Attachment 6 - WAM Critical Service Specification_FAA-E-3024_Rev. A 11 21 2016.pdf

Surveillance and Broadcast Services Program

Wide Area Multilateration (WAM)

CRITICAL SERVICE SPECIFICATION

FAA-E-3024, Revision A

November 21, 2016

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

FAA-E-3024, Rev. A / November 21, 2016 iii

REVISION RECORD

Revision Date Description Approval

Rev.- February 8, 2012 NCP 34082/AJE06-SBS-1014 ERO CCB

Rev. A

November 21, 2016

NCP 36379/JM232-SBS-1012 NAS CCB

This Page Intentionally Left Blank.

v

Table of Contents

1 INTRODUCTION

1.1 Background

1.2 Purpose

1.3 Scope

1.4 Service Description

1.4.1 Functional Overview

1.4.1.1 Message Receive and Decode Function

1.4.1.2 Interrogate Function

1.4.1.3 Target Processing and Report Distribution Function

1.4.1.4 Maintenance Function

1.4.2 External Interfaces

1.4.2.1 External Interface to Aircraft

1.4.2.1.1 Inputs to the WAM Service from Aircraft

1.4.2.1.2 Outputs from the WAM Service to Aircraft

1.4.2.2 External Interface to SDPs

1.5 Document Overview

2 APPLICABLE DOCUMENTS

2.1 Government Documents

2.1.1 Specifications

2.1.2 Standards

2.1.3 Orders

2.2 Non-Government Documents

2.3 Documentation Sources

2.3.1 FAA Documents

2.3.2 Electronic Industries Alliance Documents

2.3.3 RTCA, Inc Documents

2.3.4 ICAO Documents

3 REQUIREMENTS

3.1 Definitions

3.1.1 Access Control Mechanisms

3.1.2 ADS-B Message

3.1.3 ADS-B Service

3.1.4 ADS-R Message

3.1.5 ADS-R Service

3.1.6 Coverage Volume

3.1.7 Service Status Report

3.1.8 Duty Cycle

3.1.9 Least Significant Bit (Lsb)

3.1.10 ME Field

3.1.11 WAM Service Volume

3.1.12 Most Significant Bit (Msb)

3.1.13 Receiver

3.1.14 SBS Monitor

3.1.15 Service Availability

3.1.16 Service Delivery Point

vi

3.1.17 Service Domain

3.1.18 Service Enhancement

3.1.19 Service Volume

3.1.20 Shall

3.1.21 Should

3.1.22 Transmitter

3.1.23 Update Interval

3.1.24 Minimum Output Period

3.1.25 Target Report Update

3.1.26 Probability of Update

3.1.27 Mode A / Mode C Validation

3.1.28 Victim Transponder

3.1.29 Will

3.1.30 Time of Message Receipt (ATCRBS/Mode-S/1090ES)

3.1.31 Time of Message Receipt (UAT)

3.1.32 Time of Applicability (TOA)

3.1.33 Data Item Age

3.1.34 WAM Target Report

3.1.35 WAM Service

3.1.36 Interrogation

3.1.37 Message

3.1.38 Periodic Reporting

3.1.39 Throttled Reporting

3.1.40 Data Driven Reporting

3.1.41 Latency

3.1.42 Extrapolation Time

3.2 Functional Requirements

3.2.1 Message Receive and Decode

3.2.1.1 Receiver Retrigger

3.2.1.2 1090ES

3.2.1.3 UAT

3.2.1.4 ATCRBS

3.2.1.5 Mode-S

3.2.2 Interrogation

3.2.2.1 Interrogation Modes

3.2.2.2 ATCRBS Interrogation

3.2.2.3 Mode-S Interrogation

3.2.3 Target Processing and Report Distribution

3.2.3.1 Input Message Processing

3.2.3.1.1 Horizontal Position Determination

3.2.3.1.2 Flight Level Determination

3.2.3.1.3 Multilateration Time Reference

3.2.3.1.4 Process Mode C Code for ATCRBS Targets

3.2.3.1.5 Time of Applicability Determination

3.2.3.1.6 Message Information Storage

3.2.3.1.7 Target Identification Reporting and Validation

3.2.3.1.8 Target Altitude Reporting and Validation

3.2.3.1.9 Altitude Correction

3.2.3.2 Report Generation

3.2.3.2.1 Generate CAT010 WAM Target Reports

vii

3.2.3.2.2 Generate CD-2 Message

3.2.3.2.3 Generate ASTERIX CAT048 Target Reports

3.2.3.3 Report Configuration and Filtering

3.2.3.4 Report Formatting and Output

3.2.3.5 Service Certification

3.2.3.5.1 Integrity Monitoring

3.2.3.5.2 Certification Targets

3.2.4 Maintenance Processing

3.2.4.1 SBS Monitor Maintenance Data Sets

3.2.4.2 Mode Reporting

3.2.4.3 Monitored Parameters State Reporting

3.2.5 System Enhancements

3.2.5.1 Service Tracking Enhancements

3.2.5.2 Future Automation Interfaces

3.3 Performance Requirements

3.3.1 Performance Environment

3.3.1.1 Type of Service Volume

3.3.1.2 Service Volume Fixes and Dimensions

3.3.1.3 Service Domain

3.3.1.4 Operating Environment

3.3.1.4.1 Interference Environment

3.3.1.4.2 Capacity

3.3.1.4.3 Scalability

3.3.1.5 WAM Service Delivery Points

3.3.1.6 Data Links

3.3.2 Performance Requirements

3.3.2.1 Operating Environment

3.3.2.2 Electromagnetic Compatibility

3.3.2.3 Coverage

3.3.2.4 Position Update Interval

3.3.2.4.1 Terminal Domain

3.3.2.4.2 En Route Domain

3.3.2.4.3 CD-2 Virtual Radar

3.3.2.4.4 ASTERIX Virtual Radar

3.3.2.5 Virtual Radar Probability of Position Update (Pd)

3.3.2.6 Probability of False Target Detection

3.3.2.7 Accuracy of Reported Position

3.3.2.8 Resolution

3.3.2.9 Target Identification Reliability and Validation

3.3.2.10 Altitude Reliability and Validation

3.3.2.11 Spectrum

3.3.2.12 Target Capacity

3.3.2.13 Latency

3.3.2.14 Target Acquisition Time

3.3.2.15 Time of Applicability Accuracy

3.3.2.16 WAM Service Availability

3.3.2.17 Accuracy of Reported Track Velocity

3.4 Interfaces

3.5 Security

4 QUALITY ASSURANCE

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4.1 Test Program

4.1.1 General

4.1.2 Phases of Test

4.1.2.1 First Article

4.1.2.1.1 Service Provider Qualification Tests

4.1.2.1.2 Government Qualification Tests

4.1.2.2 Implementation

4.1.2.2.1 Implementation Service Acceptance Test (ISAT)

4.1.2.2.2 Implementation System Test (IST)

4.1.2.3 Life Cycle

4.1.2.3.1 Service Re-Qualification Test (SRQT)

4.1.2.3.2 Service Performance Monitoring (SPM)

4.1.2.3.3 Government Performance Monitoring (GPM)

