This PDF file contains the front matter associated with SPIE Proceedings Volume 6681, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

A multi-dimensional scanning lidar has been developed for tracking and monitoring aerosol plumes in urban settings. The reliability of the system has been demonstrated and plans for additional units are in place to create a unique scanning lidar network. The paper discusses the current capabilities of the instrument and research underway to extract more information, such as quantitative aerosol properties, from the network.

To investigate the correlation among the meteorological events relating with global warming issue, development of accurate atmospheric observation systems of the troposphere is required. An ultraviolet high-spectral-resolution (HSR) lidar with polarization detection has been developed using narrowband Fabry-Perot interference filters. Ultraviolet wavelength is used in the system for eye-safety characteristics and high accuracy measurements compared with visible lidar systems. Various meteorological phenomena have been observed by the HSR lidar system for 10 months. By simultaneous measurement of depolarization ratio with extinction coefficient and lidar ratio, the system could separated and classify spherical and non-spherical aerosol, water clouds and ice clouds. Probability distribution of lidar ratio of aerosol and clouds has also been measured. The UV-HSR lidar system in combination with depolarization ratio measurement has shown a potential for classifying qualitative and quantitative information of aerosol and clouds and useful for analyzing the influences on the heat balance of the earth.

A lidar system has been operational at Sao Paulo, Brazil (23° S, 46° W) since 2001 and colocated is a sunphotometer belonging to AERONET . During this last years aerosol properties has been extracted from both systems and seasonal trends have been observed specially when long range transport takes place bringing plumes with biomass burning aerosol which can distinctively be extracted from a heavy loaded atmosphere as São Paulo. These events trigger poor air quality conditions which can be easily correlated. The parameters for studying these patterns are Aerosol Optical Depth, Angström Exponent and Lidar Ratio. We show here some case studies belonging to years 2003, 2004 and 2005.

Early concepts to globally measure vertical profiles of vector horizontal wind from space planned on an orbit height of 525 km, a single pulsed coherent Doppler lidar system to cover the full troposphere, and a continuously rotating telescope/scanner that mandated a vertical line of sight wind profile from each laser shot. Under these conditions system studies found that laser pulse energies of approximately 20 J at 10 Hz pulse repetition rate with a rotating telescope diameter of approximately 1.5 m was required. Further requirements to use solid state laser technology and an eyesafe wavelength led to the relatively new 2-micron solid state laser. With demonstrated pulse energies near 20 mJ at 5 Hz, and no demonstration of a rotating telescope maintaining diffraction limited performance in space, the technology gap between requirements and demonstration was formidable. Fortunately the involved scientists and engineers set out to reduce the gap, and through a combination of clever ideas and technology advances over the last 15 years, they have succeeded. This paper will detail the gap reducing factors and will present the current status.

Spaceborne 3-dimensional winds lidar and spaceborne High Spectral Resolution Lidar (HSRL) for aerosol and clouds are among the high priority future space missions recommended by the recent National Research Council (NRC) Decadal Review. They are expected to provide the important three dimensional winds data and aerosol data critically needed to improve climate models and numerical weather forecasting. HSRL and winds lidar have a common requirement for high energy solid-state lasers with output wavelengths at 1064nm, 532nm and 355nm, which can be achieved with Nd:YAG lasers and 2nd and 3rd harmonic generations. For direct detection winds lidar, only the 355nm output is needed. One of the key development needs is the demonstration of laser transmitter subsystem. Top issues include power and thermal management, lifetime, high energy UV operations, damage and contamination. Raytheon and its partner, Fibertek, have designed and built a space-qualifiable high energy Nd:YAG laser transmitter with funding from Raytheon Internal Research and Development (IR&D). It is intended to serve as a risk-reduction engineering unit and a test bed for the spaceborne HRSL and direct-detection Doppler winds Lidar missions. Close to 900 mJ/pulse at1064nm and a wall-plug efficiency of 6.5% have been achieved with our risk reduction laser. It is currently being characterized and tested at Raytheon Space and Airborne Systems. In this paper, we will discuss the design, build and testing results of this risk reduction high energy laser transmitter.

The design of an orbiting wind profiling lidar requires selection of dozens of lidar, measurement scenario, and mission geometry parameters; in addition to prediction of atmospheric parameters. Typical mission designs do not include a thorough trade optimization of all of these parameters. We report here the integration of a recently published parameterization of coherent lidar wind velocity measurement performance with an orbiting coherent wind lidar computer simulation; and the use of these combined tools to perform some preliminary parameter trades. We use the 2006 NASA Global Wind Observing Sounder mission design as the starting point for the trades.

