Carl Weimer

• Consultant at Ball Aerospace & Technologies Corp.

A general solution based on the two-stream approximation (TSA) to the radiative transfer equation is provided in plane-parallel geometry for an anisotropically scattering slab of arbitrary physical thickness. Conventional two-stream algorithms are used to compute net irradiances and mean radiances, which in turn can be used to estimate heating/cool...

Lidar multiple scattering measurements provide the probability distribution of the distance laser light travels inside snow. Based on an analytic two-stream radiative transfer solution, the present study demonstrates why/how these lidar measurements can be used to derive snow depth and snow density. In particular, for a laser wavelength with little...

We have shown that solutions to the radiative transfer equation for a homogeneous slab yield a zenith radiance reflectance that for collimated beam incidence in the nadir direction can be expressed in terms of the lidar ratio, defined as the extinction coefficient divided by the 180 $$^\circ $$ ∘ backscattering coefficient. The recently developed Q...

Inversion of electromagnetic (EM) signals reflected from or transmitted through a medium, or emitted by it due to internal sources can be used to investigate the optical and physical properties of a variety of scattering/absorbing/emitting materials. Such media encompass planetary atmospheres and surfaces (including water/snow/ice), and plant canop...

Snow is a crucial element in the Earth’s system, but snow depth and mass are very challenging to be measured globally. Here, we provide the theoretical foundation for deriving snow depth directly from space-borne lidar (ICESat-2) snow multiple scattering measurements for the first time. First, based on the Monte Carlo lidar radiative transfer simul...

The application of diffusion theory and Monte Carlo lidar radiative transfer simulations presented in Part I of this series of study suggests that snow depth can be derived from the first-, second- and third-order moments of the lidar backscattering pathlength distribution. These methods are now applied to the satellite ICESat-2 lidar measurements...

Quantum parametric mode sorting has been shown to enable photon counting with precise time gating and exceptional noise rejection that significantly exceeds what is possible with linear filters. While previous experimental demonstrations were in a collinear optical configuration, its response to off-axis scattering must be understood to apply it mo...

Lasers with orbital angular momentum (OAM) have potential applications in communication technology, manipulation of particles, and remote sensing. Because of its unusual light-scattering properties, the OAM laser's interaction with a molecular atmosphere must be studied to ensure that it is not lossy for communication or remote-sensing applications...

Photon sieves (PS) have many applications and various designs in focusing light. However, a traditional PS only has a light transmissivity up to ∼25% and a focusing efficiency up to ∼7%, which hinder the application of them in many fields, especially for satellite remote sensing. To overcome these inherent drawbacks of traditional PSs, a concept of...

Regular photon sieve (PS) may only have up to ~25% transmission of light. The low transmission limits its applications in many fields such as satellite remote sensing when the reflected light incident on the PS is relatively weak. Binary PS was developed to overcome the low transmission problem of PS. However, binary PS which involves using differe...

Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system,...

Sunlight contamination dominates the backscatter noise in space-based lidar measurements during daytime. The background scattered sunlight is highly variable and dependent upon the surface and atmospheric albedo. The scattered sunlight contribution to noise increases over land and snow surfaces where surface albedos are high and thus overwhelm lida...

Electromagnetic (EM) beams with orbital angular momentum (OAM) may have great potential applications in communication technology and in remote sensing of the Earth-atmosphere system and outer planets. Study of their interaction with optical lenses and dielectric or metallic objects, or scattering of them by particles in the Earth-atmosphere system,...

Beam attenuation coefficient, c, provides an important optical index of plankton standing stocks, such as phytoplankton biomass and total particulate carbon concentration. Unfortunately, c has proven difficult to quantify through remote sensing. Here, we introduce an innovative approach for estimating c using lidar depolarization measurements and d...

The present invention pertains to systems and methods for the capture of information regarding scenes using single or multiple three-dimensional LADAR systems. Where multiple systems are included, those systems can be placed in different positions about the imaged scene such that each LADAR system provides different viewing perspectives and/or angl...

Ball Aerospace has been developing Flash LIDAR systems for more than 7 years, and space qualified their first system on the Sensor Test for Orion Relative-navigation Risk Mitigation (STORRM) mission in May of 2011 on STS-134. The STORRM unit demonstrated the capabilities of the flash LIDAR system for relative navigation, but other applications exis...

Ball Aerospace has developed multiple flash lidar technologies which can benefit planetary exploration missions. This paper describes these developments, culminating in a successful flight demonstration on STS-134.

Laser remote sensing has played a key part in the success of planetary missions. This paper will illustrate how a new "adaptive lidar" will enable new and improved science.

