiometer calibration, and particularly relates to an internal and external calibration system and an internal and external calibration method for a satellite-borne microwave radiometer.
Background
The microwave hygrometer receiver adopts on-orbit real-time periodic calibration, the low-temperature radiation source is cosmic cold air background radiation, and the high-temperature radiation source is a microwave absorption black body. The calibration source consists of three parts, namely a microwave absorbing black body, a temperature measuring circuit and a shielding case, and the antenna is calibrated once per rotation. The microwave absorbing black body covers the projection aperture of the antenna, and a cylindrical shielding cover is arranged outside the microwave absorbing black body to eliminate stray radiation from the surrounding environment. However, the provision of the shield increases the volume and weight of the microwave radiometer.
Meanwhile, the satellite traditional microwave radiometer does not have a third reference source as a reference, so that drift amount cannot be obtained for a long time, the intergeneration microwave radiometer has system deviation and changes along with the change of an observation target, a correction model is challenging, and uncertain factors are brought to long-time climate research.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides an internal and external calibration system of a satellite-borne microwave radiometer, which can correct the error of a conventional calibration method through an internal and external calibration mode and accurately acquire the brightness temperature value of an observation target in real time.
The invention provides an internal and external calibration system of a satellite-borne microwave radiometer, which comprises: the device comprises a microwave radiometer, an internal noise injection module, a GPS occultation signal receiving module, an external occultation module, a periodic self-calibration module and an on-satellite calibration processing module;
the internal noise injection module is used for obtaining the low-temperature reference source temperature and the high-temperature reference source temperature of the microwave radiometer and taking the low-temperature reference source temperature and the high-temperature reference source temperature as calibration reference sources;
the microwave radiometer is used for carrying out real-time nonlinear calibration on a calibration reference source in seconds by adopting a high-temperature and low-temperature two-point calibration mode to obtain a primary observation brightness temperature value of an observation target and sending the primary observation brightness temperature value to the on-satellite calibration processing module;
a program control lifting mechanism is additionally arranged outside the microwave radiometer and used for realizing the switching between an edge-facing path observation mode and a periodic calibration observation mode;
the GPS occultation signal receiving module is used for switching to an adjacent-edge path observation mode through the program-controlled lifting mechanism, receiving periodic self-calibration temperature occultation signals taking a month as a unit and sending the signals to the external occultation module;
the external occultation module is used for realizing occultation events according to the received periodic self-calibration temperature occultation signals taking months as units, obtaining an external calibration correction value and sending the external calibration correction value to the on-satellite calibration processing module;
the periodic self-calibration module is used for switching to a periodic calibration observation mode through the program-controlled lifting mechanism, performing periodic observation on the matched load by taking days as a unit to obtain an internal calibration correction amount, and sending the internal calibration correction amount to the on-satellite calibration processing module;
and the on-satellite calibration processing module is used for carrying out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and taking the corrected observation target brightness temperature value as the final observation brightness temperature value of the observation target.
As one improvement of the above technical solution, the microwave radiometer is a superheterodyne microwave radiometer, a direct detection type microwave radiometer, a real aperture microwave radiometer, a synthetic aperture microwave radiometer, a full power microwave radiometer, or a full polarization microwave radiometer.
As one of the improvements of the above technical solution, the calibration reference source is calibrated in real time in seconds by using a high-temperature and low-temperature two-point calibration manner to obtain an initial observed brightness temperature value of the observation target, which specifically includes:
utilizing an internal noise injection module, and obtaining the temperature of a low-temperature reference source when an antenna of the microwave radiometer is aligned with a space cold air background; then, an internal noise injection module is utilized to couple the noise signal to the observation target temperature in a time-sharing manner to obtain the high-temperature reference source temperature of the microwave radiometer; taking the temperature of the low-temperature reference source and the temperature of the high-temperature reference source as calibration reference sources;
according to the two-point calibration principle, a two-point calibration equation is established by adopting a high-temperature and low-temperature two-point calibration mode, and the calibration reference source is calibrated in real time in seconds:
RA＝a0+a1CA (1)
wherein, a0Scaling the bias term of the equation for two points; a is1Scaling a first order of the equation for two points; cAObserving a target voltage value; rAThe radiant quantity converted by the Planck law for observing the target temperature; cHThe high-temperature voltage value of the calibration reference source is obtained; rHThe radiant quantity is converted from the high-temperature reference source temperature through the Planck law; cCThe low-temperature voltage value of the calibration reference source is obtained; rCThe radiation quantity is converted from the low-temperature reference source temperature through the Planck law;
according to the formula (2), for RAAnd (3) carrying out nonlinear calibration correction:
RA'＝a0+a1CA+a2CA 2＝RA+a2CA 2 (2)
wherein R isA' the radiant quantity of the initial observation brightness temperature value of the observation target obtained after primary correction converted by the Planck law, a2Is a non-linear term;
to RA' obtaining observations by Replanck conversionAnd (5) primary observation brightness temperature values of the target.
