Satellite imagery

A relatively simple long baseline interferometer (LBI) system, which uses analog tape recorders, is described; it operates at decametric wavelength (26.3 MHz). A base station at Boulder with an array of 76 full‐wave dipoles is used in conjunction with a small, readily portable antenna of sixteen full‐wave dipoles that can be set up at various outlying field sites by two men in less than three hours. Commercial rubidium clocks are employed for timing and for local oscillator signals at each station. Tapes are aligned and data are correlated by an analog multiplier after each run at the base station. The use of pseudo‐random code generators which can be reset and started on a given clock pulse at each station greatly simplifies tape alignment and system calibration.

@article{sargent1970a,
    author = "Sargent, Howard H. and Klemperer, W. K.",
    title = "A Decametric Long Baseline Interferometer System",
    year = "1970",
    journal = "Radio Science",
    abstract = "A relatively simple long baseline interferometer (LBI) system, which uses analog tape recorders, is described; it operates at decametric wavelength (26.3 MHz). A base station at Boulder with an array of 76 full‐wave dipoles is used in conjunction with a small, readily portable antenna of sixteen full‐wave dipoles that can be set up at various outlying field sites by two men in less than three hours. Commercial rubidium clocks are employed for timing and for local oscillator signals at each station. Tapes are aligned and data are correlated by an analog multiplier after each run at the base station. The use of pseudo‐random code generators which can be reset and started on a given clock pulse at each station greatly simplifies tape alignment and system calibration.",
    url = "https://doi.org/10.1029/rs005i010p01283",
    doi = "10.1029/rs005i010p01283",
    number = "10",
    pages = "1283-1286",
    volume = "5"
}

@incollection{moran197653,
    author = "Moran, J.M.",
    title = "5.3. Very Long Baseline Interferometer Systems",
    year = "1976",
    booktitle = "Methods in Experimental Physics",
    url = "https://doi.org/10.1016/s0076-695x(08)60709-7",
    doi = "10.1016/s0076-695x(08)60709-7",
    pages = "174-197"
}

@article{shao1977long,
    author = "Shao, Michael and Staelin, David H.",
    title = "Long- baseline optical interferometer for astrometry",
    year = "1977",
    journal = "Journal of the Optical Society of America",
    url = "https://doi.org/10.1364/josa.67.000081",
    doi = "10.1364/josa.67.000081",
    number = "1",
    pages = "81",
    volume = "67"
}

@article{christodoulidis1985observing2,
    author = "Christodoulidis, D. C. and Smith, D. E. and Kelenkiewicz, R. and Klosko, S. M. and Dunn, P. J",
    title = "Observing plate motions and deformations from satellite lasar ranging",
    year = "1985",
    journal = "Journal of Geophysical Research, v. 90, p. 9249-9263",
    note = "talkorigins\_source = {true}; raw\_reference = {Christodoulidis, D. C., Smith, D. E., Kelenkiewicz, R., Klosko, S. M., and Dunn, P. J., 1985, Observing plate motions and deformations from satellite lasar ranging: Journal of Geophysical Research, v. 90, p. 9249-9263.}"
}

@article{doi101109tgrs1985289425,
    author = "Coates, R. and Frey, H. and Mead, G. and Bosworth, J.",
    title = "Space-Age Geodesy: The NASA Crustal Dynamics Project",
    year = "1985",
    journal = "IEEE Transactions on Geoscience and Remote Sensing",
    url = "https://www.semanticscholar.org/paper/898c0bd7ddecc054d4b1ed2479c094df644040ab",
    doi = "10.1109/TGRS.1985.289425",
    is_oa = "true",
    number = "4",
    pages = "360-368",
    semanticscholar_citation_count = "59",
    semanticscholar_id = "898c0bd7ddecc054d4b1ed2479c094df644040ab",
    volume = "GE-23"
}

@misc{carter1986studying1,
    author = "Carter, W. E. and Robertson, D. D",
    title = "Studying the earth by very-long- baseline interferometer",
    year = "1986",
    howpublished = "Scientific American, v. 255, no. 5, p. 46-54",
    note = "talkorigins\_source = {true}; raw\_reference = {Carter, W. E., and Robertson, D. D., 1986, Studying the earth by very-long- baseline interferometer: Scientific American, v. 255, no. 5, p. 46-54.}"
}

The infrared spatial interferometer (ISI) is a high-resolution aperture synthesis imaging system for the 10- μ m region located at Mt. Wilson Observatory since Jan. 1988. The compactness of the novel-design Pfund telescopes allows all optics and electronics to be mounted in two semitrailers. 1,2 Each of the two telescopes consists of a fixed f /3.14 parabolic mirror with 1.65-m aperture and a 2-m diam flat mirror in an altaz fork mount, which tracks the source. Hererodyne detection is achieved using LN 2 cooled HgCdTe photodiodes and phase-locked CO 2 laser local oscillators. The quantum efficiency including telescope transmission losses is ~25%, and the IF passband is 200–2000 MHz. Phase fluctuations on the LO signal caused by the atmosphere between the telescopes are compensated with a path length control system. As in many radio interferometers the fringes are stopped with a lobe rotator acting on the LO system. Correlation of the received signals over the IF passband is maintained with an IF delay line. A newly costructed He–Ne laser metrology system ensures that the telescopes can be pointed to a precision of ~0.01 sec of arc. Critical internal distances can also be monitored with this system. In addition the telescopes are equipped with conventional optical encoders. Although designed for baselines up to 1000 m, the initial range is 4–35 m yielding angular resolutions of 0.25–0.03 sec of arc.

