This PDF file contains the front matter associated with SPIE Proceedings Volume 7323, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

We present first experimental results with an imaging LIDAR developed for rendezvous and docking of a spacecraft and a passive sample canister in the Martian orbit. The LIDAR covers a field of view of 20 by 20 degrees at a range of 5,000 m down to 1 m to cooperative targets. The frame rate is 1 Hz. In close range, the canister's position is calculated from the measurement results of the individual cooperative targets attached to its surface in known configuration. The design of the LIDAR is aimed at low weight and power consumption employing a fiber laser and a small receiver aperture resulting in a small scanning mirror. The scanning concept is based on a Gimbal-mounted scan mirror avoiding scan gaps for optimally exploiting the laser's power and minimizing the scan time. Sensor concept and technologies can be also be adapted for future Planetary or Lunar Lander applications.

A new experimental full-waveform LADAR system has been developed that fuses a pixel-aligned color imager within the same optical path. The Eye-safe LADAR Test-bed (ELT) consists of a single beam energy-detection LADAR that raster scans within the same field of view as an aperture-sharing color camera. The LADAR includes a pulsed 1.54 μm Erbium-doped fiber laser; a high-bandwidth receiver; a fine steering mirror for raster scanning; and a ball joint gimbal mirror for steering over a wide field of regard are all used. The system has a 6 inch aperture and the LADAR has pulse rate of up to 100 kHz. The color imager is folded into the optical path via a cold mirror. A novel feature of the ELT is its ability to capture LADAR and color data that are registered temporally and spatially. This allows immediate direct association of LADAR-derived 3D point coordinates with pixel coordinates of the color imagery. The mapping allows accurate pointing of the instrument at targets of interest and immediate insight into the nature and source of the LADAR phenomenology observed. The system is deployed on a custom van designed to enable experimentation with a variety of objects.

A facet model of a helicopter containing 35,000 facets is used to compare coherent ladar waveform performance in precision and in resolution. The helicopter represents a convenient man made object for these tests. Several coherent ladar waveforms have been compared previously applying "range-resolved Doppler and intensity" (RRDI) or "inverse synthetic aperture ladar" (ISAR) algorithms in order to numerically construct an image of the target in slant-range and Doppler frequency spread. The targets are generally at large distances and are much smaller than the diffraction limited laser spot size or the diffraction limited detector's field-of-view. In this study we emphasize the "tangent-FM" waveform and review its performance relative to other waveforms. Note that thousands of facet models of interest are available on the internet and are usually low cost or even free. We also utilized a new "analytic signal" construction, recently published, for a small improvement in the final image quality.

This paper discusses the initial steps of the development of a novel navigation method that integrates three-dimensional (3D) point cloud data, two-dimensional (2D) gray-level (intensity), and data from an Inertial Measurement Unit (IMU). A time-of-flight camera such as MESA's Swissranger will output both the 3D and 2D data. The target application is position and attitude determination of unmanned aerial vehicles (UAV) and autonomous ground vehicles (AGV) in urban or indoor environments. In urban and indoor environments a GPS position capability may not only be unavailable due to shadowing, significant signal attenuation or multipath, but also due to intentional denial or deception. The proposed algorithm extracts key features such as planar surfaces, lines and corner-points from both the 3D (point-cloud) and 2D (intensity) imagery. Consecutive observations of corresponding features in the 3D and 2D image frames are then used to compute estimates of position and orientation changes. Since the use of 3D image features for positioning suffers from limited feature observability resulting in deteriorated position accuracies, and the 2D imagery suffers from an unknown depth when estimating the pose from consecutive image frames, it is expected that the integration of both data sets will alleviate the problems with the individual methods resulting in an position and attitude determination method with a high level of assurance. An Inertial Measurement Unit (IMU) is used to set up the tracking gates necessary to perform data association of the features in consecutive frames. Finally, the position and orientation change estimates can be used to correct for the IMU drift errors.