As an improvement of the above technical solution, the internal noise injection module includes: the device comprises a high-frequency noise source, a temperature measuring circuit, a noise injection circuit, a coupling switch and a low-temperature source acquisition module;
the high-frequency noise source is used for generating a stable noise signal;
the temperature measuring circuit is used for accurately measuring the thermistor temperature value of the observation target and converting the thermistor temperature value through a Planck law to obtain the radiant quantity of the observation target; the device is also used for accurately measuring the thermistor temperature value of the matched load and converting the thermistor temperature value through a Planck law to obtain the radiant quantity of the matched load;
the noise injection circuit is used for coupling a noise signal to the observation target temperature in a time-sharing manner to obtain the high-temperature reference source temperature of the microwave radiometer;
the coupling switch is used for controlling the noise signal to be coupled to the fixed target temperature in a preset time in a coupling mode;
and the low-temperature source acquisition module is used for acquiring the temperature of the low-temperature reference source when an antenna in the microwave radiometer is aligned with the cosmic cold air background.
As one improvement of the above technical solution, the program-controlled lifting mechanism is switched to a periodic calibration observation mode, periodic observation is performed on the matched load in units of days to obtain an internal calibration correction amount, and the internal calibration correction amount is sent to the satellite calibration processing module; the method specifically comprises the following steps:
the program-controlled lifting mechanism is switched to a periodic calibration observation mode, periodic observation is carried out on the matched load with the measurable temperature in a day unit, a theoretical temperature value measured by the matched load is obtained through two-point periodic calibration, the theoretical temperature value is differed from an actual temperature value measured by the matched load, the difference value is used as a drift amount, the drift amount is used as an internal calibration correction amount, and the internal calibration correction amount is sent to the on-satellite calibration processing module.
As one improvement of the technical scheme, the program-controlled lifting mechanism is switched to an adjacent-edge path observation mode, a occultation event is realized according to a received periodic self-calibration temperature occultation signal taking a month as a unit, an external calibration correction value is obtained and is sent to an on-satellite calibration processing module; the method specifically comprises the following steps:
the method comprises the steps that a program-controlled lifting mechanism is switched to a side-approaching path observation mode, a GPS occultation signal receiving module is used for receiving periodic self-calibration temperature occultation signals with a month as a unit, the atmospheric refractive index, additional carrier phase delay and a bending angle are obtained, and then an atmospheric profile is obtained through inversion;
and carrying out radiation transmission calculation on the atmospheric profile obtained by inversion to obtain a theoretical occultation atmospheric brightness temperature value, carrying out difference on the theoretical occultation atmospheric brightness temperature value and a preset threshold value, wherein the difference value is an external calibration correction value, and sending the external calibration correction value to an on-satellite calibration processing module.
As one improvement of the above technical solution, the internal and external calibration correction processing is performed on the initial observed brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and the corrected observation target brightness temperature value is used as a final observation brightness temperature value of the observation target; the method specifically comprises the following steps:
according to the formula (3), the primary observation brightness temperature value of the observation target is subjected to inner calibration correction processing and outer calibration correction processing:
TB＝replanck(a0+a1CA+a2CA 2+ΔRC+ΔRG) (3)
wherein, TBThe corrected brightness temperature value of the observation target is obtained; Δ RCCalibrating the correction quantity for the internal standard; Δ RGCalibrating the correction value for the outside;
will TBAnd the final observed brightness temperature value of the observed target.
As an improvement of the above technical solution, the system further includes: the scoring module is used for solving the mean square error of the obtained observation brightness temperature value of the final observation target to obtain a difference value, and scoring the calibration result according to the difference value;
specifically, if the difference is less than 1k, the result of this calibration is rated as a top grade and 10 points;
if the difference is greater than or equal to 1k and less than 5k, the scaling result is rated as a medium grade and rated as 1-5 points; wherein, the difference is equal to 1k, then the score is 5, and the score is lower along with the increment of the difference;
if the difference is larger than 3k, the result of this scaling is rated as a difference and rated as 0.
