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Geometric Calibration of Near Focus Infrared (IR) Sensors for Spacecraft Missions
No full textOn-orbit spacecraft missions ranging from observation and object tracking to situational awareness and close-quarters navigation rely on electro-optical (EO) sensors. These sensors serve as the spacecraft’s primary vision system, providing critical data for computer vision (CV) algorithms and guidance, navigation, control (GN&C) software, etc. To ensure accurate data is fed to downstream applications, EO sensor data must undergo rigorous calibration to transform raw measurements into high-fidelity inputs. However, EO sensors designed for close-range spacecraft missions often feature a wide field of view (FOV) with short focus distances, posing unique calibration challenges. Traditional EO sensor calibration methods, which typically employ collimators focused at near-infinity distances, are not well suited for short-range EO systems. As a result, novel calibration techniques are required to achieve precise sensor characterization. This presentation first reviews existing EO sensor calibration methodologies and their limitations for short-range applications. It then introduces an innovative calibration approach utilizing a hot-wire target and specialized processing algorithms, offering a better alternative to conventional methods. Finally, the presentation presents experimental results from a proof-of-concept study conducted on a wide FOV, long-wave infrared (LWIR) EO sensor. The findings highlight the efficacy of this novel calibration technique in enhancing EO sensor performance, ultimately advancing the capabilities of close-range spacecraft missions
The First Year of HARP2/PACE Performance Based on its Ground and On-Orbit Characterization
No full textThe Hyper-Angular Rainbow Polarimeter-2 (HARP2) was launched on board the Plankton, Aerosol, Cloud and ocean Ecosystem (PACE) mission, in February 2024, for the global measurement of aerosol and cloud properties as well as to provide atmospheric correction over the footprint of the Ocean Color Instrument (OCI). HARP2 is designed to collect data over a wide field of view in the cross-track direction (+/-47deg) allowing for global coverage in about two days, as well as an even wider field of view in the along-track direction (+/-54 deg) providing measurements over a wide range of scattering angles. HARP2 samples 10 angles at 440, 550, and 870nm focusing on aerosol and surface retrievals, and up to 60 angles at 670nm for the hyper-angular retrieval of cloud microphysical properties. The HARP2 instrument collects three nearly identical images with linear polarizers aligned at 0°, 45°, and 90° that can be converted to push-broom images of the I, Q, and U Stokes parameters for each angle, and each wavelength. The HARP2 technology was first demonstrated with the HARP CubeSat satellite which collected a limited dataset for 2 years from 2020 to 2022. HARP2 extends these measurements to a full global coverage in two days, seven days a week.
This talk will show a brief description of the instrument and will focus on the calibration and characterization of the HARP2 instrument at the ground and on-orbit. The calibration and characterization of such a wide FOV instrument with polarization sensitivity produces particular challenges that are not common on other classes of instrument with narrower FOV. HARP2 was characterized at the ground from the spectral, radiometric, and polarimetric perspectives, as function of temperature, and aiming for high accuracy across the whole field of view of the instrument. Multiple techniques have been developed to address this characterization, which has resulted in about 1TByte of calibration data.
Once in orbit, the HARP2 team has also developed special strategies for the continued monitoring of the calibration parameters as well as for tracking the absolute calibration of the system. These strategies include lunar and solar calibration, flat field, dark current monitoring, vicarious calibrations looking at well know ground target, intercomparison between sensors, etc. Results from the ground and on-orbit calibration will be presented and discussed in detail
Curriculum Subcommittee Agenda October 2, 2025
No full textApproval of Minutes - September 4, 2025 Program Proposals Semester Course Approval Reviews Other Business Program Reminders Adjourn: 3:00 p
Faculty Senate Minutes September 8, 2025
No full textCall to Order Approval of Minutes - April 28, 2025 University Business Faculty Senate Business Information EPC Report - April 3, 2025 Report Empowering Teaching Excellence (ETE) Annual Report Center for Instructional Design and Innovation Annual Report Old Business New Business Adjourn - 4:30 p
Estimation of Breach Hydrograph Resulting From Dam Embankment Failure due to Internal Erosion or Overtopping: Comparison of Simplified Methods With Real-Case Failure Data and Recommendations
No full textThe opening of a breach in an embankment dam, whether due to overtopping or internal erosion, is a critical failure mode for these structures. Estimating the resulting breach hydrograph is essential for assessing downstream risks. While no universal physical model covers all dam types, empirical formulas are commonly used. EDF analyzed 14 such formulas, comparing them with rupture data from 32 embankment dam failures. The best formulas - Froehlich 1995, Xu & Zhang 2009, and CLF 2020 - yield a “best estimate” for peak flow. However, due to variability, results should be interpreted cautiously. Consider estimating breach characteristics like width and erosion rate for better understanding and comparison
Conclusions From the Performance Assessment of Industry Applicable Internal Erosion Initiated Breach Prediction Models
