Abstract: Geolocating one or more emitters includes obtaining a set of lines of bearing (LOBs) indicative of location(s) of emitter(s), determining intersections of LOBs of the set and generating clusters informed by those intersections, assigning the LOBs of the set to cluster(s) based on proximity, identifying a cluster having the greatest number of assigned LOBs from the set; determining an emitter location area based on a best point estimate for the cluster, and indicating a location of an emitter as the emitter location area. Additional emitters can be located by removing from the set of LOBs those LOBs assigned to the identified cluster, and repeating aforementioned aspects. Initially, the set of LOBs can be selected from a larger collection as a representative subset thereof.

Abstract: A system for direction of arrival determination includes a waveform detector and processing circuitry. The waveform detector includes a first pair of dielectric structures and a second pair of dielectric structures. The processing circuitry is configured to determine a direction of arrival of an electromagnetic wave incident on the waveform detector. The direction of arrival is determined based on relative power levels in the first pair of dielectric structures responsive to the electromagnetic wave and based on relative power levels in the second pair of dielectric structures responsive to the electromagnetic wave.

Abstract: A differential signal strength direction determination systems (DSSDDS) may be programmed to provide an output that will enable an individual to determine a direction in which a source of a signal of interest is located with increased accuracy. The programming of the DSSDSS may improve accuracy by consolidating corresponding parts of a signal over time, by modifying a signal strength scale to enable an individual to better discern between the strengths of various signals and/or by providing a user-perceptible output that enables an individual to better discern between the strengths of various signals.

Abstract: A system and method to provide a means of communication, command and control between a mobile antenna and a satellite receiver that allows the receiver to send tuning information to the antenna and the antenna to provide feedback to the receiver when a signal has been acquired. The antenna and the receiver can share the appropriate states and status such as diagnostics, test, GPS coordinates, etc.

Abstract: Method embodiments are disclosed to determine arrival directions of electromagnetic signals that have a known signal frequency and a known guided signal wavelength. These methods are realized with an antenna configured to define, at the signal frequency, at least one metamaterial cell between first and second signal ports. They then include the step of rotating the antenna until the differential power from the first and second signal ports is substantially zero and then determining the arrival direction as a normal to the metamaterial cell. In other method embodiments, the antenna is stationary and a differential power is determined wherein the differential power is defined as the difference between received powers from the first and second ports. The arrival direction of electromagnetic signals are then determined from the differential power.

Abstract: Signal detection assisted by use of moving antennae. A signal of interest may be detected in signal samples measured by a single antenna installed on a moving platform. A first sample is collected at time T1 and a second signal sample at time T2 by the single antenna. The first signal sample is treated as having been received by a first antenna mounted on the moving platform and the second signal sample is treated as having been received by a second antenna mounted on the moving platform. The samples are processed by a receiver of the first and second signal samples to detect the signal of interest.

Abstract: The location of a land-based radio frequency (RF) emitter is determined from an airborne platform. RF signaling is received from the RF emitter via first and second antennas. In response to the received RF signaling, signal samples for both antennas are produced and processed to determine the location of the RF emitter.

Abstract: Method embodiments are disclosed to determine arrival directions of electromagnetic signals that have a known signal frequency and a known guided signal wavelength. These methods are realized with an antenna configured to define, at the signal frequency, at least one metamaterial cell between first and second signal ports. They then include the step of rotating the antenna until the differential power from the first and second signal ports is substantially zero and then determining the arrival direction as a normal to the metamaterial cell. In other method embodiments, the antenna is stationary and a differential power is determined wherein the differential power is defined as the difference between received powers from the first and second ports. The arrival direction of electromagnetic signals are then determined from the differential power.

Abstract: Method of locating one or more transmitters on the basis of an array of sensors moving with respect to the transmitters comprising at least the following steps: determining the direction vectors âk corresponding to the response of the array of sensors to a source with incidence (?, ?) as a function of the incidence parameters ?, ?, and of the parameter ? related to the distortion of the phases on the sensors, transforming this vector âk so as to eliminate the unknown parameter ?, into a vector ?km, ??km, using the transformed vector to obtain the position of the transmitter using a maximized locating criterion.

Abstract: Method of using one or more transmitters and/or one or more parameters associated with a transmitter by using a reception station comprising a device suitable for measuring over time a set of K parameters dependent on the transmitters associated with vectors {circumflex over (?)}k representative of the transmitters for 1?k?K. The method includes a step of extracting the parameter or parameters consisting in grouping together by transmitter the parameters which are associated therewith by means of a technique of independent component analysis.

