Abstract: A radar scan conversion protocol is defined to communicate radar data from application servers to thin clients with reduced network bandwidth requirements. The radar scan conversion protocol may be implemented as an extension to existing thin client protocols. The system is also capable of transmitting audio and video data through the application servers to the thin clients using appropriate compressed formats in order to minimize network bandwidth requirements.

Abstract: A bistatic radar system (100), method and computer program (178) are provided for mapping of oceanic surface conditions. Generally, the system (100) includes at least one transmitter (102) and at least one receiver (106) located separate from one another, and each having a local oscillator locked to a Global Positioning System (GPS) signal received by a GPS synchronization circuit (134) to provide the necessary coherency between the transmitted and received signals. Preferably, the present invention enables an existing backscatter radar systems to be quickly and inexpensively upgraded to a bistatic radar system (100) through the addition of a transmitter (102) and/or receiver (106) separate from the backscatter radar system, the GPS circuit (134), and use of the computer program (178) and method of the present invention.

Abstract: The present invention relates to a method for determining position and velocity of targets from signals scattered by the targets. One uses a first and a second station comprising transmitter/receiver (s1,s2) of electromagnetic or acoustic signals and carries out mono-static measurements (M1,M2) from each station, and also a bi-static measurement between the stations (B12), and calculates first through the two mono-static measurements a number of target candidates with 2-dimensional position and 2-dimensional velocity, whereupon these are tested against the result of the bi-static measurement and the target candidates which are found In all measurements with suitable error margins are retained.

Abstract: In a method for detecting target objects and determining their direction, range, speed and the like for a radar device, the invention provides that at least three transmitting and receiving devices for radar beams are arranged in such a manner that their beam fields (a, b, c, d, e) form the dectection area of the radar device, and the at least three transmitting and receiving devices are activated and deactivated successively in such a manner that at least two adjacent transmitting and recieving devices are activated simultaneously.

Abstract: The present invention relates to a system for using signals scattered by targets to determine position and velocity for each of the targets and comprises a set of transmitters and receivers of electromagnetic or acoustic signals, said transmitters and receivers dispersed to known points. Each pair of transmitter and receiver, mono-static or bi-static, is named a measuring facility. The ranges of the transmitters are chosen so that a target at an arbitrary point within the position space can be measured via scattering in the target by at least four, but preferably many more, measuring facilities.

Abstract: A method and a device for detecting objects that has at least two near distance sensors installed on a vehicle. The at least two near distance sensors have detection ranges that overlap at least partially. The relative positions of possible detected objects with respect to the at least two near distance sensors are determined in the overlap area by the triangulation principle. Possible apparent objects obtained by determining the relative position of possible detected objects are identified using dynamic object monitoring.

Abstract: A system for the detection and determination of the success of interception of incoming missiles, used in conjunction with a defense weapon system capable of identifying and tracking incoming missiles and interceptors. The system comprises at least one of a plurality of sensing units. Each sensing unit comprises: an optical sensor for detecting optical signals within a predetermined range; tracking means coupled to the optical sensor for tracking an intercepting missile or an incoming missile; processing means for processing optical input detected by the optical sensor and analyzing the optical input to identify an optical signature and determine detonation of interceptor or incoming missile; communicating means for communicating data between the sensing unit and the defense weapon system; and control means for controlling the tracking means, the processing means and the communicating data.

Abstract: In a pulse-radar method, in particular for motor vehicles, different time slots (21, . . . , 24) of a time frame (20) are predefined. During one time slot, a radar sensor (1) emits at least one radar pulse and receives the echo signal(s). During the remaining time slots (22, 23, 24) the radar sensor (1) monitors whether interference signals occur. On the basis of the interference signals occurring per time slot (21, . . . , 24), a decision is made whether the radar sensor (1) should continue its transmitting and receiving operation in the predefined time slot (21) or should switch to one of the remaining time slots (22, 23, 24) of the time frame (20). The method is suited for the concurrent operation of a plurality of radar sensors, without this causing interference.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: An apparatus for identifying a buried object using ground penetrating radar (GPR) in a system containing at least one GPR sensor, comprises a data processor for detecting spatial correlations in data received from a GPR sensor in the apparatus and an image processor capable of building a data structure corresponding to an image of the buried object from data processed by the data processor. A method for identifying a buried object using GPR in a system containing a GPR sensor comprising detecting spatial correlations in data received from the GPR sensor in the system and building a data structure corresponding to an image of the buried object from the received data.

