35 results about "FDOA" patented technology

A system and method for determining the geolocation of a signal emitter moving at an unknown velocity by combining signal data of a target detection platform (e.g., a radar system) and signal data collected by two or more moving signal collection platforms (e.g., RF signal receivers). In one embodiment, the target detection platform determines tentative location and velocity of the signal emitter, and the signal collection platforms are configured to perform TDOA and / or FDOA analysis of the collected signal data corresponding to a signal of the signal emitter. In one embodiment, solutions provided from the TDOA and / or FDOA analysis are unbiased by using the tentative velocity of the signal emitter, and the geolocation of the signal emitter is determined by matching the TDOA / FDOA solutions and the detected tentative location.

Systems and methods for detection and geolocation of multiple emitters that are emitting RF signal energy on a common frequency, and that may be implemented to separate, geolocate, and / or determine the number of emitters (e.g., radio users) emitting on a common RF frequency. Real-time signal qualification processing may be employed to continuously monitor and collect incoming receiver tuner data for signal activity and ignore irrelevant noise data. Each set of data blocks from an emitter transmission signal may be defined as an emission cluster, and a set of time difference of arrival (TDOA) / frequency difference of arrival (FDOA) pairs may be computed for each emission cluster with each TDOA / FDOA pair yielding a geolocation result. A statistical qualification method may be used to produce a final geolocation answer from each set of emission cluster geolocation results, and a geolocation error ellipse computed for the final geolocation answer of each emission cluster. The final geolocation answer of each emission cluster may be run through a correlation and fusion algorithm.

Systems and methods that may be implemented to determine the location of an emitter of electromagnetic radiation having an unknown location, using a cooperative TDOA-based location methodology. The cooperative TDOA-based location methodology (e.g., such as TDOA / TDOA, TDOA / FDOA, etc.) may be implemented using at least one cooperative transmitter that transmits a cooperative electromagnetic (EM) signal from a known location that is received at multiple different EM sensing platforms that are also each of known location. The known geolocation of the cooperative transmitter may be used to resolve the signal arrival timing relationships between the different sensing platforms that is utilized to determine the location of another EM transmitter of unknown location.

The invention relates to a rapid positioning method of a binary TDOA / FDOA satellite-to-earth integration positioning system. According to the invention, problems that exist during accurate estimation of a TDOA / FDOA and rapid positioning in a binary positioning system can be solved. The method comprises the following steps that: a binary TDOA / FDOA positioning model is constructed; and a real-time combination estimation is carried out on a TDOA and an FDOA through a fourth order cumulant two dimensional separation parameter estimation method; object location is carried out through an IMM-UKF filtering method; and then, a relationship between a positioning precision and a signal to noise ratio of a receiving signal is analyzed; at last, a situation of an influence of all factors on a positioning error is analyzed. According to the invention, a complete and trusted assessment can be carried out on a positioning system; there is no requirement on a type of a signal that is emitted by a ground radiation source and thus the rapid positioning method has a strong adaptability and a wide application range; moreover, the method has good anti-noise and anti-interference capabilities; and a positioning convergence rate is high and a high positioning precision can be reached. Therefore, the invention has a high practical application value.

Systems and methods that may be implemented to determine the location of an emitter of electromagnetic radiation, such as an RF signal emitter having an unknown location, using at least two electromagnetic radiation sensor antennas that are co-located on a single sensing platform in combination with at least one other electromagnetic radiation sensor antenna located on another sensing platform.

Systems and methods that may be implemented to determine the location of an emitter of electromagnetic radiation, such as an RF signal emitter having an unknown location, using at least two electromagnetic radiation sensor antennas that are co-located on a single sensing platform in combination with at least one other electromagnetic radiation sensor antenna located on another sensing platform.

Systems and methods that may be implemented to determine the location of an emitter of electromagnetic radiation having an unknown location, using a cooperative TDOA-based location methodology. The cooperative TDOA-based location methodology (e.g., such as TDOA / TDOA, TDOA / FDOA, etc.) may be implemented using at least one cooperative transmitter that transmits a cooperative electromagnetic (EM) signal from a known location that is received at multiple different EM sensing platforms that are also each of known location. The known geolocation of the cooperative transmitter may be used to resolve the signal arrival timing relationships between the different sensing platforms that is utilized to determine the location of another EM transmitter of unknown location.

