scholarly journals Introduction of the in-orbit test and its performance for the first meteorological imager of the Communication, Ocean, and Meteorological Satellite

2014 ◽  
Vol 7 (8) ◽  
pp. 2471-2485 ◽  
Author(s):  
D. H. Kim ◽  
M. H. Ahn
Keyword(s):  
Signal To Noise Ratio ◽  
Channel Noise ◽  
Test Results ◽  
User Requirement ◽  
Spacecraft Design ◽  
A Value ◽  
Improved Performance ◽  
And Performance ◽  
Shortwave Infrared ◽  
Meteorological Satellite

Abstract. The first geostationary Earth observation satellite of Korea – the Communication, Ocean, and Meteorological Satellite (COMS) – was successfully launched on 27 June 2010. After arrival at its operational orbit, the satellite underwent an in-orbit test (IOT) that lasted for about 8 months. During the IOT period, the main payload for the weather application, the meteorological imager, went through successful tests for demonstrating its function and performance, and the test results are introduced here. The radiometric performance of the meteorological imager (MI) is tested by means of signal-to-noise ratio (SNR) for the visible channel, noise-equivalent differential temperature (NEdT) for the infrared channels, and pixel-to-pixel nonuniformity for both the visible and infrared channels. In the case of the visible channel, the SNR of all eight detectors is obtained using the ground-measured parameters with the background signals obtained in orbit. The overall performance shows a value larger than 26 at 5% albedo, exceeding the user requirement of 10 by a significant margin. Also, the relative variability of detector responsivity among the eight visible channels meets the user requirement, showing values within 10% of the user requirement. For the infrared channels, the NEdT of each detector is well within the user requirement and is comparable with or better than the legacy instruments, except for the water vapor channel, which is slightly noisier than the legacy instruments. The variability of detector responsivity of infrared channels is also below the user requirement, within 40% of the requirement, except for the shortwave infrared channel. The improved performance result is partly due to the stable and low detector temperature obtained due to spacecraft design, i.e., by installing a single solar panel on the opposite side of the MI.

scholarly journals Introduction to the in orbit test and its performance of the first meteorological imager of the Communication, Ocean, and Meteorological Satellite

2013 ◽  
Vol 6 (6) ◽  
pp. 10889-10920 ◽  
Author(s):  
D. Kim ◽  
M. H. Ahn
Keyword(s):  
Performance Test ◽  
Signal To Noise Ratio ◽  
Channel Noise ◽  
Functional Requirements ◽  
Successful Operation ◽  
User Requirement ◽  
Spacecraft Design ◽  
Improved Performance ◽  
And Performance ◽  
Meteorological Satellite

Abstract. The first geostationary earth observation satellite of Korea, named Communication, Ocean, and Meteorological Satellite (COMS), is successfully launched on 27 June 2010 in Korea Standard Time. After arrival of its operational orbit, the satellite underwent in orbit test (IOT) lasting for about 8 months. During the IOT period, the meteorological imager went through tests for its functional and performance demonstration. With the successful acquisition of the first visible channel image, signal chain from the payload to satellite bus and to the ground is also verified. While waiting for the outgassing operation, several functional tests for the payload are also performed. By taking an observation of different sizes of image, of various object targets such as the Sun, moon, and internal calibration target, it has been demonstrated that the payload performs as commanded, satisfying its functional requirements. After successful operation of outgassing which lasted about 40 days, the first set of infrared images is also successfully acquired and the full performance test started. The radiometric performance of the meteorological imager is tested by signal to noise ratio (SNR) for the visible channel, noise equivalent differential temperature (NEdT) for the infrared channels, and pixel to pixel non-uniformity. In case of the visible channel, SNR of all 8 detectors are obtained using the ground measured parameters and background signals obtained in orbit and are larger than 26 at 5% albedo, exceeding the user requirement value of 10 with a significant margin. The values at 100% albedo also meet the user requirements. Also, the relative variability of detector responsivity among the 8 visible channels meets the user requirement, showing values of about 10% of the user requrirement. For the infrared channels, the NEdT of each detector is well within the user requirement and is comparable with or better than the legacy instruments, except the water vapor channel which is slightly noisier than the legacy instruments. The variability of detector responsivity of infrared channels is also below the user requirement, within 40% of the requirement except shortwave infrared channel. The improved performance result is partly due to the stable and low detector temperature obtained with the spacecraft design, by installing a single solar panel to the opposite side of the meteorological imager.

scholarly journals Design and performance of a three-wavelength LED-based total scatter and backscatter integrating nephelometer