Mobile laser scanning is an emerging technology for accurate and fast surveying and surveillance applications. By using RIEGL's new V-line laser scanners with online waveform analysis capable of discriminating multiple targets per laser shot, true 3D information can be obtained. Thus the detection of objects concealed by vegetation or camouflage tarps is facilitated. We present experimental results disclosing a vehicle hidden behind bushes employing a terrestrial laser scanning system. The laser scanner offers measurement rates of up to 125 kHz and ranging capabilities up to 500 m at a scan range of 360° for the frame and 100° for the line axis. The obtained experimental results prove that multi-target capability is mandatory for the envisaged application. In dense vegetation, up to 10 targets per laser shot are identified.

The aim of this paper is to present new method that can be used for automatically extracting 3D models in the terrestrial laser scanning (TLS) point clouds of Chinese traditional architecture. Based on the inherent geometric and topological constraints in Chinese traditional architectures, spatial direction and topology analysis are used to express the rules. We develop a rule-based automatic modelling algorithm and apply it to extract the wooden structural elements.

Full-waveform laser altimetry has been used in the research community since the mid-1990s and this technology holds great potential for the science and defense communities. Laser waveforms are a digital recording of the entire temporal profile from the reflected laser energy. The shape of the returned laser waveform is a function of both laser and surface properties. Waveform metrics were extracted for each waveform and include peak amplitude, peak standard deviation, integrated canopy energy, integrated ground energy, total waveform energy, ratio between canopy and ground energy, rise time to the first peak, fall time of the last peak, and vegetation height. The utilization of such metrics provides a potential for discriminating and identifying discrete targets on a per-shot basis. Analysis of the entire reflected laser energy profile provides a detailed description of distributed targets/features along the laser line-of-sight. Waveform data collected over Camp Shelby, Mississippi reveal separation of conifer from broadleaf vegetation. Metrics such as integrated canopy energy and fall time were found to be higher in hardwood forest than pine forest. Other landscape features such as the presence of a burn are also detected with full-waveform data, which would otherwise be missed with discrete return elevation data. With new full-waveform systems entering the commercial sector, new possibilities emerge to utilize the lidar data to classify land cover as well as quantify surface parameters.

The development of an experimental full-waveform LADAR system has been enhanced with the assistance of the LadarSIM system simulation software. The Eyesafe LADAR Test-bed (ELT) was designed as a raster scanning, single-beam, energy-detection LADAR with the capability of digitizing and recording the return pulse waveform at up to 2 GHz for 3D off-line image formation research in the laboratory. To assist in the design phase, the full-waveform LADAR simulation in LadarSIM was used to simulate the expected return waveforms for various system design parameters, target characteristics, and target ranges. Once the design was finalized and the ELT constructed, the measured specifications of the system and experimental data captured from the operational sensor were used to validate the behavior of the system as predicted during the design phase. This paper presents the methodology used, and lessons learned from this "design, build, validate" process. Simulated results from the design phase are presented, and these are compared to simulated results using measured system parameters and operational sensor data. The advantages of this simulation-based process are also presented.

An airborne LIDAR (LIght Detection And Ranging) system can rapidly generate 3D points by densely sampling the terrain surfaces using laser pulses. The LIDAR points can be efficiently utilized for automatic reconstruction of 3D models of the objects on the terrain and the terrain itself. The data simulation of such a LIDAR system is significantly useful not only to design an optimal sensor for a specific application but also to assess data processing algorithms with various kinds of test data. In this study, we thus attempted to develop data simulation software of an airborne LIDAR system generally consisting of a GPS, an IMU and a laser scanner. We focused particularly on the geometric modeling of the sensors and the object modeling of the targets and background. Hence the data simulation software has been developed using these models. For the geometric modeling, we derived the sensor equation by modeling not only the geometric relationships between the three modules, such as a GPS, an IMU and a laser scanner but also the systematic errors associated with them. Moreover, for rapid and effective simulation, we designed the data model for both targets and background. We constructed the model data by converting the VRML formatted data into the designed model and stored these data in a 3D spatial database that can offer more effective 3D spatial indexing and query processing. Finally, we developed a program that generates simulated data along with the system parameters of a sensor, a terrain model and its trajectories over the model given.