The invention also provides an internal and external calibration method of the satellite-borne microwave radiometer, which comprises the following steps:
obtaining the temperature of a low-temperature reference source and the temperature of a high-temperature reference source of the microwave radiometer through an internal noise injection module, and taking the temperature of the low-temperature reference source and the temperature of the high-temperature reference source as calibration reference sources;
the microwave radiometer performs real-time nonlinear calibration on a calibration reference source in seconds by adopting a high-temperature and low-temperature two-point calibration mode to obtain a first-time observation brightness temperature value of an observation target, and sends the first-time observation brightness temperature value to the on-satellite calibration processing module;
a program control lifting mechanism additionally arranged outside the microwave radiometer is switched into a periodic calibration observation mode, and in the periodic calibration observation mode, a periodic self-calibration module performs periodic observation on the matched load by taking the day as a unit to obtain an internal calibration correction quantity and sends the internal calibration correction quantity to an on-satellite calibration processing module;
a program control lifting mechanism additionally arranged outside the microwave radiometer is utilized to switch into an adjacent path observation mode, and in the adjacent path observation mode, a GPS occultation signal receiving module receives periodic self-calibration temperature occultation signals with a month as a unit and sends the signals to an external occultation module; the external occultation module realizes occultation events according to the occultation signals to obtain external calibration correction values, and sends the external calibration correction values to the on-satellite calibration processing module;
and the on-satellite calibration processing module carries out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and the corrected observation target brightness temperature value is used as the final observation brightness temperature value of the observation target.
As an improvement of the above technical solution, the method further includes: calculating the mean square error of the obtained observation brightness temperature value of the final observation target to obtain a difference value, and grading the calibration result according to the difference value;
specifically, if the difference is less than 1k, the result of this calibration is rated as a top grade and 10 points;
if the difference is greater than or equal to 1k and less than 5k, the scaling result is rated as a medium grade and rated as 1-5 points; wherein, the difference is equal to 1k, then the score is 5, and the score is lower along with the increment of the difference;
if the difference is larger than 3k, the result of this scaling is rated as a difference and rated as 0.
Compared with the prior art, the invention has the beneficial effects that:
1. the microwave radiometer is not internally provided with a calibration black body, can meet the requirements of miniaturization and light weight, and is suitable for small satellites and microsatellite platforms.
2. The method comprises the steps of respectively adopting periodic observation with day as a unit and periodic self-calibration with month as a unit to obtain an internal calibration correction value and an external calibration correction value, and carrying out internal and external correction on a primary observation brightness temperature value of an observation target obtained by a microwave radiometer, so that long-time system drift of the microwave radiometer can be prevented, and the consistency of the microwave radiometer between generations is improved.
3. At present, GPS occultation signals are more and more common, and can be used as a calibration reference of a microwave radiometer because the GPS occultation signals do not need calibration.
4. The on-satellite calibration processing module is used for directly processing the observed brightness temperature value of the observed target on the satellite in real time without transmitting data to the ground for processing, has high timeliness, can be used in the fields of military operation and the like, and has wide development prospect.
Drawings
FIG. 1 is a schematic structural diagram of an internal and external calibration system of a satellite-borne microwave radiometer according to the present invention;
FIG. 2 is a schematic structural diagram of a satellite-borne microwave radiometer internal and external calibration system according to the present invention, in which a program control lifting mechanism additionally provided outside the microwave radiometer switches an adjacent path observation mode or a periodic calibration observation mode;
FIG. 3 is a schematic diagram of a satellite-borne microwave radiometer internal and external calibration system according to the present invention, in which the microwave radiometer switches to an adjacent-edge path observation mode.
Detailed Description
The invention will now be further described with reference to the accompanying drawings.
As shown in fig. 1, the present invention provides an internal and external calibration system for a satellite-borne microwave radiometer, which comprises: the device comprises a microwave radiometer, an internal noise injection module, a GPS occultation signal receiving module, an external occultation module, a periodic self-calibration module and an on-satellite calibration processing module;
the internal noise injection module is used for obtaining the low-temperature reference source temperature and the high-temperature reference source temperature of the microwave radiometer;
specifically, when an antenna in the microwave radiometer is aligned with a space cold air background, obtaining a low-temperature reference source temperature, injecting noise to an observation target temperature in a time-sharing manner by adopting a built-in noise coupling mode to obtain a high-temperature reference source temperature of the microwave radiometer, and taking the low-temperature reference source temperature and the high-temperature reference source temperature as calibration reference sources; replacing a conventional calibration black body;
wherein the internal noise injection module comprises: the device comprises a high-frequency noise source, a temperature measuring circuit, a noise injection circuit, a coupling switch and a low-temperature source acquisition module;
the high-frequency noise source is used for generating a stable noise signal;
the high-frequency noise source is a noise source from microwave to terahertz waveband, the stability is 0.01K/year, the precision of the temperature measuring circuit is 0.001K, and the high-frequency noise source is used as an important component of a calibration reference source and used for ensuring the calibration precision.