Abstract: A system and method for detecting and tracking a target object, including the calculation of the target object's altitude, is disclosed. During the processing of signals received by a receiver, the system selectively calculates the altitude of the target object from signals modified by an interference effect pattern formed by the signals broadcast by a transmitter, or from the calculation of geometric shapes associated with three or more transmitters and determining the intersection point of those shapes.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: A cellular radar system is disclosed for detecting and tracking objects in a surveillance area that is divided into cells. Each cell is scanned by at least two radars to produce two (or more) respective datastreams for the cell. Orbiting unmanned air vehicles can be used as radar platforms. The resulting datastreams for each cell are then multilaterated by a processor to produce a multilaterated datastream for each cell. The multilaterated datastreams for all cells are then combined by the processor and the resulting data used to detect or track one or more objects in the surveillance area. The fused multilaterated datastreams allow objects to be tracked as they move from cell to cell.

Abstract: A measuring system and method of detecting an object distance by transmission media with different wave velocities are described. The measuring system has a computer, a primary detector and a secondary detector. The primary detector is connected to the computer through bus communication and the secondary detector connected to the primary one through two different transmission media. The primary detector is able to receive separately a first signal and a second signal emitted simultaneously from the secondary detector through the transmission media. Moreover, the first signal has light-speed and the second signal has sound-speed. To calculate the distance between the objects which the primary and the secondary detector are attached respectively. The delay time of second signal and the wave velocity of the supersonic media are multiplied.

Abstract: A surface imaging radar system for an airborne platform, the system comprises a transmitter for generating a radar signal. The system also comprises an antenna configured to transmit a radar signal generated by the transmitter and receive radar return information from one or more directions directly below the airborne platform to an angular direction of approximately 30 degrees greater than straight down. The system also includes a processor configured to generate surface information based on the received radar return information and an image processor for generating an image based on the surface information.

Abstract: Bistatic radar compatible for investigating the employment of a high-altitude UAV working in tandem with a group of low-altitude UAVs. The bistatic radar is divided into a position-adaptive bistatic mode and a close-range monostatic mode. In position-adaptive (robotic) bistatic mode, each low-altitude UAV estimates a new parameter denoted as the differential path length to adaptively implement self-adjustments in position. This approach provides each UAV with the potential for looking down the “throat” of an obscuration channel. In the event that a particular low-altitude UAV detects an obscuration channel, the low-altitude UAV will transfer to a close-range monostatic mode in an effort to interrogate the obscuration channel for targets.

Abstract: A radar scan conversion protocol is defined to communicate radar data from application servers to thin clients with reduced network bandwidth requirements. The radar scan conversion protocol may be implemented as an extension to existing thin client protocols. The system is also capable of transmitting audio and video data through the application servers to the thin clients using appropriate compressed formats in order to minimize network bandwidth requirements.

Abstract: The present invention is an apparatus and method for displaying a foreign body in a relatively uniform mass having similar electromagnetic impedance as the foreign body comprising of at least two ultra wide band holographic radar units adapted to generate, transmit and receive a plurality of 12-20 GHz frequency signals in a dual linear antenna with slant-angle illumination. The invention may be utilized to obtain qualitative and quantitative data regarding the composition of the object under investigation.

Abstract: An intrusion detection system and method are provided that can utilize impulse radio technology to detect when an intruder has entered a protection zone. In addition, the intrusion detection system and method can utilize impulse radio technology to determine a location of the intruder within the protection zone and also track the movement of the intruder within the protection zone. Moreover, the intrusion detection system and method can utilize impulse radio technology to create a specially shaped protection zone before trying to detect when and where the intruder has penetrated and moved within the protection zone.

Abstract: A bistatic radar system and method. In the illustrative embodiment, a receiver is positioned in a horizontal plane. A transmitter is then positioned in Middle Earth Orbit at a position that is nearly vertical to the plane of the receiver. This configuration provides significant flexibility for the radar system. As such, the radar system may engage in flight patterns, in which the transmitter and receiver have velocity vectors in opposite directions (GMTI mode), the same direction (SAR mode) and variations in between (mixed mode). Lastly, a broad beam is generated from the transmitter and illuminates an area enabling several receivers to simultaneously observe the illuminated area.

