ICAO Address City, Country, Code

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1 ICAO Address City, Country, Code UAT SWG09-WP04 Manual on detailed technical specifications for the Technical Manual on the Universal Access Transceiver (UAT) [Level 1] Revision 3.0xx 21 September 2004 Can we find another word for payload and target [=traffic]? Document # Prepared by: DD MM YYYY.

2 Change Record Date/Version Change 15 Jan 2003/v0.1 Original Draft 17 March 2003/v0.2 Incorporate changes from review at January Montreal meeting 4 April 2003/v0.3 Incorporate changes from review at Montreal meeting 31 March 4 April Added material in Section 1, clean up Emitter Category/Call Sign encoding, 6 May 2003/v0.4 added sections and 5.2.5, added text to Section 6 Inputs from Brussels meeting: remove all informative material and any material relating to equipage classes to be presented in the UAT Implementation Manual create a global requirement concerning rounding of the LSB of a 21 July 2003/v0.5 field/remove numerous repetitive notes referring to rounding of LSB centralize data timeout requirement in section Add text on Information Frame definition for WG review. Changes to Figure 2-1 on Lat/Lon encoding for clarity [to be provided] Input from 12 Sept 2003 telecon Add Section on transceiver T/R switching requirements 16 Sept 2003/v0.6 Replace Section 4.2 to require suppression output for all classes of equipment As accepted during the review and incorporation of changes that were identified 21 Oct 2003/v1.0 during ACP WG-C Meeting #6, Toulouse For review during the UAT Subgroup Meeting in Montreal, 1-4 March Applying any changes or corrections that have been identified in the proposed change to the UAT MOPS (RTCA DO-282) leading to the publication of DO- 282A: Corrections to Table 2-6 ( ) Editorial corrections to Figure 2-1 ( ) A/V L/W Code consistent with the ASA MASPS ( ) Update language defining NAC P ( ) 20 Feb 2004/v1.1 True/Magnetic Heading Indicator Flag ( ) Track Target Heading or Track Angle ( ) Expansion of Frame Types in Table 2-58 ( ) Correction of formula and insertion of Note for MSO ( ) Clarification related to Precision and Non-Precision related to use of Geometric versus Pressure Altitude ( and ) Correction/addition of Data Timeout entries in Table 3-1 ( ) Expansion of requirement for Mutual Suppression (4.2) 3 March 2004/v1.2 As modified during the UAT Subgroup meeting in Montreal, 1-4 March As agreed to during the ICAO ACP WG-C Meeting in Montreal April 20 April 2004/v Changes to Mutual Suppression in 4.2 to conform to agreements in RTCA WG-5 9 July 2004/V2.1 for the UAT MOPS during Meeting 21 for the approval of RTCA DO-282A. Changes agreed to during the UAT Subgroup meeting in Madrid September 2004/V2.2 September To reflect changes discussed with Nikos Fistas and further agreed to by the UAT 17 September 2004/V2.3 Subgroup during their review of his comments. As reviewed and agreed to during the meeting of the ACP WG-C on September 2004/V3.0 September 2004.

3 FOREWORD The Universal Access Transceiver (UAT) is a wideband multi-purpose data link operating on [978] MHz intended to operate globally on a single channel with a channel signaling rate of just over 1Mbps. By design, UAT supports multiple broadcast services including Flight Information Service Broadcast (FIS- B) and Traffic Information Service Broadcast (TIS-B) in addition to ADS-B. This is accomplished using a hybrid medium access approach that incorporates both time-slotted and random unslotted access. By virtue of its waveform, signaling rate, precise time reference, and message-starting discipline, UAT can also support independent measurement of range to most other participants in the medium. There are two basic types of broadcast transmissions - or messages - on the UAT channel: the ADS-B Message, and the Ground Uplink Message. The ADS-B Message is broadcast by an aircraft to convey its State Vector (SV), and other information. In addition, UAT ground stations can support Traffic Information Service Broadcast (TIS-B) through transmission of individual ADS-B messages. The Ground Uplink Message is used by ground stations to uplink flight information such as text and graphical weather data, advisories, and other aeronautical information, to all any UAT equipped aircraft that are may be in the service volume of the ground station. Regardless of type, each message has two fundamental components: the message payload that contains user information, and message overhead, principally consisting of forward error correction code parity, that supports the transfer of the data.

