Abstract: A lightning strike detection and mapping system includes a processor for generating a location signal of a lightning strike based on detected signals representative thereof. The location signal is used to drive a display for displaying an indication of the lightning strike thereon. A monitoring device monitors the power source of the system and generates a signal indicative of the level thereof which is read by the processor and used to drive the display to display a representation of the power level signal. Accordingly, the system is capable of monitoring its power source for displaying a representation of the power level thereof on a common lightning strike mapping display.

Abstract: A sampled data lightning strike detection and mapping system receives a signal waveform representative of a lightning strike and samples the waveform to generate a train of data samples representative thereof. A data sample of the train is identified as exceeding a predetermined threshold and designated as the trigger sample. The system recovers a predetermined number of data samples, preceeding the trigger sample, of the train for processing to detect and map the lightning strike.

Abstract: A sampled data lightning strike detection and mapping system receives a signal waveform representative of a lightning strike and other electrical activity and samples the waveform to generate a train of data samples representative thereof. The data samples of the train are processed by a first processor to detect the lightning strike and estimate a location thereof. A predetermined number of data samples of the train are processed by a second processor to generate a plurality of frequency signals representative of a frequency spectrum of the processed data samples. The system includes a display which is driven by the first processor to display an indication of the lightning strike based on the estimated location thereof and further driven by the second processor to display a representation of the frequency spectrum. In a preferred embodiment, the first and second processors are embodied in a common signal processor.

Abstract: Satellite radar apparatus measures the backscatter coefficient of the sea to determine the speeds and directions of winds at sea. The apparatus implements three aiming directions per swath with the track thereof on the Earth being parallel. The radar technique used operates by pulse compression, and on reception noise is measured in parallel with the measurement of signal plus noise. The apparatus includes an assembly for calibrating the product of transmission power multiplied by reception gain, which assembly includes a servo-control loop connected to the transmission line via a directional coupler.

Abstract: A hand-held electronic apparatus for the detection and ranging of lightning strikes wherein radio frequency signals from lightning activity are filtered to allow selected low frequency emissions to be compared with standard voltages in order to activate light emitting diodes which correspond to distances to lightning activity: 0-10 miles, 10-20 miles, etc. The device only the electrostatic field component of the radio signals from lightning activity. The electrostatic component typically dominates over the electromagnetic component at comparatively short distances of 40 miles or less.

Abstract: A microburst precursor detector utilizes a multiplicity of radar beams and samples radar returns, in each beam, from meteorological radar signal reflectors and processes the signal returns in a statistical manner to determine average radar reflectivity and to extract doppler signal parameters. These parameters are utilized to determine a second set of parameters; average doppler frequency within each radar beam, doppler spectral spread within each radar beam, and the skewness of the doppler spectrum in each beam. The second set of parameters is processed to establish the existence of a microburst, predicted surface impact, time to impact, wind shear surface location and track, and the magnitude of the wind shear.

Abstract: The pulsed Doppler weather radar system reduces ambiguities in measured parameters by staggering at least one pulse of each frame of n pulses transmitted by the radar system. The staggered pulse creates an isolated pulse doublet pair to provide three or more independent and auxiliary Doppler parameter estimates. The parameter estimates are combined optimally in a neuromorphic processor matched to the phenomena of interest, particularly capitalizing on multiparameter volumetric correlations to improve data quality.

Abstract: A coherent laser radar system operating at an eyesafe wavelength above 1.4 microns has been provided for measurement of the position and velocity of hard targets and aerosol targets, said system comprising a frequency-stable master laser and an injection-seeded Q-switched slave laser for generating signals for transmission to the target. Means for obtaining highly accurate velocity and range measurements are provided. Data from signal transmissions and receptions taken over a range of angles are analyzed to map target positions and velocities in time and space.

Abstract: A method and system for unambiguous pre-detection real time measurement of lightning strokes.

