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Dan Hamilton is the Article 114 Representative to the SBS Office.  

Background:  The Surveillance and Broadcast Services (SBS) program was created to manage a program that will enable the air traffic control (ATC) system to migrate from one that relies on radar technology to a system that uses precise location data from the global positioning satellite network. An enabler of this evolution is the Automatic Dependent Surveillance Broadcast (ADS-B) technology. With this technology, both controllers and pilots will see radar-like displays of highly accurate traffic data. The system will also provide pilots access to weather services, terrain maps, flight information services as well as traffic information for better situational awareness.    

Automatic Dependent Surveillance – Broadcast (ADS-B)   

Terminal Fusion 

Andrew Stachowiak is the NATCA Article 114 ADS-B Terminal Fusion Representative / SME.  

Background: The Fusion Focus Group continues to track and resolve facility reported issues with Fusion generated from the 155 terminal sites. These discrepancies are mitigated by experts from all of the software and hardware fields. Please report any issues to your OSF and our NATCA SBS group for assistance. It is critical that actual data is recorded for evaluation and proper resolution. 

Radar Divestiture  

Andrew Stachowiak is the NATCA Article 114 Radar Divestiture Representative / SME. 

Background:  Over two years ago, the NATCA SBS team started a collaboration with the agency in efforts to optimize the NAS. The implementation of ADS-B as the preferred surveillance source for the Fusion Tracker, created the opportunity to modify our radar infrastructure. The SPA (Surveillance Portfolio Analysis) work group performed an extensive inventory analysis report for all of the radar sources in the FAA. The program’s mission is to capitalize on the benefits of new surveillance technologies by strategically reshaping our radar infrastructure to gain efficiencies and optimize services for air traffic control (ATC) operations today and into the future. This will be a long and completely transparent process involving data gathering, expert analysis, local facility coordination, and a safety panel for each proposed radar removal. In some situations, additional radar feeds could be added to enhance surveillance. As this program matures, activities and other information will be updated here.   

The Radar Divestiture website: http://www.faa.gov/air_traffic/technology/radardivestiture 

Activities: virtual kick off outreach for HQZ in the D10 airspace was accomplished Feb 2nd. 

Track-Based Display Mode (TBDM) 

Andrew Stachowiak is the NATCA Article 114 TBDM Representative.  

Background: Track Based Display Mode (TBDM) is a new display mode in ERAM. TBDM makes ADS-B the preferred sensor and provides controllers using ERAM with smoothed track positions rather than last-reported or extrapolated target positions Smoothed track positions are displayed in sync with the preferred radar sweep (4.6 or 12 secs); use of the smoothed track position maximizes display accuracy. Reports from 0 to 8 radars along with ADS-B can be fused to form a single aircraft track. TBDM provides no changes to target/track symbology and the display update rate remains the same. TBDM enables the use of ADS-B as the preferred surveillance source to support 3NM Separation no longer limited to 3NM separation based on distance from a radar sensor. ADS-B will backfill Radar Cones of Silence and airspace beyond the distance and site limitations of existing SRRs and LRRs. New SBS Validation capabilities support significant future expansion of 3NM validation and separation anywhere in EnRoute Airspace at or below FL230 with validated ADS-B targets to the 3 NM Terminal service volume validation threshold. The TBDM adaptation changes coming out of a successful key site operation (Seattle Center (ZSE)/ Boston Center (ZBW), determined that the adaptation changes would be (nearly) transparent to the Controller workforce. Therefore, based on that Key site testing information, AJV-P approved NAS-wide Notices allowing the use of ADS-B for 3NM separation when operating in TBDM. An ADS-B validation build deployed at ZSE and SBS completed coverage plots showing where validated ADS-B may be used for 3NM separation. ZSE may expand 3NM operations using ADS-B in accordance with N JO 7110.773 and N JO 7210.920. SBS validation capabilities support the expansion of 3NM separation in ZSE airspace (CTV-2018). L3Harris deployed a validation build to RCS15 (ZSE) which allows 3NM separation throughout overlapped ADS-B radio station coverage. ERAM adaptation changes required for expanded 3NM polygons are no longer a limitation based on distance from a radar sensor.  

