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Technologies for Passive Microwave Remote Sensing

Description:

Scope Title:

Components or Methods to Improve the Sensitivity, Calibration, or Resolution of Microwave/Millimeter-Wave Radiometers

Scope Description:

NASA requires novel solutions to challenges of developing stable, sensitive, and high-resolution radiometers and spectrometers operating from microwave frequencies to 1 THz. Novel technologies are requested to address challenges in the current state of the art of passive microwave remote sensing. Technologies could improve the sensitivity, calibration, or resolution of remote-sensing systems or reduce the size, weight, and power (SWaP). Companies are invited to provide unique solutions to problems in this area. Possible technologies could include:

  • Low-noise receivers (e.g., total power, pseudo-correlation, polarimetric) at frequencies up to 1 THz.
  • Solutions to reduce system 1/f noise over time periods greater than 1 sec.
  • Internal calibration systems or methods to improve calibration repeatability over time periods greater than days or weeks.
  • Noise sources up to 1 THz.
  • Broad-band (multi-octave) packaged low-noise amplifiers covering up to 70 GHz.

Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 08 Sensors and Instruments
  • Level 2 08.1 Remote Sensing Instruments/Sensors

Desired Deliverables of Phase I and Phase II:

  • Prototype
  • Research
  • Analysis
  • Software

Desired Deliverables Description:

Research, analysis, software, or hardware prototyping of novel components or methods to improve the performance of passive microwave remote sensing: 

  • Depending on the complexity of the proposed work, Phase I deliverables may include a prototype system or a study.
  • Phase II deliverables should include a prototype component or system with test data verifying functionality.

State of the Art and Critical Gaps:

Depending on frequency, current passive microwave remote-sensing instrumentation is limited in sensitivity (as through system noise, 1/f noise, or calibration uncertainty), resolution, or in SWaP. Critical gaps depend on specific frequency and application.

Gaps include include technologies to reduce 1/f noise with submillimeter amplifier-based receivers, particularly using internal calibration sources such as noise sources or pseudo-correlation architectures. Other gaps include highly linear receiver front ends capable of being calibrated in the presence of radio-frequency interference (RFI) that may change the operating point of prefilter components.

Relevance / Science Traceability:

Critical need: Creative solutions to improve the performance of future Earth-observing, planetary, and astrophysics missions. The wide range of frequencies in this scope are used for numerous science measurements such as Earth science temperature profiling, ice cloud remote sensing, and planetary molecular species detection.

References:

  • Ulaby, Fawwaz; and Long, David: Microwave radar and radiometric remote sensing, Artech House, 2015.
  • Wilson, W.J.; Tanner, A.B.; Pellerano, F.A.; and Horgan, K.A.: "Ultra stable microwave radiometers for future sea surface salinity missions," Jet Propulsion Laboratory, National Aeronautics and Space Administration, 2005.
  • Racette, P. and Lang, R.H.: "Radiometer design analysis based upon measurement uncertainty," Radio science, 40(05), pp. 1-22, 2005.
  • Cooke, C.M. et al.: "A 670 GHz integrated InP HEMT direct-detection receiver for the tropospheric water and cloud ice instrument," IEEE Transactions on Terahertz Science and Technology, 11(5), pp. 566-576, 2021.

Scope Title:

Advanced Digital Electronic or Photonic Systems Technology for Microwave Remote Sensing

Scope Description:

Technology critical to increasing the utility of microwave remote sensing based on photonic (or other novel analog) systems, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs) are showing great promise. This topic solicits proposals for such systems or subsystems to process microwave signals for passive remote-sensing applications for spectrometry or total power radiometry. Example applications include:

 

  • Photonic (or other analog) components or systems to implement spectrometers, beamforming arrays, correlation arrays, oscillators, noise sources, and other active or passive microwave instruments having size, weight, and power (SWaP) or performance advantages over digital technology.
  • ASIC-based solutions for digital beamforming, creating one or more beams to replace mechanically scanned antennas.
  • Digitizers for spectrometry starting at 20 Gsps, 20 GHz bandwidth, 4 or more bit resolution, and simple interface to a FPGA.
  • ASIC implementations of polyphase spectrometer digital signal processing with ~1 W/GHz; 10-GHz-bandwidth polarimetric spectrometer with 1,024 channels; and radiation-hardened and minimized power dissipation.

 

All systems or subsystems should also focus on low-power, radiation-tolerant broad-band microwave spectrometers for NASA applications. Proposals should compare predicted performance and SWaP to conventional radio-frequency and digital-processing methods.

Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 08 Sensors and Instruments
  • Level 2 08.1 Remote Sensing Instruments/Sensors

Desired Deliverables of Phase I and Phase II:

  • Research
  • Analysis
  • Prototype
  • Hardware

Desired Deliverables Description:

Demonstration of novel subsystem or system to enable increased capability in passive microwave remote-sensing instruments. Photonic systems specifically are low-TRL emerging technologies, so offerors are encouraged to identify and propose designs where photonic technology would be most beneficial. For electronic solutions, low-power spectrometers (or other applications in the Scope Description) for an ASIC or other component that can be incorporated into multiple NASA microwave remote-sensing instruments are desired:

  • Depending on the complexity of the proposed work, Phase I deliverables may include a prototype system or a study.
  • Phase II deliverables should include a prototype component or system with test data verifying functionality.