@inproceedings{bester1988longbaseline,
    author = "Bester, Manfred and Danchi, W. C. and Townes, Charles H.",
    title = "Long-baseline infrared spatial interferometer",
    year = "1988",
    booktitle = "Annual Meeting Optical Society of America",
    abstract = "The infrared spatial interferometer (ISI) is a high-resolution aperture synthesis imaging system for the 10- μ m region located at Mt. Wilson Observatory since Jan. 1988. The compactness of the novel-design Pfund telescopes allows all optics and electronics to be mounted in two semitrailers. 1,2 Each of the two telescopes consists of a fixed f /3.14 parabolic mirror with 1.65-m aperture and a 2-m diam flat mirror in an altaz fork mount, which tracks the source. Hererodyne detection is achieved using LN 2 cooled HgCdTe photodiodes and phase-locked CO 2 laser local oscillators. The quantum efficiency including telescope transmission losses is \textasciitilde 25\%, and the IF passband is 200–2000 MHz. Phase fluctuations on the LO signal caused by the atmosphere between the telescopes are compensated with a path length control system. As in many radio interferometers the fringes are stopped with a lobe rotator acting on the LO system. Correlation of the received signals over the IF passband is maintained with an IF delay line. A newly costructed He–Ne laser metrology system ensures that the telescopes can be pointed to a precision of \textasciitilde 0.01 sec of arc. Critical internal distances can also be monitored with this system. In addition the telescopes are equipped with conventional optical encoders. Although designed for baselines up to 1000 m, the initial range is 4–35 m yielding angular resolutions of 0.25–0.03 sec of arc.",
    url = "https://doi.org/10.1364/oam.1988.wc2",
    doi = "10.1364/oam.1988.wc2",
    pages = "WC2"
}

@incollection{yen1988the,
    author = "Yen, J. L. and Leone, P. and Watson, G. A. and Wiedfeldt, R. and Zao, J. and Cannon, W. H. and Mathieu, P. and Tan, H. and Popelar, J. and Gait, J. A.",
    title = "The Canadian Geophysical Long Baseline Interferometer",
    year = "1988",
    booktitle = "The Impact of VLBI on Astrophysics and Geophysics",
    url = "https://doi.org/10.1007/978-94-009-2949-4\_160",
    doi = "10.1007/978-94-009-2949-4\_160",
    pages = "489-490"
}

The Canadian geophysical long baseline interferometer, a new very long baseline interferometer system, has been developed and put into operation. The system tracks source delay and fringe rotation during observation using a wave front clock. After the low‐noise receiver the signals from radio sources are channelized and down converted to baseband, each baseband channel is one bit digitized at a rate of 12 mbar/s and then recorded on a single video cassette recorder for processing. The total bandwidth of the system can be easily increased by replication of baseband channels. During processing the tapes are played back in synchronism and the recovered astronomy data are processed in a simple correlator to obtain the source visibility. The use of the wave front clock allows bursts of wideband astronomy data to be sampled at a high rate at each station and then recorded at a lower rate for processing. Because bursts recorded at different stations at the same wave front clock epoch are emitted by the source at the same time, they are correlated. The fringe visibility obtained from processing the bursts would provide high‐delay resolution geodetic measurements commensurate with the wide bandwidth of the bursts.

@article{yen1991the,
    author = "Yen, J. L. and Leone, P. and Watson, G. A. and Zao, J. K. and Popelar, J. and Petrachenko, W. T. and Feil, G. and Cannon, W. H. and Mathieu, P. and Newby, P. and Tan, H. and Wietfeldt, R. D. and Galt, J. A.",
    title = "The Canadian geophysical long baseline interferometer",
    year = "1991",
    journal = "Radio Science",
    abstract = "The Canadian geophysical long baseline interferometer, a new very long baseline interferometer system, has been developed and put into operation. The system tracks source delay and fringe rotation during observation using a wave front clock. After the low‐noise receiver the signals from radio sources are channelized and down converted to baseband, each baseband channel is one bit digitized at a rate of 12 mbar/s and then recorded on a single video cassette recorder for processing. The total bandwidth of the system can be easily increased by replication of baseband channels. During processing the tapes are played back in synchronism and the recovered astronomy data are processed in a simple correlator to obtain the source visibility. The use of the wave front clock allows bursts of wideband astronomy data to be sampled at a high rate at each station and then recorded at a lower rate for processing. Because bursts recorded at different stations at the same wave front clock epoch are emitted by the source at the same time, they are correlated. The fringe visibility obtained from processing the bursts would provide high‐delay resolution geodetic measurements commensurate with the wide bandwidth of the bursts.",
    url = "https://doi.org/10.1029/90rs00241",
    doi = "10.1029/90rs00241",
    number = "1",
    pages = "89-99",
    volume = "26"
}