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5 TABLE OF CONTENTS 1 INTRODUCTION OUTLINE OF THE MANUAL OBJECTIVE AND SCOPE DEFINITIONS UAT MESSAGE PAYLOAD UAT ADS-B MESSAGE PAYLOAD PAYLOAD ELEMENTS PAYLOAD TYPE ADS-B PAYLOAD COMPOSITION BY PAYLOAD TYPE CODE GENERAL PAYLOAD ENCODING RULES Payload Transmission Order Truncation of Data Into Payload Fields PAYLOAD CONTENTS HEADER Element PAYLOAD TYPE CODE Field Encoding ADDRESS QUALIFIER Field Encoding ADDRESS Field Encoding ICAO 24-Bit Aircraft Address of Transmitting Aircraft Reserved for Regional Use ICAO 24-Bit Aircraft Address of TIS-B Target Aircraft TIS-B Track File Identifier Surface Vehicle Address Fixed ADS-B Beacon Address STATE VECTOR Element for ADS-B (Address Qualifiers of 0, 1, 4 & 5) LATITUDE and LONGITUDE Field Encoding ALTITUDE TYPE Field Encoding ALTITUDE Field Encoding NIC Field Encoding A/G STATE Field Encoding Determination of Vertical Status Validation of Vertical Status HORIZONTAL VELOCITY Subfields Encoding as North Velocity Form Encoding as Ground Speed Form Encoding as East Velocity Form Encoding as Track Angle/Heading Form VERTICAL VELOCITY or A/V LENGTH/WIDTH CODE Field Encoding as Vertical Velocity Form Vertical Velocity Source Subfield Encoding VV Sign Subfield Encoding Vertical Rate Subfield Encoding Encoding as A/V Length and Width Code Form UTC Field Encoding i

6 Reserved Bits STATE VECTOR Element for TIS-B for Address Qualifiers of 2 & TIS-B SITE ID Field Encoding Encoding for All Other Fields MODE STATUS Element EMITTER CATEGORY AND CALL SIGN CHARACTERS #1 AND #2 Field CALL SIGN CHARACTERS #3, #4 AND #5 Field CALL SIGN CHARACTERS #6, #7 AND #8 Field EMITTER CATEGORY CALL SIGN EMERGENCY/PRIORITY STATUS Field Encoding UAT VERSION Field Encoding SIL Field Encoding TRANSMIT MSO Field Encoding Reserved Bits NAC P Field Encoding NAC V Field Encoding NIC BARO Field Encoding CAPABILITY CODES Field Encoding CDTI Traffic Display Capability Subfield TCAS/ACAS Installed and Operational Subfield OPERATIONAL MODES Field Encoding TCAS/ACAS Resolution Advisory Active Flag IDENT Switch Active Flag Receiving ATC Services Flag True/Magnetic Indicator Flag Call Sign Identification (CSID) Reserved Bits AUXILIARY STATE VECTOR Element SECONDARY ALTITUDE Field Encoding Reserved Bits TARGET STATE Element (Payload Type Codes 3 and 4 ) TARGET HEADING or TRACK ANGLE INFORMATION Field Encoding Target Heading/Track Angle Indicator Flag Encoding Target Source Indicator (Horizontal) Subfield Encoding Mode Indicator (Horizontal) Subfield Encoding Reserved Bits Target Heading or Track Angle Subfield Encoding TARGET ALTITUDE INFORMATION Field Encoding Target Altitude Type Flag Encoding Target Source Indicator (Vertical) Subfield Encoding Mode Indicator (Vertical) Subfield Encoding Target Altitude Capability Subfield Encoding Target Altitude Subfield Encoding TARGET STATE Element (Payload Type Code 6 ) TRAJECTORY CHANGE Element UAT GROUND UPLINK MESSAGE PAYLOAD UAT-SPECIFIC HEADER GROUND STATION LATITUDE Field Encoding GROUND STATION LONGITUDE Field Encoding POSITION VALID Field Encoding UTC Coupled Field Encoding Reserved Bits ii

