ASSC: A NextGen surface surveillance system
Thursday, October 04, 2012

EDITOR’S NOTE: This is the next in a series spotlighting each of the safety and technology programs in which NATCA is participating collaboratively with the FAA. To review each of the programs previously spotlighted, please click HERE.


PROGRAM NAME: Airport Surface Surveillance Capability

ACRONYM: ASSC

NATCA ASSC NATIONAL REPRESENTATIVE: Jim Scarpelli
(Cleveland Tower and TRACON) jscar2019@gmail.com

NATCA PROJECT REPRESENTATIVES (SBS/ADS-B Workgroup): Lead: Rick Heckman (Philadelphia Tower and TRACON), members: Colin Flaherty (Anchorage Center), Eric Labardini (Houston Center), Craig Bielek (Boston TRACON), Thomas Zarick (Denver Center).

WHAT IT DOES: ASSC is a NextGen product designed to aid terminal controllers in tracking the surface movement of aircraft and vehicles. ASSC will track airborne aircraft up to 200 feet above the airport surface and track aircraft on the final approach inside of the outer marker. It can also be used for precision runway monitoring (PRM) via multilateration (MLAT) technology at airports where PRM is deployed.

HOW IT WORKS: ASSC is very similar to the current Airport Surface Detection Equipment, Model X (ASDE-X) system utilized at the core 35 airports in the NAS. ASDE-X was an improvement over the ASDE3 system (which is still in use at the nine target airports) in that it augmented traditional Surface Movement Radar (SMR) and Airport Surveillance Radar (ASR), with data provided by transponder MLAT and Automatic Dependent Surveillance-Broadcast (ADS-B).  

The compilation of this data provides a single track that is correlated with flight plan information and displayed on color monitors to the controller. MLAT is a transponder-based system that uses multiple sensors, called Remote Units (or RUs) in the field, which then uses triangulation to calculate the targets position. ADS-B uses the Global Navigation Satellite System (i.e. GPS) to supplement the position verification of the aircraft or vehicle. The primary difference between ASSC and ASDE-X is that both the ASR and SMR sensors are being eliminated from the ASSC system. An aircraft must have a working transponder in order to be seen by Air Traffic, and a vehicle must have a transponder like piece of equipment known as a “squitter.” A squitter transmits a signal out which then allows the vehicle to be tracked in the mapping area of the AOA automatically.     

THE TASKS PERFORMED BY ASSC: The specifications for ASSC are set to provide positional accuracy for a target of 20 feet or less in any 100 contiguous feet of a taxiway or runway. This requirement is a stricter standard than that in ASDE-X. Another improvement compared to ASDE3 is that a local database allows all equipped vehicles to be automatically tagged and tracked. Additionally, aircraft are tagged inbound and outbound based on information in the NAS. Currently, aircraft only have a data tag on the inbound leg, and vehicles have no associated data tag.

The safety benefits of ASSC as compared to the current ASDE3/AMASS system is its ability to provide better track continuity, a reduction of false targets, a higher probability of target detection on the AOA, and improved surveillance during heavy precipitation or other weather phenomena. Safety logic, consistent with ASDE-X is also a requirement of ASSC. Surveillance coverage can be easily expanded if there is airport expansion by adding more RUs around the airfield, or in the approach corridors.

FACILITIES IN LINE TO RECEIVE ASSC: San Francisco (SFO) and Cleveland (CLE) are the key sites. Cincinnati (CVG), Pittsburgh (PIT), Anchorage (ANC), Kansas City (MCI), Portland, Ore. (PDX), Andrews AFB (ADW), and New Orleans (MSY) will be deployed after the system proves operational at SFO (October 2013) and CLE (August 2014).  

JIM SCARPELLI’S PERSPECTIVE ON THE PROGRAM: “I joined the SBS/ADS-B work group in March of this year with the ASSC project already in motion. It has taken a while to get up to speed on what this project is, and what it means to NATCA and the future of Air Traffic Control. NATCA leadership has made it clear that they support new technologies, NextGen, and the collaborative efforts with the FAA. Both are alive and well in ASSC.

“Recently NATCA identified an issue in the vehicle squitter specifications that could have lead to serious safety problems. Once the issue was raised, and verified, the FAA took immediate steps to change the specifications with the manufacturer.

“As a lifetime terminal controller it is hard for me to see the future of ground surveillance without the SMR component. To me, this is the part of the ASSC program that will have to prove itself over time. The fact is, however, that this is the direction the FAA is taking, and this program is not funded to have an SMR input. ASSC will rely on MLAT, ADS-B, and transponders (squitters) as the primary components of the system.   

“With San Francisco’s unique runway configuration and traffic mix, ASSC will be seriously tested from the start. The FAA is working hard to have this spotlight pointed in the right direction and NATCA is helping to make it work… not only at these nine sites, but also for all future sites that will get other NextGen systems.”

RECENT DEVELOPMENTS: The SBS workgroup recently visited Boston Logan Airport where BOS MassPort partnered with the FAA and the equipment manufacturer to test vehicle squitters. This was a test not only for BOS MassPort, but also a look at how the system will work for air traffic. (The difference being that BOS utilizes ASDE-X, which incorporates an SMR, whereas ASSC will not have one). All indications are that the test has been successful for both. BOS MassPort uses the squitters to track the vehicles in a quasi command center, which allows them to watch vehicle movement for their own equipment. They have also mounted iPads in key vehicles, with a downloaded BOS AOA app, and the vehicle driver is then able to identify his vehicle and see exactly where it is on the surface.  

According to BOS Facility Representative James Peterson, this added awareness by MassPort and by the vehicle driver is added comfort to the controller. Jim also adds “to effectively capture the full safety benefits of this system would be to have all vehicles operating on or near runways equipped with a transponder (squitter). The ASDE-X system was designed with this in mind and to not utilize the system to its full potential would be irresponsible.”

The Art. 48 SBS/ADS-B team echoes those statements as it applies to Airport Surface Surveillance Capability. We have been very clear, that for the system to be safe and successful, vehicles will need to be squitter-equipped, so as to make them visible to the controllers.  

The most recent development from the FAA is that U.S. Transportation Secretary Ray LaHood announced that $1.2 million in grants will be released to various airports for Airport Vehicle Surveillance Equipment.