Methods and systems for mitigating noise for microwave remote sensing
Radiometer systems and methods that mitigate flicker (1/f) noise are provided. A microwave radiometer system with accuracy impacted by 1/f noise comprises active components which, between measurements, are powered off and on. By powering the active components off and on, 1/f noise is mitigated. Disclosed systems and methods include performing a first measurement with a sensor of a radiometer, after performing the first measurement, switching power to one or more active components of the radiometer off, the active components comprising one or more of an amplifier, a square law detector, and an A/D converter, after switching the power to the one or more active components off, switching the power to the one or more active components on, and after switching the power to the one or more active components on, performing a second measurement with the sensor.
1 . A radiometer, comprising:
a sensor;
one or more active components, the active components comprising one or more of an amplifier, a power measurement device, and an A/D converter;
a processor; and
computer-readable storage medium storing computer-readable instructions that, when executed by the processor, cause the processor to:
perform a first measurement with the sensor;
after performing the first measurement, switch power to the one or more active components off;
after switching the power to the one or more active components off, switch the power to the one or more active components on;
in parallel with switching the power to the one or more active components off, process the first measurement; and
after switching the power to the one or more active components on, perform a second measurement with the sensor.
2 . The radiometer of claim 1 , wherein the one or more active components comprise one or more input amplifiers.
3 . The radiometer of claim 1 , wherein the one or more active components comprise one or more A/D converters.
4 . The radiometer of claim 1 , wherein the power measurement device is a square law detector.
5 . The radiometer of claim 1 , wherein the second measurement comprises no additional 1/f noise as compared to the first measurement.
6 . The radiometer of claim 1 , wherein the first and second measurements comprise one or more of a hot calibration measurement and a cold calibration measurement.
7 . The radiometer of claim 1 , wherein switching the power to the one or more active components off comprises switching the power off for a time period greater than zero seconds before switching the power to the one or more active components on.
8 . The radiometer of claim 7 , wherein the second measurement is performed a time period of more than zero seconds after the first measurement is completed.
9 . The radiometer of claim 1 , wherein the first and second measurements are measurements of a scene temperature.
10 . The radiometer of claim 1 , wherein the first and second measurements are a series of measurements, wherein between each measurement of the series of measurements the power to the one or more active components is switched off and on.
11 . The radiometer of claim 10 , wherein the instructions further cause the processor to use the series of measurements to build a raster scan of a scene.
12 . The radiometer of claim 1 , wherein the instructions further cause the processor to, after switching the power to the one or more active components off and prior to switching the power to the one or more active components on, wait a period of time sufficient for a voltage within each of the one or more active components to reach zero.
13 . The radiometer of claim 1 , wherein each of the first and second measurements are associated with one or more of atmospheric noise power, radiant energy emitted from a ground, solar radiation, and sensor calibration.
14 . A method of using a radiometer, the method comprising:
performing a first measurement with a sensor of the radiometer;
after performing the first measurement, switching power to one or more active components of the radiometer off, the active components comprising one or more of an amplifier, a power measurement device, and an A/D converter;
after switching the power to the one or more active components off and prior to switching the power to the one or more active components on, wait a period of time sufficient for a voltage within each of the one or more active components to reach zero;
after switching the power to the one or more active components off, switching the power to the one or more active components on; and
after switching the power to the one or more active components on, performing a second measurement with the sensor.
15 . The method of claim 14 , wherein the one or more active components comprise one or more input amplifiers.
16 . The method of claim 14 , wherein the one or more active components comprise one or more A/D converters.
17 . The method of claim 14 , wherein the second measurement comprises no additional 1/f noise as compared to the first measurement.
18 . A computer program product comprising:
a non-transitory computer-readable storage medium having computer-readable program code embodied therewith, the computer-readable program code configured, when executed by a processor, to execute a method, the method comprising:
performing a first measurement with a sensor of a radiometer;
after performing the first measurement, switching power to one or more active components of the radiometer off, the active components comprising one or more of an amplifier, a power measurement device, and an A/D converter;
after switching the power to the one or more active components off, switching the power to the one or more active components on;
in parallel with switching the power to the one or more active components off, processing the first measurement; and
after switching the power to the one or more active components on, performing a second measurement with the sensor.
19 . The computer program product of claim 18 , wherein the one or more active components comprise one or more A/D converters.
20 . The computer program product of claim 18 , wherein the one or more active components comprise one or more input amplifiers.