No full textThe EDF funded Performance Assessment of Industry Applicable IE Initiated Breach Prediction Models project was initiated with a workshop at HERU in Stillwater in October 2019. In the following 4 years a team of modelers comprising both model developers and industry model users analyzed the performance of 6 different breach modelling codes against a range of different data sets, including hypothetical, field and real dam failure case studies. Each of the data sets reflected a dam or levee failure initiated by internal erosion, and which subsequently developed into an open breach. Modelers were required to simulate breach formation from the initial ‘pipe’ flow through to open breach and the associated dam or levee failure. Four phases of modelling work were undertaken, with the initial Phase 0 focusing on hypothetical data to test the team approach. Phase 1 focused on assessing performance against sets of field data, whilst Phase 2 focused on assessing performance against observed Lawn Lake and Big Bay dam failure data. The final Phase 4 work took a different approach by focusing on data uncertainty (both case study and modelling data uncertainty) to see how the observed and predicted conditions potentially overlapped. This final stage of work allowed us to determine whether a model might recreate the observed conditions given the correct combination of modelling parameters
Ahead of His Time? A Reanalysis of the Air-Tunnel Stepped Chute Studies of Marcos José Tozzi
No full textStepped spillways offer energy dissipation advantages and construction efficiencies over smooth spillway chutes. Energy dissipation is typically estimated using empirical relations that depend on chute slope, unit discharge and relative step height. Open-channel tests of model spillways experience self-aerated air-water flow downstream from the aeration inception point, and the presence of air dramatically affects energy dissipation and flow depth, making it difficult to separately determine the effects of step geometry and other basic flow properties. The 1992 doctoral dissertation of Marcos José Tozzi from the Polytechnic School of the University of São Paulo included open channel stepped spillway tests with water as well as closed conduit tests using air as the working fluid. A new review of the air-tunnel tests was recently made to seek a better understanding of geometric influences on stepped chute flow resistance. The work contributes useful background information for new closed conduit water tunnel tests of stepped chute flow resistance
Can Computational Fluid Dynamics be the Basis for the Next Generation of Breach models?
No full textDam and embankment failures can have devastating consequences for communities, infrastructure, and the environment. Therefore, accurate modelling of dam and embankment breaches is crucial for effective flood risk assessment and emergency response planning to precisely estimate areas and people that are prone to risk and plan for reducing the damage to properties and the environment. Recently, many advances have been made to improve the accuracy of breach modelling, including the development of physically based one and two dimensional numerical models that takes into account the various processes that take place during the breach of an embankment dam or a flood embankment.
This paper presents the recent work that was undertaken at HR Wallingford to further improve the various breach modelling aspects by exploring the possibilities of using Computational Fluid Dynamics (CFD) models to simulate a breach. Although commercial CFD packages exist that can model air-water interaction well, there are none that currently model air-water-soil erosion at a suitable scale. Therefore, this work started by looking first at potential CFD core methods that can be used such as CFD with Discrete Element Method (CFD-DEM), Smoothed Particle Hydrodynamics Discrete Element Method (SPH-DEM), and Material Point Method (MPM) with a focus on their capabilities to simulate the complex breach processes. Example cases of using CFD-DEM are presented showing the challenges in setting up CFD models, selecting the various parameters required for such models and computational power needed to run a simulation. Based upon that, a number of near future and long-term recommendations for the use of CFD for breach modelling are made to contribute to the development of more accurate and reliable tools for assessing the potential impacts of dam and embankment failures
Climate Information Use in Transportation Planning: A Survey of Metropolitan Planning Organizations
No full textClimate change and its potential to impact transportation systems poses urgent challenges for sustainability and societal well-being, emphasizing a need to plan to reduce transportation infrastructure’s vulnerability to impacts such as sea level rise, extreme weather events, and increased erosion. Previous research has focused on document analysis and case studies and has highlighted the importance of including transportation professional needs in regard to understanding how transportation professionals use climate science. Through direct inclusion of transportation professional perspectives, this paper aims to fill the gaps in understanding about the use of climate information in transportation planning. To obtain data about local and regional level transportation infrastructure planning and the importance of increased funding on the demand for climate information, we conducted an online survey of regional transportation practitioners (n = 105) from United States Metropolitan Planning Organizations (MPOs). The survey examined what types of climate-related information these regional planners are using in the context of transportation infrastructure planning, how it is used, and what types of decision support practitioners think would be most useful. We also explore how the implementation of the Bipartisan Infrastructure Law / Infrastructure Investment and Jobs Act (BIL/IIJA), alongside other factors, may impact the demand for and use of climate information. We find that information providers need to improve decision support tools so they are (a) easy to use and interpret, (b) include explicit methods for modeling tradeoffs among options, and (c) allow the user to easily identify the impacts of alternative scenarios and decisions. Our data suggest that one of the most obvious ways to increase the use of climate information is to provide continuing education opportunities that empower transportation professionals to understand and use climate information and tools toward resilience goals. Based on responses, we also see opportunities for improved networking to connect transportation professionals with prior climate services experience to those who have less experience
Curriculum Subcommittee Agenda November 6, 2025
No full textApproval of Minutes - October 2, 2025 Program Proposals Other Business Adjourn: 3:00 p