7 APPLICATION DATA VALID Field Encoding SLOT ID Field Encoding TIS-B SITE ID Field Encoding Reserved Bits GROUND UPLINK APPLICATION DATA Information Frames Length subfield encoding Reserved subfield encoding Frame Type subfield encoding Frame Data subfield encoding SYSTEM TIMING AND MESSAGE TRANSMISSION PROCEDURES AVIONICS PROCEDURES FOR PROCESSING OF TIME DATA UTC Coupled Condition Non-UTC Coupled Condition ADS-B MEDIA ACCESS TIMING The Message Start Opportunity (MSO) Relationship of the MSO to the Modulated Data TIME REGISTRATION AND LATENCY Requirements When in Non-Precision Condition and UTC Coupled Requirements When in Precision Condition and UTC Coupled Requirements When Non-UTC Coupled Data Timeout SPECIAL REQUIREMENTS FOR TRANSCEIVER IMPLEMENTATIONS Transmit-Receive Turnaround Time Receive-Transmit Turnaround Time GROUND STATION PROCEDURES FOR PROCESSING OF TIME DATA UTC Coupled Condition Non-UTC Coupled Condition UAT GROUND STATION MEDIA ACCESS Transmission Time Slots Transmission Time Slot Rotation and Channels Transmission of Ground Uplink Message INTERFACE REQUIREMENTS FOR THE AIRBORNE EQUIPMENT UAT RECEIVER OUTPUT REQUIREMENTS (REPORT GENERATION) RECEIVER TIME OF MESSAGE RECEIPT REPORT ASSEMBLY ON RECEIPT OF ADS-B MESSAGE REPORT ASSEMBLY ON RECEIPT OF GROUND UPLINK MESSAGE MESSAGE RECEPTION-TO-REPORT COMPLETION TIME MUTUAL SUPPRESSION iii

8 LIST OF FIGURES Figure 2-1: Angular Weighted Binary Encoding of Latitude and Longitude Figure 3-1: GPS/GNSS Time Mark Pulse Figure 3-2: Relationship of Channel Numbers to Transmission Time Slot Numbers LIST OF TABLES Table 2-1: ADS-B Payload Elements Table 2-2: Composition of UAT ADS-B Message Payload... 4 Table 2-3: Encoding of HEADER Element into UAT ADS-B Message Payload Table 2-4: ADDRESS QUALIFIER Encoding Table 2-5: Format of STATE VECTOR Element Table 2-6: Angular Weighted Binary Encoding of Latitude and Longitude Table 2-7: ALTITUDE TYPE Encoding Table 2-8: ALTITUDE Encoding Table 2-9: NIC Encoding Table 2-10: A/G STATE Field Encoding Table 2-11: North Velocity Format Table 2-12: North/South Sign Encoding Table 2-13: North Velocity Magnitude Encoding Table 2-14: Ground Speed Format Table 2-15: Ground Speed Encoding Table 2-16: East Velocity Format Table 2-17: East/West Sign Encoding Table 2-18: East Velocity Magnitude Encoding Table 2-19: Track Angle/Heading Format Table 2-20: Track Angle/Heading Type Encoding Table 2-21: Track Angle/Heading Encoding Table 2-22: Vertical Velocity Format Table 2-23: Vertical Velocity Source Encoding Table 2-24: Sign Bit for Vertical Rate Encoding Table 2-25: Vertical Rate Encoding Table 2-26: A/V Length and Width Format Table 2-27: Aircraft/Vehicle Length and Width Encoding Table 2-28: Position Offset Applied Encoding Table 2-29: UTC Encoding Table 2-30: Format of STATE VECTOR Element (For TIS-B) Table 2-31: Format of MODE STATUS Element Table 2-32: EMITTER CATEGORY Encoding Table 2-33: Call Sign Character Encoding Table 2-34: EMERGENCY/PRIORITY STATUS Encoding Table 2-35: UAT Version Number Table 2-36: SIL Encoding Table 2-37: NAC P Encoding Table 2-38: NAC V Encoding Table 2-39: NIC BARO Encoding Table 2-40: CAPABILITY CODES Encoding Table 2-41: OPERATIONAL MODES Encoding Table 2-42: Format of AUXILIARY STATE VECTOR Element iv