@misc{ramapriyan2001satellite,
    author = "Ramapriyan, H.K.",
    title = "Satellite Imagery in Earth Science Applications",
    year = "2001",
    booktitle = "Image Databases",
    url = "https://doi.org/10.1002/0471224634.ch3",
    doi = "10.1002/0471224634.ch3",
    pages = "35-82"
}

@article{s2f01488e4cd91a77bd768694edeea03bd990265d4,
    author = "Sharov, A. and Gutjahr, K. and Meyer, F. and Schardt, M.",
    title = "METHODICAL ALTERNATIVES TO THE GLACIER MOTION MEASUREMENT FROM DIFFERENTIAL SAR INTERFEROMETRY",
    year = "2002",
    url = "https://www.semanticscholar.org/paper/f01488e4cd91a77bd768694edeea03bd990265d4",
    is_oa = "true",
    semanticscholar_citation_count = "11",
    semanticscholar_id = "f01488e4cd91a77bd768694edeea03bd990265d4"
}

@article{takahashi2002very,
    author = "Takahashi, F. and Kondo, T. and Takahashi, Y. and Koyama, Y.",
    title = "Very long baseline interferometer",
    year = "2002",
    journal = "IEEE Aerospace and Electronic Systems Magazine",
    url = "https://doi.org/10.1109/maes.2002.1028083",
    doi = "10.1109/maes.2002.1028083",
    number = "8",
    pages = "43-44",
    volume = "17"
}

@article{s249b11a6e03bb95379b371e5e8b38ccc5b6a18772,
    author = "Taramelli, A. and Barbour, J.",
    title = "A new DEM of Italy using SRTM data",
    year = "2006",
    url = "https://www.semanticscholar.org/paper/49b11a6e03bb95379b371e5e8b38ccc5b6a18772",
    is_oa = "true",
    semanticscholar_citation_count = "11",
    semanticscholar_id = "49b11a6e03bb95379b371e5e8b38ccc5b6a18772"
}

The Saratoga transfer protocol was developed by Surrey Satellite Technology Ltd (SSTL) for its Disaster Monitoring Constellation (DMC) satellites. In over seven years of operation, Saratoga has provided efficient delivery of remote-sensing Earth observation imagery, across private wireless links, from these seven low-orbit satellites to ground stations, using the Internet Protocol (IP). Saratoga is designed to cope with high bandwidth-delay products, constrained acknowledgement channels, and high loss while streaming or delivering extremely large files. An implementation of this protocol has now been developed at the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) for wider use and testing. This is intended to prototype delivery of data across dedicated astronomy radio telescope networks on the ground, where networked sensors in Very Long Baseline Interferometer (VLBI) instruments generate large amounts of data for processing and can send that data across private IP- and Ethernet-based links at very high rates. We describe this new Saratoga implementation, its features and focus on high throughput and link utilization, and lessons learned in developing this protocol for sensor-network applications.12

@inproceedings{doi101109aero20115747332,
    author = "Wood, Lloyd and Smith, Charles and Eddy, W. and Ivancic, W. and Jackson, C.",
    title = "Taking Saratoga from space-based ground sensors to ground-based space sensors",
    year = "2011",
    booktitle = "2011 Aerospace Conference",
    abstract = "The Saratoga transfer protocol was developed by Surrey Satellite Technology Ltd (SSTL) for its Disaster Monitoring Constellation (DMC) satellites. In over seven years of operation, Saratoga has provided efficient delivery of remote-sensing Earth observation imagery, across private wireless links, from these seven low-orbit satellites to ground stations, using the Internet Protocol (IP). Saratoga is designed to cope with high bandwidth-delay products, constrained acknowledgement channels, and high loss while streaming or delivering extremely large files. An implementation of this protocol has now been developed at the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) for wider use and testing. This is intended to prototype delivery of data across dedicated astronomy radio telescope networks on the ground, where networked sensors in Very Long Baseline Interferometer (VLBI) instruments generate large amounts of data for processing and can send that data across private IP- and Ethernet-based links at very high rates. We describe this new Saratoga implementation, its features and focus on high throughput and link utilization, and lessons learned in developing this protocol for sensor-network applications.12",
    url = "https://arxiv.org/pdf/1101.2172",
    doi = "10.1109/AERO.2011.5747332",
    is_oa = "true",
    pages = "1-8",
    semanticscholar_citation_count = "7",
    semanticscholar_id = "d144af8bbf94dfb0f423db087237dd15b63c7aa6"
}