Covid-19 mitigation put on-hold the future roll-out plan of TBDM and the 3nm airspace expansion project. New ADS-B coverage maps, developed by Regulus support, were shared with our Seattle Center (ZSE) / Boston Center (ZBW) TBDM key sites. Covid-19 mitigation also put on-hold planning for the expansion of designated 3nm separation areas. Special permission was given by the PMO and ERAW group to reach out to Indianaoplis Center (ZID) and Miami Center (ZMA) about the possibility of having a planning meeting to implement TBDM. ZMA will transition to TBDM prior to the next SBA (Space-Based ADS-B) SRM Panel projected during the 2nd quarter of FY21. This allows the SBA Safety Case to be re-baselined with TBDM rather than SBDM. ZMA enabled TBDM December 10, and they will adapt their sort cells for ADS-B 1/29/2021. ZID enabled TBDM 1/9/2021. TBDM is available to every ARTCC and in existing 3nm airspace if that applies. Because of Covid-19 mitigation protocols each ARTCC was briefed on this availability and they are contacting the TBDM Team to coordinate their transition to TBDM on a case-by-case basis. Oakland Center (ZOA) enabled TBDM on 1/29/2021 and briefed the change to the controllers through Cedar. ZOA plans to enable existing 3NM airspace adapted for ADS-B on 3/25/2021. Jacksonville Center (ZJX) enabled TBDM on 2/25/2021 and briefed the change to the controllers through Cedar. ZMP was briefed by the TBDM workgroup on 2/23/2021 and will enable TBDM on 3/25/2021.     

ADS-B Avionics  

Andrew Stachowiak is the NATCA Article 114 ADS-B avionics issues SME.  

NATCA SBS continues to work with the Agency toward a more proactive approach to ADS-B  avionics issues that result in position error. These issues occur when standards for installation or configuration within aircraft or ground systems are not met. ADS-B is a cooperative surveillance source relying on position accuracy determined onboard the aircraft. Controllers and facilities are encouraged to report any identified events through ATSAP and via automation trouble reports. Issues with the uAvionix SkyBeacon wingtip mounted ADS-B unit used for general aviation aircraft are still being worked along with AVS (flight standards) and AIR (flight certification) in efforts to correct these issues. A quad zero automation test is in the works. There have been some recent flight planning routes exchanged that will involve a flight check of this uAvionix transponder issue in and or near the Houston Tracon airspace. A volunteer aircraft that was to be used for this flight test is now unavailable. We are pursuing other options.  

Surface Surveillance 

Dan Hamilton, SBS Lead Rep 

Surface Surveillance encompasses ASDE-X and ASSC. Programs falling under this category include SMR Infrastructure SLEP (Service life extension program,) SMR SLEP, SMR Replacement, MLAT Divestiture, Baseline merge and any other program impacting our surface surveillance platforms 

The surface team has started engagement with the ATAP team regarding the deployment of taxiway alerting into the ASSC system. New Orleans (MSY) will be the first facility to receive the additional alert. MLAT divestiture remains a question mark as data gathering continues. In the next couple months, the team hopes to facilitate some initial outreach briefings to service area leadership. At some point, (COVID dependent) data needs to be gathered at the facility level which will require direct facility interaction. The team will be following the same process as the radar divestiture team. Meetings also continue for the ASDE3 SLEP program and ASDE3 replacement. The replacement program would hopefully start deployment in the next 5 years.  

Space Based ADS-B (ASEPS)  

Dan Hamilton, SBS Lead Rep. 

Background:  With the terrestrial ADS-B platform fully deployed, the focus has turned to areas where surveillance is more difficult to achieve. Space Based ADS-B (SBA) utilizes low orbiting satellites to track aircraft that are ADS-B 1090ES Equipped. SBA provides updates every second, much like FUSION in STARS. SBA provides all the data controllers currently see on all platforms. It is also possible to gain additional data such as selected altitude. The team has been working with ZMA as they are the key site for operational evaluation in the Caribbean. As work in ZMA progresses, the team is also working with the ATOP team in the development of future concepts for SBA in the oceanic environment. Future concepts include work with New York Center (ZNY), Anchorage Center (ZAN) and Oakland Center (ZOA).  

Meeting regarding performance requirements continue. Current requirements, based on ADS-B, and the ERAM 5mi separation requirement are not being met by SBA. As noted in prior reports, it’s important to remember there are no current requirements strictly for SBA. Therefore, the team is comparing performance to requirements that most closely relate to the surveillance source, which in this case is SBA.  