9 Table 2-43: Format of TARGET STATE Element (Payload Type Codes 3 and 4 ) Table 2-44: TARGET HEADING or TRACK ANGLE INFORMATION Format Table 2-45: Target Source Indicator (Horizontal) Encoding Table 2-46: Mode Indicator (Horizontal) Subfield Encoding Table 2-47: Target Heading or Track Angle Encoding Table 2-48: TARGET ALTITUDE INFORMATION Format Table 2-49: Target Altitude Type Values Table 2-50: Target Source Indicator (Vertical) Encoding Table 2-51: Mode Indicator (Vertical) Subfield Encoding Table 2-52: Target Altitude Capability Encoding Table 2-53: Target Altitude Encoding Table 2-54: Format of TARGET STATE Element Table 2-55: Format of the UAT Ground Uplink Message Payload Table 2-56: Encoding of TIS-B Site ID Table 2-57: Format for Information Frames Table 2-58: Frame Type Encoding Table 3-1: UAT ADS-B Transmitter Data Timeout Table 3-2: Transmission Time Slot Definition for the UAT Ground Segment v

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11 1 1 Introduction 1.1 Outline of the Manual This manual contains detailed technical specifications technical requirements related to the implementation of the Standards and Recommended Practices (SARPs) for the Universal Access Transceiver (UAT). A companion document, the UAT Implementation Manual, provides additional guidance material of an informative nature. Section 1 of this document presents the objectives and scope of thise manual and provides definition of key terms used in the manual Section 2 contains the specifications for the provides details on UAT message payloads and formats. Section 3 contains the specifications describes procedures for the airborne aircraft equipment avionics and the ground transmitters, including requirements for processing timing information. Section 4 contains the describes interface requirements for airborne aircraft equipment. Appendix A provides a set of Acronyms and Definitions of Terms. 1.2 Objective and Scope The objective of this manual (in conjunction with the SARPs) is to define a set of internationally agreed detailed technical specifications characteristics of for the UAT system that accomplish the following: 1. Establish a basis for RF compatibility of UAT with to other systems from UAT and vice versa. 2. Establish a common basis for UAT intersystem interoperability across implementations manufactured and certified in different regions of the world. This manual alone is not considered adequate for manufacture or certification of UAT equipment and is not a replacement for local certification guidance. 1.3 Definitions UAT: Universal Access Transceiver (UAT) is a broadcast data link intended to operate globally on a single channel, with a channel signaling rate of Mbps. (align with SARPs and reference these) UAT ADS-B Message: UAT ADS-B Messages are broadcast by each aircraft once per second to convey state vector and other information. UAT ADS-B Messages can be in one of two forms depending on the amount of information to be transmitted in a given second: the Basic UAT ADS-B Message or the Long UAT ADS-B Message (see of the UAT SARPs for definition of each). (align with SARPs and reference these)

12 2 UAT Ground Uplink message: The UAT Ground Uplink message is used by ground stations to uplink flight information such as text and graphical weather data, advisories, and other aeronautical information, to any aircraft that may be in the service volume of the ground uplink station message (see of the UAT SARPs for further details). (align with SARPs and reference these) Basic Standard Receiver: A general purpose receiver with less rejection of interference from adjacent channel DMEs than the High Performance receiver (see of the UAT SARPs for further details). (align with SARPs and reference these) High Performance Receiver: A UAT receiver with additional filter selectivity to aid in the rejection of adjacent channel DME interference (see of the UAT SARPs for further details). (align with SARPs and reference these) Optimum Sampling Point: The optimum sampling point of a received UAT bit stream is at the nominal center of each bit period, when the frequency offset is either plus or minus khz. (align with SARPs and reference these) Protected service volume: A part of the facility coverage where the facility provides a particular service in accordance with relevant SARPs and within which the facility is afforded frequency protection. Pressure Altitude: An atmospheric pressure expressed in terms of altitude which corresponds to that pressure in the Standard Atmosphere (Annex 8 refers). ADS-B reference point: tbd Additional Acronyms and Definitions of terms are provided in Appendix A.