Abstract: Linear or planar arrays of vertically polarized dipole or monopole radiators for an IFF/SSR antenna are interleaved with existing linear arrays comprising a PSR antenna and fed by stripline corporate feed structures which provide the Sum and Side Lobe Suppression (SLS) Channels for IFF/SSR operations, thereby providing two antenna functions within a single antenna aperture area.

Abstract: A radar detector for exploration of subsurface embedded objects comprising an antenna array (1) for high-frequency electromagnetic waves, which is connected and individually switchable with at least one transmit/receive unit, a time-controlled signal processor, an evaluation device for SAR and a display device. The antenna array (1) exhibiting at least three antennas (sx, rx, sy, ry) scanning an area by their positioning.

Abstract: An auto-docking system has been provided that can automatically dock a ship. The auto-docking system provides a close in radar system and a secondary propulsion system that is under control of a docking processor.

Abstract: A docking information system disposed on a ship provides navigational information to the operator of the ship. The system includes a short range radar system and a display to provide a range between the ship and a dock or an obstacle and, optionally, a relative velocity between the ship and the dock or the obstacle.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: A pulse doppler radar system simultaneously operating monostatically and bistatically. A pair of radar unit operate monostatically transmitting a radio frequency (RF) energy signal and receiving a RF return from the RF energy signal. In addition, simultaneously, one unit operates as a receiver receiving a bistatic return from the other. Information from the bistatic return is combined with information from monostatic returns to locate individual targets.

Abstract: Systems and methods are described for synthesis of total surface current vector maps by fitting normal modes to radar data. A method includes extracting a scalar data set from a radar signal from a radar. Velocity components are calculated from the radar signal. The velocity components are fitted to a set of scalar eigenfunctions and eigenvalues to simultaneously solve for the best set of normal modes and the corresponding set of constants. The corresponding set of constants represent a corresponding set of amplitudes. The set of constants and the set of normal modes are used to create a two dimensional vector field used in creating a total vector map.

Abstract: Systems and methods are described for HF radar frequency sharing with GPS time modulation multiplexing. A method is provided that includes generating clock signals from the time information contained in a GPS signal. Radio frequency signals are transmitted and received in a sequence whose start times are dictated by the clock signals. The clock signals also control the modulation of the radio frequency signals. The radio frequency signals are modulated by using a sweep modulation. An apparatus to implement the method includes a GPS receiver, a state machine, a clock generator, a microprocessor, a memory chip, a signal synthesizer, and a digital data output device. The GPS receiver extracts time information from GPS signals. The state machine controls radar functions versus time. The microprocessor performs modulation multiplexing on radar signals.

Abstract: A system and method for detecting and tracking a target object, including the calculation of the target object's altitude, is disclosed. During the processing of signals received by a receiver, the system selectively calculates the altitude of the target object from signals modified by an interference effect pattern formed by the signals broadcast by a transmitter, or from the calculation of geometric shapes associated with three or more transmitters and determining the intersection point of those shapes.

Abstract: A radar field-of-view enhancement method particularly adapted for vehicle radar detection systems having a specified detection zone. In accordance with the invention, a pair of discrete radar beams are employed having differing arc widths. Return signals from the discrete beams are compared and related to the area of a desired detection zone. This approach increases the reliability of detection in the detection zone while minimizing false alarms and missed detection areas. The beams are alternately switched on using discrete sources or by implementing a discrete phase shifting element interposed between the sources.

Abstract: An airport runway incursion detection and warning system for monitoring ground traffic in he vicinity of a runway or taxiway of an airport. The system utilizes a microwave radar transceiver, commonly referred to as a motion detector, connected to a voice annunciator to provide a verbal warning of aircraft or ground vehicle runway incursion. In one embodiment, the microwave transceiver is integrated into a runway lamp and includes a transformer to all w the transceiver to operate from an existing runway lamp power system.

Abstract: A method and a radar sensor for determining an elevation angle error of a multibeam radar sensor are described. In order to detect an elevation angle of the multibeam radar system with respect to a predefined target, a plurality of laterally arranged cutting planes at a predefined distance are formed. The values of the corresponding antenna diagrams in each plane are stored in a suitable form, for example, normalized and in a parametric form taking into account the elevation angle &agr;. In order to reduce the size of the memory, it is sufficient to store one symmetry half for reasons of symmetry if additional information, for example, road clutter values are added, so that the upward or downward direction of the angle can be recognized. By comparing the measured echo values obtained by normalization and application of a quality factor, a corresponding elevation angle &agr; is obtained for each cutting plane.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: The bistatic radar system uses a scanning beam antenna located at the transmitter to transmit a focused beam of high frequency energy into a predefined space, with the transmitted beam comprising a series of pulses. The transmitter also includes apparatus for determining pulse origination data comprising: pulse origination time and direction of propagation for each of the pulses in the transmitted beam emanating from the antenna, where the antenna is scanned in a predetermined scan pattern in at least an azimuthal direction. The bistatic radar system also includes at least one receiver, located at a site remote from the transmitter and includes apparatus for generating pulse component receipt data indicative of receipt of components of the pulses that are contained in the transmitted beam that are reflected from scatterers in the predefined space.