@article{s23ac11eff5fd794b12adfdd7bf0849bf1ad5f24d4,
    author = "Hashimoto, Manabu and 京都大学防災研究所 and 山本, 圭吾 and Yamamoto, Keigo and 宮城, 洋介 and Miyagi, Yosuke and 宇宙航空研究開発機構 and Klokov, A. and Sato, Motoyuki and 齊藤, 昭則 and Saito, A. and Mineyama, Dai and 京都大学院理学研究科",
    title = "Estimate of a non-planar fault model based on crustal deformation data due to the Iwate-Miyagi Nairiku earthquake(Mw6.9)",
    year = "2011",
    url = "https://www.semanticscholar.org/paper/3ac11eff5fd794b12adfdd7bf0849bf1ad5f24d4",
    is_oa = "true",
    semanticscholar_id = "3ac11eff5fd794b12adfdd7bf0849bf1ad5f24d4"
}

Abstract. Advancements in radar technology are increasing our ability to detect Earth surface deformation in permafrost environments. In this paper we use satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) to describe the growth of a large, relatively young pingo in the Tuktoyaktuk Coastlands. High-resolution RADARSAT-2 imagery (2011–2014) analyzed with the Multidimensional Small Baseline Subset (MSBAS) DInSAR revealed a maximum 2.7 cm yr−1 of domed uplift located in a drained lake basin. Satellite measurements suggest that this feature is one of the largest diameter pingos in the region that is presently growing. Observed changes in elevation were modeled as a 348  ×  290 m uniformly loaded elliptical plate with clamped edge. Analysis of historical aerial photographs suggested that ground uplift at this location initiated sometime between 1935 and 1951 following drainage of the residual pond. Uplift is largely due to the growth of intrusive ice, because the 9 % expansion of pore water associated with permafrost aggradation into saturated sands is not sufficient to explain the observed short- and long-term deformation rates. The modeled thickness of ice-rich permafrost using the Northern Ecosystem Soil Temperature (NEST) was consistent with the maximum height of this feature. Modeled permafrost aggradation from 1972 to 2014 approximated elevation changes estimated from aerial photographs for that time period. Taken together, these lines of evidence indicate that uplift is at least in part a result of freezing of the sub-pingo water lens. Seasonal variations in the uplift rate seen in the DInSAR data closely match the modeled seasonal pattern in the deepening rate of freezing front. This study demonstrates that interferometric satellite radar can detect and contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments. The present-day growth rate is smaller than predicted by the modeling and no clear growth is observed at other smaller pingos in contrast with field studies performed mainly before the 1990s. Investigation of this apparent discrepancy provides an opportunity to further develop observation methods and models.

@article{doi105194tc107992016,
    author = "Samsonov, S. and Lantz, T. and Kokelj, S. and Zhang, Yu",
    title = "Growth of a young pingo in the Canadian Arctic observed by RADARSAT-2 interferometric satellite radar",
    year = "2015",
    journal = "The Cryosphere",
    abstract = "Abstract. Advancements in radar technology are increasing our ability to detect Earth surface deformation in permafrost environments. In this paper we use satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) to describe the growth of a large, relatively young pingo in the Tuktoyaktuk Coastlands. High-resolution RADARSAT-2 imagery (2011–2014) analyzed with the Multidimensional Small Baseline Subset (MSBAS) DInSAR revealed a maximum 2.7 cm yr−1 of domed uplift located in a drained lake basin. Satellite measurements suggest that this feature is one of the largest diameter pingos in the region that is presently growing. Observed changes in elevation were modeled as a 348 × 290 m uniformly loaded elliptical plate with clamped edge. Analysis of historical aerial photographs suggested that ground uplift at this location initiated sometime between 1935 and 1951 following drainage of the residual pond. Uplift is largely due to the growth of intrusive ice, because the 9 \% expansion of pore water associated with permafrost aggradation into saturated sands is not sufficient to explain the observed short- and long-term deformation rates. The modeled thickness of ice-rich permafrost using the Northern Ecosystem Soil Temperature (NEST) was consistent with the maximum height of this feature. Modeled permafrost aggradation from 1972 to 2014 approximated elevation changes estimated from aerial photographs for that time period. Taken together, these lines of evidence indicate that uplift is at least in part a result of freezing of the sub-pingo water lens. Seasonal variations in the uplift rate seen in the DInSAR data closely match the modeled seasonal pattern in the deepening rate of freezing front. This study demonstrates that interferometric satellite radar can detect and contribute to understanding the dynamics of terrain uplift in response to permafrost aggradation and ground ice development in remote polar environments. The present-day growth rate is smaller than predicted by the modeling and no clear growth is observed at other smaller pingos in contrast with field studies performed mainly before the 1990s. Investigation of this apparent discrepancy provides an opportunity to further develop observation methods and models.",
    url = "https://www.the-cryosphere.net/10/799/2016/tc-10-799-2016.pdf",
    doi = "10.5194/TC-10-799-2016",
    is_oa = "true",
    number = "2",
    pages = "799-810",
    semanticscholar_citation_count = "29",
    semanticscholar_id = "7bb9bcc0645e1cf8ecb5fd6fb530e18bc65b8574",
    volume = "10"
}