4.1.3 Verification Requirements Traceability Matrix (VRTM)

4.1.4 Verification Methods

List of Tables

Table 3-1: WAM Message Parameter Validity Time Table 3-2: Maintenance Data Sets Table 3-3: Traffic Density Environments

List of Figures

Figure 1-1: Surveillance and Broadcast Services Partitioning Figure 1-2: WAM Service Functions Figure 3-1: Service Volumes (SV) Figure 3-2: Mode-S Reply Rate Distributions for Ground Receiver Figure 3-3: ATCRBS Reply Rate Distributions for Ground Receiver

1 INTRODUCTION

1.1 Background

The Federal Aviation Administration (FAA)’s Surveillance and Broadcast Services Program is deploying Automatic Dependent Surveillance–Broadcast (ADS-B) technology based Services into the NAS. Four distinct Services are being provided:

1. Automatic Dependent Surveillance-Broadcast (ADS-B),

2. Automatic Dependent Surveillance-Rebroadcast (ADS-R),

3. Traffic Information Service-Broadcast (TIS-B),

4. Flight Information Service-Broadcast (FIS-B).

The Surveillance and Broadcast Services Program is planning to introduce a fifth Service into the NAS; Wide Area Multilateration (WAM). The WAM Service will support critical Traffic

Control (ATC) Surveillance applications in the NAS. The provision of this service will permit radar separation standards to be employed in place of procedural separation standards for aircraft in areas not covered by existing radar. The service will also provide a backup surveillance capability in the event of an ADS-B Service outage.

The WAM Service will provide data to FAA defined Service Delivery Points (SDP). The SDPs are the demarcation point between the Services and the systems which ultimately use the data.

The WAM Service will provide WAM Position and Service Status Reports to ATC

Automation, other authorized user systems, and the SBS Monitor system, via SDPs.

The service will be used for the benefit of safe operation of aircraft only and will not be optimized for any outside interests. The Service Provider may provide data to user systems in addition to those specified by the FAA, but has to comply with FAA Order 1200.22c, Data and

Interface Equipment Used by Outside Interests, and have FAA approval.

Figure 1-1 provides an overview of the partitioning of the WAM Service in relation with the existing Critical and Essential Services. The WAM Service is described in the following paragraphs.

The WAM service is a surveillance service provided by multilateration technology.

Multilateration technology utilizes signals from Air Traffic Control Radar Beacon System

(ATCRBS) (Modes A and C) and Mode S transponders, and requires no changes in current aircraft equipage. WAM will also multilaterate off 1090ES and UAT ADS-B transmissions.

Three or more ground stations measure the time-of-arrival of the same transponder message.

Aircraft position is determined by joint processing of the time-difference-of-arrival (TDOA) measurements computed between a reference and the ground stations measured time-of-arrival at a central location. Only one message need be received at 3 or more stations within an update interval for accurate position determination. Aircraft identity and barometric altitudes are determined by decoding the Mode A and Mode C information within transponder replies and squitters.

Multilateration and ADS-B surveillance are distributed surveillance technologies. Multiple ground stations are dispersed throughout a geographic area to receive downlink signals from aircraft. Data received by multiple ground stations is centrally processed and distributed to automation equipment for use by ATC personnel. The key advantage of the distributed architecture is that the coverage volume can be designed to suit the needs of each WAM Service

Volume. This distributed surveillance solution is particularly useful in mountainous terrain where multiple point sensors are required to cover a desired service volume since the coverage of any single point sensor may be very limited due to terrain obstructions.

1090ES TX UAT TX1090 RX UAT RX

FIS-B

Processing TIS-B/Fusion

Processing

Function

UAT TX

Ground Interface Function

1090ES TX

FIS-B Data

Sources

ADS-B Critical Services +

ADS-R Service*

TIS-B & FIS-B

Essential Service

Uplink Air InterfaceDownlink Air Interface Uplink Air Interface

ADS-B Downlink ADS-R Broadcast

TIS-B

Broadcast

FIS-B

Broadcast

Contractor

Monitoring and Control

Ground Interface, ADS-R

Processing Function

Operational & other Data

FAA

Monitoring

Other Data

Users

(e.g. Airlines)

ATC

Automation

& Display

ADS-B Equipped

Aircraft & Vehicles

Contractor

Monitoring and Control

FAA

Monitoring

Other Data

Users

(e.g. Airlines)

ADS-B

Downlink

Downlink Air Interface

UAT RX 1090ES RX

SDP SDP SDP SDP SDP

*Design = Critical, Initial Implementation = Essential

ADS-B Equipped

Aircraft & Vehicles

1090 RX UAT RX

MLAT Critical Service

Uplink Air InterfaceDownlink Air Interface

ATCRBS, Mode S and

ADS-B Downlink

ATCRBS & Mode S

MLAT Interrogations

Ground Interface and MLAT

Processing Function

FAA

Monitoring

Other Data

Users

(e.g. Airlines)

ATC

Automation

& Display

ATCRBS, Mode S and ADS-B

Equipped Aircraft

SDP SDP SDP

1030 TX

TIS-B/Radar

Data Sources

Contractor

Monitoring and Control

Figure 1-1: Surveillance and Broadcast Services Partitioning

1.2 Purpose

This document is to be used in the procurement of a Wide Area Multilateration (WAM) Service per the requirements in this document.