The temperature measuring circuit is used for accurately measuring the thermistor temperature value of the observation target and converting the thermistor temperature value through a Planck law to obtain the radiant quantity of the observation target; the device is also used for accurately measuring the thermistor temperature value of the matched load and converting the thermistor temperature value through a Planck law to obtain the radiant quantity of the matched load;
the noise injection circuit is used for coupling a noise signal to the observation target temperature in a time-sharing manner to obtain the high-temperature reference source temperature of the microwave radiometer;
the coupling switch is used for controlling the noise signal to be coupled to the fixed target temperature in a preset time in a coupling mode;
and the low-temperature source acquisition module is used for acquiring the temperature of the low-temperature reference source when an antenna in the microwave radiometer is aligned with the cosmic cold air background.
The microwave radiometer performs real-time nonlinear calibration on a calibration reference source in seconds by adopting a high-temperature and low-temperature two-point calibration mode to obtain a primary observation brightness temperature value of an observation target, and sends the primary observation brightness temperature value to the on-satellite calibration processing module;
a program control lifting mechanism is additionally arranged outside the microwave radiometer and used for realizing the switching between an edge-facing path observation mode and a periodic calibration observation mode; the system comprises a temporary edge path observation mode, a periodic calibration observation mode and a temporary edge path observation mode, wherein the temporary edge path observation mode is an external calibration observation mode, and the periodic calibration observation mode is an internal calibration observation mode; as shown in fig. 2, the program-controlled lifting mechanism moves upwards and is switched into an internal scaling observation mode; the program control lifting mechanism moves downwards and is switched into an external calibration observation mode, namely a ground observation mode;
specifically, an internal noise injection module is utilized, and when an antenna of the microwave radiometer is aligned with a cosmic cold air background, the temperature of a low-temperature reference source is obtained; then, an internal noise injection module is utilized to couple the noise signal to the observation target temperature in a time-sharing manner to obtain the high-temperature reference source temperature of the microwave radiometer; taking the temperature of the low-temperature reference source and the temperature of the high-temperature reference source as calibration reference sources;
according to the two-point calibration principle, a two-point calibration equation is established by adopting a high-temperature and low-temperature two-point calibration mode, and the calibration reference source is calibrated in real time in seconds:
RA＝a0+a1CA (1)
wherein, a0Scaling the bias term of the equation for two points; a is1Scaling a first order of the equation for two points; cAObserving a target voltage value; rAThe radiant quantity converted by the Planck law for observing the target temperature; cHThe high-temperature voltage value of the calibration reference source is obtained; rHThe radiant quantity is converted from the high-temperature reference source temperature through the Planck law; cCThe low-temperature voltage value of the calibration reference source is obtained; rCThe radiation quantity is converted from the low-temperature reference source temperature through the Planck law;
according to the formula (2), for RAAnd (3) carrying out nonlinear calibration correction:
RA'＝a0+a1CA+a2CA 2＝RA+a2CA 2 (2)
wherein R isA' the radiant quantity of the initial observation brightness temperature value of the observation target obtained after primary correction converted by the Planck law, a2Is a non-linear term;
to RAAnd obtaining an initial observation brightness temperature value of the observation target through replanck conversion.
The microwave radiometer is a superheterodyne microwave radiometer, a direct detection type microwave radiometer, a real aperture microwave radiometer, a synthetic aperture microwave radiometer, a full power microwave radiometer or a full polarization microwave radiometer.
The GPS occultation signal receiving module is used for receiving a periodic self-calibration temperature occultation signal taking a month as a unit and sending the periodic self-calibration temperature occultation signal to the external occultation module in the switching to the external calibration observation mode;
specifically, in the switching to the external calibration observation mode, the antenna of the microwave radiometer is rotated circumferentially, the earth observation range is plus or minus 50 degrees by taking a nadir point as a reference, the cold vacancy is 107 degrees, the adjacent edge detection angle is minus 107 degrees, the GPS occultation receiving module is placed at the positive front end of the observation field of view of the microwave radiometer, and periodically receives periodic self-calibration temperature occultation signals with the month as a unit and sends the signals to the external occultation module;
the external occultation module is used for realizing occultation events according to the received periodic self-calibration temperature occultation signals taking months as units, obtaining an external calibration correction value and sending the external calibration correction value to the on-satellite calibration processing module;
specifically, in the switching to the external calibration observation mode, a GPS occultation signal receiving module is used for receiving periodic self-calibration temperature external occultation signals with a month as a unit to obtain an atmospheric refractive index, additional carrier phase delay and a bending angle so as to obtain an atmospheric profile through inversion;
and carrying out radiation transmission calculation on the atmospheric profile obtained by inversion to obtain a theoretical occultation atmospheric brightness temperature value, carrying out difference on the theoretical occultation atmospheric brightness temperature value and a preset threshold value, wherein the difference value is an external calibration correction value, and sending the external calibration correction value to an on-satellite calibration processing module.
