Various communication systems may benefit from enhanced reception methods. For example, various transponders and surveillance systems may benefit from reception methods that can distinguish between overlapping pulses from multiple sources. A method can include receiving, at an antenna, a first series of pulses from a first source. The method can also include receiving, at the antenna, a second series of pulses from a second source. The first series and the second series can at least partially overlap each other. The method can further include de-interleaving the first series from the second series using at least one non-time-domain technique.

The radar includes an antenna having a radiation pattern forming a sum channel, SUM, a radiation pattern forming a difference channel, DIFF, and a pattern forming a control channel, CONT, a first transmission and reception chain being associated with the SUM channel and a second transmission and reception chain being associated with the CONT channel, a reception channel being associated with the DIFF channel. Each of the transmission and reception chains is able to transmit and to receive simultaneously, the transmission chain comprising a filtering operation that filters signals transmitted at 1090 MHz and the reception chain comprising a filtering operation that filter signals transmitted at 1030 MHz, in such a way that the chains operate independently of one another.

A density of Mode S interrogations and responses in the environment covered by a secondary radar is characterized according to the following steps: a first step wherein the radar: detects and locates Mode S targets by way of their synchronous responses to the interrogations emitted by the radar; detects asynchronous responses emitted by the Mode S targets, and not elicited by the radar; for each target, associates its asynchronous responses with its synchronous response to the radar; a second step wherein the radar: based on the association, determines the response rate of each target by counting the number of synchronous and asynchronous responses received from the target per given time period; with the environment being divided into elementary space cells, determines the response rate per cell by counting the number of synchronous and asynchronous responses received by each target in each cell, the rate characterizing the density of Mode S interrogations per cell.

An avian detection system for determining risks of collision between a collision object and bird objects includes avian radar system(s) providing a first type of information data relating to objects detected, and a transponder receiver receiving transponder data transmitted or broadcasted by transponders provided at the collision objects. Processors are configured to receive first type of information data corresponding to the detected objects and provide radar plots. The processors are further configured to receive the transponder data and provide transponder plots, to create and store a number of object tracks based on the provided radar plots and transponder plots, with each track holding object data corresponding to or determined from data of matching plots, and to determine one or more risks of collision or collision risk levels for the collision object based on object data of a plurality of the obtained object tracks.

A mode S Interrogation Side Lobe Suppression System (ISLS) for an electronically scanned interrogator is described. One aspect introduces the 90° phase offset between the main and control beams thereby enabling the full power capability of the TRU to be effectively utilized and the effective beamwidth in Mode S to be sharply defined. The system allows the transmission of the simultaneous ISLS pulse of a Mode S all-call interrogation to be transmitted using the same array as is used by the main beam.

Various communication systems may benefit from enhanced reception methods. For example, various transponders and surveillance systems may benefit from reception methods that can distinguish between overlapping pulses from multiple sources. A method can include receiving, at an antenna, a first series of pulses from a first source. The method can also include receiving, at the antenna, a second series of pulses from a second source. The first series and the second series can at least partially overlap each other. The method can further include de-interleaving the first series from the second series using at least one non-time-domain technique.

An each pattern is provided a reception pathway, the method uses the synchronous replies and the asynchronous replies, unsolicited of Fruit type, transmitted by targets present in the aerial environment of the radar and detected over a given number of antenna revolutions. At each detection of a reply the value of its off-aim in bearing and the value of relative power received on each of the pathways are calculated as is its elevation by extrapolation with the synchronous detections close to the same target and associated with the detection. The values obtained over the given number of revolutions are stored, the measured patterns being sampled on the basis of the stored values.

An each pattern is provided a reception pathway, the method uses the synchronous replies and the asynchronous replies, unsolicited of Fruit type, transmitted by targets present in the aerial environment of the radar and detected over a given number of antenna revolutions. At each detection of a reply the value of its off-aim in bearing and the value of relative power received on each of the pathways are calculated as is its elevation by extrapolation with the synchronous detections close to the same target and associated with the detection. The values obtained over the given number of revolutions are stored, the measured patterns being sampled on the basis of the stored values.

A method according to the present invention includes calculating, based on a reported position of a vehicle, a probability that an actual position of the vehicle is within a region of interest. The method further includes determining whether a threat of a collision exists between the vehicle and an object based on the probability that the actual position of the vehicle is within the region of interest and a reported position of the object. The method further includes generating an alert if it is determined a threat of a collision exists between the vehicle and the object.

Various communication systems may benefit from suitable use of redundancy. For example, surveillance systems in avionics applications may benefit from having functional redundancy. A system can include a collision avoidance or alerting system function in wired connection to a directional antenna. The system can also include a first mode-S transponder function in wired connection to the directional antenna. The system can further include a second mode-S transponder function in wired connection to the directional antenna, wherein the first mode-S transponder function is independent from the second mode-S transponder function.