Stray light, any unwanted radiation that reaches a focal plane, presents a significant challenge for both airborne and satellite remote sensing systems by reducing image contrast, creating false signals or obscuring faint ones, and ultimately degrading radiometric accuracy. These detrimental effects can have a profound impact on the usability of collected data, which must be radiometrically calibrated to be useful for scientific applications. Understanding the full impact of stray light on data scientific utility is of concern for lower cost, more compact satellite systems which inherently provide fewer opportunities for stray light control. To address these concerns, we present a general methodology for integrating an optomechanical system model with the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model. The results reported in this paper describe the collection of necessary raytrace data from an optomechanical system model (in this case, using FRED optical engineering software), and include the initial demonstration of the integration method by imaging DIRSIG test scenes. By integrating a high-fidelity optomechanical system model with a physics-driven, synthetic image generation model like DIRSIG, we are now able to explore system trade studies and conduct sensitivity analyses on parameters of interest, including those that influence stray light, by analyzing their effects on realistic test scenes. This new capability (which can be used with reasonable levels of sampling/fidelity and which has been used by industry) further aids in demonstrating the quantitative linkage between system trade studies and impact to scientific users, which will enhance the writing of system requirements. possible through optical path differences. Geometric phase lenses, which are significantly thinner than refractive lenses for the same numerical aperture (NA), most commonly use a spherical phase profile. This is especially effective for normally incident light, but like other thin lenses the performance degrades noticeably for off-axis incidence and wider fields-of-view. In this study, we investigate if various aspheric designs provide better off-axis performance. We simulate aspheric singlet and doublet liquid crystal geometric phase lenses (24.5 mm diameter, 40 mm back focal length at 633 nm), aiming to optimize spot size performance at field angles of 0, 3, and 7, using Zemax and a simple ray tracing algorithm in MATLAB. By using different phase functions, including Zernike fringe and polynomial expansions, we find conditions which provide improved off-axis performance. We show improved performance of a compact lens system utilizing these polarization-dependent optics, while maintaining low loss and substantially improved leakages over prior holographic lenses. (Discussions also included selected considerations related to lateral chromatic aberration and clarification of some Figure labels.) Anisotropic materials can comprise multilayer stacks made from uniaxial-uniaxial or isotropic-uniaxial layers. These structures can be used to achieve unique optical filters and can be modeled as a bulk structure using effective medium theory. The optical properties of these anisotropic media can be described in terms of effective parameters such as permittivity and permeability tensors. In this work, optical propagation through such layered media is analyzed using Berreman 4 × 4 matrix along with appropriate boundary conditions. Reflection and transmission are investigated as functions of the incident angle and wavelength (which covers the angular effects seen in F/No-driven convergent or divergent cones of light) . The effective medium theory is validated by varying the number of layers and the thickness of layers. Results are compared with those obtained using the transfer matrix approach, where the constituent uniaxial layer is itself composed from dissimilar isotropic materials. This analysis can be extended to Gaussian beam propagation through such anisotropic materials using angular plane wave approach. LUVOIR show promising possibilities for compensation using a purpose-designed coating on the secondary mirror. Measurements are planned but are currently TBD. lightfields simulate The lightfield describes the radiance at a given point provide by a ray coming from a particular direction. Integrating the lightfield for all possible rays passing through that point gives total irradiance. For a static scene, the lightfield is unique. Cameras act as integrators of the light field. The irradiance at each camera pixel can be mapped to the points in the entrance pupil of the camera lens and a series of directions defined by the wavefront error associated with the lens. Consequently, if the lightfield is known at the entrance pupil, then the camera image can be created simply from the aberrations associated with the camera lens. The advantage of this technique is that the lightfield only needs to be calculated once for a given scene. Images of this scene for any lens can then be simulated as long as the lightfield is known at its entrance pupil. Here, an array of ideal pinhole cameras was placed in a 50mm x 50mm region of a 3D scene created in freeware rendering software. The pinhole camera images encode the ray directions for rays passing through the pinholes. The set of images from this array then describes the lightfield. Images for real camera lenses with different types of aberrations are then simulated directly from the lightfield. Images from different types of camera lenses and the consequences of different aberrations can be compared with this technique. zone lightly reinforced) were studied. Results show an interaction between cell size and reinforcement zone(s) which appear to have definite optimal combinations – and where stiffness appears more important than simply adding mass for real/fabricated configurations. Each optimum would depend on mirror outer diameter and core depth. show this paper was not the abstract is included for completeness given potential reader interest.) after the stress (Chair’s used to hopefully help clarify abstract.) The X ray beam line Projection X-ray Microscopy (PXM) is used (with a) wiggler insert part in (a) Taiwan Photon Source. The PXM system has two mirrors and one Double Crystal Monochromator (DCM). The Vertical Collimating Mirror (VCM) is the first mirror (seen by the) wiggler, thus the thermal absorption is an important issue. Meanwhile, the DCM sees very high-power density (Chair’s note - ~ solar loading in Earth orbit), so the DCM uses liquid nitrogen cooling. The X ray optical foot print can be calculated by SHADOW software on the VCM and DCM. The X-ray thermal load can be weighed and input to a Finite Element Method (FEM) model used to calculate thermal deformation. The mirror surface deformation can be fit by a B-spline and fed-back to the SHADOW software so as to evaluate system performance differences introduced by thermal deformation, and help the designer determine mirror tolerances. (Mirrors are polished Si & 3-point mounted.) 1064nm of a frequency stabilized laser source many amplifiers distributed the array. in long baseline coherent beam combination that each source be combined with sub-wavelength accuracy over the entire array. In addition to perturbations due to mechanical and atmospheric disturbances, phase noise introduced by the amplifiers and seed distribution network must also be accounted for to achieve the necessary accuracy. This work investigates the excess phase noise introduced by the amplifier stages and fiber optic links and locking schemes that could be used to synchronize such an array. The test bed used to interrogate phase noise is based on an all polarization maintaining fiber-based Mach-Zehnder interferometer with FPGA based digital I/Q quadrature detection at 1 MS/s yielding direct measurement of amplitude and phase with servo control for phase locking. Results for various MOPA and fiber link configurations based on Yb-doped fiber The raised cosine is a bandwidth efficient pulse shaping waveform with relatively high peak to average power ratio (PAPR). Reducing the PAPR while maintaining waveform integrity and bandwidth efficiency increases the over (all) transmission rate by utilizing the spectrum more effectively. We modify the raised cosine by reducing the adjacent symbol contribution to the PAPR while maintaining the Error Vector Magnitude integrity at a relatively small increase in required bandwidth over the raised cosine waveform. The attained PAPR reduction is on the order of 1.5 dB for the smaller excess bandwidth. classification considers the application of the novel Artificial Intelligence (AI) based methods to the inverse problem of light transport in scattering media such as human skin. A spectral image classi fi cation pipeline based on Artificial Neural Networks (ANNs) been developed by implementing and several configurations of ANNs classi fi ers that fit for the scattering and absorption properties of the The training of the ANNs has been performed by the further developed unified Monte Carlo-based computational framework for light transport in scattering media. The hyperspectral data is acquired at each pixel as a function of time, varying the illumination/detection wavelength and polarization of light. The results of nearly real-time chromophore mappings for parameters such as distributions of melanin, Microwave oscillators are used to generate high quality microwave signals. With a conventional electronics circuit it is not possible to generate such signals because of a lack in the degree of spectral purity and stability. These drawbacks are mainly due to the presence of passive components giving rise to resistive loss and their frequency dependency on energy storage capability. A p hotonic based oscillator is a substantial way of generating high quality microwave waveforms with high frequencies. Here, a photonic based opt

