The system and mechanical design of a four-wavelength lidar system is described. The system is designed to be maximally adaptive to deployment scenario in terms of both size/weight/power and detection application. The wavelengths included in the system are 266 nm, 355 nm, 1064 nm, and 1574 nm – all generated from Nd:YAG based pump laser sources. The system is designed to have a useful range from 400 meters to 5,000 meters, depending on the wavelength and atmospheric conditions.
KEYWORDS: LIDAR, Imaging systems, Sensors, 3D image processing, 3D acquisition, Cameras, Control systems, Stereoscopic cameras, Process control, Image processing
The Space Dynamics Laboratory (SDL), working with Naval Research Laboratory (NRL) and industry leaders Advanced Scientific Concepts (ASC) and Hood Technology Corporation, has developed a small SWAP (size, weight, and power) 3D imaging flash ladar (LAser Detection And Ranging) sensor system concept design for small tactical unmanned air systems (STUAS). The design utilizes an ASC 3D flash ladar camera and laser in a Hood Technology gyro-stabilized gimbal system. The design is an autonomous, intelligent, geo-aware sensor system that supplies real-time 3D terrain and target images. Flash ladar and visible camera data are processed at the sensor using a custom digitizer/frame grabber with compression. Mounted in the aft housing are power, controls, processing computers, and GPS/INS. The onboard processor controls pointing and handles image data, detection algorithms and queuing. The small SWAP 3D imaging flash ladar sensor system generates georeferenced terrain and target images with a low probability of false return and <10 cm range accuracy through foliage in real-time. The 3D imaging flash ladar is designed for a STUAS with a complete system SWAP estimate of <9 kg, <0.2 m3 and <350 W power. The system is modeled using LadarSIM, a MATLAB® and Simulink®- based ladar system simulator designed and developed by the Center for Advanced Imaging Ladar (CAIL) at Utah State University. We will present the concept design and modeled performance predictions.
CELiS (Compact Eyesafe Lidar System) is an elastic backscatter light detection and ranging (lidar) system developed for monitoring air quality environmental compliance regarding particulate matter (PMk) generated from off-road use of wheeled and tracked vehicles as part of the SERDP (Strategic Environmental Research and Development Program) Measurement and Modeling of Fugitive Dust Emission from Off-Road DoD Activities program. CELiS is small, lightweight and easily transportable for quick setup and measurement of PMk concentration and emissions. CELiS operates in a biaxial configuration at the 1.5μm eyesafe wavelength with a working range of better than 6 km and range resolution of 5 m. In this paper, we describe an algorithm that allows for semi-quantitative PMk determination under a set of guiding assumptions using a single wavelength lidar. Meteorological and particle measurements are used to estimate the total extinction (α) and backscatter (β) at a calibration point located at the end range of the lidar. These α and β values are used in conjunction with the Klett inversion to estimate α and β over the lidar beam path. A relationship between β, α and PMk mass concentrations at calibration points is developed, which then allows the β and α values derived to be converted to PMk at each lidar bin over the lidar beam path. CELiS can be used to investigate PMk concentrations and emissions over a large volume, a task that is very difficult to accomplish with typical PMk sensors.
CELiS (Compact Eyesafe Lidar System) is a tactical elastic lidar system commissioned by the Strategic Environmental
Research and Development Program (SERDP) for the purpose of air quality environmental compliance issues
surrounding the offroad use of wheeled and tracked vehicles. A complete CELiS instrument weighs less than 300 lbs., is
less than 2 cubic meters in volume and uses 700 W of 120V AC power. CELiS has a working range of better than 2km
and a range resolution of 5m.