Abstract: Oblique spaced antenna method and system for measuring atmospheric wind fields within a predetermined volume, whereina pulsed beam of high frequency radar waves is transmitted in predetermined transmitting directions into the volume of the atmosphere to be investigated,parts of the radar waves which return from the volume to be investigated are received from predetermined receiving directions at a plurality of spaced receiving locations, andthe received waves are processed to derive information about the wind velocity within the volume to be investigated, to allow direct determination of parameters of the wind field, such as divergence, vorticity etc.The transmitting and receiving directions are oblique with respect to the vertical direction.

Abstract: A microburst precursor detector utilizes a multiplicity of radar beams and samples radar returns, in each beam, from meterological radar signal reflectors and processes the signal returns in a statistical manner to determine average radar reflectivity and to extract doppler signal parameters. These parameters are utilized to determine a second set of parameters; average doppler frequency within each radar beam, doppler spectral spread within each radar beam, and the skewness of the doppler spectrum in each beam. The second set of parameters is processed to establish the existence of a microburst, predicted surface impact, time to impact, wind shear surface location and track, and the magnitude of the wind shear.

Abstract: Method and apparatus for detecting low altitude wind shear through the use of autocorrelation on the received and processed echo signals. Self Autocorrelation of echo signals and autocorrelation of echo signals from consecutive pulses are used to calculate the low altitude Doppler velocities over distance. In an alternate embodiment, autocorrelation of echo signals from alternate pulses is also required. Wind shear is calculated from low altitude Doppler velocity as a function of location.

Abstract: A lightning direction finder controller (LDFC) for use at remote sites in a Lightning Detection Network provides information on lightning return strokes to a network controller. The LDFC digitizes and processes return stroke data from an analogue direction finder unit, time tags each return stroke with an absolute time accurate to the nearest 10.sup.-4 second of NIST time, and provides an interface for satellite and/or land line communication of lightning flash data to the network controller. The LDFC includes a CPU board, a multi-function analogue and digital input/output board that provides an interface to the analog direction finder unit, and an Interface Facility that provides an interface for: satellite and/or bisynchronous communications, a local data storage device, diagnostic devices, and a satellite controlled clock. A watchdog timer on the Interface Facility resets the CPU of the LDFC when data communications cease, or the execution of the main program halts.

Abstract: An airborne Icing Hazard Detector for aircraft uses dual frequency radar beams which are transmitted into a cloud ahead of the aircraft. The reflected signals at each of the two frequencies are compared and processed to determine the presence, amount and location of regions of liquid water in the cloud. The presence of liquid water is determined as a result of liquid water attenuating the power of one of the signals a greater amount than the other signal, due to different attenuation characteristics of the two signals at the two frequencies. A temperature sensor provides ambient temperature information to determine if the detected liquid water is super-cooled. Upon detection of a predetermined amount of liquid water and the determination that it is super-cooled, an advance warning indication is provided to allow the pilot to avoid flying through the volumetric region of supercooled liquid water and risking ice formation on the aircraft.

Abstract: A system for predicting the occurence of microburst/windshear comprising at least one sensor for receiving lightning produced signals, a processor for processing those received signals to produce data and generate a warning when the processed data indicates that a microburst/windshear is about to occur.

Abstract: The lightning range system for determining distance between a lightning discharge and an airborne object includes a receiver on the airborne object adapted to receive electromagnetic radiation signals generated by a lightning discharge along both a direct and a surface reflected path. Signal processing apparatus is interconnected with the receiver for determining the difference in the time of arrival of the direct and reflected signals. A computer is provided to calculate the range of the lightning discharge from the difference in the time of arrival of the direct and reflected signals. In a preferred embodiment, the signal processing apparatus is digital and includes at least a 10-bit analog-to-digital converter with at least a 36 megahertz sampling rate.