A long standing need for the application of laser radar (LADAR) to a wider range of targets is a technique for creating a "target model" from target photographs. This is feasible since LADAR images are 3D and photographs at selected azimuth/elevation angles will allow the required models to be created. Preferred photographic images of a wide range of selected targets were specified and collected. These photographs were processed using code developed in house and some commercial software packages. These "models" were used in model-based automatic target recognition (ATR) algorithms. The ATR performance was excellent. This technique differs significantly from other techniques for creating target models. Those techniques require CAD models which are much harder to manipulate and contain extraneous detail. The technique in this paper develops the photographic-based target models in component form so that any component (e.g., turret of a tank) can be independently manipulated, such as rotating the turret. This new technique also allows models to be generated for targets for which no actual LADAR data has ever been collected. A summary of the steps used in the modeling process is as follows: start with a set of input photographs, calibrate the imagery into a 3D world space to generate points corresponding to target features, create target geometry by connecting points with surfaces, mark all co-located points in each image view and verify alignment of points, place in a 3D space, create models by creating surfaces (i.e., connect points with planar curves) and scale target into real-world coordinates.

The first space application of photon-counting lidars occurred shortly after the landing of Apollo 11 on the Moon. Various scientific groups used lasers to range to retroreflector panels left on the lunar surface by the astronauts. Because of the great distances involved (384,000 km one-way) and practical limitations on laser energy and telescope aperture, the detected signals were necessarily at the single photon level. The Lunar Laser Ranging (LLR) effort has continued uninterrupted over the past four decades and has allowed scientists to study solar system dynamics, Earth-lunar interactions, and lunar properties. It has also served as a testbed for relativistic theories. Since the mid-1990's, the author has applied the photon-counting technique to a number of new space applications. These include: (1) an eyesafe satellite laser ranging system which presently tracks high altitude (6000 km) satellites with sub-cm precision at kHz rates with only 60 microjoules of transmitted energy; (2) an airborne, high resolution 3D imaging lidar which operates day or night and can be scaled to globally and contiguously map extraterrestrial moons from 100 km orbits; (3) an upcoming NASA mission for mapping the Earth's surface in 3D from a 600 km orbit; and (4) interplanetary ranging and time transfer via two-way laser transponders. The present paper provides an overview of these efforts.

Laser-based remote sensing is undergoing a remarkable advance due to novel technologies developed at MIT Lincoln Laboratory. We have conducted recent experiments that have demonstrated the utility of detecting and imaging low-density aerosol clouds. The Mobile Active Imaging LIDAR (MAIL) system uses a Lincoln Laboratory-developed microchip laser to transmit short pulses at 14-16 kHz Pulse Repetition Frequency (PRF), and a Lincoln Laboratory-developed 32x32 Geiger-mode Avalanche-Photodiode Detector (GmAPD) array for singlephoton counting and ranging. The microchip laser is a frequency-doubled passively Q-Switched Nd:YAG laser providing an average transmitted power of less than 64 milli-Watts. When the avalanche photo-diodes are operated in the Geiger-mode, they are reverse-biased above the breakdown voltage for a time that corresponds to the effective range-gate or range-window of interest. The time-of-flight, and therefore range, is determined from the measured laser transmit time and the digital time value from each pixel. The optical intensity of the received pulse is not measured because the GmAPD is saturated by the electron avalanche. Instead, the reflectivity of the scene, or relative density of aerosols in this case, is determined from the temporally and/or spatially analyzed detection statistics.

Data density has a crucial impact on the accuracy of Digital Elevation Models (DEMs). In this study, DEMs were created from a high point-density LIDAR dataset using the bare earth extraction module in Quick Terrain Modeler. Lower point-density LIDAR collects were simulated by randomly selecting points from the original dataset at a series of decreasing percentages. The DEMs created from the lower resolution datasets are compared to the original DEM. Results show a decrease in DEM accuracy as the resolution of the LIDAR dataset is reduced. Some analysis is made of the types of errors encountered in the lower resolution DEMs. It is also noted that the percentage of points classified as bare earth decreases as the resolution of the LIDAR dataset is reduced.

In ground based Lidar system, the targets are used in the process of registration, georeferencing for point cloud, and also can be used as check points. Generally, the accuracy of capturing the flat target center is influenced by scanning range and scanning angle. In this research, the experiments are designed to extract accuracy index of the target center with 0-90°scan angles and 100-195 meter scan ranges using a Leica HDS3000 laser scanner. The data of the experiments are listed in detail and the related results are analyzed.