1.3 Scope

This document details the requirements for a WAM Service that the Federal Aviation

Administration (FAA) will acquire under the Surveillance and Broadcast Services Program.

The required functionality of the Service as well as the performance that is required is included herein. The interfaces that the Service is to provide are also specified.

1.4 Service Description

The WAM Service will be deployable NAS-wide, where required, as a surveillance backup to

ADS-B in terminal and en route airspace. The WAM Service may operate within the Service

Volumes as ADS-B.

1.4.1 Functional Overview

The WAM Service receives ADS-B Messages transmitted on either the UAT or 1090ES data links and receives interrogation replies from ATCRBS and Mode S equipped aircraft/vehicles, generates Target Reports based on these messages, and distributes the Target Reports to SDPs.

The SDPs may be ATC Automation systems, authorized user systems, or systems that further distribute data to end user systems.

The WAM Service can be broken into four major logical functions. This division of functionality is not meant to imply any particular architecture. The functions are offered only as a convenient means of describing and organizing the requirements for the Service. Figure 1-

2 summarizes the WAM Service functions, inside the shaded box, and the external interfaces, outside of the box.

1.4.1.1 Message Receive and Decode Function

The Message Receive and Decode Function receives Radio Frequency (RF) UAT ADS-B, 1090ES ADS-B, Mode S and ATCRBS Messages. The function also determines the time of arrival of each message. Each point in the WAM Service Volume must be visible to three or more instances of the Message Receive and Decode Function. The Message Receive and

Decode Function box in Figure 1-2 is meant to represent all ground locations that are required per the Service Provider's design to cover the WAM Service Volume. The Message Receive and Decode Function sends decoded messages to the Target Processing and Report Distribution

Function.

1.4.1.2 Interrogate Function

The Interrogate function schedules and transmits Mode S and ATCRBS interrogations for the purpose of detecting and tracking ATCRBS transponders, downloading aircraft parameters such as Mode A code, Mode C altitude and aircraft identity, and maintaining the required update rate. Interrogations are used for transponder equipped aircraft that do not have or have lost their "ADS-B out" capability.

Aircraft Service Delivery Point

Message Receive &

Decode Function

WAM Service Status Reports

1030 Interrogations (ATCRBS, Mode-S)

WAM Target Reports

Service Delivery Points (FAA Monitoring, ATC, or Authorized Users)

WAM

Service

Interrogatio n

Function

Target Processing & Report Distribution Function

Maintenanc eFunction

ADS-B Messages (1090ES, UAT) 1090 Replies (ATCRBS, Mode-S)

Figure 1-2: WAM Service Functions

1.4.1.3 Target Processing and Report Distribution Function

The Target Processing and Report Distribution Function takes the decoded Message information and formats it into WAM Target Reports. The function performs multilateration on received messages to estimate position and extracts data from 1090ES squitters, UAT messages, Mode S replies and ATCRBS replies. Specifically, the Processing and Report

Distribution Function:

Generates Target Reports from received messages, Provides for configuration of certain parameters, Filters Reports based on specified criteria, Synchronizes clocks from distributed sensors (WAM Ground Stations) and

Distributes Target Reports to SDPs via a Virtual Radar interface or an ASTERIX report interface

1.4.1.4 Maintenance Function

The Maintenance function includes, but is not limited to, providing service status and equipment status to the FAA. The Maintenance function also may also include statistics on the quality of the data within the WAM Service Volume.

1.4.2 External Interfaces

The WAM Service interfaces with the following external systems:

Aircraft equipped with UAT and 1090ES ADS-B avionics and/or Mode S or ATCRBS transponders.

SDPs (ATC Automation Systems, SBS Monitor Systems, and other authorized external users)

Detailed interface requirements between these systems are contained in Interface Requirements

Documents referenced in sections §2 and §3.

The Service Provider may provide data to user systems in addition to those specified by the

FAA, but has to comply with FAA Order 1200.22c, Data and Interface Equipment Used by

Outside Interests, and have FAA approval.

1.4.2.1 External Interface to Aircraft

The interfaces to Aircraft are largely defined by the ATCRBS, Mode S, UAT and 1090ES data link MOPS. Any additional requirements for these interfaces are specified herein.

1.4.2.1.1 Inputs to the WAM Service from Aircraft

The WAM Service receives ATCRBS and Mode S Replies on 1090 MHz, and ADS-B

Messages on the UAT and 1090ES links from Aircraft to support ATC surveillance applications. The received Messages comply with applicable RTCA ADS-B data link MOPS

(RTCA/DO-282B/DO-282A for UAT, and RTCA/DO-260B/DO-260A/DO-260 for 1090ES), RTCA/DO-144A of ATCRBS, and RTCA/DO-181D for Mode S replies. To meet specified

WAM Service Volume requirements, a network of ground sites (i.e., implementations of the

Message Receive and Decode Function) will be required to receive, decode and timestamp the transmitted Messages.

1.4.2.1.2 Outputs from the WAM Service to Aircraft

The WAM Service transmits ATCRBS and Mode S interrogation messages at 1030 MHz through the Interrogate Function. This Function schedules and transmits interrogation messages. The WAM Service formats interrogations in accordance with ICAO SARPs Annex

10 Volume IV.

1.4.2.2 External Interface to SDPs

The WAM Service sends Target Reports to SDPs, supporting ATC Automation Systems, SBS

Monitor Systems, and other authorized external users including Airlines Operations Centers.

The Target Reports contain surveillance related data on aircraft within the WAM Service

Volume. The WAM Service additionally sends Service Status Reports containing monitored information, such as alerts and alarms to SDPs. The minimum set of monitored parameters are described in Section §3.2.4 of this document.

1.5 Document Overview

This specification consists of the following sub-sections:

Section 2 – Provides references for documentation applicable to this specification, Section 3 – Includes definitions and functional, performance, interface, and security requirements for the WAM Service, Section 4 – Contains the WAM quality assurance information, Section 5 – Provides a listing of acronyms utilized throughout the document.

2 APPLICABLE DOCUMENTS

The following documents form a part of this specification and are applicable to the extent specified herein. In the event of a conflict between the documents referenced herein and the contents of this specification, the contents of this specification shall [001] be considered a superseding requirement.

