A location reporting paging communication system comprising space satellites, ground stations and a remote receiving unit adapted to resolve a global position from signals transmitted from a communication transmitter. The subscriber in possession of the remote receiving unit updates the paging network with global positioning information. A caller paging a subscriber in possession of the remote receiving unit may request the global location of the remote receiving unit. The paging network could divulge or block such information from a caller depending on the requirements of the subscriber.

Location reporting satellite paging system with optional blocking of location reporting

A radar detection and imaging system provides for the simultaneous imaging of the stationary objects on the earth's surface and the detection and imaging of moving targets. The radar system includes at least one transmitting aperture and a plurality of receiving apertures that are simultaneously operated in a synthetic aperture radar (SAR) mode caused by the motion of the satellite or airborne platform on which they are mounted. Each receiving aperture is connected to its own coherent receiver and the digitized signals from all receivers are processed to image both stationary clutter and moving targets. The system employs space- time adaptive processing (STAP) algorithms to better compensate for channel mismatches, better suppress stationary clutter, and to suppress mainbeam jamming. Moving target detection and estimation modules are also included and are their performance is improved as a result of the STAP algorithms. The system also employs SAR processing algorithms to create high- resolution images of stationary objects, and to image moving targets. The SAR and STAP algorithms are uniquely integrated in the radar signal processor (RSP) to provide improved performance while reducing the computational requirements, facilitating real-time implementation.

Multi-channel moving target radar detection and imaging apparatus and method

Illustrative embodiments of a method and apparatus are provided for determining azimuth for a system using signals from a constellation of satellites of the global navigation satellite system. The method includes the steps of identifying a direction of a selected satellite of the constellation of satellites and determining a azimuth by correlating the identified direction of the selected satellite with the location of the system.

Azimuth determination for GPS/INS systems via GPS null steering antenna

Multi-dimensional wavelet tomography is performed by iteratively projecting a multi-dimensional image across a range of orientations so as to produce a plurality of one-dimensional projections which collectively form a projection image thereof; and then performing wavelet decomposition upon the projection image thereof so as to form a plurality of projection subimages each containing particular boundary and angular characteristics of the original image. Such wavelet decomposition facilitates segmentation and reconstruction of selected characteristics of the original image.

Multi-dimensional wavelet tomography

Cluster MTI detection (71) is performed and track pseudomeasurements are generated from detected clusters. Existing tracks are then extrapolated (73). Measurements are associated (74) with existing group/single tracks. Area visibility is determined for miscorrelated tracks (76). Association and assignment are performed for transitioned tracks (77). Kalman filtering updates are performed (78) on correlated tracks. Existing tracks are managed (79). Unassigned measurements are initiated as tentative tracks (80). This process is repeated for each radar revisit.

Method for tracking a target having substantially constrained movement

In a method for the detection, localization and velocity determination of moving targets from raw radar data from a coherent, single- or multi-channel image system (SAR), for representing the surface of the earth with different backscatter ratios, chronologically successive azimuth spectra are continuously formed during a defined period of time and a frequency shift of the backscatter ratio portion is obtained by determining the position of the maximum of the correlations between respectively two azimuth spectra formed chronologically directly in succession. Then the frequency shifts of the entire raw radar data set are evaluated for producing a frequency shift map. By searching for values deviating from the nominal Doppler rate in the Doppler rate map, a respective moving target is detected and the center of an image of the detected moving target is formed from this. By neglecting its radial acceleration, the tangential velocity of the moving target is determined by means of a Doppler rate taken from the Doppler rate map, and finally the radial velocity of the moving target is determined from the ratio of a length of the moving target in the range direction on the Doppler rate map and the duration of a scanning time by the antenna.

Method for the detection, localization and velocity determination of moving targets from raw radar data from a coherent, single- or multi-channel image system carried along in a vehicle

In a method of extracting phase errors caused by the atmosphere in the backscatter signal of an on-board coherent imaging radar system from radar raw data, firstly to image areas with different backscatter ratios over a predetermined period of time consecutive azimuth spectra are continuously formed. Thereupon, a frequency offset (ΔF(t)) of the backscatter ratio component is obtained by determining the location of the maximum of the correlations between two respective immediately consecutively formed azimuth spectra. Then, a double integration for the difference of the frequency offset (ΔF(t)) and a desired value (ΔFsoll) of the frequency offset is carried out, the frequency offset desired value (ΔFsoll) being determined either from the carrier forward velocity (Vv) or by a low-pass filtering of the frequency offset (ΔF(t)), and finally for standardization the result of the double integration is multiplied by a constant (2π/Δt) to obtain thereby the phase error (φe (t)).

Method of extracting phase errors caused by the atmosphere in the backscatter signal of a coherent imaging radar system carried by a carrier from radar raw data and apparatus for carrying out the method

Verfahren zur Detektion, Lokalisierung und Geschwindigkeitsbestimmung von Bewegtzielen aus Radar-Rohdaten eines von einem Träger mitgeführten, kohärenten, ein- oder mehrkanaligen Abbildungssystems

Method of extracting phase errors caused by the atmosphere in the back-scatter signal of a coherent imaging radar system

Pour former l'image de la surface terrestre a rapports de retrodiffusion divers sont formes de facon continue des spectres azimutaux se succedant dans le temps pendant une duree determinee et on obtient un decalage de frequence ( DELTAF(t)) de la fraction rapport de retrodiffusion par determination de la position du maximum de la correlation entre deux spectres azimutaux formes immediatement l'un apres l'autre dans le temps. Puis, pour etablir une carte des decalages de frequence ( DELTAF(t,r)), on evalue les decalages de frequence du jeu d'ensemble des donnees radar brutes et on obtient une carte des taux Doppler (D(t,r)). Par une recherche de valeurs s'ecartant d'un taux Doppler nominal (Dnom ) sur la carte des taux Doppler, on detecte une cible mobile (B) et on forme le centre de gravite d'une image de cette cible. En negligeant l'acceleration radiale de la cible mobile, on determine sa vitesse tangentielle (VT ) par un taux Doppler (DmB ) vu sur la carte des taux Doppler (D(t,m)) et sa vitesse radiale (VR ) a partir du rapport entre la longueur (rB ) de la cible dans la direction de l'eloignement sur la carte des taux Doppler et de la duree (tB ) d'eclairage par l'antenne.

Procede de detection, de localisation et de determination de la vitesse de cibles mobiles a partir de donnees radar brutes d'un systeme d'imagerie coherent

Keydel Wolfgang

Papers

Method for the detection, localization and velocity determination of moving targets from raw radar data from a coherent, single- or multi-channel image system carried along in a vehicle

Method of extracting phase errors caused by the atmosphere in the backscatter signal of a coherent imaging radar system carried by a carrier from radar raw data and apparatus for carrying out the method

Verfahren zur Detektion, Lokalisierung und Geschwindigkeitsbestimmung von Bewegtzielen aus Radar-Rohdaten eines von einem Träger mitgeführten, kohärenten, ein- oder mehrkanaligen Abbildungssystems

Method of extracting phase errors caused by the atmosphere in the back-scatter signal of a coherent imaging radar system

Procede de detection, de localisation et de determination de la vitesse de cibles mobiles a partir de donnees radar brutes d'un systeme d'imagerie coherent