1.3 System Summary  
1-5

Since the advent of the air transportation, safety has been the keystone of this business. Safety rests on three pillars, which are Communication, Navigation and Surveillance. Communication and Navigation had been developed before the air transportation became massive. The traffic getting denser and denser, Surveillance became more and more necessary.
The very first surveillance tool appeared in the 1930’s: the radar. Widely used during the Second World War, the radar has come into general use for various purposes (air traffic control, weather monitoring, road speed control, etc). While the air traffic becomes denser, safety calls for new surveillance tools other than the radar. Thus, several surveillance systems were developed like:
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The transponder that works with the ground Secondary Surveillance Radar (SSR)

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The Traffic Collision Avoidance System (TCAS)

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The Terrain Awareness and Warning System (TAWS)

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The Weather Radar (WXR) -

All these systems work for a better awareness of the traffic and the environment around the aircraft for either the flight crew or the air traffic controller.
Today technology allows getting a more accurate awareness of traffic and environment. This is the purpose of Automatic Dependent Surveillance – Broadcast (ADS-B), Airborne Traffic Situational Awareness (ATSAW) applications, Runway Awareness and Advisory System (RAAS) and On-board Airport Navigation System (OANS). And the constant traffic growth will call for other new systems to meet the safety requirements.
In three paragraphs, the reader may have noticed the endless list of surveillance systems available in the cockpit. Therefore, the aim of this brochure is for our customers:
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Already equipped with one of these systems:

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To decode all these acronyms

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To understand how these systems work

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To efficiently use these systems.

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Not equipped with some of these systems: to select the right systems according to their needs.

1.1. WHAT IS SURVEILLANCE?
The definition of surveillance is a question of perspective: either flight crew’s perspective or air traffic controller’s one.
1.1.1. SURVEILLANCE FROM THE FLIGHT CREW’S PERSPECTIVE
At the flight crew level, there are two kinds of surveillance: the air-to-ground surveillance and the air-to-air one.
Flight crews and air traffic controllers commonly share the air-to-ground surveillance. The air-to-ground surveillance enables the air traffic controller to manage the traffic in a safe and efficient manner. The air-to-ground surveillance uses:

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When inside radar coverage, the well-known transponder coupled with SSR

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When outside radar coverage, voice position reports at regular intervals or ADS-C application
　
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