Innovative algorithm development for full-waveform lidar data processing extends this remote sensing technology's capabilities to even more complicated acquisition scenarios then previously determined, namely success of surveys over obscured areas. Waveform decomposition and the extraction of waveform metrics provide a straightforward approach to identifying vertical structure within each laser measurement. However, there are some limitations in this approach as faint returns within the waveform go undetected in the processing chain. These faint returns are the result of reduced energy levels due to obscurant scattering, attenuation and absorption. Lidar surveys over non-homogeneous wooded regions indicate that there are meaningful ground returns within dense tree coverage if extracted correctly from the data. One difficulty associated with detecting weaker returns is the presence of a hardware induced ring by the Avalanche Photo Diode (APD) detector in the returned waveform. By using a waveform stacking technique with adjacent waveforms in near geospatial proximity to the original, these faint returns can be augmented and detected during data processing without the inclusion of the false ring. In comparison to the traditional approach, the waveform stacking technique provides a 9% increase in faint signal extraction for the particular dataset. These faint signals are low level last returns that correspond to perceived ground reflections under canopy cover. The enhanced capability in the presence of foliage provides a decrease in operational effort associated with data density, dwell or targeting techniques and survey expense.

Sparse aperture imaging systems are capable of producing high resolution images while maintaining an overall light collection area that is small with respect to a fully filled aperture yielding the same resolution. However, conventional sparse aperture systems pay the penalty of reduced contrast at mid-band spatial frequencies. The modulation transfer function (MTF), or normalized autocorrelation, provides a quantative measure of both the resolution and contrast of an optical imaging system. Numerical MTF calculations were thus used to examine mid-band contrast recovery through the systematic increase of autocorrelation redundancy in a Golay-9 sparse array. In a Golay-9 sparse aperture arrangement, three sets of three sub-apertures can be shown to lie at unique radii from the center of the array. In order to increase the mid-frequency contrast we then have two options. The first, and most influential, is to increase the size of the sub-apertures located at the intermediate radius from the array origin. This directly increases autocorrelation redundancy at mid-band frequencies. The second option, though less effective, is to increase the relative mid-band frequency response by attenuating the outer most sub-apertures. We will demonstrate that by increasing the diameters of the mid-radii sub-apertures, mid-band contrast can be increased by over 45%, compared to uniform sub-aperture diameter arrays. We will also demonstrate that attenuating the outer most sub-apertures can further increase mid-band contrast recovery, but only by less than 1%. The effects on array fill factor will also be discussed.

We show through numerical modeling that the range resolution of a multi-band, sparse frequency CW-LFM chirped signal has an effective bandwidth related to the modulation bandwidth and the band frequency offsets of all bands. The range resolution predicted from the effective bandwidth of our sparse CW-LFM signal is comparable to that of standard continuous bandwidth CW-LFM signals. We also discuss unique issues that arise from the use of sparse frequency CWLFM chirped signals, such as ambiguity and peak to side-lobe ratio fluctuations, and how they are related to the multiple frequency components of the signal.

Holographic Aperture Ladar (HAL) is an intriguing variant of Synthetic Aperture Ladar (SAL). As with conventional SAL, HAL systems seek to increase cross-range scene resolution by synthesizing a large effective aperture through the motion of a smaller receiver, and through the subsequent proper phasing and correlation of the detected signals in post-processing. Unlike in conventional SAL, however, holographic aperture ladar makes use of a two-dimensional translating sensor array, not simply a translating point detector. In real world applications less than ideal conditions will be detrimental to final image quality. As the HAL transform requires precise knowledge of each data collection site in order to properly phase a possibly large collection of coherent sub-images, laser pulse jitter and system platform vibration are two factors that may result in non-optimum final image quality. To examine these effects, we first define the following metrics which, in part, quantify final image quality: cross-range resolution (ΔCR); peak-to-integrated-side-lobe-ratio (PISLR); peak-to-side-lobe-ratio (PSLR); and, pupil plane RMS wavefront error. We then numerically examine the effects of data collection site uncertainty in a HAL system via Monte Carlo simulation. In our model we consider only a single point object, though we use otherwise realistic parameters for sub-aperture diameter, range, wavelength, etc. The effects of positional uncertainty on the image quality metrics are then calculated, and the results compared to ideal expectations. We will present characteristic results for several different synthetic aperture diameters and will identify regions of diffraction-limited performance by considering Marechal's well known λ/14 RMS wavefront error criterion.