The Electronically Steerable Flash Lidar (ESFL) is a lidar concept created at Ball Aerospace and developed in conjunction with NASA. It represents a new paradigm for airborne or spaceborne lidar remote sensing. Instead of the mechanical scanning common to airborne lidars, or the fixed beam approach found in spaceborne lidars, ESFL allows the number...

Oceanographic lidars from space are a promising new technology for ocean observation. The success of the atmospheric lidar on the CALIPSO Pathfinder satellite has shown the feasibility of future space-based lidar instruments designed to measure ocean properties. Space-based laser, electronics, and detector technologies have advanced to a degree tha...

Analysis of data measured by the NASA Langley airborne High Spectral Resolution Lidar is presented focusing on measurements over the ocean. The HSRL is a dual wavelength polarized system (1064 and 532 nm) with the inclusion of a molecular backscatter channel at 532 nm. Data from aircraft flights over the Pamlico Sound out to the Atlantic Ocean, ove...

Laser remote sensing of the Earth from space offers many unique capabilities stemming from the unique properties of lasers. Lidars make possible three-dimensional characterizations that enable new scientific understanding of the natural processes that shape the planet's oceans, surface, and atmosphere. However, the challenges to further expand on t...

Current and proposed spaceborne lidar sensors sample the land surface using observations along transects in which consecutive observations in the along-track dimension are either contiguous (e.g. VCL, DESDynI, Livex) or spaced (ICESat, ICESat-2). In contrast, vegetation inventories distribute field observations either in regular grids or within pat...

The present invention pertains in general to a single, integrated flash LADAR system and method. The system includes data processing hardware and software, a passive two-dimensional camera, a three-dimensional camera, a light source, and a common optical path. One or more star trackers can also be included. In addition, auxiliary components, such a...

The Topographic Mapping Flash Lidar (TMFL) developed at Ball Aerospace combines a pushbroom format transmitter at 1064 nm with a flash focal plane receiver. The wide 20 degree field of view of the instrument enables broad swath coverage from a single laser pulse without the need for a scanning mechanism. These features make the TMFL design particul...

The Topographic Mapping Flash Lidar (TMFL) instrument developed at Ball Aerospace has been used to investigate the phenomenon of multiple scattering of the lidar signal inside a medium such as a water cloud. This behavior has been observed during a recent flight of the instrument aboard a Twin Otter aircraft flying over a steam plume. TMFL illumina...

Current and proposed spaceborne lidar sensors sample the land surface using observations along transects in which consecutive observations in the along-track dimension are either contiguous (e.g. VCL, DESDynI, Livex) or spaced (ICESat). These sampling patterns are inefficient because multiple observations are made of a spatially autocorrelated phen...

The Electronically Steerable Flash Lidar (ESFL) instrument developed at Ball Aerospace is one that provides unprecedented flexibility to adapt to the scene of the moment. For probing the structure of forests, ESFL provides several features that can be changed shot-to-shot, enabling real time adaptability. The number of beams transmitted to the scen...

The Topographic Mapping Flash Lidar (TMFL) instrument built by Ball Aerospace is a pushbroom lidar operating at 1064nm that provides the ability to map the topographic structure of river beds and surrounding terrain. The receiver is a pixilated array, allowing small-scale resolution of micro-topography that is critical to understanding river dynami...

The CALIPSO satellite has been characterizing aerosols and clouds in the Earth's atmosphere using a dual wavelength lidar. Future missions will include lidars for measuring the Earth's forests' role in the carbon cycle.

Validated models describing on-orbit performance of Earth sensing instruments provide understanding of the calibration of the instrument and insight that can be used to guide design choices for future missions. The success of the Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) launched as part of the CALIPSO instrument suite provides an o...

Late last year, a prototype Flash LIDAR instrument flew on a series of airborne tests to demonstrate its potential for improved vegetation measurements. The prototype is a precursor to the Electronically Steerable Flash LIDAR (ESFL) currently under development at Ball Aerospace and Technology Corp. with funding from the NASA Earth Science Technolog...

The CALIOP lidar on the CALIPSO satellite has been operating in space for 3 ½ years, characterizing the earth's aerosol and cloud layers. While designed for atmospheric studies, it is proving valuable for demonstrating the potential for space-based laser remote sensing to other problems in earth science. For example, its high sensitivity and dynami...

This paper provides background material for a collection of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) algorithm papers that are to be published in the Journal of Atmospheric and Oceanic Technology. It provides a brief description of the design and performance of CALIOP, a three-channel elastic backscatter lidar on the Cloud-Aerosol...