Abstract: An interactive graphical user interface (GUI) for displaying frequency, amplitude and direction information provided by an intelligence system is provided comprising: a plot of RF versus amplitude, and a graph of frequency versus direction. The intelligence system has a front end to generate digital data based on received radio frequency (RF) signals, a post processing stage to process the digital data, and a direction finding stage to prevent the post-processing stage from processing portions of the digital data that correspond to RF signals arriving from a direction other than a predetermined direction. The GUI is updated continuously in near real time. Methods of operating the GUI are also provided.

Abstract: A method for selecting radionavigation beacons using an onboard navigation system aboard an aircraft from a list of eligible beacons, includes a step for formulating a criterion for selecting a pair of beacons (BX, BY) from among beacons forming part of a list of eligible beacons, and the selection criterion is based on a search for a maximum duration of membership, for instants subsequent to the instant t1, for which the 2D terrestrial position of the aircraft belongs to the zones of employment of all the pairs of beacons achievable from among the eligible beacons, on the basis of a given predictive trajectory of the aircraft.

Abstract: A system and method to provide a means of communication, command and control between a mobile antenna and a satellite receiver that allows the receiver to send tuning information to the antenna and the antenna to provide feedback to the receiver when a signal has been acquired. The antenna and the receiver can share the appropriate states and stats such as diagnostics, test, GPS coordinates, etc.

Abstract: The invention relates to a method of localization of one or more sources, said source or sources being in motion relative to a network of sensors, the method comprising a step of separation of the sources in order to identify the direction vectors associated with the response of the sensors to a source having a given, incidence, characterized in that it comprises at least the following steps: associating the direction vectors a1m . . . aKm obtained for the mth transmitter and respectively at the instants t1 . . . tK, localizing the mth transmitter from the associated vectors a1m . . . aKm.

Abstract: A Direction Finding Method and System Using Probabilistic Mapping is disclosed. Also disclosed is a preferred system that employs a technique for taking in data sets (lines of bearing) from DF receivers and characterizing those signals with their respective probabilities of error. Then using a unique method, the preferred system can display the triangulated position on a map with an overlay of probability fields indicating the emitter location with varying levels of confidence. Even further, the preferred system is able to redraw the probability fields on the map display in real-time as new data is collected and updated. In this way, a far more efficient EL System has been achieved in which the emitter's position can be determined more quickly. It should be noted that with this invention, triangulation can be done with just a single (mobile) DF Set in the EL System. Today's systems for triangulation must use at least three DF Sets.

Abstract: Mobile device (3) and method for receiving and processing program-accompanying digital data, which are transmitted by a radio transmitter (1), for example a DAB transmitter, and of which at least certain comprise location parameters. The mobile device (3) includes a radio receiver (38), which can receive radio programs with program-accompanying digital data, and a position locating module (39) for establishing the current position, for example a GPS receiver. The mobile device (3) further comprises a filter module (37), by means of which, on the basis of the current position, determined by the said position locating module (39), location-specific information can be filtered from the received program-accompanying data, which contain, for example, order numbers, URL addresses or executable program data files. The received program-accompanying data can be filtered moreover by the said filter module (37) on the basis of a user profile (35) stored in the mobile device (3).

Abstract: A Real-time Emitter Locating (EL) System and Method is disclosed. The system provides a technique for taking in data sets (lines of bearing) from DF receivers and characterizing those signals with their respective probabilities of error. Then using a unique method, the preferred system applies a recursive processing technique to this continuous stream of data, displaying transmitter positions with significantly less uncertainty. Furthermore, the preferred system is able to perform these functions in real-time. The system is further capable of being fully automated to reduce the processing time and reduce the necessity of human intervention. Still further, in an alternative embodiment of the present invention the system can be remotely controlled over a communications network whereby collected locating data from a single DF set, or alternatively from more than one DF sets can be combined to arrive at estimated positions for a transmitter.

Abstract: This invention concerns a method for passive localization of a target (12) and air-air localization in particular. This method includes a step for acquisition of the signal transmitted by the target using sensors equipping the carrier (11) and forming two interferometers. This step includes at least two independent measurement series carried out along separate trajectories. The method also includes a measurement processing step to estimate the parameters characterizing the target easily. The invention applies in particular to the passive localization of a target whose transmission frequency varies in a narrow band.