2.1 Government Documents

2.1.1 Specifications

FAA-G-2100H Electronic Equipment, General Requirements, May 9,

2.1.2 Standards

FAA-STD-067 Standard Practice, Preparation of Specifications, December

4th, 2009

FAA TSO-C112c Air Traffic Control Radar Beacon System / Mode Select

(ATCRBS/Mode-S) Airborne Equipment, December 18, FAA TSO-C154c Universal Access Transceiver (UAT) Automatic Dependent

Surveillance – Broadcast (ADS-B) Equipment Operating on

Frequency of 978 Megahertz (MHz), December 2, 2009.

FAA TSO-C166b Extended Squitter Automatic Dependent Surveillance-

Broadcast (ADS-B) and Traffic Information Service (TIS-B)

Equipment Operating on Radio Frequency of 1090 Megahertz

(MHz), December 2, 2009.

NAS-IR-82530001 Surveillance and Broadcast Services (SBS) Service Delivery

Point (SDP) to ATC Automation and Service Monitoring

User Subsystems Interface Requirements Document, Revision A, February 23, 2012

NAS-IR-82530004 Surveillance and Broadcast Services (SBS)

Wide Area Multilateration (WAM) Common Digitizer-2

(CD-2) to En Route ATC Automation and Service

Monitoring User Subsystems Interface Requirements

Document, Revision -, February 2, 2012

NAS-IR-82533422 Surveillance and Broadcast Services (SBS) Wide Area

Multilateration (WAM) Service ASTERIX Virtual Radar to

ATC Automation Interface Requirements Document, Version

1.3

2.1.3 Orders

FAA Order 1010.51A U. S. National Standard for the IFF Mark X (SIF) Air Traffic

Control Radar Beacon System (ATCRBS) Characteristics, March 8, 1971

FAA Order 6000.53C Remote Maintenance Monitoring Interface Development and

Implementation, April 25, 2011

FAA Order 6050.19F Radio Spectrum Planning, September 5, 2005

FAA Order 6365.1A US National Aviation Standard for the Mode Select (Mode S)

Beacon System, January 3, 1983

FAA Order 1200.22c Data and Interface Equipment Used by Outside Interests

2.2 Non-Government Documents

ICAO Annex 10, Volume IV International Standards, Recommended Practices (SARPs) and Procedures for Air Navigation Services Aeronautical

Telecommunications (including Amendment 85), July 2007

RTCA/DO144A Minimum Operational Performance Standards for Air Traffic

Control Radar Beacon System (ATCRBS) Airborne

Equipment, October 2, 2008

RTCA/DO-181D Minimum Operational Performance Standards for Air Traffic

Control Radar Beacon System/Mode Select (ATCRBS/Mode-

S) Airborne Equipment, October 2, 2008

RTCA/DO-260 Minimum Operational Performance Standards for 1090 MHz

Extended Squitter Automatic Dependent Surveillance –

Broadcast (ADS-B), September 13, 2000

RTCA/DO-260, Change 1 Change 1 to the Minimum Operational Performance

Standards for 1090 MHz Extended Squitter Automatic

Dependent Surveillance – Broadcast (ADS-B), June 27, 2006

RTCA/DO-260A Minimum Operational Performance Standards for 1090 MHz

Broadcast (ADS-B) and Traffic Information Services –

Broadcast (TIS-B), Revision A, April 10, 2003

RTCA/DO-260A, Change 1 Change 1 to the Minimum Operational Performance

Dependent Surveillance – Broadcast (ADS-B) and Traffic

Information Services – Broadcast (TIS-B), Revision A, June

27, 2006

RTCA/DO-260A, Change 2 Change 2 to the Minimum Operational Performance

Dependent Surveillance – Broadcast (ADS-B) and Traffic

Information Services – Broadcast (TIS-B), Revision A, December 13, 2006

RTCA/DO-260B Minimum Operational Performance Standards for 1090 MHz

Broadcast (ADS-B) and Traffic Information Services –

Broadcast (TIS-B), Revision B, December 2, 2009

RTCA/DO-282A Minimum Operational Performance Standards for Universal

Access Transceiver (UAT) Automatic Dependent

Surveillance Broadcast (ADS-B), December 13, 2006.

RTCA\DO-282B Minimum Operational Performance Standards for Universal

Access Transceiver (UAT) Automatic Dependent

Surveillance Broadcast (ADS-B), December 2, 2009.

2.3 Documentation Sources

2.3.1 FAA Documents

Copies of FAA specifications, standards, and publications may be obtained from the FAA

Contracting Officer. Requests should clearly identify the desired material by number and state the intended use of the material.

2.3.2 Electronic Industries Alliance Documents

Copies of Electronic Industries Alliance (EIA) standards may be obtained from the Electronic

Industries Alliance, 2500 Wilson Boulevard, Arlington, VA 22201-3834, by calling (703) 907-

7500, or through the web site http://www.eia.org.

2.3.3 RTCA, Inc Documents

Copies of RTCA, Inc. documents may be obtained from RTCA, Incorporated, 1828 L Street

NW, Suite 805, Washington, DC 20036, by calling (202) 833-9339, or through the web site http://www.rtca.org.

2.3.4 ICAO Documents

Copies of documents that are published by the International Civil Aviation Organization

(ICAO) may be obtained from the ICAO Document Sales Unit, 999 University Street, Montreal, Quebec, Canada H3C 5H7, or by calling (514) 954-8022, or by sending an email to sales@icao.int, or by visiting the “Publications” link on the ICAO web site at:

http://www.icao.int.

http://www.eia.org/ http://www.rtca.org/ mailto:sales@icao.int http://www.icao.int/

3 REQUIREMENTS

3.1 Definitions

The definitions in this Section are for informational purposes. Should any of these terms need to become a part of the Contract between the Service Provider and the Government, they will be specifically incorporated in the Contract.

3.1.1 Access Control Mechanisms

Protection of system resources against unauthorized access: a process by which use of system resources is regulated according to a security policy and is permitted by only authorized entities according to that policy.