Global measurement of tropospheric winds is a key measurement for understanding atmospheric dynamics and improving numerical weather prediction. Global wind profiles remain a high priority for the operational weather community and also for a variety of research applications including studies of the global hydrologic cycle and transport studies of aerosols and trace species. In addition to space based winds, high altitude airborne Doppler lidar systems flown on research aircraft, UAV's or other advanced sub-orbital platforms would be of great scientific benefit for studying mesoscale dynamics and storm systems such as hurricanes. The Tropospheric Wind Lidar Technology Experiment (TWiLiTE) is a three year program to advance the technology readiness level of the key technologies and subsystems of a molecular direct detection wind lidar system by validating them, at the system level, in an integrated airborne lidar system. The TWiLiTE Doppler lidar system is designed for autonomous operation on the WB57, a high altitude aircraft operated by NASA Johnson. The WB57 is capable of flying well above the mid-latitude tropopause so the downward looking lidar will measure complete profiles of the horizontal wind field through the lower stratosphere and the entire troposphere. The completed system will have the capability to profile winds in clear air from the aircraft altitude of 18 km to the surface with 250 m vertical resolution and < 3 m/s velocity accuracy. Progress in technology development and status of the instrument design will be presented.

We have developed a remote Raman system, using an 8-in telescope and a 532-nm pulse laser (20 Hz and 20 mJ/pulse), which is capable of operating in daylight. From distances of 50 and 100 m and with an integration time of just 1 second (equivalent to 20 laser pulses at 20 Hz), good quality Raman spectra with high signal-to-noise ratios were readily obtained. The Raman system was also tested using only single-laser-pulse excitation (8 ns pulse width) with an integration time of 2 μs. The spectra obtained from single-laser-pulse excitation also show clear Raman features and can be used for rapid, unambiguous identification of various chemical substances. We successfully identified a number of substances, including organic chemicals (acetone, naphthalene, nitro-methane, nitro-benzene and cyclohexane); inorganic chemicals and minerals (nitric acids, sulfuric acid, potassium perchlorate, gypsum, ammonium nitrate, epsomite, melanterite, calcite and sulfur); and amino acids. The remote Raman system has a range of applications, such as environmental monitoring (e.g., detection of hazardous chemicals and chemical spills from a safe distance in real time) or homeland security (e.g., rapid identification of chemicals on a conveyor belt or from a fast-moving object).

BAE Systems presents the results of a program to model the performance of Raman LIDAR systems for the remote detection of atmospheric gases, air polluting hydrocarbons, chemical and biological weapons, and other molecular species of interest. Our model, which integrates remote Raman spectroscopy, 2D and 3D LADAR, and USAF atmospheric propagation codes permits accurate determination of the performance of a Raman LIDAR system. The very high predictive performance accuracy of our model is due to the very accurate calculation of the differential scattering cross section for the specie of interest at user selected wavelengths. We show excellent correlation of our calculated cross section data, used in our model, with experimental data obtained from both laboratory measurements and the published literature. In addition, the use of standard USAF atmospheric models provides very accurate determination of the atmospheric extinction at both the excitation and Raman shifted wavelengths.

In this paper, we explore the possibility of determining the nature and variability of urban aerosol hygroscopic properties using multi-wavelength Raman lidar measurements at 355nm, as well as backscatter measurements at 532nm and 1064nm. The addition of these longer wavelength channels allow us to more accurately validate the homogeneity of the aerosol layer as well as provide additional multiwavelength information that can be used to validate and modify the aerosol models underlying the hygroscopic trends observed in the Raman channel. In support of our hygroscopic measurements, we also discuss our calibration procedures for both the aerosol and water vapor profiles. The calibration algorithm we ultimately use for the water vapor measurements are twilight measurements where water vapor radiosonde data from the OKX station in NYS, are combined with total water vapor obtained from a GPS MET station. These sondes are then time correlated with independent near surface RH measurements to address any bias issues that may occur due to imperfect calibration due to lidar overlap issues and SNR limitations in seeing the water vapor at high altitudes. In particular, we investigate the possibility of using ratio optical scatter measurements which eliminate the inherent problem of variable particle number and illustrate the sensitivity of different hygroscopic aerosols to these measurements.