Abstract: A method of determining an azimuth and elevation of a radiation emission source using a single-axis direction finding system is provided. The method includes receiving a plurality of radiation signals at the single-axis direction finding system. The plurality of radiation signals are emitted from the radiation source, each of the plurality of radiation signals being received at one of a plurality of attitudes of the single-axis direction finding system. The method also includes measuring an angle of arrival of each of the plurality of radiation signals with respect to the single-axis direction finding system. Additionally, the method includes calculating an azimuth angle of each of the plurality of radiation signals with respect to the single-axis direction finding system using the respective measured angle of arrival. Further, the method includes calculating a respective vector corresponding to each of the azimuth angles at different elevation angles within a predetermined range.

Abstract: A Real-time Emitter Locating System and Method is disclosed. The system provides a technique for taking in data sets (lines of bearing) from DF receivers and characterizing those signals with their respective probabilities of error. Then using a unique method, the preferred system applies a recursive processing technique to this continuous stream of data, displaying transmitter positions with significantly less uncertainty. Furthermore, the preferred system is able to perform these functions in real-time. The system is further capable of being fully automated to would reduce the processing time and reduce the necessity of human intervention. Still further, in an alternative embodiment of the present invention the system can be remotely controlled over a communications network and collect whereby locating data from several DF sets can be combined. In this way, a far more efficient EL System can be achieved in which the emitter's position can be determined more quickly from a centralized command facility.

Abstract: A Direction Finding Method and System Using Probabilistic Mapping is disclosed. Also disclosed is a preferred system that employs a technique for taking in data sets (lines of bearing) from DF receivers and characterizing those signals with their respective probabilities of error. Then using a unique method, the preferred system can display the triangulated position on a map with an overlay of probability fields indicating the emitter location with varying levels of confidence. Even further, the preferred system is able to redraw the probability fields on the map display in real-time as new data is collected and updated. In this way, a far more efficient EL System has been achieved in which the emitter's position can be determined more quickly. It should be noted that with this invention, triangulation can be done with just a single (mobile) DF Set in the EL System. Today's systems for triangulation must use at least three DF Sets.

Abstract: The present invention determines the geolocation of an emitter, using at least one observer measuring signal change while moving on at least two observation tracks. The measurement of emitter signal change is begun between a first observer position and a second observer position. The second observer position is predicted at the time the last measurement from which signal change will be derived is made. The method utilizes knowledge of the measurement start and end points to determine a second pair of observer signal-change measurement start and end positions such that the emitter line-of-position (LOP) determined by the second signal change measurement will intersect the LOP associated with the first signal change measurement at possibly multiple points, but at each of these point intercept orthogonally to within the signal change measurement errors.

Abstract: A Doppler Direction Finder comprises at least one antenna (52) spaced from a location point (53). The at least one antenna (52) is arranged in use to be rotated about the rotation point (53). The at least one antenna (52) is arranged to provide a first output signal comprising a signal received by said at least one antenna (52) combined with the Doppler Shift component. There are means (70) for providing a second output signal comprising the received signal without the Doppler Shift component. Processing means (54-82) process the first and second signals to obtain the Doppler Shift component. Determining means (88) determine from the Doppler Shift component the direction from which the received signal is received.

Abstract: A method for determining the position of a mobile station within a cellular telephone system having a plurality of base stations. A signal is transmitted from a rotating antenna. The rotating antenna has a beam which rotates around a cell in the cellular telephone system. The beam has a rotational timing that is known by the mobile station. The signal is received at the mobile station. Based on a reception time when the signal is received by the mobile station, an angular displacement value corresponding to the position of the mobile station is determined. A first round trip signal propagation time between a stationary antenna and the mobile station is measured using a voice information signal. The position of the mobile station is determined in accordance with the angular displacement value and the first round trip signal propagation time.A method for determining the position of a mobile station within a cellular telephone system having a plurality of base stations.

Abstract: Method which involves determining the position of a number of measured objects by determining a number of directions to the measured objects from at least two measuring stations, of which at least one is mobile, the method being used to decide which of the points of intersection between the directions correspond to measured objects and which ones do not correspond to measured objects. Changes in the mutual movements between the measuring stations and the points of intersection are in this case determined by comparison between the paths in which the points of intersection and the measuring stations are moving. The points of intersection whose movement is not affected by changes in the movement of other points of intersection, or by changes in the movement of at least one measuring station, correspond to positions of measured objects.