3.1.2 ADS-B Message

An ADS-B Message is an expression of the ADS-B target information in a data link specific format broadcast from aircraft/vehicles. ADS-B Messages are transmitted and received on either the UAT or 1090ES data links, per the formats defined in the Minimum Operational

Performance Standards (MOPS) documents, RTCA/DO-282B and RTCA/DO-260B, respectively.

3.1.3 ADS-B Service

The ADS-B Service as used in this document applies to the component of the Surveillance and

Broadcast Services ground infrastructure that receives ADS-B Messages, processes them, and distributes them in the form of ADS-B Reports to the SDPs and the ADS-R Service.

3.1.4 ADS-R Message

An ADS-R Message is broadcast, by the ADS-B Rebroadcast Service, on either the UAT or

1090ES data link, per the TIS-B Message format in RTCA/DO-282B and the ADS-B

Rebroadcast Message formats defined in §2.2.18 of RTCA/DO-260B. An ADS-R Message is the retransmission of ADS-B data that was received on one data link on the other data link.

3.1.5 ADS-R Service

The ADS-B Rebroadcast (ADS-R) Service rebroadcasts ADS-B Messages received over one

ADS-B data link on the other ADS-B data link.

3.1.6 Coverage Volume

A Coverage Volume is an airspace volume within which Broadcast Services are provided.

Service is ordered on a Coverage Volume basis. A Coverage Volume contains one or more

Service Volumes.

3.1.7 Service Status Report

A Service Status Report contains Service status information and is generated periodically by the WAM Service. The Service Status Report is provided in the FAA CAT019 Report format detailed in NAS-IR-82530001.

3.1.8 Duty Cycle

The percentage of time the transmit function, a sub-function of the Interrogate Function, is keyed in proportion to total service time.

3.1.9 Least Significant Bit (Lsb)

The least significant bit of data.

3.1.10 ME Field

The ME Field is the 56 bits that define the Mode-S 1090 MHz Extended Squitter (1090ES)

Message.

3.1.11 WAM Service Volume

The WAM Service Volume is the volume of airspace in which the performance of the WAM

Service satisfies the requirements contained within §3.0 of this document.

3.1.12 Most Significant Bit (Msb)

The most significant bit of data.

3.1.13 Receiver

The term “receiver” as used in this document refers to the receiver sub-function of the Message

Receive and Decode Function.

3.1.14 SBS Monitor

The SBS Monitor is a Government system that will independently monitor the performance of

Surveillance and Broadcast Services. To the WAM Service, the SBS Monitor will be a Service

Delivery Point. The SBS Monitor will provide an interface to the Remote Maintenance

Monitoring System (RMMS) per FAA Order 6000.53. This interface will provide WAM

Service Status to the RMMS.

3.1.15 Service Availability

Service Availability (A0) is defined as:

DowntimeUptime

Uptime Ao

Uptime is defined as the element of time during which the service provider’s system is performing its required service functions. Downtime is the element of time during which the service provider’s system is not performing its required service functions. The sum of Uptime and Downtime is the total time the service is planned to be provided by the Service Provider.

It excludes time for testing and integration prior to the service being made available for operational use. It also excludes time for scheduled preventive maintenance.

3.1.16 Service Delivery Point

The Service Delivery Point is the physical demarcation point for the WAM Service. WAM

Target Reports and Service Status Reports are delivered by the WAM Service to the Service

Delivery Point. The specific Service Delivery Points for each Service Volume will be defined in the Contract Schedule. Each WAM Service Volume will have one or more SDPs. The interface between the WAM Service and the SDP is defined in NAS-IR-82530001.

3.1.17 Service Domain

For purposes of this specification, there are two Service domains: (2) Terminal and (3) En

Route/Off-Shore. The WAM Service is not intended to be utilized in the (1) Surface Service

Domain. Each Service Volume specified by the FAA will have a single domain identified.

3.1.18 Service Enhancement

Capabilities identified as desirable for the WAM Service to meet a future need but are not within the “core” capabilities for the WAM service. The Service would need to provide these enhanced capabilities in the future, if and when they are ordered. Included in this specification are the currently identified Service Enhancement (SE) requirements. Service Enhancement requirements are noted with an “SE” marking following the requirement number for each sentence containing the requirements for these future capabilities.

3.1.19 Service Volume

A Service Volume is an airspace volume within which a specific Broadcast Services application is supported and the associated performance requirements are achieved.

3.1.20 Shall

When used in this specification, the word “shall” refers to an explicit requirement of a service function or the entire service.

3.1.21 Should

When used in this specification, the word “should” refers to a desired characteristic of a service function or the entire service.

3.1.22 Transmitter

The term “transmitter” as used in this document refers to the transmit sub-function of the

Interrogate Function.

3.1.23 Update Interval

Update interval refers to the reference time period that defines the desired maximum time between WAM Target Report updates. Update Interval is used for defining surveillance performance and is always associated with a Probability of Update metric.

3.1.24 Minimum Output Period

Minimum Output Period is the minimum time allowed between target reports for each target when a virtual radar output is not in use and when Throttled Reporting is active. The Minimum

Output Period begins when a target report is issued and ends after a configurable interval. The first position update made after the end of the Minimum Output Period triggers the next Target

Report Update.

3.1.25 Target Report Update

A Target Report Update occurs when a target report arrives at an SDP with updated position information. "Updated position information" is information derived from one or more aircraft transmissions received after the transmission(s) used in the last Target Report Update.

3.1.26 Probability of Update

Probability of Update is the probability that at least one Target Report Update will occur for a target during each successive Update Interval. The Update Interval is specified for each WAM

Service Volume.

3.1.27 Mode A / Mode C Validation

Mode A/Mode C validation is the process of testing and declaring the correctness of the Mode

A or Mode C code received from a target. This document specifies performance requirements for Mode A/Mode C validation but does not specify validation methods.

3.1.28 Victim Transponder

A Victim Transponder is one which receives interrogations from the WAM Service with amplitude sufficient to cause the transponder to process the interrogation. The transponder may reply or suppress a reply for a period of time based on the received amplitude of the interrogation. Each interrogation requires some processing time on the transponder during which the transponder cannot reply to other surveillance systems.

3.1.29 Will

When used in this specification, the word “will” provides information for a characteristic of a service function or of the entire service.