Ball Aerospace offers a mature, highly capable 3D flash-imaging LIDAR system for planetary exploration. Multi mission applications include orbital, standoff and surface terrain mapping, long distance and rapid close-in ranging, descent and surface navigation and rendezvous and docking. Our flash LIDAR is an optical, time-of-flight, topographic imag...

Systematic global wind measurements with 70 km horizontal resolution and, depending on altitude from the PBL to stratosphere, 250m-2km vertical resolution and 0.5m/s - 2 m/s velocity precision are recognized as key to the understanding and monitoring of complex climate modulations, validation of models, and improved precision and range for weather...

Recent studies of Antarctic ice core record (Rothlisberger et al, 2008) indicate correlations between Antarctic warming (cooling) and the reduction (increase) of dust (Ca) and sea salt (Na) deposited during the last 800,000 years. While changes in ocean surface wind speeds are suggested as being responsible for the correlation of the dust decrease...

Global climate change studies, weather and visibility forecasting, and pollution transport monitoring and research all require knowledge of aerosol distributions, gas chemistry profiles, and winds. The ultimate goal is to resolve the temporal trends of three dimensional fluxes of atmospheric constituents. The NRC Decadal Survey1 places priorities o...

Global satellite observations of lidar backscatter measurements acquired by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission and collocated sea surface wind speed data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E), are used to investigate the relation between wind driv...

OAWL, OA-HSRL ─ To offer broadened trade space for wind and aerosol profiling technologies addressing NOAA and NASA goals as outlined in the NRC Decadal Survey (3D-winds, ACE, and GACM missions) ─ OA approach saves mass, cost, volume, complexity, number of lasers, technical risk (e.g. can reuse CALIPSO/MOLA/GLAS telescope design), and mission perfo...

A technique we refer to as Elevation Information in Tail (EIT) has been developed to provide improved lidar altimetry from CALIPSO lidar data. The EIT technique is demonstrated using CALIPSO data and is applicable to other similar lidar systems with low-pass filters. The technique relies on an observed relation between the shape of the surface retu...

The laser transmitter for the CALIPSO aerosol lidar mission has been operating as orbit as planned since June 2006. We will discuss the design and qualification process that led to this successful result.

The CALIPSO satellite has completed nearly a year of on-orbit operation. This paper discusses development and on-orbit performance of the dual-wavelength, polarization sensitive LIDAR developed for NASA by prime contractor Ball Aerospace and Technologies Corp.

LIDAR systems are becoming an important tool in many areas of remote data collection. Recently, BATC has applied their integrated modeling toolset, EOSyM (End-to-end Optical System Model), to development of a LIDAR system model. With the recent successful launch and deployment of the Calipso remote sensing instrument, an additional opportunity was...

The CALIPSO satellite launched on April 28, 2006. It successfully entered into the Aqua (A) -train of Earth observing satellites along with its co-manifested CloudSat satellite. CALIPSO includes a Payload built for NASA by Ball Aerospace & Technologies Corp. The Payload includes three instruments for earth remote sensing: A two-wavelength polarizat...

This study presents an empirical relation that links the volume extinction coefficients of water clouds, the layer integrated depolarization ratios measured by lidar, and the effective radii of water clouds derived from collocated passive sensor observations. Based on Monte Carlo simulations of CALIPSO lidar observations, this method combines the c...

The CALIPSO LIDAR utilizes a receiver telescope with a narrow Field-of-View (FOV) to reject background light and meet SNR requirements - FOV ≈ 130 murad. To maximize SNR the laser is collimated (divergence ≈100 murad) and must be aligned to the receiver telescope FOV to within +/- 12 murad (allocated). To make accurate LIDAR measurements the...

IN 2005 a lidar instrument will be launched aboard the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite for measuring the three dimensional distribution of atmospheric clouds and aerosols. A key part of the lidar instrument is a 532 nm tunable etalon, which allows daytime operation. The design rationale and mea...

The CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) mission is designed to study the impact of clouds and aerosols on the Earth's radiation budget. Three instruments and their infrastructure make up the payload. They are a two-wavelength, polarization-sensitive lidar, a wide-field camera (WFC) operating at 645 nm, and a...

The properties of diode lasers that make them attractive as spectroscopic sources are discussed, along with the use of extended cavities to enhance their tuning range and reduce their linewidths. Semiconductors can now provide efficient, tunable, narrow linewidth laser light over much of the red and near-i.r. region of the spectrum. The progress in...

Conventional immersion aircraft thermometers suffer significant performance limitations, particularly for high- speed aircraft and at high angles-of-attack and side-slip. Moreover, immersion thermometers cannot perform through hot thick aircraft boundary layers and greatly increase the radar cross section of low observable aircraft. OPHIR Corporati...