An important issue in synthetic aperture ladar is phase noise mitigation, since phase noise corrupts image quality. There are many phase noise contributors including, residual platform motion, local oscillator phase/frequency instability, atmospheric turbulence, and additive receiver noise. The Phase Gradient Autofocus (PGA) algorithm is a common phase noise correction algorithm utilized in synthetic aperture radar. The Cramer-Rao Lower Bound for the phase-difference estimate variance of PGA can be found in the radar literature. This lower bound describes the precision of the phasedifference estimate between any two pulses as a function of the carrier-to-noise ratio (CNR). However, this lower bound does not account for speckle saturation limitations, present in both synthetic aperture ladar and radar. This paper extends the PGA performance theory to include a high CNR saturation term which accounts for speckle decorrelation. This term is shown to be proportional to the ratio of the image spot size to the laser pulse repetition frequency (PRF). This paper also describes impact of PGA estimate variance on image cross-range resolution. We show, given a fixed PRF and fixed PGA phase-difference estimate variance, that resolution initially improves with increasing dwell times but eventually saturates to a level proportional to the product of the PGA estimate variance and the laser PRF.

An essential milestone in the development of lidar for biological aerosol detection is accurate characterization of agent, simulant, and interferent scattering signatures. MIT Lincoln Laboratory has developed the Standoff Aerosol Active Signature Testbed (SAAST) to further this task, with particular emphasis on the near- and mid-wave infrared. Spectrally versatile and polarimetrically comprehensive, the SAAST can measure an aerosol sample's full Mueller Matrix across multiple elastic scattering angles for comparison to model predictions. A single tunable source covers the 1.35-5 μm spectral range, and waveband-specific optics and photoreceivers can generate and analyze all six classic polarization states. The SAAST is highly automated for efficient and consistent measurements, and can accommodate a wide angular scatter range, including oblique angles for sample characterization and very near backscatter for lidar performance evaluation. This paper presents design details and selected results from recent measurements.

A multi-wavelength, multi-static lidar has been designed and is being tested for the characterization of atmospheric aerosols. This design builds upon multi-static lidar, multiple scattering analyses, and supercontinuum DIAL experiments that have previously been developed at Penn State University. Scattering measurements at two polarizations are recorded over a range of angles using CCD imagers. Measurements are made using three discrete visible wavelength lasers as the lidar sources, or using a supercontinuum source with a wavelength range spanning the visible and near-IR wavelengths. The polarization ratios of the scattering phase functions are calculated for multiple wavelengths to analyze and determine the aerosol properties of artificially generated fog.

Extending our developments of a previously reported supercontinuum lidar system has increased the capability for measuring long path atmospheric concentrations. The multi-wavelength capability of the supercontinuum laser source has the advantage of obtaining multiple line differential absorption spectra measurements to determine the concentrations of various atmospheric constituents. Simulation software such as MODTRANTM 5 has provided the means to compare and evaluate the experimental measurements. Improvements to the nanosecond supercontinuum laser fiber coupled transceiver system have allowed open atmospheric path lengths greater than 800 m. Analysis of supercontinuum absorption spectroscopy and measurements utilizing the updated system are presented.

The weaponization and dissemination of biological warfare agents (BWA) constitute a high threat to civilians and military personnel. An aerosol release, disseminated from a single point, can directly affect large areas and many people in a short time. Because of this threat real-time standoff detection of BWAs is a key requirement for national and military security. BWAs are a general class of material that can refer to spores, bacteria, toxins, or viruses. These bioaerosols have a tremendous size, shape, and chemical diversity that, at present, are not well characterized [1]. Lockheed Martin Coherent Technologies (LMCT) has developed a standoff lidar sensor with high sensitivity and robust discrimination capabilities with a size and ruggedness that is appropriate for military use. This technology utilizes multiwavelength backscatter polarization diversity to discriminate between biological threats and naturally occurring interferents such as dust, smoke, and pollen. The optical design and hardware selection of the system has been driven by performance modeling leading to an understanding of measured system sensitivity. Here we briefly discuss the challenges of standoff bioaerosol discrimination and the approach used by LMCT to overcome these challenges. We review the radiometric calculations involved in modeling direct-detection of a distributed aerosol target and methods for accurately estimating wavelength dependent plume backscatter coefficients. Key model parameters and their validation are discussed and outlined. Metrics for sensor sensitivity are defined, modeled, and compared directly to data taken at Dugway Proving Ground, UT in 2008. Sensor sensitivity is modeled to predict performance changes between day and night operation and in various challenging environmental conditions.