Systems (100) and methods (400) for space-based geolocation. The methods involve receiving by at least two first satellites a maritime signal transmitted from a vessel on or near Earth. The first satellites are deployed in space so as to have overlapping coverage areas. The maritime signal (received at the at least two first satellites) is then used to determine a geographic location of the vessel on Earth using at least one of a Time Difference of Arrival (“TDOA”) and a Frequency Difference of Arrival (“FDOA”).

Systems and methods for detection and geolocation of multiple emitters that are emitting RF signal energy on a common frequency, and that may be implemented to separate, geolocate, and / or determine the number of emitters (e.g., radio users) emitting on a common RF frequency. Real-time signal qualification processing may be employed to continuously monitor and collect incoming receiver tuner data for signal activity and ignore irrelevant noise data. Each set of data blocks from an emitter transmission signal may be defined as an emission cluster, and a set of time difference of arrival (TDOA) / frequency difference of arrival (FDOA) pairs may be computed for each emission cluster with each TDOA / FDOA pair yielding a geolocation result. A statistical qualification method may be used to produce a final geolocation answer from each set of emission cluster geolocation results, and a geolocation error ellipse computed for the final geolocation answer of each emission cluster. The final geolocation answer of each emission cluster may be run through a correlation and fusion algorithm.

The invention discloses a direct positioning method based on time difference and frequency difference. In view of a passive dual-satellite time difference and frequency difference positioning problem, the invention discloses a positioning method of firstly determining a target position range based on TDOA (Time Difference Of Arrival) and then based on a FDOA (Frequency Difference Of Arrival) model, the FDOA does not need to be measured, the difficulty of solving the time difference and the frequency difference is avoided, and the positioning precision is higher than that in a method of firstly measuring the FDOA and then performing positioning. Compared with the method of firstly measuring the time difference and the frequency difference and then performing positioning, the method of the invention has the advantages of simple processing and high positioning precision, and particularly in a condition of a low signal to noise ratio, the positioning precision has large advantages. The method does not need to change hardware design of the positioning system only needs to adopt a new positioning algorithm and is applied to engineering application and promotion. The dual-satellite time difference and frequency difference positioning precision can be improved, and a certain reference value is provided for positioning of other platforms and other positioning mechanisms.

The invention relates to a method and to a system for locating a transmitter E transmitting a signal to a receiver A comprising N channels (N=1), the characteristics of said signal being unknown to the receiver and said signal being reflected by P reflectors Bi (P=1) with known positions, characterised in that the method comprises at least the following steps: Step 1: a step of multi-channel joint estimation / detection of the time differences of arrival or TDOA ti and the frequency differences of arrival or FDOA fi of each reflected ray; Step 2: a step of angular estimation of the direction Theta 1 of the direct ray of the signal emitted using a goniometry method; Step 3: a step of locating the position (x, y) of transmitter E in the plane at least on the basis of the pairs (ti, fi).

A system and method for determining the geolocation of a signal emitter moving at an unknown velocity by combining signal data of a target detection platform (e.g., a radar system) and signal data collected by two or more moving signal collection platforms (e.g., RF signal receivers). In one embodiment, the target detection platform determines tentative location and velocity of the signal emitter, and the signal collection platforms are configured to perform TDOA and / or FDOA analysis of the collected signal data corresponding to a signal of the signal emitter. In one embodiment, solutions provided from the TDOA and / or FDOA analysis are unbiased by using the tentative velocity of the signal emitter, and the geolocation of the signal emitter is determined by matching the TDOA / FDOA solutions and the detected tentative location.

