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  • 1
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    Guidance and Control for Mars Atmospheric Entry: Adaptivity and Robustness (1997)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: In this paper, we address the atmospheric entry guidance and control problem for Mars precision landing. The guidance and control design is based on the principle of tracking a reference drag versus velocity profile in the entry flight corridor, which is determined by physical constraints of the flight. An integrated adaptive/robust control approach to atmospheric entry guidance and control is introduced to deal with different uncertainties.
    Keywords: Lunar and Planetary Science and Exploration
    Format: application/pdf
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  • 2
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    Single Photon HgCdTe Avalanche Photodiode and Integrated Detector Cooler Assemblies for Space Lidar Applications (2018)
    In:  CASI
    Details
    Publication Date: 2019-07-20
    Description: A linear mode photon counting HgCdTe avalanche photodiode (APD) focal plane array (FPA) detector was developed for space lidar applications. An integrated detector cooler assembly (IDCA) was manufactured using a miniature Stirling cooler. The HgCdTe APD demonstrated a greater than 60% photon detection efficiency from 0.9 to 4.3 m wavelength and a dark count rate less than 250,000/s. The IDCA cooled the FPA to 110K from ambient room temperature at a total electrical power of 7 W. The IDCA has passed environmental tests, including vibration, thermal cycling and thermal vacuum tests.
    Keywords: Optics
    Type: GSFC-E-DAA-TN54477 , SPIE Defense + Commercial Sensing; Apr 17, 2018 - Apr 19, 2018; Orlando, FL; United States
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  • 3
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    Novel Photon-Counting Detectors for Free-Space Communication (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present performance data for novel photon counting detectors for free space optical communication. NASA GSFC is testing the performance of three novel photon counting detectors 1) a 2x8 mercury cadmium telluride avalanche array made by DRS Inc. 2) a commercial 2880 silicon avalanche photodiode array and 3) a prototype resonant cavity silicon avalanche photodiode array. We will present and compare dark count, photon detection efficiency, wavelength response and communication performance data for these detectors. We discuss system wavelength trades and architectures for optimizing overall communication link sensitivity, data rate and cost performance. The HgCdTe APD array has photon detection efficiencies of greater than 50 were routinely demonstrated across 5 arrays, with one array reaching a maximum PDE of 70. High resolution pixel-surface spot scans were performed and the junction diameters of the diodes were measured. The junction diameter was decreased from 31 m to 25 m resulting in a 2x increase in e-APD gain from 470 on the 2010 array to 1100 on the array delivered to NASA GSFC. Mean single photon SNRs of over 12 were demonstrated at excess noise factors of 1.2-1.3.The commercial silicon APD array has a fast output with rise times of 300ps and pulse widths of 600ps. Received and filtered signals from the entire array are multiplexed onto this single fast output. The prototype resonant cavity silicon APD array is being developed for use at 1 micron wavelength.
    Keywords: Space Communications, Spacecraft Communications, Command and Tracking
    Type: GSFC-E-DAA-TN29655 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States|Free-Space Laser Communication and Atmospheric Propagation; Feb 15, 2016 - Feb 16, 2016; San Francisco, CA; United States
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  • 4
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    Development of Low Noise and High Speed SWIR Receivers (2010)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: No abstract available
    Keywords: Optics; Engineering (General); Instrumentation and Photography
    Type: LEGNEW-OLDGSFC-GSFC-LN-1000 , Society of Photo-Instrumentation Engineers (SPIE) Defense, Security and Sensing; Apr 05, 2010 - Apr 09, 2010; Orlando, FL; United States
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  • 5
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    Comparison of 16-Channel Laser Photoreceivers for Topographic Mapping (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Topographic mapping lidar instruments must be able to detect extremely weak laser return signals from high altitudes including orbital distance. The signals have a wide dynamic range caused by the variability in atmospheric transmission and surface reflectance under a fast moving spacecraft. Ideally, lidar detectors should be able to detect laser signal return pulses at the single photon level and produce linear output for multiple photon events. Silicon avalanche photodiode (APO) detectors have been used in most space lidar receivers to date. Their sensitivity is typically hundreds of photons per pulse, and is limited by the quantum efficiency, APO gain noise, dark current, and preamplifier noise. NASA is pursuing three approaches for a 16-channel laser photoreceiver for use on the next generation direct-detection airborne and spacebome lidars. We present our measurement results and a comparison of their performance.
    Keywords: Electronics and Electrical Engineering; Optics
    Type: LEGNEW-OLDGSFC-GSFC-LN-1186 , Society of Photo-Instrumentation Engineers (SPIE) Defense, Security and Sensing Conference; Aug 21, 2011 - Aug 26, 2011; San Diego, CA; United States
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  • 6
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    Low-Noise Free-Running High-Rate Photon-Counting for Space Communication and Ranging (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present performance data for low-noise free-running high-rate photon counting method for space optical communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies (50) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their performances using both the 2 detected photon threshold and coincidence methods.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN30952 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
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  • 7
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    Low-Noise Free-Running High-Rate Photon-Counting for Space Communication and Ranging (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present performance data for low-noise free-running high-rate photon counting method for space optical communication and ranging. NASA GSFC is testing the performance of two types of novel photon-counting detectors 1) a 2x8 mercury cadmium telluride (HgCdTe) avalanche array made by DRS Inc., and a 2) a commercial 2880-element silicon avalanche photodiode (APD) array. We successfully measured real-time communication performance using both the 2 detected-photon threshold and logic AND-gate coincidence methods. Use of these methods allows mitigation of dark count, after-pulsing and background noise effects without using other method of Time Gating The HgCdTe APD array routinely demonstrated very high photon detection efficiencies ((is) greater than 50%) at near infrared wavelength. The commercial silicon APD array exhibited a fast output with rise times of 300 ps and pulse widths of 600 ps. On-chip individually filtered signals from the entire array were multiplexed onto a single fast output. NASA GSFC has tested both detectors for their potential application for space communications and ranging. We developed and compare their performances using both the 2 detected photon threshold and coincidence methods.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN30890 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
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  • 8
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    High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN28840 , IEEE Aerospace Conference; Mar 05, 2016 - Mar 12, 2016; Big Sky, MT; United States
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  • 9
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    Femtosecond Photon-Counting Receiver (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An optical correlation receiver is described that provides ultra-precise distance and/or time-pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.
    Keywords: Optics; Instrumentation and Photography
    Type: GSFC-E-DAA-TN31104 , SPIE Defence + Commercial Sensing (SPIE DCS 2016); Apr 17, 2016 - Apr 21, 2016; Baltimore, MD; United States|SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
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  • 10
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    Femtosecond Photon-Counting Receiver (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: An optical correlation receiver is described that provides ultra-precise distance and/or time/pulse-width measurements even for weak (single photons) and short (femtosecond) optical signals. A new type of optical correlation receiver uses a fourth-order (intensity) interferometer to provide micron distance measurements even for weak (single photons) and short (femtosecond) optical signals. The optical correlator uses a low-noise-integrating detector that can resolve photon number. The correlation (range as a function of path delay) is calculated from the variance of the photon number of the difference of the optical signals on the two detectors. Our preliminary proof-of principle data (using a short-pulse diode laser transmitter) demonstrates tens of microns precision.
    Keywords: Communications and Radar
    Type: GSFC-E-DAA-TN31163 , SPIE Photonics West; Feb 13, 2016 - Feb 18, 2016; San Francisco, CA; United States
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