The periodic self-calibration module is used for periodically observing the matched load in a day unit in a mode of switching to the internal calibration observation mode to obtain an internal calibration correction quantity and sending the internal calibration correction quantity to the on-satellite calibration processing module;
specifically, in the switching to the internal calibration observation mode, periodic observation is performed on the matched load with measurable temperature periodically in a unit of day, a theoretical temperature value measured by the matched load is obtained through two-point periodic calibration, the theoretical temperature value is differed from an actual temperature value measured by the matched load, the difference value is used as a drift amount, the drift amount is used as an internal calibration correction amount, and the internal calibration correction amount is sent to the on-satellite calibration processing module.
And the on-satellite calibration processing module is used for carrying out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and taking the corrected observation target brightness temperature value as the final observation brightness temperature value of the observation target.
Specifically, according to formula (3), performing internal and external calibration correction processing on the initial observation brightness temperature value of the observation target:
TB＝replanck(a0+a1CA+a2CA 2+ΔRC+ΔRG) (3)
wherein, TBTo be correctedObserving a target brightness temperature value; Δ RCCalibrating the correction quantity for the internal standard; Δ RGCalibrating the correction value for the outside;
will TBAnd the final observed brightness temperature value of the observed target.
The system further comprises: the scoring module is used for solving the mean square error of the obtained observation brightness temperature value of the final observation target to obtain a difference value, and scoring the calibration result according to the difference value;
specifically, if the difference is less than 1k, the result of this calibration is rated as a top grade and 10 points;
if the difference is greater than or equal to 1k and less than 5k, the scaling result is rated as a medium grade and rated as 1-5 points; wherein, the difference is equal to 1k, then the score is 5, and the score is lower along with the increment of the difference;
if the difference is larger than 3k, the result of this scaling is rated as a difference and rated as 0.
The invention also provides an internal and external calibration method of the satellite-borne microwave radiometer, which comprises the following steps:
obtaining the temperature of a low-temperature reference source and the temperature of a high-temperature reference source of the microwave radiometer through an internal noise injection module, and taking the temperature of the low-temperature reference source and the temperature of the high-temperature reference source as calibration reference sources;
the microwave radiometer performs real-time nonlinear calibration on a calibration reference source in seconds by adopting a high-temperature and low-temperature two-point calibration mode to obtain a first-time observation brightness temperature value of an observation target, and sends the first-time observation brightness temperature value to the on-satellite calibration processing module;
a program control lifting mechanism additionally arranged outside the microwave radiometer is switched into a periodic calibration observation mode, and in the periodic calibration observation mode, a periodic self-calibration module performs periodic observation on the matched load by taking the day as a unit to obtain an internal calibration correction quantity and sends the internal calibration correction quantity to an on-satellite calibration processing module;
a program control lifting mechanism additionally arranged outside the microwave radiometer is utilized to switch into an adjacent path observation mode, and in the adjacent path observation mode, a GPS occultation signal receiving module receives periodic self-calibration temperature occultation signals with a month as a unit and sends the signals to an external occultation module; the external occultation module realizes occultation events according to the occultation signals to obtain external calibration correction values, and sends the external calibration correction values to the on-satellite calibration processing module;
and the on-satellite calibration processing module carries out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and the corrected observation target brightness temperature value is used as the final observation brightness temperature value of the observation target.
Wherein the method further comprises: calculating the mean square error of the obtained observation brightness temperature value of the final observation target to obtain a difference value, and grading the calibration result according to the difference value;
specifically, if the difference is less than 1k, the result of this calibration is rated as a top grade and 10 points;
if the difference is greater than or equal to 1k and less than 5k, the scaling result is rated as a medium grade and rated as 1-5 points; wherein, the difference is equal to 1k, then the score is 5, and the score is lower along with the increment of the difference;
if the difference is larger than 3k, the result of this scaling is rated as a difference and rated as 0.