A high repetition rate, wavelength agile heterodyne detection lidar system is being developed at Coherent Applications, Inc. (CAI). The motivation behind this endeavor is the potential ultra-high sensitivity of heterodyne detection for measuring the low intensity signals of long-range measurements of aerosols. Since speckle noise limits the overall signal-to-noise for each pulse to a maximum of unity, important considerations in heterodyne detection system design are the tradeoffs using lower energy pulses at high pulse repetition frequency (prf) compared with high-energy pulses at low prf. Differential scattering/differential absorption lidar (DISC/DIAL) measurements require precise determination of ratios of the signal levels at two or more wavelengths, and measurements need to be completed within a brief period, so that conditions remain constant. The additional requirement to average a large number of pulses to overcome speckle noise dictates that a high pulse repetition rate is needed. Detection sensitivity is further increased by reducing the receiver bandwidth, and this requires that the optical frequencies of the transmitter and the local oscillator lasers must be maintained with a stable and fixed offset relative to each other at the heterodyne intermediate frequency. This paper provides a general description of the aerosol lidar system that integrates high-speed laser stabilization and intermediate frequency locking of two wavelength agile lasers for heterodyne detection lidar.

We present some of our results in the design and implementation of Brillouin-tailored fibers for narrow linewidth fiber lasers and systems. We consider both rare-earth-doped active and passive fibers, and both traditional and large mode area (LMA) fibers. We show that by properly tailoring the acoustic profile, > 10 dB of Stimulated Brillouin scattering (SBS) suppression can be implemented. Data from manufactured fibers demonstrating > 10 dB SBS reduction, relative to traditional fibers of equivalent mode size, will be presented. Fiber laser configurations utilizing these fibers will be briefly described. Using models developed in-house, we show that transform-limited peak powers > 10 kW can be achieved. Importantly, we also consider the passive fibers employed as pigtails, component fibers, power delivery fibers, etc. in these systems. SBS can become the leading power impairment in systems incorporating 'reasonable' lengths of passive fiber. For example, this might be a 1-meter passive fiber pigtail at the output end of a pump/signal fiber combiner in a counter-propagating configuration. The counter-propagating configuration offers a reduced effective fiber length reducing the effects of non-linearities such as SBS. We will also discuss the possibility of designs with reduced photodarkening.

The Army Research Laboratory (ARL) is researching a short-range ladar imager for small unmanned ground vehicles for navigation, obstacle/collision avoidance, and target detection and identification. To date, commercial ladars for this application have been flawed by one or more factors including, low pixelization, insufficient range or range resolution, image artifacts, no daylight operation, large size, high power consumption, and high cost. The ARL conceived a scanned ladar design based on a newly developed but commercial MEMS mirror and a pulsed Erbium fiber laser. The desired performance includes a 6 Hz frame rate, an image size of 256 (h) × 128 (v) pixels, a 60° × 30° field of regard, 20 m range, eyesafe operation, and 40 cm range resolution (with provisions for super-resolution or accuracy). The ladar will be integrated on an iRobot PackBot. To date, we have built and tested the transceiver when mounted in the PackBot armmounted sensor head. All other electronics including the data acquisition and signal processing board, the power distribution board, and other smaller ancillary boards are built and operating. We are now operating the ladar and working on software development. This paper will describe the ladar design and progress in its development and performance.