13 3 2 UAT Message Payload 2 Note: The term Message specifically refers to an actual UAT transmission. UAT Messages are one of two (2) general types: (1) ADS-B Messages, or (2) Ground Uplink Messages. Additionally, UAT ADS-B Messages can be in one of two fixed length forms referred to as the Basic or Long format, depending on the amount of ADS-B information to be transmitted. 2.1 UAT ADS-B Message Payload data content Note: ADS-B information transmitted in UAT ADS-B Messages is referred to as the Payload. Payload is composed of combinations of Payload elements that result in several Payload types available for UAT ADS-B Messages as shown in Table 2-1 and Table Payload Elements The UAT ADS-B Message payload shall be organized into payload elements as shown in Table 2-1. Note: These elements contain the individual message fields (e.g., LATITUDE, ALTITUDE, etc.) that correspond to the various report elements issued by an UAT ADS-B Receiving Subsystem to an ADS-B application. Table 2-1: ADS-B Payload Elements Payload Element # of Bytes Applicable ADS-B Subparagraph Reports References HEADER (HDR) 4 All STATE VECTOR (SV) 13 State Vector (Note 1) MODE STATUS (MS) 12 Mode Status AUX. STATE VECTOR (AUX SV) 5 State Vector, Air Reference Velocity TARGET STATE (TS) 4 Target State (Note 2) TRAJECTORY CHANGE + 0 (TC+0) 12 Trajectory Change TRAJECTORY CHANGE + 1 (TC+1) 12 Trajectory Change Notes: 1. There are two variants of the State Vector Element is specific to ADS-B and relates to those specific differences particular to TIS-B. 2. There are two variants of the Target State Element is used with Payload Type Codes 3 and describes the Target State Element for Payload Type Code 6. They are different only in their position in the total payload.

14 Payload Type The UAT ADS-B Message shall contain a PAYLOAD TYPE CODE encoded in the first 5 bits of the payload. Note: The Payload Type Code allows the receiver to interpret the contents of the UAT ADS-B Message payload per the definition contained in through ADS-B Payload Composition by Payload Type Code The assignment of payload elements of Table 2-1 to each Payload Type Code shall be as defined in Table 2-2. Payload Type Code (HDR byte 1, bits 1 5) Table 2-2: Composition of UAT ADS-B Message Payload UAT ADS-B Message Payload Byte Number (Note 1) HDR SV Res( Note 2) Byte Not present in Type 0 1 HDR SV MS AUX SV 2 HDR SV Reserved (Note 2) AUX SV 3 HDR SV MS TS Res (No te 2) 4 HDR SV Reserved for TC+0 (Note 2) TS Res (No te 2) 5 HDR SV Reserved for TC+1 (Note 2) AUX SV 6 HDR SV Res. (Note 2) TS Res AUX SV 7 HDR SV 8 HDR SV Reserved (Note 3) 9 HDR SV 10 HDR SV 11 through HDR Reserved (Note 2) 29 30, 31 HDR Reserved for Developmental Use (Note 4) Notes: 1. Payload Type Code 0 indicates a Basic UAT ADS-B Message; byte 18 is reserved for future definition. (Comment: This means that byte 25 is not present and consequently no MSO number is transmitted and no range validation can be achieved. See Also no call sign or aircraft registration # is being sent. In case the 24 bit ICAO address is not available, this give identification difficulties and may not be operationally acceptable ( see also PANS ATM new para ))