State of the Art and Critical Gaps:

  • Photonic systems for microwave remote sensing are an emerging technology not used in current NASA microwave missions, but they may enable significant increases in bandwidth or reduction in SWaP. Again, state-of-the-art digital electronic solutions typically consume many watts of power.
  • Digital beamforming: most digital beamforming applications have focused on either specific narrowband approaches for commercial communications or military radars. NASA needs solutions that consume low power and operate over wide bandwidths.
  • Digitizers: High-speed digitizers exist but have poorly designed output interfaces. Specifically designed ASICs could reduce this power by a factor of 10, but pose challenges in design and radiation tolerance. A low-power solution could be used in a wide range of NASA remote-sensing applications.
  • Spectrometers: The state of the art is currently the use of conventional microwave electronics for frequency conversion and filtering for spectrometers. Wideband spectrometers still generally require over 10 W. Current FPGA-based spectrometers require ~10 W/GHz.

 

Relevance / Science Traceability:

Photonic systems may enable significantly increased bandwidth of Earth-viewing, astrophysics, and planetary science missions. In particular, this may allow for increased bandwidth or resolution receivers, with applications such as hyperspectral radiometry.

Broadband spectrometers are required for Earth-observing, planetary, and astrophysics missions. The rapid increase in speed and reduction in power per gigahertz in the digital realm of digital spectrometer capability is directly applicable to planetary science and enables radio-frequency interference (RFI) mitigation for Earth science.

References:

  • Ulaby, Fawwaz; and Long, David: Microwave radar and radiometric remote sensing, Artech House, 2015.
  • Chovan, Jozef; and Uherek, Frantisek: "Photonic Integrated Circuits for Communication Systems," Radioengineering, vol. 27, issue 2, pp. 357-363, June 2018.
  • Pulipati, S. et al.: "Xilinx RF-SoC-based Digital Multi-Beam Array Processors for 28/60 GHz Wireless Testbeds," Moratuwa Engineering Research Conference (MERCon), Moratuwa, Sri Lanka, July 2020.
  • Johnson, Joel T. et al.: "Real-Time Detection and Filtering of Radio Frequency Interference Onboard a Spaceborne Microwave Radiometer: The CubeRRT Mission," IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 13, pp. 1610-1624, 2020.
  • Le Vine, David M.: "RFI and Remote Sensing of the Earth from Space," Journal of Astronomical Instrumentation, 8.01, 2019,  https://ntrs.nasa.gov/citations/20170003103

Scope Title:

Advanced Deployable Antenna Apertures at Frequencies up to Millimeter-Wave

Scope Description:

Deployable antenna apertures are required for a wide range of NASA passive remote-sensing applications from SmallSat platforms. Current deployable antenna technology is extremely limited, particularly above Ka-band. NASA requires low-loss deployable antenna apertures at frequencies up to 200 GHz or beyond. Deployed aperture diameters of 0.5 m or larger are desired, but proposers are invited to propose concepts for smaller apertures at higher frequencies. Typical bandwidths required for these antennas may be 10% or more for microwave radiometers.

NASA also requires low-loss broad-band deployable or compact antenna feeds with bandwidths of two octaves or more. Frequencies of interest start at 500 MHz. Loss should be as low as possible (less than 1%) to minimize radiometric uncertainty caused by changes in the antenna physical temperature. The possibility of thermal control and/or monitoring of the antenna is desired to further improve system calibration stability. 

Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 08 Sensors and Instruments
  • Level 2 08.1 Remote Sensing Instruments/Sensors

Desired Deliverables of Phase I and Phase II:

  • Analysis
  • Prototype
  • Hardware

Desired Deliverables Description:

Phase I deliverables should consist of analysis and potential prototyping of key enabling technologies.

Phase II deliverables should include a deployable antenna prototype.

State of the Art and Critical Gaps:

Current low-loss deployable antennas are limited to Ka-band. Deployable apertures at higher frequencies are required for a wide range of applications, as aperture size is currently an instrument size, weight, and power (SWaP) driver for many applications up to 200 GHz.

Typical radiometer frequencies without deployable antenna technologies include (but are not limited to) 50-57 GHz, 88 GHz, 112-120 GHz, and 176-190 GHz. Radar remote sensing would also benefit from deployable antenna technologies at 65-70 GHz, 94 GHz, and 167-175 GHz.

Relevance / Science Traceability:

Antennas at these frequencies are used for a wide range of passive and active microwave remote sensing, including measurements of water vapor and temperature. NASA requires low-loss deployable antenna apertures at frequencies up to 200 GHz or beyond. NASA also requires low-loss broad-band deployable or compact antenna feeds with bandwidths of two octaves or more; these frequencies of interest start at 500 MHz. 

References:

  • Passive remote sensing such as performed by the Global Precipitation Mission (GPM) Microwave Imager (GMI): https://gpm.nasa.gov/missions/GPM/GMI
  • Chahat, N. et al.: "Advanced CubeSat Antennas for Deep Space and Earth Science Missions: A review," IEEE Antennas and Propagation Magazine, vol. 61, no. 5, pp. 37-46, Oct. 2019, doi: 10.1109/MAP.2019.2932608.

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