Interval Management   

Tom Zarick is the NATCA Article 114 Interval Management Representative 

Chris Aymond is the Interval Management SME for Terminal 

Background:   Interval Management, or IM, combines ground-based and flight-deck systems to provide precise inter-aircraft spacing between aircraft, providing air traffic with another tool to manage traffic flows. The objective of the IM application is to achieve and/or maintain an assigned spacing goal (ASG) between the IM aircraft and the ATC-designated aircraft by having the pilot follow speed commands generated by the flight deck avionics. The ASG is provided by the controller and may be given in time or distance.   

ADSB-In Retrofit Solution (AIRS) & CAS (CDTI Assisted Separation) 

Background:  AIRS and CAS are applications within the Interval Management domain that the Agency and American Airlines are engaged in an effort to promote the benefits and viability of ADSB-In.  

The deployment strategy for IM will consist of three phases. The first phase or Phase 1, (similar to the AIRS concept) will consist of a subset of the IM functionality which will be limited to the same runway operations. Phase 2 will introduce more complex IM operations utilizing more of the flight deck avionics that adds functionality for Dependent Staggered Approaches (DSA) and Dependent Converging and Crossing Runways (DCCR). Phase 3 will introduce advanced IM capabilities that will be deployed to only a handful of facilities due to its limited benefits.  

Upcoming Activities:  

The Agency has decided that D10 should be the key site for the CAS trial.  (pending final approval from the facility).  The CAS Ops Description will be updated once engagement with the facility begins. 

No updates recently on the ADS-B In indicator.  Last report was August 2023 for ERAM and 2024 timeframe for STARS. 

The “simple IM” lab activities are still ongoing with Mitre.  The goal is to assess if controllers can conduct and IM miles-in-trail operation in a mixed equipage environment using only the ADS-B In capability indicator.  The challenge continues to simulate an ERAM environment virtually. 

American equipped three aircraft during the month of February (estimate was seven).  They already have seven aircraft undergoing the install for the month of March which should help with the shortfall.   

WAM (Wide Area Multilateration)  

Andrew Stachowiak is the NATCA Article 114 Terminal Representative / SME.  

Background: WAM is a surveillance source that backs up ADS-B. MLAT constellation over wide area = WAM. 

Multilateration (MLAT) is:  

  • Technology that utilizes multiple low-maintenance, ground radio stations to determine aircraft position and provide surveillance coverage within a defined region.  
  • Cooperative system which requires aircraft transponder signals – ADS-B link v2 and UAT aircraft do not require interrogations 
  • Enhances the coverage area of a traditional radar or acts as a stand-alone surveillance system 
  • Surveillance requirements analysis determines the number and positioning of each radio necessary to achieve required coverage 
  • The process of determining location in two (or three) dimensions based on the time difference between the transponder’s signal reception at multiple sensors 

Key concepts of MLAT processing include the following: Transponder signal is received at multiple radio stations, Signal is time-stamped at each station, Time stamped signal is sent from each station to a target processor, the target processor calculates the Time Difference of 

Arrival (TDOA) between all sensor pairs detecting the target, the calculated TDOAs are used to determine the target position, and the target position information is output by the target processor to track processing functions. 


  • STARS treats WAM input as just another surveillance sensor input 
  • WAM data will be integrated with all other available sensor data in STARS Fused Mode 
  • Fusion is preferred mode of operation – no change 
  • STARS Fusion w/ WAM data and Final Monitor Aid (FMA) – no change 
  • WAM cannot be selected in Single Sensor Mode (SSM) – Not selectable (grayed out) from Data Control Bar (DCB).  

Mode S removal – Atlanta area identified as high spectrum congestion area with 5 ASR sensors plus ADS-B providing overlapping surveillance coverage in Atlanta Tracon (A80) airspace. Atlanta (ATL), CSG, LZU, Macon (MCN), MGE (MGE is military owned and maintained) 

Collaborate with A80 personnel to replace an existing Mode S system with Wide Area Multilateration (WAM), kick off meeting 2/10/2021. 

Why? – Relieve spectrum congestion (1090 MHz) in area, continue to provide alternate surveillance data in addition to ADS-B (preferred means of surveillance),  

Provide STARS more accurate and more frequent WAM track data updates, reduce costs associated with maintaining legacy radar sensors providing overlapping surveillance coverage. 

WAM sites: Colorado (ERAM), Juneau (MEARTS), CLT, SCT (STARS) 

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