15 2. Not yet defined. in this version of this Manual. Reserved for definition in future versions. 3. Payload Type Codes 7 10 will allow a degree (no full backwards compatibility?) of backward compatibility with future versions of UAT message definitions for receivers operating according to this version of this Manual. 4. Payload Type Codes 30 and 31 are intended for developmental use, such as to support on-air flight testing of new payload types, prior to their adoption. in future Manual versions. These Payload Type Codes should be ignored by operational equipment. (Comment: In summary: payload type 0 transmits only HDR and SV; Payload type 1 and 3 seem reasonably complete while payload codes 2 and 4-29 seem not complete and can not be used at this moment; note that payload code do NOT include SV information. Why should we not just identify codes 0, 1 and 3 and leave the rest open.? Reference to Section 3 of the Implementation Manual on scheduling of UAT ADS-B messages.) General Payload Encoding Rules Payload Transmission Order The UAT ADS-B Message payload shall be transmitted in byte order with byte #1 first. Within each byte, bits shall be transmitted in order with bit #1 transmitted first. Bit-level definition of the payload is provided in through Truncation of Data Into Payload Fields When converting raw data with more resolution than that required by a payload field, the accuracy of the data shall be maintained such that it is not worse than +/- ½ LSB where the LSB is that of the payload field Payload Contents HEADER Element Format for the HEADER element is defined in Table 2-3. This encoding shall apply to UAT ADS-B Messages with PAYLOAD TYPE CODES of 0 through 31. Each of the fields shown is defined in through Table 2-3: Encoding of HEADER Element into UAT ADS-B Message Payload Payload Byte # Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 1 (MSB) PAYLOAD TYPE CODE (LSB) ADDRESS QUALIFIER 2 (MSB)A1 A2 A ADDRESS 4... A22 A23 A24 (LSB)..

16 PAYLOAD TYPE CODE Field Encoding Definition of the PAYLOAD TYPE CODE field encoding that shall be used for all UAT ADS-B Messages is provided in Table 2-2. Note: The PAYLOAD TYPE CODE field is a 5-bit (bit 1 of byte 1 through bit 5 of byte 1) field used to identify the payload for decoding by the receiver ADDRESS QUALIFIER Field Encoding The ADDRESS QUALIFIER field is used to indicate the ADS-B message originator type. Definition of the ADDRESS QUALIFIER field encoding that shall be used for all UAT ADS-B Messages is provided in Table 2-4. Note: The ADDRESS QUALIFIER field is a 3-bit (bit 6 of byte 1 through bit 8 of byte 1) field used to indicate what the 24-bit ADDRESS field represents. Address Qualifier (binary) Bit 6 Bit 7 Bit 8 Table 2-4: ADDRESS QUALIFIER Encoding Address Qualifier (decimal) ADS-B message originator Address Type Reference subparagraph ADS-B message generated by an aircraft target with ICAO 24-bit aircraft address Reserved for national Regional use ADS-B/TIS-B message generated by an aircraft target with ICAO 24-bit aircraft address and re-transmitted from a ground station via TIS-B (ADS-B/TIS-B) ADS-B/TIS-B message target generated by a ground station with track file identifier by which the TIS-B data source identifies the target aircraft being described in the message ADS-B message generated by a Surface Vehicle ADS-B message generated by a Fixed ADS B Beacon (Reserved) (Reserved) Note: Address Qualifier values 6 and 7 are reserved for future definition ADDRESS Field Encoding The meaning of the ADDRESS field shall depend on the ADDRESS QUALIFIER field as described in through Note: The ADDRESS field is a 24-bit (bit 1 of byte 2 through bit 8 of byte 4) field used in conjunction with the ADDRESS QUALIFIER field to identify the originator of the ADS-B message participant.