Abstract: A synchronization system and method for a lightning location system having a plurality of remote lightning detectors transmitting data to a lightning position analyzer via a communication system having variable transmission delays. Each lightning detector includes a clock for identifying the time of occurrence of a lightning event such as cloud to ground lightning discharge, the time of occurrence data being transmitted to the position analyzer along with other data representing the lightning event. The position analyzer also includes a clock for identifying the time of arrival at the analyzer of data representing a lightning event. Lightning events are correlated by the position analyzer by comparing the time intervals between the occurrence of lightning events detected by one detector and the time intervals between the occurrence of lightning events detected by a second detector.

Abstract: The invention relates to an apparatus for detecting an electromagnetic pulse having a given origin, more particularly due to a nuclear explosion. This apparatus comprises means for sensing the electrical component of an electromagnetic pulse, means for differentiating a signal supplied by the sensing means from an electromagnetic pulse of a given origin from another pulse and means for taking note of the result of the detection. The differentiation means advantageously comprise means for detecting the passage of the signal supplied by the sensing means at a value exceeding a threshold value, a time counter started by the detection means during the detection of said passage, means for integrating the signal supplied by the sensing means and means for comparing the value of the integrated signal up to time t.sub.1 following the starting of the sensor with a reference value.

Abstract: The installation comprises a certain number of measuring stations, represed here as three in number referenced respectively 1, 2 and 3, equipped respectively with antennae I.sub.1, I.sub.2, I.sub.3, which are connected by transmission lines L.sub.1, L.sub.2 and L.sub.3 to a central data acquisition unit 4, itself connected to a real time data processing unit 5. The central unit 4 comprises receiving means, means for sorting and associating the data and means for momentary storage of the sorted and associated data.

Abstract: The thunderstorm sensor of the present invention includes a pair of orthogonally positioned magnetic loop antennas to provide signals representative of the north-south and east-west components of the magnetic field produced by a lightning discharge. The system also includes an omni-directional electric field antenna to provide a signal representative of the electric field produced by a lightning discharge. The magnetic field and electric field signals from the antennas are coupled to an analog signal processor and digitizer which provides digital representations of the peak north-south and peak east-west components of the radiated magnetic field. The analog signal processor and digitizer also provides digital representations of the peak radiated electric field and the electric field sampled at a time subsequent to the time of occurrence of the peak radiated field wherein the second sampled electric field value represents the electrostatic field change due to the lightning discharge.

Abstract: The lightning ranging system for determining distance between a lightning discharge and an airborne object includes a receiver on the airborne object adapted to receive electromagnetic radiation signals generated by a lightning discharge along both a direct and a surface reflected path. Signal processing apparatus is interconnected with the receiver for determining the difference in the time of arrival of the direct and reflected signals. A computer is provided to calculate the range of the lightning discharge from the difference in the time of arrival of the direct and reflected signals. In a preferred embodiment, the signal processing apparatus is digital and includes at least a 10-bit analog-to-digital converter with at least a 36 megahertz sampling rate.

Abstract: A method for detecting lightning as an electrical atmospheric disturbance and for providing an indication of the geographic position of that disturbance includes the stationing of at least three receivers at known geographic locations in spaced relationship to each other. Signals are encoded at each of the receivers representative of the time of arrival of an electrical indication of an emission from the lightning strike, in relation to a common timing source. All of the encoded signals are transmitted to a central facility and thereafter processed for deriving the position of the lightning strike irrespective of whether the position of the lightning occurred within or outside the perimeter bounded by the three receivers. The system is synchronized with the U.S. Coast Guard LORAN navigation network, and includes various features which permit a more accurate analysis of lightning position.

Abstract: A process and apparatus for the day-or-night monitoring of weather phenomena by means of the analysis of the movements of air masses, wherein the movements are determined by monitoring and receiving the multi-band VLF electromagnetic radiation generated in the atmosphere with directionally selective receivers. The received frequencies are then compared with values which have been correlated with atmospheric events. Means are provided for displaying the predictive results for events occurring up to 500 km away from the VLF receivers--typically updatable within seconds--in at least two stages according to the (near or far) range desired or the type of electrical polarization.