As shown in FIG. 3, when the microwave radiometer is switched to the near-edge observation mode, the atmosphere profile of the near-edge observation tangential direction of the microwave radiometer and the refraction direction of the occultation signal form an angle θ2I.e. deviation of refraction from scan angle theta2(ii) a The included angle between the tangential direction of the microwave radiometer and the direction of the bottom of the sky is theta1I.e. the scanning angle theta of the microwave radiometer1。
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and are not limited. Although the present invention has been described in detail with reference to the embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. An internal and external calibration system of a satellite-borne microwave radiometer is characterized by comprising: the device comprises a microwave radiometer, an internal noise injection module, a GPS occultation signal receiving module, an external occultation module, a periodic self-calibration module and an on-satellite calibration processing module;
the internal noise injection module is used for obtaining the low-temperature reference source temperature and the high-temperature reference source temperature of the microwave radiometer and taking the low-temperature reference source temperature and the high-temperature reference source temperature as calibration reference sources;
the microwave radiometer is used for carrying out real-time nonlinear calibration on a calibration reference source in seconds by adopting a high-temperature and low-temperature two-point calibration mode to obtain a primary observation brightness temperature value of an observation target and sending the primary observation brightness temperature value to the on-satellite calibration processing module;
a program control lifting mechanism is additionally arranged outside the microwave radiometer and used for realizing the switching between an edge-facing path observation mode and a periodic calibration observation mode;
the GPS occultation signal receiving module is used for switching to an adjacent-edge path observation mode through the program-controlled lifting mechanism, receiving periodic self-calibration temperature occultation signals taking a month as a unit and sending the signals to the external occultation module;
the external occultation module is used for realizing occultation events according to the received periodic self-calibration temperature occultation signals taking months as units, obtaining an external calibration correction value and sending the external calibration correction value to the on-satellite calibration processing module;
the periodic self-calibration module is used for switching to a periodic calibration observation mode through the program-controlled lifting mechanism, performing periodic observation on the matched load by taking days as a unit to obtain an internal calibration correction amount, and sending the internal calibration correction amount to the on-satellite calibration processing module;
and the on-satellite calibration processing module is used for carrying out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and taking the corrected observation target brightness temperature value as the final observation brightness temperature value of the observation target.
2. The on-board microwave radiometer internal-external calibration system of claim 1, wherein the microwave radiometer is a superheterodyne microwave radiometer, a direct detection microwave radiometer, a real aperture microwave radiometer, a synthetic aperture microwave radiometer, a full power microwave radiometer, or a full polarization microwave radiometer.
3. The inside and outside calibration system of the satellite-borne microwave radiometer according to claim 2, wherein the calibration reference source is calibrated in real time in seconds by means of high-temperature and low-temperature two-point calibration to obtain an initial observed brightness temperature value of the observed target, specifically:
utilizing an internal noise injection module, and obtaining the temperature of a low-temperature reference source when an antenna of the microwave radiometer is aligned with a space cold air background; then, an internal noise injection module is utilized to couple the noise signal to the observation target temperature in a time-sharing manner to obtain the high-temperature reference source temperature of the microwave radiometer; taking the temperature of the low-temperature reference source and the temperature of the high-temperature reference source as calibration reference sources;
according to the two-point calibration principle, a two-point calibration equation is established by adopting a high-temperature and low-temperature two-point calibration mode, and the calibration reference source is calibrated in real time in seconds:
RA＝a0+a1CA (1)
wherein, a0Scaling the bias term of the equation for two points; a is1Scaling a first order of the equation for two points; cAObserving a target voltage value; rAThe radiant quantity converted by the Planck law for observing the target temperature; cHThe high-temperature voltage value of the calibration reference source is obtained; rHThe radiant quantity is converted from the high-temperature reference source temperature through the Planck law; cCThe low-temperature voltage value of the calibration reference source is obtained; rCThe radiation quantity is converted from the low-temperature reference source temperature through the Planck law;
according to the formula (2), for RAAnd (3) carrying out nonlinear calibration correction:
RA'＝a0+a1CA+a2CA 2＝RA+a2CA 2 (2)
wherein R isA' the radiant quantity of the initial observation brightness temperature value of the observation target obtained after primary correction converted by the Planck law, a2Is a non-linear term;
to RAAnd obtaining an initial observation brightness temperature value of the observation target through replanck conversion.
4. The on-board microwave radiometer internal-external calibration system of claim 1, wherein the internal noise injection module comprises: the device comprises a high-frequency noise source, a temperature measuring circuit, a noise injection circuit, a coupling switch and a low-temperature source acquisition module;
the high-frequency noise source is used for generating a stable noise signal;
the temperature measuring circuit is used for accurately measuring the thermistor temperature value of the observation target and converting the thermistor temperature value through a Planck law to obtain the radiant quantity of the observation target; the device is also used for accurately measuring the thermistor temperature value of the matched load and converting the thermistor temperature value through a Planck law to obtain the radiant quantity of the matched load;
the noise injection circuit is used for coupling a noise signal to the observation target temperature in a time-sharing manner to obtain the high-temperature reference source temperature of the microwave radiometer;
the coupling switch is used for controlling the noise signal to be coupled to the fixed target temperature in a preset time in a coupling mode;
and the low-temperature source acquisition module is used for acquiring the temperature of the low-temperature reference source when an antenna in the microwave radiometer is aligned with the cosmic cold air background.
