The invention refers to a method and a base station for validating information regarding the position of a target-aircraft, the information contained in an ADS-B signal periodically broadcast by the target-aircraft, with the method being executed in the ADS-B base station.

An Identification Friend or Foe (IFF) interrogation system and method adapted for: transmitting RF broadcast signal to be received by complementary transponder(s) of the IFF system being within the interrogation range and thereby arm the complementary transponders for sensing laser beam illumination; receiving an RF response signal from the complementary transponder(s); operating a laser activation interface module, which is configured for interfacing an external laser transmitter, to determine activation of transmission of an interrogating laser beam by the external laser transmitted; and receiving and processing RF signals to identify therein RF response signal(s), which are transmitted by the complementary IFF transponder(s) in response to detection of the trans mitted laser beam. In some implementations the complementary transponder is configured to encode, in the RF response signal, an identification code of the interrogator in the form of data indicative of a time pattern representing time interval(s) between the transmissions of the RF broadcast signal and the interrogating laser beam. In turn, the interrogation system may be adapted to decode the identification code from the RF response signal and thereby determine whether the RF response signal is addressed thereto. In some cases where the laser beam of the external laser transmitter has a cross-sectional area smaller than the interrogation region, there is further provided a beam scattering directive providing instructions for directing the optical axis of the external laser transmitter to wards light scattering surfaces in the vicinity of the interrogation region so it is illuminated by scattering of the laser beam by the scattering surfaces.

An Identification Friend or Foe (IFF) interrogation system and method adapted for: transmitting RF broadcast signal to be received by complementary transponder(s) of the IFF system being within the interrogation range and thereby arm the complementary transponders for sensing laser beam illumination; receiving an RF response signal from the complementary transponder(s); operating a laser activation interface module, which is configured for interfacing an external laser transmitter, to determine activation of transmission of an interrogating laser beam by the external laser transmitted; and receiving and processing RF signals to identify therein RF response signal(s), which are transmitted by the complementary IFF transponder(s) in response to detection of the trans mitted laser beam. In some implementations the complementary transponder is configured to encode, in the RF response signal, an identification code of the interrogator in the form of data indicative of a time pattern representing time interval(s) between the transmissions of the RF broadcast signal and the interrogating laser beam. In turn, the interrogation system may be adapted to decode the identification code from the RF response signal and thereby determine whether the RF response signal is addressed thereto. In some cases where the laser beam of the external laser transmitter has a cross-sectional area smaller than the interrogation region, there is further provided a beam scattering directive providing instructions for directing the optical axis of the external laser transmitter to wards light scattering surfaces in the vicinity of the interrogation region so it is illuminated by scattering of the laser beam by the scattering surfaces.

An identification friend or foe (IFF) transponder includes: an electronic receiver to receive encoded challenges from an IFF interrogator; a processing circuit including a decode circuit to decode the received challenges into encrypted challenges using a time of day (TOD) and/or a cryptographic key, a decrypt circuit to decrypt the encrypted challenges into challenges using the TOD and/or the key, a reply circuit to generate replies to the challenges, and an encode circuit to encode the generated replies using the TOD and/or the key; an electronic transmitter to transmit the encoded replies to the IFF interrogator; and an alert circuit to detect the encrypted challenges from the received challenges without using the TOD or the key, use the detected challenges to determine if the TOD is incorrect and/or the key is wrong, and issue an alert in response to determining the TOD is incorrect and/or the key is wrong.

An identification friend or foe (IFF) transponder includes: an electronic receiver to receive encoded challenges from an IFF interrogator; a processing circuit including a decode circuit to decode the received challenges into encrypted challenges using a time of day (TOD) and/or a cryptographic key, a decrypt circuit to decrypt the encrypted challenges into challenges using the TOD and/or the key, a reply circuit to generate replies to the challenges, and an encode circuit to encode the generated replies using the TOD and/or the key; an electronic transmitter to transmit the encoded replies to the IFF interrogator; and an alert circuit to detect the encrypted challenges from the received challenges without using the TOD or the key, use the detected challenges to determine if the TOD is incorrect and/or the key is wrong, and issue an alert in response to determining the TOD is incorrect and/or the key is wrong.

A radar device includes a transmitter, a receiver and processing circuitry. The transmitter transmits a first pulse signal and a second pulse signal, a pulse width of the second pulse signal being wider than a pulse width of the first pulse signal. The receiver may receive a first reception signal including a reflection signal of the first pulse signal and a second reception signal including a reflection signal of the second pulse signal. The processing circuitry may be configured to compare, in a first section that is at least partly in a distance direction, a signal intensity of the first reception signal with a signal intensity of the second reception signal, and generate a display signal based on a result of the comparison.

In some examples, a system is configured to mount on an ownship vehicle and includes a phased-array radar device configured to transmit radar signals and receive returned radar signals. In some examples, the system also includes a surveillance transponder configured to receive surveillance signals from another vehicle. In some examples, the system further includes processing circuitry configured to detect an object based on the returned radar signals and determine a position of the other vehicle and a velocity vector of the other vehicle based on the received surveillance signals. In some examples, the system includes common signal and data processing circuitry that processes both data from the phased-array radar device and data from the surveillance transponder.

A device and techniques for generating and filtering a signal for transmission, such as the signal used to interrogate distance measuring equipment (DME), which may be tuned to a channel or frequency selected from a wide bandwidth. A system according to the techniques of this disclosure may generate a narrow band intermediate frequency (IF) signal with desired pulse characteristics, mix the IF signal with a local oscillator (LO) to upconvert to the desired radio frequency (RF) signal, then filter the upconverted RF signal through one of several narrow band filters in a filter bank to remove any undesired signal images. The system may select the filter from the filter bank depending on the transmitted RF frequency. In this manner the system of this disclosure may generate signals to span a wide RF bandwidth by using a narrow bandwidth IF signal generator.

Various wireless systems may benefit from suitable sharing of antennas and related equipment. For example a various avionics systems may benefit from systems and methods for providing a distance measurement equipment L-band shared antenna. Circuitry can include an interface to a bottom omni-directional antenna. The circuitry can also include a radio frequency splitter in switchable communication with the interface to the bottom omni-directional antenna. The circuitry can further include an interface between the radio frequency splitter and a distance measurement equipment receiver. The circuitry can additionally include an interface between the radio frequency splitter and a surveillance receiver.

An antenna system for providing identification functionality comprising a main antenna and an auxiliary antenna, wherein the antennas are configured to at least transmit electromagnetic waves. The antenna system comprises a first channel interface and a second channel interface, a first switch and a transmission input means. The first switch is configured to switch between a first operation mode and a second operation mode. When set in the first operation mode the second channel interface is set to be in connection with the auxiliary antenna and when set in the second operation mode the second channel interface is set to be in connection with the main antenna. If transmission via the first transmission channel is expected the transmission input means is configured to set the first switch in the first operation mode. Thereby the main antenna can be used for transmission of signals both provided via the first and second channel interfaces and when transmission via the first and second channel interfaces simultaneously is required the signal provided via the first channel interface will be transmitted by the main antenna and the signal provided via the second channel interface will be transmitted by the auxiliary antenna.