Abstract: A method of validating ADS-B is described herein. The method includes receiving, from time synchronized vehicles, ADS-B data (identifier, horizontal position information, and altitude information for a first vehicle) with a timestamp (defining a time of reception of the ADS-B message). The method includes receiving, from each vehicle, a determined position at the time of reception of the ADS-B message. The method includes determining differences in time of arrival for the ADS-B message to each vehicle, extracting altitude information from the ADS-B data, and determining an estimated horizontal position of the first vehicle based on the differences in time of arrival, the determined positions received from each vehicle, and the extracted altitude information. The method includes determining whether the horizontal position information in the ADS-B message is valid based on a comparison of the estimated horizontal position of the first vehicle and the horizontal position information in the ADS-B message.

Abstract: In some examples, a system that mounts on a vehicle includes a transceiver configured to transmit a first surveillance message including a first value for a quality parameter, wherein the first value indicates a first level of integrity or accuracy for the first surveillance message. The transceiver is also configured to receive a reply message to the first surveillance message. The system also includes processing circuitry configured to determine a second value for the quality parameter in response to the transceiver receiving the reply message, wherein the second quality parameter indicates a second level of integrity or accuracy for surveillance messages transmitted by the transceiver, and wherein the second level of integrity or accuracy is higher than the first level. The transceiver is configured to transmit a second surveillance message including the second value for the quality parameter in response to the processing circuitry determining the second quality parameter.

Abstract: In some examples, a system includes a receiver configured to receive communication from a traffic management system and a transmitter configured to transmit surveillance messages. The system also includes processing circuitry configured to determine, in a first instance, that the receiver has not received a command signal from the traffic management system. The processing circuitry is also configured to suppress transmission of surveillance messages by the transmitter in response to determining that the receiver has not received the command signal. The processing circuitry is further configured to determine, in a second instance, that the receiver received the command signal from the traffic management system. The processing circuitry is configured to cause the transmitter to transmit the surveillance messages in response to determining that the receiver received the command signal.

Abstract: In some examples, a system that mounts on a vehicle includes a transceiver configured to transmit a first surveillance message including a first value for a quality parameter, wherein the first value indicates a first level of integrity or accuracy for the first surveillance message. The transceiver is also configured to receive a reply message to the first surveillance message. The system also includes processing circuitry configured to determine a second value for the quality parameter in response to the transceiver receiving the reply message, wherein the second quality parameter indicates a second level of integrity or accuracy for surveillance messages transmitted by the transceiver, and wherein the second level of integrity or accuracy is higher than the first level. The transceiver is configured to transmit a second surveillance message including the second value for the quality parameter in response to the processing circuitry determining the second quality parameter.

Abstract: In some examples, a system includes a receiver configured to receive communication from a traffic management system and a transmitter configured to transmit surveillance messages. The system also includes processing circuitry configured to determine, in a first instance, that the receiver has not received a command signal from the traffic management system. The processing circuitry is also configured to suppress transmission of surveillance messages by the transmitter in response to determining that the receiver has not received the command signal. The processing circuitry is further configured to determine, in a second instance, that the receiver received the command signal from the traffic management system. The processing circuitry is configured to cause the transmitter to transmit the surveillance messages in response to determining that the receiver received the command signal.

Abstract: A display system for a subject aircraft is provided. The system includes a processing unit configured to receive air traffic spacing information associated with a lead aircraft and flight information associated with the subject aircraft and to generate display signals associated with the air traffic spacing information and the flight information; and a display unit coupled to the processing unit and configured to receive the display signals from the processing unit and to render a horizontal situation indicator with spacing symbology based on the air traffic spacing information and the flight information.

Abstract: A method is described that includes receiving, by a spacing system of an ownship aircraft, a current position of the ownship aircraft and a reference position of a target aircraft, wherein the reference position is a position of the target aircraft prior to a current position of the target aircraft. The method may also include, projecting, by the spacing system of the ownship aircraft, the reference position on a trajectory of the ownship aircraft, determining a first distance between the projected reference position and the current position, projecting, by the spacing system of the ownship aircraft, the current position on a trajectory of the reference position, determining a second distance between the projected current position and the reference position, and adjusting, by the spacing system and based on an average between the first distance and the second distance, a velocity of the ownship aircraft.

Abstract: A display system for a subject aircraft is provided. The system includes a processing unit configured to receive air traffic spacing information associated with a lead aircraft and flight information associated with the subject aircraft and to generate display signals associated with the air traffic spacing information and the flight information; and a display unit coupled to the processing unit and configured to receive the display signals from the processing unit and to render a horizontal situation indicator with spacing symbology based on the air traffic spacing information and the flight information.

Abstract: A method is described that includes receiving, by a spacing system of an ownship aircraft, a current position of the ownship aircraft and a reference position of a target aircraft, wherein the reference position is a position of the target aircraft prior to a current position of the target aircraft. The method may also include, projecting, by the spacing system of the ownship aircraft, the reference position on a trajectory of the ownship aircraft, determining a first distance between the projected reference position and the current position, projecting, by the spacing system of the ownship aircraft, the current position on a trajectory of the reference position, determining a second distance between the projected current position and the reference position, and adjusting, by the spacing system and based on an average between the first distance and the second distance, a velocity of the ownship aircraft.