5. The internal and external calibration system of the satellite-borne microwave radiometer according to claim 1, wherein the program-controlled lifting mechanism is switched to a periodic calibration observation mode, periodic observation in units of days is performed on the matched load, an internal calibration correction quantity is obtained and sent to the on-satellite calibration processing module; the method specifically comprises the following steps:
the program-controlled lifting mechanism is switched to a periodic calibration observation mode, periodic observation is carried out on the matched load with the measurable temperature in a day unit, a theoretical temperature value measured by the matched load is obtained through two-point periodic calibration, the theoretical temperature value is differed from an actual temperature value measured by the matched load, the difference value is used as a drift amount, the drift amount is used as an internal calibration correction amount, and the internal calibration correction amount is sent to the on-satellite calibration processing module.
6. The inside and outside calibration system of the satellite-borne microwave radiometer according to claim 1, wherein the monitoring module is switched to an edge-approaching path observation mode through the program-controlled lifting mechanism, and a occultation event is realized according to a received periodic self-calibration temperature occultation signal in a month unit, so as to obtain an outside calibration correction value, and the outside calibration correction value is sent to the on-satellite calibration processing module; the method specifically comprises the following steps:
the method comprises the steps that a program-controlled lifting mechanism is switched to a side-approaching path observation mode, a GPS occultation signal receiving module is used for receiving periodic self-calibration temperature occultation signals with a month as a unit, the atmospheric refractive index, additional carrier phase delay and a bending angle are obtained, and then an atmospheric profile is obtained through inversion;
and carrying out radiation transmission calculation on the atmospheric profile obtained by inversion to obtain a theoretical occultation atmospheric brightness temperature value, carrying out difference on the theoretical occultation atmospheric brightness temperature value and a preset threshold value, wherein the difference value is an external calibration correction value, and sending the external calibration correction value to an on-satellite calibration processing module.
7. The inside and outside calibration system for the satellite-borne microwave radiometer according to claim 1, wherein the inside and outside calibration correction processing is performed on the initial observation brightness temperature value of the observation target according to the received inside calibration correction amount and outside calibration correction amount, so as to obtain a corrected observation target brightness temperature value, and the corrected observation target brightness temperature value is used as a final observation brightness temperature value of the observation target; the method specifically comprises the following steps:
according to the formula (3), the primary observation brightness temperature value of the observation target is subjected to inner calibration correction processing and outer calibration correction processing:
TB＝replanck(a0+a1CA+a2CA 2+ΔRC+ΔRG) (3)
wherein, TBThe corrected brightness temperature value of the observation target is obtained; Δ RCCalibrating the correction quantity for the internal standard; Δ RGCalibrating the correction value for the outside;
will TBAnd the final observed brightness temperature value of the observed target.
8. The on-board microwave radiometer internal-external calibration system of claim 1, further comprising: the scoring module is used for solving the mean square error of the obtained observation brightness temperature value of the final observation target to obtain a difference value, and scoring the calibration result according to the difference value;
specifically, if the difference is less than 1k, the result of this calibration is rated as a top grade and 10 points;
if the difference is greater than or equal to 1k and less than 5k, the scaling result is rated as a medium grade and rated as 1-5 points; wherein, the difference is equal to 1k, then the score is 5, and the score is lower along with the increment of the difference;
if the difference is larger than 3k, the result of this scaling is rated as a difference and rated as 0.
9. An internal and external calibration method for a satellite-borne microwave radiometer is characterized by comprising the following steps:
obtaining the temperature of a low-temperature reference source and the temperature of a high-temperature reference source of the microwave radiometer through an internal noise injection module, and taking the temperature of the low-temperature reference source and the temperature of the high-temperature reference source as calibration reference sources;
the microwave radiometer performs real-time nonlinear calibration on a calibration reference source in seconds by adopting a high-temperature and low-temperature two-point calibration mode to obtain a first-time observation brightness temperature value of an observation target, and sends the first-time observation brightness temperature value to the on-satellite calibration processing module;
a program control lifting mechanism additionally arranged outside the microwave radiometer is switched into a periodic calibration observation mode, and in the periodic calibration observation mode, a periodic self-calibration module performs periodic observation on the matched load by taking the day as a unit to obtain an internal calibration correction quantity and sends the internal calibration correction quantity to an on-satellite calibration processing module;
a program control lifting mechanism additionally arranged outside the microwave radiometer is utilized to switch into an adjacent path observation mode, and in the adjacent path observation mode, a GPS occultation signal receiving module receives periodic self-calibration temperature occultation signals with a month as a unit and sends the signals to an external occultation module; the external occultation module realizes occultation events according to the occultation signals to obtain external calibration correction values, and sends the external calibration correction values to the on-satellite calibration processing module;
and the on-satellite calibration processing module carries out internal and external calibration correction processing on the initial observation brightness temperature value of the observation target according to the received internal calibration correction amount and external calibration correction amount to obtain a corrected observation target brightness temperature value, and the corrected observation target brightness temperature value is used as the final observation brightness temperature value of the observation target.
