Methods and apparatus are provided for a traffic warning system (TWS) for light aircraft. The TWS comprises a processor coupled to a transceiver, adapted to measure signal strength and send/receive messages containing station ID and preferably altitude and position data. Memory, display and various flight data instruments, such as GPS, altimeter, etc., are also coupled to the processor. The transceiver-processor automatically identifies TWS equipped aircraft within range using an ad-hoc network and exchanges ID and position information. The processor determines range from signal strength and/or received position information and, given enough data, determines direction, altitude, speed, etc., of the other aircraft, which it presents to the pilot. These values and their rate of change are compared to stored alarm thresholds, and the pilot is warned when another aircraft triggers the threshold. Evasive action is recommended where possible.

The present invention is a combined aircraft TCAS/Transponder with common antenna system and transmitter. Common TCAS/Transponder multi-monopole top and bottom antennas may be connected to a top and bottom antenna modules, the top and bottom antenna modules being electrically coupled to the combined TCAS/Transponder transmitter/receiver block through connection lines.

A direction finding antenna system for determining the relative bearing of a second aircraft from a first aircraft in conjunction with a Traffic Alert Collision Avoidance System (TCAS). The system includes a first antenna and a second antenna located on a top surface of the first aircraft, spaced apart along a first axis, as well as a third antenna and a fourth antenna located on a bottom surface of the first aircraft, spaced apart along a second axis orthogonal to the first axis. The system further includes a transmitting, receiving, and processing system coupled to the first, second, third, and fourth antennas, wherein the transmitting, receiving, and processing system is configured to transmit TCAS interrogations, receive TCAS replies, and process the TCAS replies to determine the relative bearing of the second aircraft from the first aircraft.

A station for assisting the control of an aircraft includes warning means (5) adapted to deliver an alert for avoiding a later collision when there is a risk that the predicted flight trajectory of the aircraft crosses any predicted flight path of another aircraft. An arrangement (4) is adapted to determine whether the aircraft carrying said station is within an airspace volume with defined geometrical dimensions and time of appearance and disappearance or not and make the function of the warning means dependent upon this comparison by, when located in said airspace volume, deactivating said warning means with respect to other aircraft of a predefined identity, and when not located in said airspace volume, activate or keep the function of said warning means activated with respect to aircraft of said predefined identity. (FIG. 1).

A system and method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system, wherein the method includes the steps of providing a standard ADS-B transmitter and encoder, a phase modulator including a digital synthesizer, radio-frequency electronics, antennas, and a radar transceiver; synthesizing digital-based band signals from the ADS-B transmitter with additional random phase modulation using the digital synthesizer; using the antennas to both transmit and receive signals; and estimating angles-of-arrival for every target in a field-of-view. The method may include the steps of demodulating the signals received by the antennas, providing a digital signal processor, and performing matched filtering on received signals. The method may also include the step of estimating a target range of identified targets using the digital signal processor.