3.1.30 Time of Message Receipt (ATCRBS/Mode-S/1090ES)

The Time of Message Receipt (TOMR) of a 1090 Squitter, Mode S reply or ATCRBS reply is measured relative to the arrival of the leading edge of the first preamble pulse of a 1090 Squitter or Mode S reply, or the first frame pulse of an ATCRBS reply. When a message is received at multiple locations by the service, the Time of Applicability of the resulting WAM Target

Report is based on the oldest/first primitive TOMR which contributes to the position solution.

3.1.31 Time of Message Receipt (UAT)

The Time of Message Receipt (TOMR) of a UAT ADS-B Message is measured relative to the arrival of the optimum sample point of the first bit of the UAT synchronization sequence. When a message is received at multiple locations by the service, the Time of Applicability of the resulting WAM Target Report is based on the oldest/first primitive TOMR which contributes to the position solution.

Notes:

1. See Sections §2.2.2.3 and §2.2.6.2.2 of RTCA/DO-282B.

2. The optimum sample point is the nominal center of the bit period.

3.1.32 Time of Applicability (TOA)

The time of applicability of the position in a report is the TOMR of the message used for multilateration.

3.1.33 Data Item Age

The age of a measurement or data item is the difference between the present time and the

TOMR of the first message used to formulate the measurement or the TOMR of the message from which the data was extracted to populate the report field.

3.1.34 WAM Target Report

Multilateration derived information concerning a single target expressed in a data link independent format and exchanged between non-RF systems. A WAM Target Report is derived from one or more Messages received on the ATCRBS, Mode S, UAT or 1090ES data links. The WAM Target Report is provided to the SDP in either the FAA CD-2 report format, the ASTERIX CAT048 format, or FAA ASTERIX CAT010 format as defined in NAS-IR-

82530004, NAS-IR-82533422, and NAS-IR-82530001 respectively.

3.1.35 WAM Service

The WAM Service as used in this document applies to the component of the Surveillance and

Broadcast Services ground infrastructure that receives ATCRBS, Mode S, 1090ES and UAT

Messages, decodes and processes them, and distributes them in the form of WAM Target

Reports to SDPs.

3.1.36 Interrogation

An interrogation is an RF transmission from the WAM service sent to elicit a reply message from aircraft with suitable transponders. Interrogations and replies conform to requirements for the ATCRBS and Mode S data links.

3.1.37 Message

In the context of this specification, a message is an RF transmission from an aircraft or ground vehicle to the WAM Service. Messages comply with the formats and protocols of Mode S and

ATCRBS for interrogation replies, and with the formats and protocols of ADS-B 1090ES and

UAT.

3.1.38 Periodic Reporting

Periodic Reporting is the process of issuing target reports with a constant but configurable time between them. Periodic Reporting has higher variability in latency but lower data rates than data driven reporting.

3.1.39 Throttled Reporting

Throttled Reporting is the process of issuing target reports in a data-driven manner except that a Minimum Output Period applies after the transmission of each report. Position updates generated during this minimum output period are not sent to the SDP. The next position update to occur after the expiration of the minimum output period triggers a target report. Throttled reporting has a data rate comparable to periodic reporting and latency variability that is the same as data driven reporting.

3.1.40 Data Driven Reporting

Data driven reporting is when the delivery of a target report is triggered by each and every position update. Data driven reporting minimizes latency but can result in high data rates.

3.1.41 Latency

Latency is the elapsed time from the TOMR of the first message received by the WAM service until the output of the first bit of the corresponding target report at the SDP.

3.1.42 Extrapolation Time

The Extrapolation Time defines the maximum allowable time delta between the time at which a report is extrapolated and the TOA of a report being used for extrapolation.

3.2 Functional Requirements

The WAM Service functional requirements are presented in the following sections. The requirements are organized by function as shown in Figure 1-2.

3.2.1 Message Receive and Decode

The Message Receive and Decode Function receives Messages, in the form of RF signals transmitted by 1090ES, UAT, Mode-S, and ATCRBS equipped Aircraft, and decodes the information contained in the signals to recover the Message information.

3.2.1.1 Receiver Retrigger

The WAM Service decoding function shall [002] use a reply processor that will re-trigger if it detects a Mode-S preamble that is at least 3 dB stronger than the reply that is currently being processed in order to ensure that the stronger signal is processed.

3.2.1.2 1090ES

a. The WAM Service shall [003] receive, decode, and process 1090ES messages from aircraft equipped with MOPS compliant Class A1 or B1 avionics. Specifically;

RTCA/DO-260 Change 1 (dated June 27, 2006), RTCA/DO-260A Change 1 (dated

June 27, 2006), RTCA/DO-260A Change 2 (dated December 13, 2006), or

RTCA/DO-260B (dated December 2, 2009).

b. The WAM service shall [004] receive, decode, and process the following ADS-B messages transmitted from targets within the service volume:

DF17 Squitters

DF18 (CF=0 or 1) Squitters

DF19 (AF=0) Squitters

3.2.1.3 UAT

a. The WAM Service shall [005] receive, decode, and process UAT messages from aircraft equipped with MOPS compliant Class A1 or B1 avionics. Specifically;

RTCA/DO-282A (dated December 13, 2006) or RTCA/DO-282B (dated December 2, 2009).

b. The WAM Service shall [006] process only ADS-B messages received on the UAT link with the Address Qualifier field not equal to 2, 3, 6, or 7.

3.2.1.4 ATCRBS

a. The WAM Service shall [007] receive, decode, and process ATCRBS messages from aircraft equipped with MOPS compliant Class B avionics. Specifically;

RTCA/DO-144A (dated October 2, 2008).

b. The WAM service shall [008] receive, decode, and process the following replies and messages transmitted from targets within the service volume:

ATCRBS Mode A replies

ATCRBS Mode C replies

3.2.1.5 Mode-S

a. The WAM Service shall [009] receive, decode, and process Mode-S messages from aircraft equipped with MOPS-compliant Level 1, Class 2 avionics. Specifically;

RTCA/DO-181D (dated October 2, 2008).

b. The WAM service shall [010] receive, decode, and process the following replies and messages transmitted from targets within the service volume:

Mode-S DF11 squitters

Mode-S DF-4 replies

Mode-S DF-5 replies

3.2.2 Interrogation

3.2.2.1 Interrogation Modes

The WAM service shall [011] provide interrogations for ATCRBS Mode 3/A, Mode C, and

Mode S UF-4 and UF-5.