10. The on-board microwave radiometer internal-external calibration method according to claim 9, further comprising: calculating the mean square error of the obtained observation brightness temperature value of the final observation target to obtain a difference value, and grading the calibration result according to the difference value;
specifically, if the difference is less than 1k, the result of this calibration is rated as a top grade and 10 points;
if the difference is greater than or equal to 1k and less than 5k, the scaling result is rated as a medium grade and rated as 1-5 points; wherein, the difference is equal to 1k, then the score is 5, and the score is lower along with the increment of the difference;
if the difference is larger than 3k, the result of this scaling is rated as a difference and rated as 0.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113221067A (en) * | 2021-04-26 | 2021-08-06 | 中国科学院国家空间科学中心 | Method and system for cross validation of weather data of occultation and microwave radiometer |
| CN115128364A (en) * | 2022-08-31 | 2022-09-30 | 国家卫星海洋应用中心 | Method and device for determining observation stability of satellite-borne microwave radiometer |
| CN115790867A (en) * | 2023-02-01 | 2023-03-14 | 国科星仪(北京)科技有限公司 | Microwave radiometer thermal vacuum calibration device and method |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030235234A1 (en) * | 2002-06-25 | 2003-12-25 | Toshihiro Sezai | Method for calibrating a total-power microwave radiometer for a satellite |
| CN101825708A (en) * | 2009-03-05 | 2010-09-08 | 中国科学院空间科学与应用研究中心 | Data acquisition unit for satellite-borne microwave radiometer and data acquisition method thereof |
| CN101876699A (en) * | 2009-04-30 | 2010-11-03 | 中国科学院空间科学与应用研究中心 | Control system and control method of satellite-borne microwave radiometer |
| CN101975971A (en) * | 2010-09-30 | 2011-02-16 | 中国科学院国家天文台 | On-star calibration method for lunar microwave sounder |
| CN102032949A (en) * | 2009-09-28 | 2011-04-27 | 中国科学院空间科学与应用研究中心 | External calibration device of geosynchronous orbit atmospheric temperature detecting instrument and external calibration method thereof |
| CN108318871A (en) * | 2018-04-04 | 2018-07-24 | 西安空间无线电技术研究所 | A kind of cold empty scaled correction method of satellite-borne microwave radiometer |
-
2020
- 2020-07-17 CN CN202010691356.XA patent/CN111947790B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030235234A1 (en) * | 2002-06-25 | 2003-12-25 | Toshihiro Sezai | Method for calibrating a total-power microwave radiometer for a satellite |
| CN101825708A (en) * | 2009-03-05 | 2010-09-08 | 中国科学院空间科学与应用研究中心 | Data acquisition unit for satellite-borne microwave radiometer and data acquisition method thereof |
| CN101876699A (en) * | 2009-04-30 | 2010-11-03 | 中国科学院空间科学与应用研究中心 | Control system and control method of satellite-borne microwave radiometer |
| CN102032949A (en) * | 2009-09-28 | 2011-04-27 | 中国科学院空间科学与应用研究中心 | External calibration device of geosynchronous orbit atmospheric temperature detecting instrument and external calibration method thereof |
| CN101975971A (en) * | 2010-09-30 | 2011-02-16 | 中国科学院国家天文台 | On-star calibration method for lunar microwave sounder |
| CN108318871A (en) * | 2018-04-04 | 2018-07-24 | 西安空间无线电技术研究所 | A kind of cold empty scaled correction method of satellite-borne microwave radiometer |
Non-Patent Citations (1)
| Title |
|---|
| 吕颖 等: "星载微波辐射计周期定标技术的综述", 《电子科学学刊》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113221067A (en) * | 2021-04-26 | 2021-08-06 | 中国科学院国家空间科学中心 | Method and system for cross validation of weather data of occultation and microwave radiometer |
| CN113221067B (en) * | 2021-04-26 | 2021-12-07 | 中国科学院国家空间科学中心 | Method and system for cross validation of weather data of occultation and microwave radiometer |
| CN115128364A (en) * | 2022-08-31 | 2022-09-30 | 国家卫星海洋应用中心 | Method and device for determining observation stability of satellite-borne microwave radiometer |
| CN115790867A (en) * | 2023-02-01 | 2023-03-14 | 国科星仪(北京)科技有限公司 | Microwave radiometer thermal vacuum calibration device and method |
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