2010 ◽  
Vol 3 (6) ◽  
pp. 4835-4864 ◽  
Author(s):  
T. Müller ◽  
M. Laborde ◽  
G. Kassell ◽  
A. Wiedensohler
Keyword(s):  
Signal To Noise Ratio ◽  
Ambient Air ◽  
Light Sources ◽  
Light Emitting ◽  
Sensitivity Functions ◽  
A Value ◽  
Commercial Instrument ◽  
And Performance ◽  
Comparison Measurements

Abstract. Integrating nephelometers are instruments that directly measure a value close to the light scattering coefficient of airborne particles. Different models of nephelometers have been used for decades for monitoring and research applications. Now, a series of nephelometers (Ecotech models M9003, Aurora 1000 and Aurora 3000) with newly designed light sources based on light emitting diodes are available. This article reports on the design of these integrating nephelometers and a comparison of the Aurora 3000 to another commercial instrument (TSI model 3563) that uses an incandescent lamp. Both instruments are three-wavelength, total and backscatter integrating nephelometers. We present a characterization of the new light source design of the Aurora 3000 and provide parameterizations for its angular sensitivity functions. These parameterizations facilitate to correct for measurement artefacts using Mie-theory. Comparison measurements against the TSI 3563 with laboratory generated white particles and ambient air are shown and discussed. Both instruments agree well within the calibration uncertainties and detection limit for total scattering with differences less than 5%. Differences for backscattering are higher by up to 11%. Highest differences were found for the longest wavelengths, where the signal to noise ratio is lowest. Differences at the blue and green wavelengths are less than 4% and 3%, respectively, for both total and backscattering.

scholarly journals Design and performance of a three-wavelength LED-based total scatter and backscatter integrating nephelometer

2011 ◽  
Vol 4 (6) ◽  
pp. 1291-1303 ◽  
Author(s):  
T. Müller ◽  
M. Laborde ◽  
G. Kassell ◽  
A. Wiedensohler
Keyword(s):  
Signal To Noise Ratio ◽  
Ambient Air ◽  
Light Sources ◽  
Light Emitting ◽  
Sensitivity Functions ◽  
A Value ◽  
Commercial Instrument ◽  
And Performance ◽  
Comparison Measurements

Abstract. Integrating nephelometers are instruments that directly measure a value close to the light scattering coefficient of airborne particles. Different models of nephelometers have been used for decades for monitoring and research applications. Now, a series of nephelometers (Ecotech models M9003, Aurora 1000 and Aurora 3000) with newly designed light sources based on light emitting diodes are available. This article reports on the design of these integrating nephelometers and a comparison of the Aurora 3000 to another commercial instrument (TSI model 3563) that uses an incandescent lamp. Both instruments are three-wavelength, total and backscatter integrating nephelometers. We present a characterization of the new light source design of the Aurora 3000 and provide parameterizations for its angular sensitivity functions. These parameterizations facilitate to correct for measurement artefacts using Mie-theory. Furthermore, correction factors are provided as a function of the Ångström exponent. Comparison measurements against the TSI 3563 with laboratory generated white particles and ambient air are also shown and discussed. Both instruments agree well within the calibration uncertainties and detection limit for total scattering with differences less than 5 %. Differences for backscattering are higher by up to 11 %. Highest differences were found for the longest wavelengths, where the signal to noise ratio is lowest. Differences at the blue and green wavelengths are less than 4 % and 3 %, respectively, for both total and backscattering.

Enhancements of Non-contact Measurements of Electrical Waveforms on the Proximity of a Signal Surface Using Groups of Pulses

2002 ◽  
Author(s):  
Fenglei Du ◽  
Greg Bridges ◽  
D.J. Thomson ◽  
Rama R. Goruganthu ◽  
Shawn McBride ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Signal To Noise Ratio ◽  
Electrostatic Force ◽  
Single Pulse ◽  
Electric Signal ◽  
Measurement Instruments ◽  
Cycle Times ◽  
Force Microscopy ◽  
And Performance

Abstract With the ever-increasing density and performance of integrated circuits, non-invasive, accurate, and high spatial and temporal resolution electric signal measurement instruments hold the key to performing successful diagnostics and failure analysis. Sampled electrostatic force microscopy (EFM) has the potential for such applications. It provides a noninvasive approach to measuring high frequency internal integrated circuit signals. Previous EFMs operate using a repetitive single-pulse sampling approach and are inherently subject to the signal-to-noise ratio (SNR) problems when test pattern duty cycle times become large. In this paper we present an innovative technique that uses groups of pulses to improve the SNR of sampled EFM systems. The approach can easily provide more than an order-ofmagnitude improvement to the SNR. The details of the approach are presented.

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