The invention discloses an external radiation source TDOA / FDOA error correction based positioning method. For the problem of external radiation source positioning under a system deviation in measurement, according to obtained TDOA and FDOA measurement information, an auxiliary variable is introduced to convert a nonlinear equation into a pseudo linear equation; an estimation model for a target position, a speed and the system deviation is built; and estimation is performed by adopting an iterative weighted least square method. A correlation least square estimation model is built by utilizing the correlation between the auxiliary variable, and the target position and the speed; and an estimation result is improved by means of correlation weighted least squares. The target position, the speed and the system deviation are jointly estimated to improve the target positioning precision. The auxiliary variable is introduced to reasonably convert a nonlinear measurement model into a pseudo linear estimation model, so that the complexity of the external radiation source positioning is reduced on the premise that the estimation performance is ensured.

The invention discloses a passive radar time difference and frequency difference coordinated positioning method under errors of a motion observation station. In view of an external illuminator positioning problem under errors of a position and a speed of the motion observation station, according to acquired TDOA and FDOA measurement, a range and a range rate are introduced as intermediate variables to enable a strong nonlinear equation to be subjected to pseudolinearization, and a target position and speed estimation model is built. According to a measurement error variance, and the observation station position and speed errors, an optimal weight is designed, and estimation is carried out by adopting an iterative weighted least square method. A correlation least square estimation model isbuilt by using the correlation between the intermediate variables and the target position and the speed, and the above target position estimation result is improved. By introducing the intermediate variables, a nonlinear measurement model is reasonably transformed to pseudolinearization, the external illuminator positioning complexity is reduced on the premise of ensuring the estimation performance, and influences on target positioning performance by errors of the observation station are reduced.

The invention relates to a time difference of arrival / frequency difference of arrival estimation method of high and low-orbit double-star high-time-varying received signals. The invention aims to solve the problem of large error and large calculation quantity of TDOA (time difference of arrival) / FDOA (frequency difference of arrival) estimation of a high and low-orbit double-star passive positioning system. According to the method of the invention, two segments of data of which the time lengths are equal are adopted to estimate the change rage of frequency difference of arrival, and the estimated values of the TDOA (time difference of arrival) and FDOA (frequency difference of arrival) at the start time point of data acquisition can be calculated accurately. The implementation process of the invention includes the following steps that: (1) two segments of data of which the time lengths are equal are acquired; (2) TDOA and FDOA are jointly estimated; and (3) the estimated values of the TDOA (time difference of arrival) and FDOA (frequency difference of arrival) at the start time point of data acquisition are calculated. With the method of the invention adopted, the fast and accurate estimation of the TDOA and FDOA of high-time-varying received signals in the high and low-orbit double-star passive system can be realized. The method has a high practical value.

The invention discloses a moving target positioning method based on a TDOA (Time Difference of Arrival) and an FDOA (Frequency Difference of Arrival). The moving target positioning method comprises the steps of: setting that one moving target for transmitting a signal, one mobile sensor used for receiving the signal and used as a reference sensor and a plurality of mobile sensors only used for receiving the signal exist; then calculating a distance difference between a transmission distance from the moving target to each mobile sensor only used for receiving the signal and a transmission distance from the moving target to the reference sensor and a distance difference change rate; next, calculating initial values of a position and a speed of the moving target; then determining a positioning problem of the moving target so as to solve to obtain an accurate estimated value of the position of the moving target; and finally, optimizing an estimated value of the speed of the moving target by utilizing the accurate estimated value of the position so as to obtain an accurate estimated value of the speed. The moving target positioning method has the advantages that the position and the speed of the moving target can be accurately estimated; calculation complexity is low; and running time is short.

The invention discloses a moving radiation source TDOA and FDOA positioning method based on a weighted multidimensional scale and the Lagrange multiplier technology. The method comprises the followingsteps: simultaneously obtaining a TDOA observed quantity and an FDOA observed quantity of a motion radiation source signal by utilizing a plurality of motion sensors, and constructing two scalar product matrixes by utilizing a distance difference observed quantity and a distance difference change rate observed quantity so as to form a multi-dimensional scale pseudo-linear equation; quantitativelyanalyzing the influence of TDOA / FDOA observation errors on the pseudo-linear equation so as to determine an optimal weighting matrix; constructing two quadratic equation constraints by utilizing algebraic characteristics of an augmented unknown vector, and constructing a biquadratic equation constraint weighted least square optimization model in combination with a pseudo-linear equation; and finally, performing numerical optimization on the model by utilizing the Lagrange multiplier technology, obtaining an optimal solution of a Lagrange multiplier by utilizing Newton iteration, and further obtaining estimated values of a radiation source position vector and a radiation source speed vector. According to the invention, the positioning precision of the moving radiation source can be furtherimproved.

