Search results
Results from the WOW.Com Content Network
A Mode A transponder code response can be augmented by a pressure altitude response, which is then referred to as Mode C operation. [2] Pressure altitude is obtained from an altitude encoder, either a separate self-contained unit mounted in the aircraft or an integral part of the transponder.
Mode 1: military only; provides 2-digit octal (6 bit) "mission code" that identifies the aircraft type or mission. [21] Mode 2: military only; provides 4-digit octal (12 bit) unit code or tail number. [22] Mode 3/A: military/civilian; provides a 4-digit octal (12 bit) identification code for the aircraft, assigned by the air traffic controller.
Around busy airspace there is often a regulatory requirement that all aircraft be equipped with altitude-reporting mode C or mode S transponders. In the United States, this is known as a Mode C veil. Mode S transponders are compatible with transmitting the mode C signal, and have the capability to report in 25-foot (7.5 m) increments; they ...
The reply sent depends on the interrogation mode. The aircraft is displayed as a tagged icon on the controller's radar screen at the measured bearing and range. An aircraft without an operating transponder still may be observed by primary radar, but would be displayed to the controller without the benefit of SSR derived data.
There have been a number of modes used historically, but four are in common use today: mode 1, mode 2, mode 3/A, and mode C. Mode 1 is used to sort military targets during phases of a mission. Mode 2 is used to identify military aircraft missions. Mode 3/A is used to identify each aircraft in the radar's coverage area.
The DME receiver in the aircraft searches for reply pulse-pairs (X-mode = 12-microsecond spacing) with the correct interval and reply pattern to its original interrogation pattern. (Pulse-pairs that are not coincident with the individual aircraft's interrogation pattern e.g. not synchronous, are referred to as filler pulse-pairs, or squitter ...
Interrogating aircraft transmit in the 1024-1150 MHz band, split into 1 MHz channels numbered 1-126; the responding station (ground, ship, or another aircraft) is 63 MHz (63 channels) above or below the originating frequency, depending on the channel and mode of operation selected.
The original design had three such "modes", Mode 1 was triggered by the interrogator by sending the two pulses 3 μs apart (±0.2 μs), Mode 2 was 5 μs and Mode 3 was 8 μs. [ 10 ] The response to these interrogations remained simple; a successful interrogation on Mode 1 or 3 caused a single pulse to be sent in reply, very shortly after the ...