17 ICAO 24-Bit Aircraft Address of Transmitting Originating Aircraft An ADDRESS QUALIFIER value of ZERO (binary 000) shall indicate that the message is an UAT ADS-B Message from an aircraft, and that the ADDRESS field holds the ICAO 24-bit aircraft address that has been assigned to that particular aircraft. The ICAO24 bit Aircraft Address shall be stored (or latched ) in the UAT ttransmitting ssystem. upon Power Up. The UAT ADS-B Transmitter ing Subsystem shall declare a device failure in the event that its own ICAO 24-bit aircraft Aaddress (i.e., the Mode-S Address) is invalid, unavailable, or set to all ZEROs or all ONEs. In such a case no ADS-B messages shall be transmitted. Note: The world-wideworldwide scheme method for the allocation, assignment and application of allocating and assigning the ICAO 24-bit ICAO aircraft addresses is contained described in Annex 10 to the Convention on International Civil Aviation, Volume III, Part I, Chapter 9, Appendix A. [ICAO Annex 10, Vol. III, Ch. 9] Reserved for national Regional Uuse An ADDRESS QUALIFIER value of ONE (binary 001) is reserved for national use. It shall not be used when the Receiving ATC Services Flag ( ) is set to ONE, indicating that the Participant aircraft originating the ADS-B message is under air traffic control receiving ATC services. The value of ONE for the ADDRESS QUALIFIER shall be reserved for Regional use. Note: Caution must be exercised because tthe use of such a value could indicate that the message is an UAT ADS-B Message from an aircraft that is not receiving ATC services, and that the ADDRESS field holds the transmitting aircraft s self-assigned a temporary 24 bit address self-assigned by the originating aircraft. Q: What if the address qualifier is TWO in ADS-B/TIS-B messages? Can ground stations re-transmit ADS-B messages from aircraft with faked 24 bit addresses? ICAO 24-Bit Aircraft Address of TIS-B Target Aircraft An ADDRESS QUALIFIER value of TWO (binary 010) shall be used in by a UAT Ground Station broadcast providing TIS-B message uplinks in the UAT ADS-B/TIS-B Message Format to indicate that the message has been generated by a ground station is for a TIS-B target and that the ADDRESS field holds the ICAO 24-bit aircraft address that has been assigned to the target aircraft being described in the message. Note: The worldwide scheme for allocating and assigning the 24-bit ICAO aircraft addresses is described in Annex 10 to the Convention on International Civil Aviation, Volume III, Chapter 9. [ICAO Annex 10, Vol. III, Ch. 9]. (This note should be aligned with the note in )

18 TIS-B Track File Identifier An ADDRESS QUALIFIER value THREE (binary 011) shall be used in by a UAT Ground Station providing TIS-B message uplinks in the UAT ADS-B/TIS-B Message Format to indicate that the message has been generated by a ground station is for a TIS-B target and that the ADDRESS field holds a 24 bit TIS-B track file identifier by which the TIS-B data source identifies the target aircraft being described in the message. Note: It is beyond the scope of this Manual to specify the method by which a TIS-B service provider would assign Ttrack file identifiers for those TIS-B targets for which the ICAO 24-bit aircraft address is unknown are assigned on a national basis Surface Vehicle Address An ADDRESS QUALIFIER value of FOUR (binary 100) shall be used by the UAT Transmitting Subsystem of a surface vehicle to indicate that the ADDRESS field holds a 24 bit the address of a surface vehicle authorized to transmit UAT ADS-B Messages. Note: It is beyond the scope of this Manual to specify the method by which UAT ADS-B surface vehicle addresses are assigned on a national basis. (Comment: We should provide some rules for assigning the groundsurface vehicles address to avoid interference with the aircraft address.) Fixed ADS-B Beacon Address An ADDRESS QUALIFIER value of FIVE (binary 101) shall be used to indicate that the ADDRESS field holds athe 24 bit address assigned to a fixed UAT ADS-B beacon. or parrot. Note: It is beyond the scope of this Manual to specify the method by which UAT ADS-B beacon addresses are assigned on a national basis. (Comment: We should provide some rules for assigning the groundsurface vehicles address to avoid interference with the aircraft address.) STATE VECTOR Element for ADS-B (Address Qualifiers of 0, 1, 4 & 5) Format for the STATE VECTOR element shall be as defined in Table 2-5. This encoding shall apply to UAT ADS-B Messages with PAYLOAD TYPE CODES of 0 through 10, when the ADDRESS QUALIFIER value is 0, 1, 4 or 5. Note: Each of the fields shown is defined in through

