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 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 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 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).

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 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.