ATM Modernization, Embedded Avionics

NATS New VCS System Will Support SESAR ATM Upgrades

By Juliet Van Wagenen | April 5, 2016
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[Avionics Today 05-04-2016] In a move that will enable current and future Single European Sky ATM Research (SESAR) initiatives, NATS, the U.K. Air Navigation Service Provider (ANSP), has contracted Harris to update its Air Traffic Control (ATC) voice communications to an all-Internet Protocol (IP), cloud-based system. By deploying Harris’ Voice Communications System for the 21st Century (VCS21), which was also selected by the FAA in 2012 to update the VCS system in the U.S., NATS is looking to maximize service capacity and performance across its two ATC centers — Swanwick and Prestwick — with a common voice platform that can connect both sites on a common interface.

ATCs using Harris VCS21 system
ATCs using Harris VCS21 system. Photo: Harris

“Our current voice systems are bound by the initial center and location they support. The Harris VCS21 system we are deploying will be virtualized across our two centers,” Simon Daykin, NATS chief architect, told Avionics Magazine, noting that this will increase flexibility across the entire U.K operation.

The U.K. boasts some of the busiest airspace in the world, with the ANSP claiming that 2.4 million flights and 250 million passengers pass through the country’s airspace each year. With air traffic numbers on the rise, the new ATC communications system aims to modernize the platform, reducing dependency on traditional point-to-point communications through a system that links directly to a Wide Area Network (WAN), enabling complete Voice over Internet Protocol (VOIP) communications.

“Our existing technologies are based, both internal to the VCS system and when interfacing to other external systems, on traditional point-to-point protocols such as [Time-Division Multiplexing] TDM/E1. The Harris VCS21 system is entirely IP within its internal architecture, meaning it doesn’t have a centralized voice switch. Rather the voice communications passes directly between relevant aspects of the system, be it controller working position, the radio or gateway to the outside world. This means within the system right out to the radios themselves, we will be using totally native IP, maximizing the benefit from the modern internal and external networks that are themselves IP-based,” Daykin explained.

Furthermore, the new system will allow NATS to support native IP at the boundary, allowing them to have direct IP links to the partners in the system, such as adjacent ATC centers and airports. The new VCS is also instrumental in reforming the underlying technical infrastructure, such as the network, by removing the reliance on older protocols and the complexity and cost they bring.

“Legacy switches today require very complex switching fabrics. They require interface cards to translate analog interfaces to digital interfaces and radio control electronics that properly format radio-control messaging. ANSPs are evolving to provide connectivity between the facilities using an IP-based plan, because that is where the telecommunications industry is going and it facilitates a lot of the concepts that are evolving, such as NextGen and SESAR. As they do that, the system doesn’t become less complicated, it actually acquires complexity by virtue of the fact that you put an IP wrapper around the switch, which is yet another piece of equipment, to allow the legacy switch to interface with the new IP network,” explained Glen Dyer, vice president of network centric products and systems at Harris Corp.

With VCS21, controller positions directly digitize voice control signals in data IP formats, meaning the overall complexity of the system is reduced as the ANSP migrates an IP Local Area Network (LAN) for system connectivity. As NATS migrates the remote radio stations to the control facilities to IP, the overall switch complexity is reduced, meaning there are less analog interface cards and a modern network communications system.

While the transition to VCS21 will initially be invisible to ATC and aircraft operators as it comes online in stages between 2018 and 2020, Daykin said it would increase resilience and enable the ANSP to deliver new ATC concepts in the future. These concepts include Free Route Airspace (FRA), which seeks to create one single and substantial airspace that will allow operators to take advantage of the most timely route available, as opposed to the pre-defined routes they currently fly, saving money and upping fuel efficiency.

The new VCS system is also capable of supporting dynamic sectorization, a process in which a number of elementary air volumes are defined, a short-term capacity demand prediction is generated using simulation of planned traffic, and the ATC sectors are then formed as the most suitable combination of the elementary sectors to meet the capacity demand at a certain moment.

What makes these concepts, among others, possible is the ability for ATCs to communicate with all aircraft in the country’s airspace.

“From a management perspective, if you are managing an ANSP function, this could help to manage upcoming facility consolidation, contingency management and associated operational planning. And having the ability for the controller to be in any ANSP facility and take on operations of any other controller is a very important piece of that,” said Dyer.

Harris will install the system at three facilities in the U.K., and it will include more than 600 controller working positions that can access up to 2,000 radios across NATS control operations. While neither company revealed the cost of the system, it is part of the SESAR project, in which NATS plans to invest nearly $1 billion in new technologies over the next five years.

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