@article{doi101117122515690,
    title = "Front Matter: Volume 10743",
    year = "2018",
    journal = "Optical Modeling and Performance Predictions X",
    booktitle = "Optical Modeling and Performance Predictions X",
    abstract = "Stray light, any unwanted radiation that reaches a focal plane, presents a significant challenge for both airborne and satellite remote sensing systems by reducing image contrast, creating false signals or obscuring faint ones, and ultimately degrading radiometric accuracy. These detrimental effects can have a profound impact on the usability of collected data, which must be radiometrically calibrated to be useful for scientific applications. Understanding the full impact of stray light on data scientific utility is of concern for lower cost, more compact satellite systems which inherently provide fewer opportunities for stray light control. To address these concerns, we present a general methodology for integrating an optomechanical system model with the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model. The results reported in this paper describe the collection of necessary raytrace data from an optomechanical system model (in this case, using FRED optical engineering software), and include the initial demonstration of the integration method by imaging DIRSIG test scenes. By integrating a high-fidelity optomechanical system model with a physics-driven, synthetic image generation model like DIRSIG, we are now able to explore system trade studies and conduct sensitivity analyses on parameters of interest, including those that influence stray light, by analyzing their effects on realistic test scenes. This new capability (which can be used with reasonable levels of sampling/fidelity and which has been used by industry) further aids in demonstrating the quantitative linkage between system trade studies and impact to scientific users, which will enhance the writing of system requirements. possible through optical path differences. Geometric phase lenses, which are significantly thinner than refractive lenses for the same numerical aperture (NA), most commonly use a spherical phase profile. This is especially effective for normally incident light, but like other thin lenses the performance degrades noticeably for off-axis incidence and wider fields-of-view. In this study, we investigate if various aspheric designs provide better off-axis performance. We simulate aspheric singlet and doublet liquid crystal geometric phase lenses (24.5 mm diameter, 40 mm back focal length at 633 nm), aiming to optimize spot size performance at field angles of 0, 3, and 7, using Zemax and a simple ray tracing algorithm in MATLAB. By using different phase functions, including Zernike fringe and polynomial expansions, we find conditions which provide improved off-axis performance. We show improved performance of a compact lens system utilizing these polarization-dependent optics, while maintaining low loss and substantially improved leakages over prior holographic lenses. (Discussions also included selected considerations related to lateral chromatic aberration and clarification of some Figure labels.) Anisotropic materials can comprise multilayer stacks made from uniaxial-uniaxial or isotropic-uniaxial layers. These structures can be used to achieve unique optical filters and can be modeled as a bulk structure using effective medium theory. The optical properties of these anisotropic media can be described in terms of effective parameters such as permittivity and permeability tensors. In this work, optical propagation through such layered media is analyzed using Berreman 4 × 4 matrix along with appropriate boundary conditions. Reflection and transmission are investigated as functions of the incident angle and wavelength (which covers the angular effects seen in F/No-driven convergent or divergent cones of light) . The effective medium theory is validated by varying the number of layers and the thickness of layers. Results are compared with those obtained using the transfer matrix approach, where the constituent uniaxial layer is itself composed from dissimilar isotropic materials. This analysis can be extended to Gaussian beam propagation through such anisotropic materials using angular plane wave approach. LUVOIR show promising possibilities for compensation using a purpose-designed coating on the secondary mirror. Measurements are planned but are currently TBD. lightfields simulate The lightfield describes the radiance at a given point provide by a ray coming from a particular direction. Integrating the lightfield for all possible rays passing through that point gives total irradiance. For a static scene, the lightfield is unique. Cameras act as integrators of the light field. The irradiance at each camera pixel can be mapped to the points in the entrance pupil of the camera lens and a series of directions defined by the wavefront error associated with the lens. Consequently, if the lightfield is known at the entrance pupil, then the camera image can be created simply from the aberrations associated with the camera lens. The advantage of this technique is that the lightfield only needs to be calculated once for a given scene. Images of this scene for any lens can then be simulated as long as the lightfield is known at its entrance pupil. Here, an array of ideal pinhole cameras was placed in a 50mm x 50mm region of a 3D scene created in freeware rendering software. The pinhole camera images encode the ray directions for rays passing through the pinholes. The set of images from this array then describes the lightfield. Images for real camera lenses with different types of aberrations are then simulated directly from the lightfield. Images from different types of camera lenses and the consequences of different aberrations can be compared with this technique. zone lightly reinforced) were studied. Results show an interaction between cell size and reinforcement zone(s) which appear to have definite optimal combinations – and where stiffness appears more important than simply adding mass for real/fabricated configurations. Each optimum would depend on mirror outer diameter and core depth. show this paper was not the abstract is included for completeness given potential reader interest.) after the stress (Chair’s used to hopefully help clarify abstract.) The X ray beam line Projection X-ray Microscopy (PXM) is used (with a) wiggler insert part in (a) Taiwan Photon Source. The PXM system has two mirrors and one Double Crystal Monochromator (DCM). The Vertical Collimating Mirror (VCM) is the first mirror (seen by the) wiggler, thus the thermal absorption is an important issue. Meanwhile, the DCM sees very high-power density (Chair’s note - \textasciitilde\ solar loading in Earth orbit), so the DCM uses liquid nitrogen cooling. The X ray optical foot print can be calculated by SHADOW software on the VCM and DCM. The X-ray thermal load can be weighed and input to a Finite Element Method (FEM) model used to calculate thermal deformation. The mirror surface deformation can be fit by a B-spline and fed-back to the SHADOW software so as to evaluate system performance differences introduced by thermal deformation, and help the designer determine mirror tolerances. (Mirrors are polished Si \& 3-point mounted.) 1064nm of a frequency stabilized laser source many amplifiers distributed the array. in long baseline coherent beam combination that each source be combined with sub-wavelength accuracy over the entire array. In addition to perturbations due to mechanical and atmospheric disturbances, phase noise introduced by the amplifiers and seed distribution network must also be accounted for to achieve the necessary accuracy. This work investigates the excess phase noise introduced by the amplifier stages and fiber optic links and locking schemes that could be used to synchronize such an array. The test bed used to interrogate phase noise is based on an all polarization maintaining fiber-based Mach-Zehnder interferometer with FPGA based digital I/Q quadrature detection at 1 MS/s yielding direct measurement of amplitude and phase with servo control for phase locking. Results for various MOPA and fiber link configurations based on Yb-doped fiber The raised cosine is a bandwidth efficient pulse shaping waveform with relatively high peak to average power ratio (PAPR). Reducing the PAPR while maintaining waveform integrity and bandwidth efficiency increases the over (all) transmission rate by utilizing the spectrum more effectively. We modify the raised cosine by reducing the adjacent symbol contribution to the PAPR while maintaining the Error Vector Magnitude integrity at a relatively small increase in required bandwidth over the raised cosine waveform. The attained PAPR reduction is on the order of 1.5 dB for the smaller excess bandwidth. classification considers the application of the novel Artificial Intelligence (AI) based methods to the inverse problem of light transport in scattering media such as human skin. A spectral image classi fi cation pipeline based on Artificial Neural Networks (ANNs) been developed by implementing and several configurations of ANNs classi fi ers that fit for the scattering and absorption properties of the The training of the ANNs has been performed by the further developed unified Monte Carlo-based computational framework for light transport in scattering media. The hyperspectral data is acquired at each pixel as a function of time, varying the illumination/detection wavelength and polarization of light. The results of nearly real-time chromophore mappings for parameters such as distributions of melanin, Microwave oscillators are used to generate high quality microwave signals. With a conventional electronics circuit it is not possible to generate such signals because of a lack in the degree of spectral purity and stability. These drawbacks are mainly due to the presence of passive components giving rise to resistive loss and their frequency dependency on energy storage capability. A p hotonic based oscillator is a substantial way of generating high quality microwave waveforms with high frequencies. Here, a photonic based opt",
    url = "https://doi.org/10.1117/12.2515690",
    doi = "10.1117/12.2515690",
    is_oa = "true",
    pages = "0",
    semanticscholar_id = "9c16196c6ed691e179894c8b8284df12807b659e"
}