Abstract: The bistatic radar network uses an incoherent transmitter for determining the presence, locus, motion, and characteristics of scatterers in a predefined space. The incoherent transmitter generates pulses of high frequency energy that vary in frequency and/or phase. The bistatic radar network having an incoherent transmitter uses a scanning beam antenna located at the transmitter to transmit a focused beam of high frequency energy into a predefined space, with the transmitted beam comprising a series of pulses, each pulse in the series of pulses having a varying frequency, phase, pulse origination time and direction of propagation as it is emanated from said antenna. The transmitter also includes apparatus for determining pulse origination data comprising: frequency, phase, pulse origination time and direction of propagation, for each of the pulses in the transmitted beam emanating from the antenna, where the antenna is scanned in a predetermined scan pattern in at least an azimuthal direction.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: In the inventive aircraft based or spacecraft based radar system with synthetic antenna aperture (SAR=Synthetic Aperture Radar) a transmit antenna and a receive antenna are provided according to a bistatic radar, which are arranged above the earth's surface, physically separate and on different platforms of which at least one is moving, so that a relative movement results between the transmit antenna and the receive antenna. Either the transmit antenna, the receive antenna, or both antennas are designed for ambiguity suppression. The radar system according to the invention is useful particularly for the systematic imaging of the earth's surface.

Abstract: The multiple beam radar system uses multiple simultaneously transmitted beams of high frequency energy to identify scatterers that are located in a predetermined volume of space. This multiple beam radar system simultaneously transmits several beams of high frequency energy, produced by an antenna which operates in a mechanically scanning mode, and simultaneously receives the returned radiation, which constitutes components of this narrow beam that have been reflected off scatterers located in the path of the beam. The transmitted (and thus received) frequency of each beam is different, providing information relating to the presence, locus and characteristics of the scatterers by analyzing the plurality of received beams.

Abstract: The invention relates to a radar station placed on the surface of the earth, and to a radar system comprising at least two such radar stations. The signal-processing equipment of the radar stations is adapted, at each point of time, to calculate probabilities of target positions and radial target velocity in relation to each individual radar station, based on the signals emitted and received by this station. These calculated values are associated over time, giving cumulative probability measures for target positions and radial velocities in relation to each individual radar station. By providing a system of at least two radar stations, it is possible to calculate the position of a target by associating target positions, such as they are perceived by the different radar stations, with each other by an association of characteristic movements of the target. This is done without having to synchronize the stations.

Abstract: A multi-faced radar system illuminates a common area of space by radiating a first signal at a first frequency from a first antenna face and a second signal at a second frequency from a second antenna face and cooperatively processes the first and second signal returns on the first and second antenna faces. A processor combines first signal energy from the first and second faces and combines second signal energy from the first and second faces. The processor then combines the aggregate first and second signal returns.

Abstract: An apparatus to determine the three-dimensional location of an airborne platform relative to a target area using two separate antenna assemblies positioned on the airborne platform. The first antenna assembly is adapted to transmit energy downward toward a surface location directly beneath the airborne platform, while the second antenna assembly is adapted to transmit energy forward towards the target area remote from the surface location. A single transmitter is associated with both of the antenna assemblies for transmitting signals toward the surface location and the target area. A receiver coupled to the antenna assemblies receives and detects the signals corresponding to the transmitted energy as reflected by the target area and the surface location. A radar processor is coupled to the receiver and is adapted to determine the range between the airborne platform and the surface location and determine the three-dimensional height of the target area from the detected signals.