3.2.2.2 ATCRBS Interrogation

a. The WAM service shall [012] comply with the ATCRBS ground equipment requirements of FAA Order 1010.51A and with the International Standards, Recommended Practices and Procedures for Air Navigation Services Aeronautical Telecommunications, Annex 10, Volume IV, to the Convention on International Civil Aviation, §3.1.1.1 and §3.1.1.4.

Note: In the event of a conflict between FAA Order 1010.51A and ICAO Annex 10, Annex

10 has precedence.

b. The WAM service shall [013] elicit ATCRBS replies by interrogations with short P4 pulses.

c. The service shall [014] NOT rely on other agents to cause ATCRBS transponders to emit replies.

3.2.2.3 Mode-S Interrogation

a. The WAM service shall [015] comply with the ground equipment requirements of FAA

Order 6365.1A, and with the International Standards, Recommended Practices and

Procedures for Air Navigation Services Aeronautical Telecommunications, Annex 10, Volume IV, to the Convention on International Civil Aviation §3.1.2.1.1, §3.1.2.1.2, and

§3.1.2.1.4.

Note: In the event of a conflict between FAA Order 6365.1A and ICAO Annex 10, Annex

10 has precedence.

b. The WAM Service shall [016] NOT emit Mode-S All-Call interrogations.

3.2.3 Target Processing and Report Distribution

3.2.3.1 Input Message Processing

3.2.3.1.1 Horizontal Position Determination

a. The WAM Service shall [017] determine the horizontal position for a target report by multilaterating on the ATCRBS and/or Mode-S replies from an aircraft.

b. For ADS-B capable aircraft, the WAM Service shall [018] generate the horizontal position for a target report by multilaterating on the 1090ES and/or UAT squitters.

3.2.3.1.2 Flight Level Determination

The WAM Service shall [019] determine the flight level of a target report by decoding the

ATCRBS or Mode-S replies from an aircraft.

Notes:

1. For RTCA/DO-260B and RTCA/DO-282B MOPS compliant aircraft, the barometric altitude information contained within the airborne position message may be utilized for determination of flight level.

2. For RTCA/DO-260/282 (V0) and RTCA/DO-260A/282A (V1) aircraft, the barometric altitude information must be obtained via a Mode-S interrogation.

3.2.3.1.3 Multilateration Time Reference

a. The WAM Service shall [020] utilize a timing reference to calculate TDOAs and perform position estimation.

b. The WAM Service shall [021] continue to meet all requirements defined in this specification for at least 1 hour in the event of a GNSS outage when installed in low traffic density environments.

c. The WAM Service shall [022] continue to meet all requirements defined within this specification for at least 96 hours in the event of a GNSS outage when installed in medium or high traffic environments.

Note: WAM Service traffic density environments are further described in § 3.3.1.4.

d. If ADS-B messages are used for reference timing and/or system status, the use shall [023] be limited to the DF18, Type Code 24 message allocated by ICAO for this purpose.

3.2.3.1.4 Process Mode C Code for ATCRBS Targets

For ATCRBS Mode C replies with the D1 bit set or with C bits having values of 0, 5, or 7, the system shall [024] assign an altitude of -99,900 feet to the target report.

3.2.3.1.5 Time of Applicability Determination

The time of applicability in a report shall [025] be equal to the TOMR of the message used to determine the position included in the report.

3.2.3.1.6 Message Information Storage

a. The WAM Service shall [026] store information received in WAM Messages per Table

3-1.

b. The WAM Service shall [027] retain the most recently received value of each parameter in Table 3-1.

Note: Previous values of the parameters can be discarded when an update is received.

Table 3-1: WAM Message Parameter Validity Time

Parameter / Contents Validity Time

SPI 24 seconds

Mode 3/A Code 60 seconds

Pressure Altitude 3 seconds

Note: A parameter is considered valid if a message has been received containing the data associated with this parameter. If an update has not been received within the indicated validity time, then there is no longer a valid value for this parameter.

3.2.3.1.7 Target Identification Reporting and Validation

a. The WAM Service shall [127] report a 3/A code of zeros (0000) and a validation status of

“Not Validated” if a 3/A code is never received from an aircraft.

b. The WAM Service shall [128] report a 3/A code of zeros (0000) and a validation status of

“Not Validated” if the service cannot validate the received code is correct (i.e., same as what the aircraft transmitted).

c. The WAM Service shall [129] report the last received validated 3/A code and a validation status of “Validated” as long as the code was received within the validity time period.

d. The WAM Service shall [130] report a 3/A code of zeros (0000) and a validation status of

“Not Validated” if the validity time period expires without the reception of a validated 3/A code from an aircraft.

3.2.3.1.8 Target Altitude Reporting and Validation

a. The WAM Service shall [131] report a Mode C altitude of zeros and a validation status of

“Not Validated” if a C code is never received from an aircraft.

b. The WAM Service shall [132] report a Mode C altitude of zeros and a validation status of

“Not Validated” if the service cannot validate the received code is correct (i.e., same as what the aircraft transmitted).

c. The WAM Service shall [133] report the last received valid Mode C altitude and a validation status of “Validated” as long as the code was received within the validity time period.

d. The WAM Service shall [134] report a Mode C altitude of zeros and a validation status of

“Not Validated” if the validity time period expires without the reception of a valid Mode

C altitude from an aircraft.

3.2.3.1.9 Altitude Correction

Utilization of uncorrected barometric altitude (as reported from the aircraft) in determination of horizontal position can potentially contribute to significant horizontal position estimate errors.

a. The WAM Service shall [135] utilize a barometric altitude correction function to reduce horizontal position errors when barometric altitude is used for horizontal position determination.

b. The WAM Service shall [136] report the status of the altitude correction function within the WAM Service Status Report.

c. The WAM Service shall [137] report an Operational Status of “NOGO” (i.e., Critically

Faulted) within the WAM Service Status Report when barometric altitude corrections can no longer be provided by the function.

Note: The reporting of the NOGO status should be triggered by the expiration of the forecast data used to determine the altitude corrections.