@article{s285f06659d1221b59802d56f8ebb2a6897bd4cadf,
    author = "Jansen‐Sturgeon, T. and Hartig, B. and Bland, P. and Madsen, G. and Bold, M. and Howie, R. and Mason, J. and Drury, R. and McCormack, D.",
    title = "FireOPAL: Continental-scale Coordinated Observations of the OSIRIS-Rex Flyby",
    year = "2018",
    url = "https://www.semanticscholar.org/paper/85f06659d1221b59802d56f8ebb2a6897bd4cadf",
    is_oa = "true",
    semanticscholar_citation_count = "2",
    semanticscholar_id = "85f06659d1221b59802d56f8ebb2a6897bd4cadf"
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The growing volume of synthetic aperture radar (SAR) imagery acquired by satellite constellations creates novel opportunities and opens new challenges for interferometric SAR (InSAR) applications to observe Earth’s surface processes and geohazards. In this paper, the Parallel Small BAseline Subset (P-SBAS) advanced InSAR processing chain running on the Geohazards Exploitation Platform (GEP) is trialed to process two unprecedentedly big stacks of Copernicus Sentinel-1 C-band SAR images acquired in 2014–2020 over a coastal study area in southern Italy, including 296 and 283 scenes in ascending and descending mode, respectively. Each stack was processed in the GEP in less than 3 days, from input SAR data retrieval via repositories, up to generation of the output P-SBAS datasets of coherent targets and their displacement histories. Use-cases of long-term monitoring of land subsidence at the Capo Colonna promontory (up −2.3 cm/year vertical and −1.0 cm/year east–west rate), slow-moving landslides and erosion landforms, and deformation at modern coastal protection infrastructure in the city of Crotone are used to: (i) showcase the type and precision of deformation products outputting from P-SBAS processing of big data, and the derivable key information to support value-adding and geological interpretation; and (ii) discuss potential and challenges of big data processing using cloud/grid infrastructure.