A method and system for locating an emitter E transmitting a signal toward a receiver A comprising N radio frequency channels (N≧1), the characteristics of said signal being unknown to the receiver and said signal being reflected off P reflectors Bi (P≧1) of known positions, includes a step of multi-channel joint estimation / detection of the time differences of arrival or TDOA τi and of the frequency differences of arrival or FDOA fi for each reflected path, a step of angular estimation of the direction θ1 of the direct path of the signal emitted by a goniometry procedure, and a step of location in the plane of the position (x,y) of the emitter E on the basis, at least, of the pairs (τi, fi).

The invention discloses a method and a system for positioning ground co-frequency multiple stationary radiation sources based on time-frequency difference, and belongs to the field of positioning technology. The method comprises steps of performing time-frequency difference estimated measurement for multiple targets including co-frequency radiation sources to obtain all measurement vectors including time-frequency fuzzy information; performing GM-UKF-PHD filtering on all the measurement vectors, and releasing the time-frequency difference blur to obtain the states of the radiation sources including weight information; and using a target state extraction method based on the weight threshold to extract states of multiple stationary radiation sources. The method and the system of the presentinvention use the GM-UKF-PHD filtering algorithm to perform multi-target state estimation according to the observed TDOA and FDOA measurement at multiple times, and improve the positioning accuracy ofthe radiation sources while solving the time-frequency difference blur. For lower frequency bands such as UHF and L / S, the method and the system have a large reference value for improving the positioning accuracy of low-band multi-ground stationary radiation sources because multiple co-frequency signals are often received at the same time.

The invention discloses an unmanned aerial vehicle high-precision positioning method based on TDOA and FDOA, wherein the method comprises the following steps: receiving a TDOA measurement value and anFDOA measurement value through a receiving station in space, and enabling the TDOA measurement value and the FDOA measurement value to be equivalent to a distance difference measurement value and a distance difference change rate measurement value; performing joint estimation on the position coordinates of the receiving station to construct a to-be-estimated vector; constructing expressions between the corresponding distance difference measurement value, the distance difference change rate measurement value and the receiving station position measurement value and the to-be-estimated vector; solving a nonlinear weighted least square optimization model of a cost error function; solving an optimal closed-form solution of the to-be-estimated vector through Taylor series joint iteration; and obtaining the position and speed of the target when an iteration termination condition is satisfied. According to the method, the position coordinates of the receiving station are subjected to joint iterative estimation, so that the influence of the position error of the receiving station on the positioning precision is reduced; and a more accurate iterative initial value is provided by utilizing positioning error correction, and the target positioning precision is improved while the convergence is ensured and the convergence speed is improved.

The invention discloses a heterogeneous information fusion positioning method based on deep learning, and belongs to the technical field of radiation source positioning. According to the invention, based on various specified positioning parameters, fusion positioning of heterogeneous information based on deep learning is realized. Positioning parameters are converted into a thermodynamic diagram, radiation source position estimation is regarded as a key point detection problem in the thermodynamic diagram, end-to-end training and testing are directly carried out, and the implementation complexity is low. Compared with a traditional fusion positioning method, different parameter information at different sensing nodes can be fused, the assumed condition that all the distributed sensing nodes can obtain multiple parameters at the same time is not needed, and the actual dynamic environment requirement can be better met. According to the invention, during actual positioning processing, the same network model can be used regardless of one, two or three of RSS, AOA or TDOA parameters, and the adaptability is good. Meanwhile, the method can be expanded to fusion positioning containing more heterogeneous information such as TOA, FDOA and other parameters.

