Time filter

Source Type

Hampton, VA, United States

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. Source

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. Source

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. Source

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.

Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2007

CAI proposes to develop an innovative approach to advance algorithms and system technology for rapid and robust assessment of damage produced by high energy laser weapon systems. Using high speed coherent detection laser radar, a combination of measurement techniques are tied together to produce an efficient sensor for long range damage assessment.

Discover hidden collaborations