19 9 Payload Byte # 5 (MSB) Table 2-5: Format of STATE VECTOR Element Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 6 LATITUDE (WGS-84). 7 (LSB) (MSB) 8 9 LONGITUDE (WGS-84) 10 (LSB) Alt Type 11 (MSB) ALTITUDE 12 (LSB) (MSB) NIC (LSB) 13 (MSB) A/G STATE Reserved 14 HORIZONTAL VELOCITY VERTICAL VELOCITY or A/V LENGTH/WIDTH CODE 17 UTC Reserved LATITUDE and LONGITUDE Field Encoding a. The LATITUDE field is a 23-bit (bit 1 of byte 5 through bit 7 of byte 7) field used to encode the latitude provided in to the UAT ADS-B message Transmitting Subsystem in conformity with WGS-84 and shall be encoded as indicated in Table 2-6. b. The LONGITUDE field is a 24-bit (bit 8 of byte 7 through bit 7 of byte 10) field used to encode the longitude provided in to the UAT ADS-B message Transmitting Subsystem in conformity with WGS-84 and shall be encoded as indicated in Table 2-6. c. The encoding of ALL ZEROs in the LATITUDE and LONGITUDE and NIC ( ) fields shall indicate that Latitude/Longitude information is unavailable. Notes: 1. Figure 2-1 provides further guidance contains on the angular weighted binary encoding of Latitude and Longitude. 2. Since the encoding of ALL ZEROs is a valid location on the earthearth, UAT ADS-B receivers Receiving Subsystems will interpret this as Latitude/Longitude information unavailable only if the NIC field is also set to ZERO

20 10 Table 2-6: Angular Weighted Binary Encoding of Latitude and Longitude Quadrant LATITUDE or Meaning LONGITUDE bits LSB = = x MSB LSB Latitude Longitude ZERO degrees (Equator) ZERO degrees (Prime Meridian) 1 st LSB degrees North LSB degrees East quadrant (90-LSB) degrees North (90-LSB) degrees East degrees (North Pole) 90 degrees East 2 nd <Illegal Values> (90+LSB) degrees East quadrant <Illegal Values> <Illegal Value> (180-LSB) degrees East <Illegal Value> 180 degrees East or West 3 rd <Illegal Value> (180-LSB) degrees West quadrant <Illegal Values> <Illegal Values> (90+LSB) degrees West degrees (South Pole) 90 degrees West 4 th (90-LSB) degrees South (90-LSB) degrees West quadrant LSB degrees South LSB degrees West Notes: 1. The most significant bit (MSB) of the angular weighted binary LATITUDE is omitted from the transmitted message. This is because all valid Latitudes, other than the Latitude of the North pole (exactly 90 degrees North), have the same value in their 2 most significant bits. The application using the ADS-B reports has the responsibility to differentiate the North and South Poles.

21 11 N Pole: nd quadrant 1st quadrant Equator: Latitude Encoding Values from to And from to rd quadrant 4th quadrant S Pole: degrees E: nd quadrant 1st quadrant 0 degrees E: degrees E = 180 degrees W: rd quadrant 4th quadrant N Pole: Longitude Encoding Values from to degrees W: Figure 2-1: Angular Weighted Binary Encoding of Latitude and Longitude

22 ALTITUDE TYPE Field Encoding a. The ALTITUDE TYPE field is a 1-bit (bit 8 of byte 10) field used to identify the source of information in the ALTITUDE field and shall be encoded as reflected in Table 2-7. (Q: Why geometric altitude? This cannot be used for separation or to determine if altitude differences exist and may not be compatible with other ADS-B systems) Altitude Type Table 2-7: ALTITUDE TYPE Encoding ALTITUDE Field ( ) 0 Pressure Altitude Geometric Altitude 1 Geometric Altitude Pressure Altitude SECONDARY ALTITUDE Field ( ) Note: Pressure Altitude refers to Barometric Pressure Altitude relative to a standard atmosphere at a standard pressure of hectopascals (29.92 inches of mercury Hg) and specifically DOES NOT refer to Barometric Corrected Altitude [QNH, QFE? