Hampton, VA, United States

Coherent Applications, Inc.

Hampton, VA, United States
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Bulyshev A.,AMA Inc. | Vanek M.,NASA | Amzajerdian F.,NASA | Pierrottet D.,Coherent Applications, Inc. | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

A novel method for enhancement of the spatial resolution of 3-diminsional Flash Lidar images is being proposed for generation of elevation maps of terrain from a moving platform. NASA recognizes the Flash LIDAR technology as an important tool for enabling safe and precision landing in future unmanned and crewed lunar and planetary missions. The ability of the Flash LIDAR to generate 3-dimensional maps of the landing site area during the final stages of the descent phase for detection of hazardous terrain features such as craters, rocks, and steep slopes is under study in the frame of the Autonomous Landing and Hazard Avoidance (ALHAT) project. Since single frames of existing FLASH LIDAR systems are not sufficient to build a map of entire landing site with acceptable spatial resolution and precision, a super-resolution approach utilizing multiple frames has been developed to overcome the instrument's limitations. Performance of the super-resolution algorithm has been analyzed through a series of simulation runs obtained from a high fidelity Flash LIDAR model and a high resolution synthetic lunar elevation map. For each simulation run, a sequence of FLASH LIDAR frames are recorded and processed as the spacecraft descends toward the landing site. Simulations runs having different trajectory profiles and varying LIDAR look angles of the terrain are also analyzed. The results show that adequate levels of accuracy and precision are achieved for detecting hazardous terrain features and identifying safe areas of the landing site.

Bulyshev A.,Analytical Mechanics Associates, Inc. | Amzajerdian F.,NASA | Roback V.E.,NASA | Hines G.,NASA | And 2 more authors.
Applied Optics | Year: 2014

Many flash lidar applications continue to demand higher three-dimensional image resolution beyond the current state-of-the-art technology of the detector arrays and their associated readout circuits. Even with the available number of focal plane pixels, the required number of photons for illuminating all the pixels may impose impractical requirements on the laser pulse energy or the receiver aperture size. Therefore, image resolution enhancement by means of a super-resolution algorithm in near real time presents a very attractive solution for a wide range of flash lidar applications. This paper describes a superresolution technique and illustrates its performance and merits for generating three-dimensional image frames at a video rate. © 2014 Optical Society of America.

Pierrottet D.,Coherent Applications, Inc. | Amzajerdian F.,NASA | Petway L.,NASA | Barnes B.,NASA | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

An all fiber Navigation Doppler Lidar (NDL) system is under development at NASA Langley Research Center (LaRC) for precision descent and landing applications on planetary bodies. The sensor produces high-resolution line of sight range, altitude above ground, ground relative attitude, and high precision velocity vector measurements. Previous helicopter flight test results demonstrated the NDL measurement concepts, including measurement precision, accuracies, and operational range. This paper discusses the results obtained from a recent campaign to test the improved sensor hardware, and various signal processing algorithms applicable to real-time processing. The NDL was mounted in an instrumentation pod aboard an Erickson Air-Crane helicopter and flown over various terrains. The sensor was one of several sensors tested in this field test by NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. © 2011 SPIE.

Hines G.D.,NASA | Pierrottet D.F.,Coherent Applications, Inc. | Amzajerdian F.,NASA
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

NASA's Autonomous Landing and Hazard Avoidance Technologies (ALHAT) project is currently developing the critical technologies to safely and precisely navigate and land crew, cargo and robotic spacecraft vehicles on and around planetary bodies. One key element of this project is a high-fidelity Flash Lidar sensor that can generate three-dimensional (3-D) images of the planetary surface. These images are processed with hazard detection and avoidance and hazard relative navigation algorithms, and then are subsequently used by the Guidance, Navigation and Control subsystem to generate an optimal navigation solution. A complex, high-fidelity model of the Flash Lidar was developed in order to evaluate the performance of the sensor and its interaction with the interfacing ALHAT components on vehicles with different configurations and under different flight trajectories. The model contains a parameterized, general approach to Flash Lidar detection and reflects physical attributes such as range and electronic noise sources, and laser pulse temporal and spatial profiles. It also provides the realistic interaction of the laser pulse with terrain features that include varying albedo, boulders, craters slopes and shadows. This paper gives a description of the Flash Lidar model and presents results from the Lidar operating under different scenarios. © 2014 SPIE.

Amzajerdian F.,NASA | Vanek M.,NASA | Petway L.,NASA | Pierrottet D.,Coherent Applications, Inc. | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

NASA considers Flash Lidar a critical technology for enabling autonomous safe landing of future large robotic and crewed vehicles on the surface of the Moon and Mars. Flash Lidar can generate 3-Dimensional images of the terrain to identify hazardous features such as craters, rocks, and steep slopes during the final stages of descent and landing. The onboard flight comptuer can use the 3-D map of terain to guide the vehicle to a safe site. The capabilities of Flash Lidar technology were evaluated through a series of static tests using a calibrated target and through dynamic tests aboard a helicopter and a fixed wing airctarft. The aircraft flight tests were perfomed over Moonlike terrain in the California and Nevada deserts. This paper briefly describes the Flash Lidar static and aircraft flight test results. These test results are analyzed against the landing application requirements to identify the areas of technology improvement. The ongoing technology advancement activities are then explained and their goals are described. © 2010 Copyright SPIE - The International Society for Optical Engineering.