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 present to develop a partially validated model from combined test data and measureables from the flight. The concept was to validate the CALIPSO system model and then use this tool to facilitate the system engineering process for future space-based designs. The system model includes the important physics of a laser, the CALIPSO optical prescription for the transmitter and receiver, thermoelastic disturbances, a simple atmospheric model, detection and signal processing of the data. This paper describes the model development process using EOSyM, some initial results with comparison to flight data and proposed future developments to expand it's use for future missions.

Structural and biophysical parameters of vegetation canopies, such as tree heights, biomass, vertical and horizontal heterogeneity are important factors affecting flows of energy, water, carbon and trace gases through terrestrial systems. Knowing such parameters is required to model processes associated with photosynthesis, energy transfer, and evapotranspiration at local and global scales. Monitoring vegetation canopies has long been one of the main tasks of several proposed and launched space missions. Lidar instruments have demonstrated the best potential to provide estimates of vegetation height, cover, and canopy vertical structural profiles. A spaceborne lidar would deliver such data on global scale producing the total land biomass value with the accuracy demanded by carbon-cycle and global-change modelers. This paper presents the preliminary results of a numerical model simulating signal returns of a spaceborne lidar for the assessment of land-vegetation canopy biomass. It is a part of work with the overall purpose to develop a trade-off analysis tool for a spaceborne lidar system as a payload of a land-vegetation observation space mission. An end-to-end propagation of a spaceborne lidar sensing pulse through vegetation canopies is considered by the model. It consists of the modules characterizing the laser and the receiver optical systems, satellite's orbit, atmosphere, vegetation canopies, optical filtering, and detectors. This tool can be used to evaluate the effects of instrument configurations on the retrieval of vegetation structures, and to carry out trade-off studies in the instrument design.

At the German Aerospace Center an airborne multi-wavelength differential absorption LIDAR for the measurement of atmospheric water vapour is currently under development. This instrument will enable the retrieval of the complete humidity profile from the surface up to the lowermost stratosphere with high vertical and horizontal resolution at a systematic error below 5%. The LIDAR will work in the wavelength region around 935 nm at three different water vapour absorption lines and one reference wavelength. A major sub-system of this instrument is a highly frequency stabilized seed laser system for the optical parametrical oscillators which generate the narrowband high energy light pulses. The development of the seed laser system includes the control software, the electronic control unit and the opto-mechanical layout. The seed lasers are Peltier-cooled distributed feedback laser diodes with bandwidths of about 30 MHz, each one operating for 200 μs before switching to the next one. The required frequency stability is ± 30 MHz ≅ ± 10^-4 nm under the rough environmental conditions aboard an aircraft. It is achieved by locking the laser wavelength to a water vapour absorption line. The paper describes the opto-mechanical layout of the seed laser system, the stabilization procedure and the results obtained with this equipment.

It is widely agreed that water vapor is one of the most important gasses in the atmosphere with regards to its role in local weather, global climate, and the water cycle. Especially with the growing concern for understanding and predicting global climate change, detailed data of water vapor distribution and flux and related feedback mechanisms in the lowest 3 km of the troposphere, where most of the atmospheric water vapor resides, are required to aid in climate models. Improved capabilities to monitor range-resolved tropospheric water vapor profiles continuously in time at many locations are needed. One method of obtaining this data in the boundary layer with improved vertical resolution relative to passive remote sensors is with a Differential Absorption LIDAR (DIAL) utilizing a compact laser diode source. Montana State University, with the expertise of its laser source development group, has developed a compact water vapor DIAL system that utilizes a widely tunable amplified external cavity diode laser (ECDL) transmitter. This transmitter has the ability to tune across a 17 nm spectrum near 830 nm, allowing it access to multiple water vapor absorption lines of varying strengths. A novel tuning system tunes and holds the ECDL to within +/- 88 MHz (0.20 pm) of the selected wavelength. The ECDL acts as a seed source for two commercial cascaded tapered amplifiers. The receiver uses commercially available optics and a fiber-coupled Avalanche Photodiode (APD) detector. Initial nighttime measurements of water vapor profiles taken over Bozeman, Montana, with comparisons to radiosonde-derived profiles will be presented.

