Abstract: A transmitter provides a plurality of output signals. The transmitter includes a processor, a modulator, a first circuit, and a second circuit. The modulator provides a modulated signal responsive to the processor. The modulated signal includes an amplitude modulated radio frequency for transmitting a pulse. The first circuit provides a first output signal, responsive to and with higher power than the modulated signal. The first output signal has a first phase during transmitting of the pulse. The second circuit provides a second output signal, responsive to and with higher power than the modulated signal. The second output signal has a second phase during transmitting of the pulse. The second phase is controlled by the second circuit in accordance with the first phase, the second phase, and indicia of a third phase provided by the processor.

Abstract: A method according to the present invention includes transmitting a Mode S interrogation and receiving a response from an aircraft that has received the Mode S interrogation. A range to the aircraft is determined based on a time period between transmitting the Mode S interrogation and receiving the response. The method further includes receiving information from one or more data sources and determining at least one of a bearing to the aircraft and a position of the aircraft using the determined range and the information from the one or more data sources. Information can be received from any number (or type) of data sources, such as ADS-B-equipped aircraft.

Abstract: There are presented various approaches to monitor performance of RF systems and circuitry such as those used in aircraft transponders. Such monitoring may be designed to verify operational performance of transponders as set forth by FAA regulations, or may be used to periodically or continually monitor integrity of transponder performance. Data may be collected by such periodic or continual monitoring, and may be analyzed to identify potentially troublesome trends in transponder performance, allowing early intervention or repair, if warranted.

Abstract: There is presented a system and method for providing aircraft runway guidance. One delineated runway alert system for a host aircraft comprises: a processor for executing one or more instructions that implement one or more functions of the runway alert system; a data storage device including geographical runway information; a receiver for obtaining current location data of the host aircraft; an apparatus to provide a current heading of the host aircraft; a data entry device for receiving data indicating a desired runway; memory for storing the one or more instructions for execution by the processor to implement the one or more functions of the runway alert system to: receive the identity of the desired runway; provide an indicia of: the desired runway; and the position of the host aircraft in relation to the desired runway.

Abstract: A transmitter provides a plurality of output signals. The transmitter includes a processor, a modulator, a first circuit, and a second circuit. The modulator provides a modulated signal responsive to the processor. The modulated signal includes an amplitude modulated radio frequency for transmitting a pulse. The first circuit provides a first output signal, responsive to and with higher power than the modulated signal. The first output signal has a first phase during transmitting of the pulse. The second circuit provides a second output signal, responsive to and with higher power than the modulated signal. The second output signal has a second phase during transmitting of the pulse. The second phase is controlled by the second circuit in accordance with the first phase, the second phase, and indicia of a third phase provided by the processor.

Abstract: A system for use with aircraft having a collision avoidance system which employs i) two transponder systems each including two antennas and a selected one of two transponders and ii) a failure warning when a transponder system failure occurs, to permit the aircraft to take off when the failure warning is the result of only one antenna failure.

Abstract: In a Traffic Alert and Collision Avoidance System on an aircraft having a plurality of antennas, an optimal bearing value is obtained for each target aircraft by generating a target data block for each response to an interrogation, each target data block including a measured bearing value and an associated priority code. A priority code is assigned based on the antenna receiving the information, and the number of valid bearing measurements used to determine a measured bearing value for the reply. If more than one target data block is obtained in a surveillance period, one target data block is retained based on predetermined criteria. The measured bearing value of all the target data blocks having the same, highest priority code are selected or combined, the result being saved in the target data block. The priority codes are then used to select the proper reply bearing measurement, the bearing track update filtering parameters, and to aid in the reply qualification for bearing track initialization.

Abstract: During ATCRBS surveillance procedures, a multiplicity of target aircraft are typically detected through target replies from interrogation signals. However, the nature of the target acquisition procedures are such that positive identification of the target aircraft is not available. Rather than ordering the target tracks with increasing range and correlating the target replies with tracks based on the ordering of the target tracks, the tracks are prioritized, based on confidence in the reliability of the identification of each track, into groups. An attempt to correlate the tracks of each group with the set of target replies is performed for the groups in order of decreasing priority. A target reply is assigned to a track when a correlation between a track and a target reply is determined.

Abstract: In a Traffic Alert and Collision Avoidance System (TCAS), response to interrogations can result in normal, multipath (image), and mixed multipath (potential image) tracks. The method for reducing the number of false tracks includes the steps of selecting a track to be updated from an existing track list. The selected track has the shortest measured range within the highest priority category track. A reply which has not yet been utilized is selected which has parameters which are within predetermined windows of the selected track parameters. (The predetermined windows are equal to or smaller than the windows for lower priority targets.) The selected track is updated using .alpha..beta..gamma. range squared filter, and the selected reply is marked as used. After all tracks are updated, the unused replies are tested to generate new tracks. Then all the tracks are examined to insure that predetermined track category criteria are met, otherwise the track is recategorized.

Abstract: A system wherein TCAS transmissions have two jitter components added to the jitter component utilized in the interscan interval to minimize TCAS interference with ground station operation. The jitter components minimize the establishment of false intruder tracks caused by responses to ground station interrogations or interrogations by other TCAS interrogators which are received in synchronism with the TCAS interrogation signals.

Abstract: An apparatus for electronically narrowing the beam width of interrogation transmissions of an interrogator utilizes three beams of the four beam system not used as the main beam for the transmission of suppression pulses. One side of the main beam is suppressed by the first sidelobe suppression pulse of the interrogation pulse sequence and then the other side of the main beam is suppressed by the second sidelobe suppression pulse within the interrogation pulse sequence. In another mode of operation, the interrogation beam width is controlled by transmitting a suppression pulse on a beam positioned 180.degree. from the main beam. This electronic narrowing of the interrogation beam width reduces the number of overlapping replies received by the interrogator and enables the interrogator to properly sort out and not lose or misinterpret replies received by proximity transponder equipped aircraft.