@article{doi103390rs13050885,
    author = "Cigna, F. and Tapete, D.",
    title = "Sentinel-1 Big Data Processing with P-SBAS InSAR in the Geohazards Exploitation Platform: An Experiment on Coastal Land Subsidence and Landslides in Italy",
    year = "2021",
    journal = "Remote. Sens.",
    abstract = "The growing volume of synthetic aperture radar (SAR) imagery acquired by satellite constellations creates novel opportunities and opens new challenges for interferometric SAR (InSAR) applications to observe Earth’s surface processes and geohazards. In this paper, the Parallel Small BAseline Subset (P-SBAS) advanced InSAR processing chain running on the Geohazards Exploitation Platform (GEP) is trialed to process two unprecedentedly big stacks of Copernicus Sentinel-1 C-band SAR images acquired in 2014–2020 over a coastal study area in southern Italy, including 296 and 283 scenes in ascending and descending mode, respectively. Each stack was processed in the GEP in less than 3 days, from input SAR data retrieval via repositories, up to generation of the output P-SBAS datasets of coherent targets and their displacement histories. Use-cases of long-term monitoring of land subsidence at the Capo Colonna promontory (up −2.3 cm/year vertical and −1.0 cm/year east–west rate), slow-moving landslides and erosion landforms, and deformation at modern coastal protection infrastructure in the city of Crotone are used to: (i) showcase the type and precision of deformation products outputting from P-SBAS processing of big data, and the derivable key information to support value-adding and geological interpretation; and (ii) discuss potential and challenges of big data processing using cloud/grid infrastructure.",
    url = "https://www.mdpi.com/2072-4292/13/5/885/pdf?version=1615190696",
    doi = "10.3390/rs13050885",
    is_oa = "true",
    number = "5",
    pages = "885",
    semanticscholar_citation_count = "85",
    semanticscholar_id = "af41d8b826f39c9de90fcae4fa802c2da4de1a03",
    volume = "13"
}

@incollection{reilley2023google,
    author = "Reilley, Mike",
    title = "Google Earth | Satellite Imagery",
    year = "2023",
    booktitle = "The Journalist’s Toolbox",
    url = "https://doi.org/10.4324/9781003431787-9",
    doi = "10.4324/9781003431787-9",
    pages = "187-205"
}