Amzajerdian F.,NASA | Pierrottet D.,Coherent Applications, Inc. | Petway L.,NASA | Hines G.,NASA | Roback V.,NASA
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

The ability of lidar technology to provide three-dimensional elevation maps of the terrain, high precision distance to the ground, and approach velocity can enable safe landing of robotic and manned vehicles with a high degree of precision. Currently, NASA is developing novel lidar sensors aimed at the needs of future planetary landing missions. These lidar sensors are a 3-Dimensional Imaging Flash Lidar, a Doppler Lidar, and a Laser Altimeter. The Flash Lidar is capable of generating elevation maps of the terrain to indicate hazardous features such as rocks, craters, and steep slopes. The elevation maps, which are collected during the approach phase of a landing vehicle from about 1 km above the ground,can be used to determine the most suitable safe landing site. The Doppler Lidar provides highly accurate ground relative velocity and distance data thus enabling precision navigation to the landing site. Our Doppler lidar utilizes three laser beams that are pointed in different directions to measure line-of-sight velocities and ranges to the ground from altitudes of over 2 km. Starting at altitudes of about 20 km and throughout the landing trajectory, the Laser Altimeter can provide very accurate ground relative altitude measurements that are used to improve the vehicle position knowledge obtained from the vehicle's navigation system. Between altitudes of approximately 15 km and 10 km, either the Laser Altimeter or the Flash Lidar can be used to generate contour maps of the terrain, identifying known surface features such as craters to perform Terrain relative Navigation thus further reducing the vehicle's relative position error. This paper describes the operational capabilities of each lidar sensor and provides a status of their development.© 2011 SPIE.

Barnes N.P.,NASA | Amzajerdian F.,NASA | Reichle D.J.,NASA | Carrion W.A.,Coherent Applications, Inc. | And 2 more authors.
Applied Physics B: Lasers and Optics | Year: 2011

Direct diode pumped Ho:YAG generated laser pulses at 2.12 μm with an optical to optical slope efficiency of 0.24. Ho:YAG and Ho:LuAG laser rods were evaluated with both wide and narrow bandwidth pump diodes. The laser wavelength varies with the level of pumping and optical design. This variation was found to be predictable. Second harmonic at 1.06 μm was produced in a 6.0 mm long BBO crystal. © US Government 2010.

Amzajerdian F.,NASA | Pierrottet D.F.,Coherent Applications, Inc. | Hines G.D.,NASA | Petway L.B.,NASA | Barnes B.W.,NASA
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Landing mission concepts that are being developed for exploration of solar system bodies are increasingly ambitious in their implementations and objectives. Most of these missions require accurate position and velocity data during their descent phase in order to ensure safe, soft landing at the pre-designated sites. Data from the vehicle's Inertial Measurement Unit will not be sufficient due to significant drift error after extended travel time in space. Therefore, an onboard sensor is required to provide the necessary data for landing in the GPS-deprived environment of space. For this reason, NASA Langley Research Center has been developing an advanced Doppler lidar sensor capable of providing accurate and reliable data suitable for operation in the highly constrained environment of space. The Doppler lidar transmits three laser beams in different directions toward the ground. The signal from each beam provides the platform velocity and range to the ground along the laser line-of-sight (LOS). The six LOS measurements are then combined in order to determine the three components of the vehicle velocity vector, and to accurately measure altitude and attitude angles relative to the local ground. These measurements are used by an autonomous Guidance, Navigation, and Control system to accurately navigate the vehicle from a few kilometers above the ground to the designated location and to execute a gentle touchdown. A prototype version of our lidar sensor has been completed for a closed-loop demonstration onboard a rocket-powered terrestrial free-flyer vehicle. © 2013 SPIE.

Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 124.99K | Year: 2013

This proposal addresses NASA's science objectives with innovative lidar architecture for atmospheric CO2 measurements. Specifically, the proposed work can support and potentially enhance the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) technologies. Using an active laser measurement technique, our system is designed to enhance the capabilities of CO2 remote sensing from high-latitude regions and nighttime observations with sensitivity in the lower atmosphere, and enable investigations of the climate-sensitive southern ocean and permafrost regions, provide insight into the diurnal cycle and plant respiration processes, and provide useful new constraints to global carbon cycle models.

Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 124.94K | Year: 2015

A laser based terminal descent sensor is proposed that will provide real-time ground-relative altitude, attitude, and vertical velocity at high data rates to a navigation computer of a vehicle during landing on a near earth object or planetary body. The operational range of the sensor in Mars, for example, can exceed ten kilometers through touchdown, and may conceivably be a low mass, volume, and cost replacement for the Terminal Descent Sensor (TDS) on missions like the Mars Science Laboratory (MSL). The sensor is compact, rugged, and can be easily integrated with other NASA smart sensor systems coming of age, such as the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project or JPL's Lander Vision System (LVS). During Phase I we propose to detail the complete system design, model the transmitter laser, and test key components that will benchmark our model in preparation of a full system development in Phase II.

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