The invention relates to a multi-moving-target positioning method based on an improved TDOA / FDOA algorithm, and mainly solves the problems that the adaptive capacity of noise errors is poor and the positioning precision is limited when a traditional algorithm is used for positioning a plurality of dynamic targets. The method comprises the following steps: firstly, setting K moving targets which do not coincide with one another in a three-dimensional space, deploying M sensors, and acquiring a measurement vector of target information; then constructing a TDOA / FDOA positioning equation set about the position information of the target and the sensor so as to estimate the speed and the position of the target; constructing a global constraint condition according to a relationship between the targets and additional variables, introducing a Lagrange multiplier technology, and adopting a quasi-Newton BFGS iterative formula to solve a positioning equation. According to the method, constraint conditions are comprehensively and systematically considered, and the Lagrange multiplier technology and the quasi-Newton BFGS iterative formula are introduced, so that calculation of a Hessian matrix is avoided, the calculation amount is greatly reduced, and the positioning precision is improved.

The invention discloses a moving radiation source TDOA and FDOA positioning method based on weighted multidimensional scale and Lagrangian multiplier technology. Firstly, a plurality of motion sensors are used to simultaneously obtain TDOA observations and FDOA observations of moving radiation source signals, Two scalar product matrices are constructed by using the distance difference observations and the distance difference change rate observations, thus forming a multi-dimensional scale pseudo-linear equation; and then quantitatively analyzing the influence of TDOA / FDOA observation errors on the pseudo-linear equation to determine the optimal weight matrix; then use the algebraic characteristics of the augmented unknown vector to construct two quadratic equality constraints, and combine the pseudo-linear equation to construct a biquadratic equality constraint weighted least squares optimization model; finally use the Lagrangian multiplier technique for this The model is numerically optimized, in which the optimal solution of Lagrangian multipliers is obtained by Newton iteration, and then the estimated values ​​of the position vector and velocity vector of the radiation source are obtained. The invention can further improve the positioning accuracy of the moving radiation source.

The invention provides a TDOA / FDOA estimation precision improving method based on singular value decomposition, and the method comprises the steps: step 1, constructing a global expansion matrix gammacomposed of a TDOA / FDOA measurement value and a second order of the TDOA / FDOA measurement value, assuming that M targets exist, the positions and speeds of the M targets being xm, and d representingthe dimension; step 2, performing singular value decomposition on the global expansion matrix gamma, and reconstructing the global expansion matrix gamma by using the maximum 2M+2d singular values; and step 3, constructing a local expansion matrix and carrying out singular value decomposition on the local expansion matrix, reconstructing the local expansion matrix by using the maximum 6d+4 singular values of the local expansion matrix, and repeating the process for n times until the change of the TDOA / FDOA measurement values of the previous and later two times is smaller than a preset range, nbeing a natural number. Simulation experiments prove that the method can improve the estimation precision of the TDOA / FDOA measurement value.

The invention discloses a passive target positioning method and system based on TDOA and FDOA measurement. The method comprises the following steps: obtaining measurement information and receiving station position information; converting the position information of the receiving station to an earth-centered earth-fixed coordinate system; establishing a measurement equation according to the measurement information and the position information of the receiving station under the earth-centered earth-fixed coordinate system; performing deformation processing on the measurement equation in combination with prior information; and solving a target position vector by using the deformed measurement equation to obtain an estimated value of a target coordinate. According to the method, target prior range information is introduced, the range prior information is processed and then converted into an approximate value of an undetermined target height coordinate, and due to the acquisition of an additional coordinate, the fuzziness of three-station TDOA and double-station TDOA-FDOA positioning is avoided. According to the method, in the process of solving the target coordinates, the parameter-containing coordinate result is directly brought to the theoretical definition constraint formula to solve the parameters, introduction of additional errors is avoided, and the final positioning error is reduced.

The invention discloses a method and a system for positioning ground co-frequency multiple stationary radiation sources based on time-frequency difference, and belongs to the field of positioning technology. The method comprises steps of performing time-frequency difference estimated measurement for multiple targets including co-frequency radiation sources to obtain all measurement vectors including time-frequency fuzzy information; performing GM-UKF-PHD filtering on all the measurement vectors, and releasing the time-frequency difference blur to obtain the states of the radiation sources including weight information; and using a target state extraction method based on the weight threshold to extract states of multiple stationary radiation sources. The method and the system of the presentinvention use the GM-UKF-PHD filtering algorithm to perform multi-target state estimation according to the observed TDOA and FDOA measurement at multiple times, and improve the positioning accuracy ofthe radiation sources while solving the time-frequency difference blur. For lower frequency bands such as UHF and L / S, the method and the system have a large reference value for improving the positioning accuracy of low-band multi-ground stationary radiation sources because multiple co-frequency signals are often received at the same time.