The distribution of pollutants in the atmosphere is key to the validation of dispersion models. While dispersion models tend to assume that air masses are homogeneous, experimental measurements of pollutants using a LIDAR show a different picture. Air masses are very complex and the concentrations of pollutants are influenced by multiple factors. In this paper we present the influence of anthropogenic structures, i.e. a intersection with heavy traffic and a small village, on the ozone concentrations in the atmosphere in their areas of influence. The data were collected using a LIDAR DIAL in the UV region (λ_on= 280nm, λ_off=286nm). The selected wavelengths correspond to the same absorption value on the SO₂ curve to avoid interferences. Measurements were conducted in two dimensions in order to determine pollutant concentrations on certain planes in the atmosphere. The area under study was about 3,2 10⁶ m² in a circular sector, ranging from -70 to 70 degrees in vertical angle, in 10 degrees steps, and 1,500 meters of radio. The resulting plane is perpendicular to the ground. The results show that over the two man-made structures the concentration of ozone is lower than in the rest of the area under study. The heavy traffic intersection is located 750 meters east of the LIDAR location, and the village is 750 meters to the west. The LIDAR location was not established before hand with the purpose of exploring the influence of the two man-made structures on the distribution of pollutants in the atmosphere, and we only realized their significance upon analysis of the results. Different sets of data have been compared, focusing in particular on the measurements during the night and in rush hours to better discern the influence of human activity on the distribution of air pollutants.

In this paper, we present results showing the usefulness of multi-wavelength lidar measurements to study the interaction of aerosols in the PBL with long range advected aerosol plumes. In particular, our measurements are used to determine the plume angstrom exponent, which allows us to differentiate smoke events from dust events, as well as partitioning the total aerosol optical depth obtained from a CIMEL sky radiometer between the PBL and the high altitude plumes. Furthermore, we show that only if the optical depth from the upper level plumes is taken into account, the correlation between the lidar derived PBL aerosol optical depth and surface PM2.5 is high. In addition, we also observe the dynamic interaction of high altitude plumes interacting with the PBL, resulting in a dramatic rise in surface PM10 concentrations without a corresponding dramatic rise in PM2.5 concentrations. These observations strongly suggest the deposition of large particulates into the PBL which is consistent with both lidar angstrom coefficient measurements and back-trajectory analysis. Finally, we investigate the correspondence between surface PM2.5 concentrations and optical backscatter coefficients as a function of altitude. To perform this study, our lidar system is replaced by a ceilometer (Vaisala CL-31) which can determine backscatter to near surface level. In particular, we confirm that near surface backscatter within the first 100 meters is a good proxy for PM2.5 but as altitude increases beyond 500 meters, the correlations degrades dramatically. These studies are useful in identifying the vertical length scales in which spaced based lidars such as Calipso can be used to probe surface PM2.5.

The design and application results of an affordable short range (less than 100 m) digital LIDAR (LIght Detection And Ranging) system will be presented. This work was initiated because many short-range standoff detection applications would benefit from such a system. The lidar features a fiber-based component integrated in the optical module, which allows for hardware partial compensation of the backscattered signal losses observed at short distances due to a biaxial configuration of the lidar optics. This is an important advantage for particle density computations. The digitized backscattered laser signals are available for signal processing. A dedicated FPGA (Field Programmable Gate Array) allows for real-time averaging of the signal waveforms captured at the maximum 50-kHz pulse repetition frequency of the laser. Several application-specific tests have been performed. The first of these was real-time onboard monitoring of pesticide drift in agricultural spraying applications. The signal levels were sufficient for control of the spraying operations and prevention of pesticide drift into sensitive areas. The second was a dust monitoring application. The lidar was installed in a quarry and signals from dust clouds were recorded. Real-time monitoring capabilities were shown to be promising. Other applications involving detection of solid targets in degraded visibility conditions caused by fog or snowfalls were also tested and are discussed.

Lidar is a powerful tool to monitor the variation of aerosol extinction coefficient profiles in atmospheric boundary layer. PM₁₀, which is most familiar to environmental specialists, is the particle mass concentration whose diameter is not larger than 10μm. In this paper, PM₁₀ profiles, measured by lidar and DA-OPC at Beijing, is given and their variation is discussed.

LiDAR (Light Detection And Ranging) has emerged as one of the most powerful and versatile remote sensing techniques for high resolution atmosphere studies. In most cases, the LiDAR backscattered signal is affected by various noises and extracting the weak signal from the noisy backscatter is a fundamental problem in the LiDAR system. This paper presents a new LiDAR de-noising technique which is based on wavelet transform. The technique is applied to the backscattered signal obtained from low power laser transmission (order of few mJ). Results prove that the technique is effective by retrieving even weak signals.