3.2.3.2 Report Generation

3.2.3.2.1 Generate CAT010 WAM Target Reports

The WAM Service shall [028] populate each WAM Target Report with the data from the corresponding fields of the received messages in accordance with NAS-IR-82530001.

3.2.3.2.2 Generate CD-2 Message

CD-2 messages shall [029] be assembled and delivered in accordance with NAS-IR-82530004.

3.2.3.2.3 Generate ASTERIX CAT048 Target Reports

The WAM Service shall [138] assemble and deliver ASTERIX CAT048 Target Reports in accordance with NAS-IR-82533422.

3.2.3.3 Report Configuration and Filtering

The WAM Service outputs reports over interfaces to Service Delivery Points (SDP). The

WAM Report CAT010 format, the Service Status Report CAT019 format, and other interface requirements are captured in NAS-IR-82530001. When configured for a WAM CD-2 Virtual

Radar output, the interface requirements are captured in NAS-IR-82530004. When configured for a WAM ASTERIX Virtual Radar, the interface requirements are captured in NAS-IR-

82533422.

a. The WAM Service shall [030] provide the following report types for each WAM Service

Volume:

1. WAM Target Reports within the Service Volume,

2. WAM Service Status Reports for the Service Volume.

b. A single report shall [031] be output for a target regardless of the number of surveillance types supported by the target (ATCRBS, Mode-S, and ADS-B).

c. The WAM Service shall [032] provide a configuration item which provides a selectable order of precedence for target report output so that only one report update is transmitted for a single aircraft.

For example, if a particular target simultaneously provides UAT squitters and Mode-S replies, the service would separately multilaterate on both the UAT and Mode-S replies and separate position reports would be generated. The precedence logic would allow for selecting which link has priority for generating the WAM report. If the logic was set for

UAT first and Mode-S second, the multilaterated UAT positions would be used for output to automation. If the UAT transponder was switched off and only Mode-S replies were received, then the Mode-S multilaterated positions would be used for output. The default order is expected to be;

1. 1090-ES ADS-B

2. UAT ADS-B

3. Mode-S

4. ATCRBS

d. The WAM Service shall [033] provide a geographic filtering option for filtering of WAM

Reports for aircraft outside of the WAM Service Volume.

Note: These requirements apply to both ASTERIX output and when configured for

Virtual Radar output.

3.2.3.4 Report Formatting and Output

a. The WAM Service shall [034] output WAM Reports in the FAA CAT010 format as defined in NAS-IR-82530001.

b. The WAM Service shall [035] output WAM Service Status Reports in the FAA CAT019 format as defined in NAS-IR-82530001.

c. The WAM Service shall [036] periodically send a Service Status CAT019 Reports to the

FAA Monitor that indicates the operational health of the WAM Service for each SDP being provided WAM Service in accordance with NAS-IR-82530001.

d. The WAM Service shall [037] output WAM Reports to the TIS-B/Fusion Processing

Function for use as TIS-B Surveillance source.

e. The WAM Service shall [038] limit the output of WAM Target Reports to not more than once per second.

Note: The requirements for report formatting and output when configured for a CD-2

Virtual Radar output are captured in NAS-IR-82530004. The requirements for report formatting and output when configured for a WAM ASTERIX Virtual

Radar output are captured in NAS-IR-82533422.

f. The WAM Service shall [119] periodically send a Service Status (WAM SDP Context)

CAT023 Report (e.g. SDP Heartbeat) that indicates the operational health of the WAM

SDP for each SDP providing WAM service to the FAA Monitor, in accordance with

NAS-IR-82530001.

g. The SDP Heartbeat shall [120] contain the incremental count of the number of reports received at the SDP, since the last Heartbeat, for each of the following reports:

WAM Reports, including Certification Target Reports

Service Volume Status Reports

h. The SDP Heartbeat shall [121] contain:

The SDP Alert Status which indicates that the SDP is providing full operational service, but is utilizing a single thread either due to a primary router failure with a switch-over to the backup, or a failure of the backup router while operating with the primary.

The SDP Alarm Status which indicates that the SDP is unable to reliably report status and/or message counts.

i. The WAM Service shall [122] send the SDP Heartbeat to the FAA Monitor at an interval of once each 5 seconds ± 2 seconds

Note: A loss of the SDP Heartbeat indicates a failure in the SDP equipment or associated communications path so the periodic Heartbeat could not be sent.

3.2.3.5 Service Certification

3.2.3.5.1 Integrity Monitoring

a. The WAM Service shall [039] include an automated integrity monitoring function that can detect radio synchronization failures that may cause degradation of the positional accuracy of the service.

b. The WAM Service shall [040] be capable of excluding radios from position calculations based on the results of the integrity monitoring function.

3.2.3.5.2 Certification Targets

a. The WAM Service shall [041] self certify its operation utilizing inputs from two or more certification targets located at accurately surveyed positions.

b. The WAM Service shall [042] multilaterate on squitters from the certification targets and verify that each target is reported at its correct position within the accuracy requirement of

§3.3.2.7.

Note: The expectation is that certification targets are placed in positions that allow for high accuracy multilateration position solutions.

c. The update interval of the certification targets shall [043] be in accordance with the update interval requirements of §3.3.2.4.1.

d. The certification targets shall [044] be an integrated component of the WAM Service.

e. The WAM Service shall [045] report the calculated position of the certification targets to the automation system as WAM target reports.

3.2.4 Maintenance Processing

The Maintenance Processing function must provide the government with sufficient information to independently assess the Service performance.

3.2.4.1 SBS Monitor Maintenance Data Sets

The Maintenance Processing function will send WAM Service Status data to the FAA so that the FAA can verify the performance of the service being provided by the service provider.

These data can include, but are not limited to data sent to users, alerts, and system performance parameters. Table 3-2 summarizes the maintenance data sets that are needed by the FAA.

The Maintenance Processing data set shall [046] be reported to the FAA in accordance with

Table 3-2.

Table 3-2: Maintenance Data Sets

Data Set Data Format Update Interval

WAM Certification Target

Report FAA ASTERIX CAT010 See § 3.2.3.5.2c

WAM Status Report FAA ASTERIX CAT019 Every 5 sec ±2sec

WAM SDP Status…