Many trace atmospheric gas constituents have optical absorption bands in the 2 - 5 micrometers atmospheric transmission window. Remote sensing of these compounds is possible with an appropriate laser source. We use stimulated Raman scattering in hydrogen to shift pulsed, Cr:LiSAF laser emission from the near infrared to this mid-infrared band. Inje...

The increase low-frequency amplitude noise on several extended cavity diode lasers was measured when frequency of phase lock servos were applied using the injection current as the feedback channel. The AM noise increase inside the FM servo bandwidth is approximately that expected from the suppression of frequency noise uncorrelated with the inheren...

As they apply to frequency standards and precision spectroscopy the characteristics and technology of tunable diode lasers are briefly reviewed. It is now possible to use nonlinear optical techniques and high quality diode lasers to extend the useful wavelength coverage of semiconductor lasers into the UV, the IR and even millimeter-wave spectral r...

A subset of electrostatic modes of a cold cloud of electrons trapped in a Penning trap has been observed and identified using a recent theoretical model. The detection of these modes is accomplished using electronic techniques which could apply to any ion species. The modes are observed in the low density, low rotation limit of the cloud where the...

Saturated-absorption signals on the calcium 657 nm transition are observed by direct absorption using diode lasers and a high flux atomic-beam cell. Line-widths as narrow as 65 kHz are observed with a high signal-to-noise ratio. Prospects for using this system as a compact wavelength/frequency reference are considered.

Diode lasers at 657 nm are used with an atomic beam and a high-flux calcium beam-cell to provide narrow saturated-absorption resonances. Stability of ≈3×10^-14τ^½ is projected based on signal-to-noise ratios. Laser cooling is possible with a frequency doubled diode laser system that produces a usable 35 mW at 423 nm

We examine, theoretically, the feasibility of producing a sample of cold (⩽4 K), high-density (≈1010/cm3) positrons in a Penning trap. We assume9Be+ ions are first loaded into the trap and laser-cooled to approximately 10 mK where they form a uniform density column centered on the trap axis. Positrons from a moderator are then injected into the tra...

The nonlinear resonant response of a bound electron to a time-varying spatially inhomogeneous electric field was studied experimentally. By use of the artificial atom ``geonium'' (an electron bound in a Penning trap), we observed up to ninth-order multipole (pentacosiododecapole) coherent excitation of the electron's magnetron motion, and up to thi...

Diode lasers are unique in providing tunable, single-frequency laser light from a compact high efficiency source. We have been exploring the application of these devices to very high resolution spectroscopy and precision measurements.

Frequency standards based on stored atomic ions are briefly reviewed. Specific examples are chosen to illustrate what is currently possible. Both rf/microwave and optical devices are discussed. The present limitations to existing experiments and possibilities for future improvement are outlined.

Experiments at the US National Institute of Standards and Technology to realize frequency standards of high accuracy using stored ions are briefly summarized. In one experiment, an RF oscillator is locked to a nuclear spin-flip hyperfine transition (frequency ≃3.03×10⁸ Hz) in ⁹Be⁺ ions which are stored in a Pen...

In this paper, we address two aspects of this general problem. First, we discuss the problem of frequency standards in the optical spectrum. analogue in the microwave region of the spectrum is the cesium beam frequency standard.) If one or a few of these reference frequencies can be accurately calibrated (perhaps by a frequency synthesis chain1) th...

A system for measuring optical fiber bandwidth utilizing the Pulse Spectrum Analysis method (PSA) has been established. This paper will discuss problems inherent to that system such as signal-to-noise ratio and off-peak error. Included are the results of bandwidth measurements on multimode telecommunication grade fibers. Finally, the PSA method is...

CALIPSO is a joint NASA - CNES satellite currently in its third year of operation in low earth orbit. The satellite is making optical measurements of the Earth's atmosphere to help quantify the impact of aerosols and clouds on the Earth's radiation budget. To do this, it carries three instruments: CALIOP, a two-wavelength polarization-sensitive ela...

An oil and gas exploration system and method for land and airborne operations, the system and method used for locating subsurface hydrocarbon deposits based upon a remote detection of trace amounts of gases in the atmosphere. The detection of one or more target gases in the atmosphere is used to indicate a possible subsurface oil and gas deposit. B...

Current space-based lidar systems for Earth remote sensing have a number of inherent limitations that impact their use for broader science applications. These include no cross-track coverage, fixed spatial sampling that forces pointing control to be performed by the spacecraft, cloud loss over many types of scenes, and in general, lifetimes set in...

Thesis (Ph. D.)--Colorado State University, 1992. Includes bibliographical references (leaves [165]-171).