Recent progress in the research of a diode pumped, single-frequency 355nm laser for direct-detection wind lidar is presented. An injection seeded Nd:YAG laser was designed and built. A 'delay-ramp-fire' technique is used to achieve single-longitudinal-mode and stable energy. In this technique, stable time relation between the resonance peak and the pump pulse is achieved by feedback controlling the delay time between the pump pulse and the ramp voltage. The resulting single frequency pulses are amplified and frequency tripled. This laser operates at 100Hz and provides 30mJ/pulse of single-frequency 355 nm output with M² value of <1.5. The frequency stability of the injection seeded Nd:YAG laser was investigated. The piezo hysteresis is found to be the main reason to cause the frequency unstability. In an environment avoiding high frequency vibration the frequency stability is determined by the motion linearity and ramping speed of the piezo actuator. A modified approach is proposed to improve the frequency stability of an injection seeded laser.

The new diagnostic method of the influence of SHF (superhigh frequency) radiation on the atmosphere at heights 20 - 30 km is considered. By the example of AIR (artificial ionization region) make by the focused nanosecond SHF pulses the process of atomic hydrogen generation is considered. The atomic hydrogen radiation at frequency of 1420 MHz is used as a marker of SHF radiation. It is determined that, thickness of the ozonosphere in the focus area changes under a variation of the electromagnetic waves intensity which sent from ground sources. Recombination rates of gases (in particular NO), influencing on the ozone concentration in the stratosphere are estimated. Computer modeling an interacting of electrons with the atmospheric components into the plasma generated by SHF is carried out and radiant power of atomic hydrogen from area adjoining to AIR is determined. It is shown that, the combination of the received information allow to localize AIR and to estimate a level of affecting SHF radiation. For more reliable detection of AIR in real time and at large distances the integrated approach using both active (lidar) and passive methods of remote sensing are needed.

In this paper, we implement and compare two complementary methods for the measurement of low cloud optical depth with a Raman-Mie lidar over the metropolitan area of New York City. The first approach, based on the method of S. Young, determines the cloud optical depth by regressing the elastic signal against a molecular reference signal above and below the cloud. Due to high aerosol loading below and above the low cloud, correction for aerosol influence was necessary and achieved with the combined Raman-elastic returns. The second approach uses N₂-Raman signal to derive cloud extinction profiles and then integrate them to determine optical depth. We find excellent agreements between these two retrievals for cloud optical depths as large as 1.5. Extinction-to-backscatter ratio within the low cloud is obtained and is shown to be consistent to values calculated from liquid water cloud model. The varied lidar ratios at cloud edge may imply the changes of cloud droplet size providing clues to the CCN seeding process. Furthermore, multiple-scattering effects on retrieving cloud optical depths are estimated by using an empirical model and specific lidar parameters.

The analysis of photochemical theory and HALOE, SAGE II, ECMWF/ERA-40 data indicate that ozone variations are inversely correlated with temperature in the upper stratosphere, while ozone variations are positively correlated with temperature in the middle stratosphere. Ozone layer mainly locates at middle stratosphere, where solar UV radiation is largely absorbt. The radiation is main action in middle stratosphere, so temperature variation depends on ozone variation. In the upper stratosphere, the ozone concentrations decrease rapidly, the photochemical actions instead of radiation actions play a principal role. The ozone-depleting reaction rates depend on temperature, so the coefficient correlation of Ozone and temperature is reverse.

A backscattering Lidar system has gone through an automation process for operation through a high-speed internet gateway in a fiber-optic network interconnecting research groups for experimental demonstrations of specific technologies or novel Internet applications. This network is essentially a large, geographically distributed laboratory facility, available worldwide to the research community, for field trials of optical components and equipment, for fundamental and applied research in optical transmission and networking technologies, and for the development of advanced Internet applications. The description of the steps taken to automate this system will be given in detail. The laser source, a meteorological mini-station, a sliding rooftop door, and a trasient recorder for acquisition were adapted for LABVIEW controlling and to be put into a web station for control through the internet and enhancing its operational capabilities. This upgrade in the system was lowcost and can provide multiple applications such as long-term operation during field campaigns and/or as an educational tool to the lidar technique and atmospheric studies.