Current coastal operations have to deal with threats at short range in complex environments with both neutral and hostile targets. There is a need for fast identification, which is possible with a laser range profiler. A number of field trials have been conducted to validate the concept of identification with a laser range profile. A laser range profiler with a high bandwidth, fast laser receiver was used to perform tests on the capability of a laser range profiler for ship identification. Typical rise and fall times are 2 ns corresponding to a range resolution of 0.6 meter. The experimental profiles of the ships and simulated range profiles based on 3D target models show very good correspondence. It is shown that laser range profiles match closely the geometric structure of the ship. Furthermore, the good match between experimental and simulated laser range profiles means that a database of laser range signatures can be constructed from 3D-models, thus simplifying the database creation. Based on the experiments a system model was made for the range profiling of air targets. The validated system model shows that air targets can be identified at ranges of several tens of kilometers. An identification algorithm was used to distinguish three aircraft from their simulated range profile with good results.

We report on a wideband lidar-radar architecture in which range resolution is independent of pulse duration thanks to the use of a widely tunable intensity-modulated laser combined with a radar-like signal processing. We use a dual frequency laser which provides a modulated beam with a modulation frequency tunable over 1 GHz. A stepped-frequency waveform is obtained and 30 cm range resolution is demonstrated. Field experiments have been conducted on mobile targets, which assess the ability of this setup to measure simultaneously the range and the velocity. A velocity resolution of 1.70 m/s is demonstrated.

In this article we address the design and exploitation of a real field laboratory demonstrator combining active polarimetric and multispectral modes in a single acquisition. Its buildings blocks, including a multi-wavelength pulsed optical parametric oscillator at emission side, and a hyperspectral imager with polarimetric capability at reception side, are described. The results obtained with this demonstrator are illustrated on some examples and discussed.

A navigation Doppler Lidar (DL) was developed at NASA Langley Research Center (LaRC) for high precision velocity measurements from a lunar or planetary landing vehicle in support of the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. A unique feature of this DL is that it has the capability to provide a precision velocity vector which can be easily separated into horizontal and vertical velocity components and high accuracy line of sight (LOS) range measurements. This dual mode of operation can provide useful information, such as vehicle orientation relative to the direction of travel, and vehicle attitude relative to the sensor footprint on the ground. System performance was evaluated in a series of helicopter flight tests over the California desert. This paper provides a description of the DL system and presents results obtained from these flight tests.

The "ColorDazl" is a device designed to be used for testing eye and sensor dazzling, at modest range, in a package that can be carried, and with a projector that could be mounted to a lethal weapon (or if desired, to another type of non-lethal device such as a "stinger"). The Tri-Laser Module (TLM) is a completely self contained subsystem of the device containing functional 3 color (RGV) laser sources. The laser beams are transmitted to the projector by an optical fiber. A 2" or larger diameter projector produces an eye-safe beam throughout its range, yet one of sufficient Irradiance or Illuminance to potentially dazzle sensors, and the unaided eye at ranges between 20' and 200' under night-time or twilight conditions. The TLM is a single pulse laser source, which can be fired every few seconds, with computer controls which keep it eye-safe at the exit aperture, and throughout the range. The output is adjustable with varying power levels and varying pulse duration of the three colors, allowing a flickering output. The system is operated from a LapTop computer which controls the total power, and pulse lengths of each individual laser, so that the total power is below 500 mW, and the energy per pulse for all 3 beams is kept below 30 mJ per pulse. This mode of operation ensures that the device is a Class 3b source as determined by ANSI Z136 classification, and is therefore free from the limitations of Class 4 which include key lock, emission delay, audible warning, etc. With simple refinements to the ColorDazl laser controller software and new projector and receiver combinations currently being considered, a higher power dazzler could be designed in the near future that will be effective and relatively safe under brighter ambient lighting and longer range conditions.

We report of a ship borne off-axis laser warning sensor designed and built at Onera. Classical laser warning sensors detect a laser beam when it is illuminating the warning sensor, meaning that the sensor is located along the laser propagation axis. Hence, large ships are difficult to protect since they require multiple laser warning sensors installed at various locations on the ship hull. On the contrary, the off-axis sensor collects the Mie scattered flux out of the beam propagation axis and looks at the beam sideways. Therefore it can be designed so as to protect the whole ship with only one sensor covering 360°. This paper describes the system and the instrument performance model in maritime environment. Field trials off the Mediterranean coast were conducted by Thales Optronique in fall 2007 in order to validate the concept in operational conditions.