Abstract: An apparatus and method are described for direction finding the source of emf emissions including a monotone signal by detecting the phase changes of the monotone signal during movement relative to the source. A software embodiment measures the amount of phase change.

Abstract: A process for locating a transmitter in which the signal is received by first and second receivers and then processed by respective analog to digital converters and filtered to yield first and second digital signals. There is relative motion between at least one of the receivers and the transmitter. A compression process local to the first receiver compresses the first digital signal. The result of the compression process is transmitted to a cross-correlation unit which is local to the second receiver and coupled also to receive the second digital signal. Locally to the first receiver, correction factors for the solution to the cross-correlation function are determined and transmitted to a correction unit at the second receiver site which applies the correction factors to the solution of the cross-correlation function. The location of the transmitter is determined based on time difference of arrival and frequency difference of arrival results output from the correction unit.

Abstract: RF energy received by an antenna (10) of a radio direction finding system is evaluated for determining the presence of a RF signal transmission source at bearing values at which the received RF energy is statistically strong (33) and which have a relatively stable signal strength (35). The scanning pattern (sequence) ( 12, 15) of the antennae is altered to increase the dwell time of the antennae at bearings having a statistically strong and relatively stable signal strength combination, and decrease the percentage of time spent scanning the remainder of the 360 degree search spectrum. External sensors (30) are used to sense changes in antennae orientation with respect to a fixed reference to thereby reduce bearing errors (27) during changes in the attitude and heading of the platform carrying the radio direction finding system.

Abstract: An antenna is divided into a plurality of sub-arrays which are arranged parallel to each other on a turntable. At least one of the sub-arrays is laterally divided into sub-array sections. Reception signals from these sub-array sections are compared with each other to detect a phase difference therebetween. This phase difference is utilized to control the beam direction of the antenna such that the antenna can be properly oriented to the satellite at all times.

Abstract: Apparatus and methods of achieving accurate, unambiguous angle information with a minimum number of antenna elements. The present invention resolves the ambiguities inherent in a long baseline phase interferometer by employing a minimum number of antennas to form shorter baselines. The present invention employs roll motion (antenna rotation) to reorient interferometer baselines and a signal processor to measure the roll angle. Taking interferometer phase data with at least two orientations of the interferometer baselines permits resolution of the ambiguities. This also allows the use of long antenna baselines thereby achieving high angular accuracy with angle ambiguities resolved using only two antenna elements per spatial angle. This reduces system complexity and reduces the required clear aperture area, factors of great significance in missile systems. The invention takes phase data at two or more interferometer baseline orientations and forms a set of simultaneous equations involving the phase ambiguities.

Abstract: The invention relates to a surveillance sensor provided with at least one surveillance radar antenna 1 and at least one co-located and co-rotating electro-optical surveillance sensor 5 mechanically connected to said radar antenna. A combined panoramic picture is compiled by combining information from both sensors using a common track unit 30.

Abstract: The present invention concerns an apparatus and method for measuring the azimuth and elevation of an object. The apparatus includes a platform; a base plate arranged to the construction of the platform rotatably in a plane, which is essentially horizontal; a sensor frame attached to the base plate; at least three sensor elements attached to the sensor frame; and an electronics unit for the control of the sensor elements, capable of performing the processing of signals received by the sensors. The sensor frame is rigidly attached to the base plate and the directional pattern of the sensor elements is such as to cover the entire angle span of interest in the elevation plane, while the pattern covers an essentially narrower angle in the azimuth plane. The direction finder does not easily lose the tracked object performing movements particularly in the elevation plane.

Abstract: An electromagnetic communications and switching system provides for line-of-sight remote selection and actuation of a wide variety of apparatus. The system has a plurality of radiating antennas having independent components defining a reference coordinate frame. A transmitter is provided for applying electrical signals to the antennas which generate a plurality of radio frequency electromagnetic fields. The signals are multiplexed so that the electromagnetic fields are distinguishable from one another. An array of control positions is provided that is fixed with respect to the reference coordinate frame. A plurality of receiving antennas are provided which are adapted for mounting on the head of an operator. The receiving antennas are provided with independent components for detecting and measuring the components of the electromagnetic fields. A sight couples the eyes of the operator and the array of control positions.