In this paper, we report the statistical characteristics of Stratospheric Sudden Warming (SSW) events observed over a low latitude station, Gadanki; 13.5°N, 79.2°E. The study uses 7 years (1998 to 2004) of quasi-continuous nighttime LiDAR temperature measurements, which corresponds to 312 observations. The statistical characteristics are presented in terms of major or minor, magnitude of warming, height of occurrence and stratopause descent with reference to the mean climatological profile. The warming events are classified into major or minor warming with respect to the observed warm temperature magnitude and reversal in the zonal wind direction in the polar region using National Centre for Environmental Prediction (NCEP) reanalysis data. In total, 14 SSW events observed and have been classified into 2 (14.3 %) major and 12 (85.7 %) minor warming events. The magnitudes of warm temperatures with respect to the mean winter temperature is in the range from 8.2 K to 18.1 K. Occurrence of SSWs are observed to accompany with the descent of stratopause layer from 0 km to 6.3 km with respect to the calculated mean winter stratopause height.

We propose and have demonstrated a prototype high-reliability pump module for pumping a Non-Planar Ring Oscillator (NPRO) laser suitable for space missions. The pump module consists of multiple fiber-coupled single-mode laser diodes and a fiber array micro-lens array based fiber combiner. The reported Single-Mode laser diode combiner laser pump module (LPM) provides a higher normalized brightness at the combined beam than multimode laser diode based LPMs. A higher brightness from the pump source is essential for efficient NPRO laser pumping and leads to higher reliability because higher efficiency requires a lower operating power for the laser diodes, which in turn increases the reliability and lifetime of the laser diodes. Single-mode laser diodes with Fiber Bragg Grating (FBG) stabilized wavelength permit the pump module to be operated without a thermal electric cooler (TEC) and this further improves the overall reliability of the pump module. The single-mode laser diode LPM is scalable in terms of the number of pump diodes and is capable of combining hundreds of fiber-coupled laser diodes. In the proof-of-concept demonstration, an e-beam written diffractive micro lens array, a custom fiber array, commercial 808nm single mode laser diodes, and a custom NPRO laser head are used. The reliability of the proposed LPM is discussed.

Presented radiating device transforms an angular displacement of a laser beam in limits of several degrees into circular movement on forming a cone which axis coincides with an optical axis of an emitter. Speed of such circular scanning does not depend on a corner of a scanning cone, and is determined by time mentioned small (within the limits of several degrees) linear moving of a laser beam with the help of standard methods. The suggested device basis is represented with a simple optical element with small losses of transformation on reflection. The reception device having a similar reception element provides gathering radiation from a wide spatial zone (close to a hemisphere), with proportional dependence of intensity of a registered signal on a corner of falling of a corresponding light beam, for example scattering back certain object of laser radiation. The radiation falling from a determined direction will be transformed to a corresponding ring zone on the receiver. Proceeding from position of a scanning beam and a ring zone on the receiver which direction reflected signal and distance up to a source of reflection is defined has come. The given devices can find application in compact systems of scanning for a wide range of systems of ecology, cartography, high technologies, medicine and biology. Absence of complex optical elements allows to avoid expensive manufacturing techniques, inaccessibility of direct influence on a working zone allows to provide high reliability of functioning of system

At the present time laser systems for atmospheric remote sensing assume the use of powerful pulse lasers in most cases and a signal backscattered from a medium is recorded with a certain step digitization corresponding to the required spatial resolution. Moreover a distance extension of sounding requires essentially disproportionate increase in radiation power and use of complex methods to extend a dynamic range of receiving devices; it also causes the multiple scattering effects which can be difficult to take into account. Qualitatively new approach which allows many by-effects to be avoided is proposed. The approach is based on use of a low-power radiation source (for example, white light) with specified gating, when time of source radiation interruption is equal to a pulse duration of an ordinary lidar (about 10^-8 c), and frequency corresponds to a propagation time of radiation in a zone where the multiple scattering can be neglected. Digitization of the recorded backscattered signal can produce by ordinary digital systems as a discrete readout of signals with the same duration. However to increase a reconstruction accuracy for the medium characteristics we propose to reconstruct the average values of these characteristics over the parts commensurable with the sounding path length. The algorithm proposes creation of recording system with corresponding gating for incoming signal. Estimations1 have shown that the measurements with accuracy of ~ 1...10 % become possible in the single scattering over the wide range of atmospheric conditions and for safety source power up to 10-20 watt. Moreover, a linear operating mode for photoelectric multiplier can be easily provided and measurements can be carried out in the daytime with the specified accuracy. Such an approach allows us to increase a precision of measurements and can be applied in various areas from the lidar and radar systems to biological and medical devices.