Abstract: The present invention is in general related to automatic alignment in multi-sensor target tracking. The process of the invention repeatedly generates estimates for sensor bias errors (b) by minimising a function, given on one hand by the magnitude of the discrepancy between measurements (M) and a measuring model, where the measuring model is a function of the unknown target location and unknown bias parameters, and on the other by the bias parameters and their predetermined statistical distributions (15). In a preferred embodiment of the present invention, the minimizing step is performed by linearising components of the function around an approximate target position (normally obtained from the tracker (10)) and around nominal (typically zero) bias errors, and the function is subsequently minimized with respect to target positions as well as to the bias parameters (b). In addition, possible time dependence of the bias parameters are modelled by the incorporation of process noise.

Abstract: A radar device for use in backing up a vehicle is disclosed herein. A plurality of wave sensors is installed on a rear portion of a vehicle for detecting an obstacle therebehind. A master controller has a plurality of transceiver circuits and a microprocessor connected to the plurality of transceiver circuits. Each transceiver circuit corresponds to one of the plurality of wave sensors. The microprocessor activates the plurality of transceiver circuits to drive the plurality of wave sensors for transmitting and receiving ultrasound wave signals thereby determining the location of the obstacle. A location display device is connected to the master controller for receiving and decoding data related to the location of the obstacle thereby indicating the direction of the obstacle and displaying in numerical form the distance between the obstacle and the vehicle.

Abstract: A switching interface for routing RF signals. The interface comprises a buffer decoder which receives first, second and third control signals and then decodes the signals to selectively turn on five RF switches. The decoded output signals from the buffer decoder are supplied to five pair of switch drivers for the RF switches. When a logic one is provided to a switch driver, the switch driver sets the RF switch to an ON position. When a logic zero to a switch driver, the switch driver set the RF switch to an OFF position. A window comparator monitors the outputs of the switch drivers for each of the five RF switches. Whenever one of the two output signals from the switch drivers is within a preset voltage range the window comparator provides a logic one and a logic zero which are supplied to a bit decode circuit.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: The disclosure pertains to methods of fast exploration in azimuth by a surveillance radar antenna and to radars implementing such methods. The method consists in driving, at slow speed, an antenna comprising two elementary electronic scanning antennas installed back to back, simultaneously controlling the electronic aiming of each elementary electronic scanning antenna, switching over the microwave signal sent alternatively between the two elementary electronic scanning antennas and, before each rotation of the radar beam, initializing the electronic aiming of each elementary electronic scanning antenna at a determined angle &thgr;i. The radar comprises an antenna with two elementary electronic scanning antennas and an aiming computer. Application especially to a sea patrol radar.

Abstract: The marine Vessel Traffic System (VTS) is an improved radar harbor surveillance sensor, computer and display system that monitors marine harbor traffic, provides advisories to vessels in areas selected by the system operators, and provide the operators of the system with an early warning of unacceptable traffic conflicts in the confined waterways of the harbor. The VTS collects harbor traffic information from multiple remote sensor collection sites around the harbor and integrates, records, merges and presents the remote site data onto a single operator display, selected from a plurality of operator displays. VTS provides quick accurate computer generated graphic display of the harbor traffic, possible surface and subsurface conflicts, and key vessel identification information and the VTS documents incidents and traffic conditions for the Coast Guard or other waterway authorities.

Abstract: Man-machine interface (MMI) for airport traffic control purposes, in particular for safe taxiing and/or approach-departure control at an airport, having a display area on which processes and states at the airport, for example the movements and the current position of aircraft, the switching state of lighting systems, etc., can be displayed and influenced. The display area is designed with a screen whose diagonal is more than 19 inches, preferably more than 21 inches.

Abstract: The stopping of a load suspended from a crane requires a swing control or, respectively, a swing damping. Upon employment of microwave measuring units, spacings between a carrying cable suspension and a load suspension point are determined on the basis of transit time measurements. The position of the load suspension point can be determined from the transit time measurements quickly and with high precision. Swinging motions are avoided by controlled opposing control of the carrying cable suspension.

Abstract: The invention is a method for radar registration by determining initially unknown azimuth and range biases (errors) in a system of multiple, overlapping coverage radars. Track data from multiple radar systems corresponding to a common target are associated into track pairs. Track pair data is then used to calculate state vectors in a multi-dimensional vector space (preferably six-dimensional), with state vector components corresponding to both position and velocity information. From these state vectors an average normalized statistical distance is calculated, where the averaging is over multiple track pairs. An azimuthal bias parameter (and preferably also a range bias parameter) are then varied to minimize the average normalized statistical distance, thereby finding the best estimates of the corrections required to register the multiple radars.