The invention discloses a method for estimating time-frequency difference of a time-frequency aliasing signal, which relates to the technical field of electronic reconnaissance. The frequency-domain cross-correlation operation is performed on an input signal to obtain a correlation function; Domain cross-correlation operation to find the correlation function of the communication signal; subtract the correlation function of the communication signal from the correlation function of the aliasing signal to obtain the correlation function of the interference signal; change the amplitude of the correlation function of the communication signal to calculate the peak of the correlation peak of the interference signal The TDOA and FDOA values ​​of the interference signal can be estimated by taking the maximum peak-to-average ratio. The present invention constructs the time difference-frequency difference maximum likelihood estimation model of aliasing signals, and adopts the method of linear subtraction to remove the correlation peak of one of the signals, thereby obtaining the correlation peak of the other signal, and according to the peak-to-average ratio of the final correlation peak , to estimate the peak value of one signal, and then obtain the global maximum value of the other signal, which is the estimated time difference-frequency difference.

The invention discloses a method for tracking a mobile radiation source by multiple drones based on position and velocity errors, which solves the problem of tracking a mobile radiation source when the drones have position and velocity errors in two-dimensional space. The implementation steps of the present invention are: randomly select an unmanned aerial vehicle as the main machine, and the remaining unmanned aerial vehicles are auxiliary machines; calculate the time difference of arrival TDOA measurement value and the frequency difference FDOA measurement value of each auxiliary machine and the main machine; The difference between the distance between the drone and the radiation source and the distance between the host and the radiation source and the rate of change of the difference; estimate the position vector and velocity vector of the radiation source when there is a state error between the main and auxiliary drones; update the state vector of the radiation source; calculate the main , the optimal heading angle of the auxiliary UAV; each UAV independently selects a single-step flight trajectory. The invention uses the position and speed error of the drone to plan the optimal track of the drone, has a simple geometric positioning model, improves the tracking performance, and can be used for positioning and tracking of mobile radiation sources.

The invention discloses a moving target positioning method based on a TDOA (Time Difference of Arrival) and an FDOA (Frequency Difference of Arrival). The moving target positioning method comprises the steps of: setting that one moving target for transmitting a signal, one mobile sensor used for receiving the signal and used as a reference sensor and a plurality of mobile sensors only used for receiving the signal exist; then calculating a distance difference between a transmission distance from the moving target to each mobile sensor only used for receiving the signal and a transmission distance from the moving target to the reference sensor and a distance difference change rate; next, calculating initial values of a position and a speed of the moving target; then determining a positioning problem of the moving target so as to solve to obtain an accurate estimated value of the position of the moving target; and finally, optimizing an estimated value of the speed of the moving target by utilizing the accurate estimated value of the position so as to obtain an accurate estimated value of the speed. The moving target positioning method has the advantages that the position and the speed of the moving target can be accurately estimated; calculation complexity is low; and running time is short.

The invention discloses an external radiation source TDOA / FDOA error correction based positioning method. For the problem of external radiation source positioning under a system deviation in measurement, according to obtained TDOA and FDOA measurement information, an auxiliary variable is introduced to convert a nonlinear equation into a pseudo linear equation; an estimation model for a target position, a speed and the system deviation is built; and estimation is performed by adopting an iterative weighted least square method. A correlation least square estimation model is built by utilizing the correlation between the auxiliary variable, and the target position and the speed; and an estimation result is improved by means of correlation weighted least squares. The target position, the speed and the system deviation are jointly estimated to improve the target positioning precision. The auxiliary variable is introduced to reasonably convert a nonlinear measurement model into a pseudo linear estimation model, so that the complexity of the external radiation source positioning is reduced on the premise that the estimation performance is ensured.