FEATHAR (Fusion, Exploitation, Algorithms, and Targeting for High-Altitude Reconnaissance) is an ONR funded
effort to develop and test new tactical sensor systems specifically designed for small manned and unmanned platforms
(payload weight < 50 lbs). This program is being directed and executed by the Naval Research Laboratory (NRL) in
conjunction with the Space Dynamics Laboratory (SDL). FEATHAR has developed and integrated EyePod, a combined
long-wave infrared (LWIR) and visible to near infrared (VNIR) optical survey & inspection system, with NuSAR, a
combined dual band synthetic aperture radar (SAR) system. These sensors are being tested in conjunction with other
ground and airborne sensor systems to demonstrate intelligent real-time cross-sensor cueing and in-air data fusion.
Results from test flights of the EyePod and NuSAR sensors will be presented.
EyePod is a compact survey and inspection day/night imaging sensor suite for small unmanned aircraft systems (UAS).
EyePod generates georeferenced image products in real-time from visible near infrared (VNIR) and long wave infrared
(LWIR) imaging sensors and was developed under the ONR funded FEATHAR (Fusion, Exploitation, Algorithms, and
Targeting for High-Altitude Reconnaissance) program. FEATHAR is being directed and executed by the Naval Research
Laboratory (NRL) in conjunction with the Space Dynamics Laboratory (SDL) and FEATHAR's goal is to develop and
test new tactical sensor systems specifically designed for small manned and unmanned platforms (payload weight < 50
lbs). The EyePod suite consists of two VNIR/LWIR (day/night) gimbaled sensors that, combined, provide broad area
survey and focused inspection capabilities. Each EyePod sensor pairs an HD visible EO sensor with a LWIR bolometric
imager providing precision geo-referenced and fully digital EO/IR NITFS output imagery. The LWIR sensor is mounted
to a patent-pending jitter-reduction stage to correct for the high-frequency motion typically found on small aircraft and
unmanned systems. Details will be presented on both the wide-area and inspection EyePod sensor systems, their modes
of operation, and results from recent flight demonstrations.
The Multiple Kill Vehicle (MKV) system, which is being developed by the US Missile Defense Agency (MDA), is a
midcourse payload that includes a carrier vehicle and a number of small kill vehicles. During the mission, the carrier
vehicle dispenses the kill vehicles to address a complex threat environment and directs each kill vehicle toward the
intercept point for its assigned threat object. As part of the long range carrier vehicle sensor development strategy, MDA
and project leaders have developed a pathfinder sensor and are in the process of developing two subsequent
demonstration sensors to provide proof of concept and to demonstrate technology. To increase the probability of
successful development of the sensor system, detailed calibration measurements have been included as part of the sensor
development. A detailed sensor calibration can provide a thorough understanding of sensor operation and performance,
verifying that the sensor can meet the mission requirements. This approach to instrument knowledge will help ensure the
program success and reduce cost and schedule risks. The Space Dynamics Laboratory at Utah State University (SDL)
completed a calibration test campaign for the pathfinder sensor in April 2008. Similar calibration efforts are planned in
2009 for the two demonstration sensors. This paper provides an overview of calibration benefits, requirements,
approach, facility, measurements, and preliminary results of the pathfinder calibration.
A study of the effects of secondary electron emission on charge pulses from a microchannel plate (MCPs) photon counting detector with crossed delay line (CDL) anode readout is presented. The detector is a 2D photon counting detector with fast count rate and good spatial resolution being developed at Los Alamos National Laboratory. The CDL anode is constructed of two orthogonal planar pairs of helically wound wires on inner and outer ceramic sides attached to a copper ground plane. The electron cloud event from the MCPs interacts with the wires generating a signal pulse. The electronics that strike the wire with sufficient energy generate secondary electrons. A model is presented for the charge pulses from the CDL anode incorporating the effects of secondary electron emission. An empirical test of the model is conducted with two different wire materials using a demountable MCP/CDL detector. Charge pulses are measured and the results are compared to the model. The result show that the charge pulses from the CDL anode are material dependent and exhibit the general behavior predicted by the model. Secondary electron emission is an integral part of the CDL anode charge pulses and must be considered in further developments of the CDL anode readout.
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