Era Systems Corporation

Sra International, Inc.

Carl A Evers

Alexander E Smith

Thomas J Breen

Russell Hulstrom

Yue Xie

Vadim Kozhevnikov

A system and method are disclosed to track aircraft or other vehicles using techniques including multilateration and elliptical surveillance. Unlike conventional approaches that use time difference of arrival for multilateration at a fixed set of reception points, this technique allows targets to be tracked from a number of dynamic or moving reception points. This allows for triangulation/multilateration and elliptical surveillance of targets from combinations of fixed, fixed and moving or only moving ground-based receivers, sea-based receivers, airborne receivers and space-based receivers. Additionally this technique allows for ADS-B validation through data derived from only two receivers to assess the validity and integrity of the aircraft self-reported position by comparing the time of arrival of the emitted message at the second receiver to the predicted time of message arrival at the second receiver based on the self-reported position of the aircraft and the time of arrival at the first receiver. The benefits of using less than three receivers for validation include greater validation coverage areas using a smaller set of ground stations at a lower infrastructure cost.

Method and apparatus for ADS-B validation, active and passive multilateration, and elliptical surveillance

A simplified multilateration and ADS-B Surveillance System is used, to perform tagging for the FAA Low Cost Ground Surveillance program. This system may also be used as the foundation for a full multilateration system, if a customer wants to upgrade. The present invention uses just one active transmitter/receiver unit as opposed to multiple passive receivers. The present invention captures UF 5 and DF 5 data, thus providing Mode A identification, which then acts as the key to obtaining the call sign from a data fusion packages&#x2014;thus making it an affordable and marketable product for small to medium-sized airports.

Aircraft tracking using low cost tagging as a discriminator

In a first, preferred embodiment of the present invention, integrated tracking is provided using passive broadband. The invention takes the system for deployable passive broadband detection and extends it by incorporating the capability to decode position for ADS-B, SSR multilateration, and broadband multilateration. In a second embodiment, validation of a self-reported position is provided. The invention takes the system for deployable passive broadband detection and extends it by incorporating the capability to decode self-reported position for ADS-B, and compare it to line of calculated position, or line of precision, derived from multilateration techniques applied to various signals received from the aircraft. In a third embodiment, validation of a self-reported ADS-B position using independent surveillance is provided by the system.

Deployable passive broadband aircraft tracking

Method and apparatus for ADS-B validation, active and passive multilateration, and elliptical surviellance

A method and system are provided for performing elliptical-based and hybrid surveillance, performing false target detection and resolution, and performing integrity monitoring using one or more receiving and transmitting elements time synchronized to a common precision time reference, and a central workstation. Antennas for transmitting and receiving elements are located at known positions separated from one another. At a given time, one of the transmitting elements transmits an interrogation signal to one or more targets, which respond to the interrogation with a reply transmission, received by one or more receiving elements. The central workstation calculates each target's ellipse of position with respect to each receiving element, using the interrogator element time of interrogation measurement and each receiving element's time of arrival measurement for the corresponding reply transmission, and then fuses the elliptical line of positions for each receiving element to compute target positions or augment passive surveillance position. At a scheduled time, the one or more transmitting elements transmit a reference signal to the receiving elements(s). The central workstation uses each of the receiving elements time stamped signals to perform integrity monitoring.

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Vienna, VA, United States of America

Carl A Evers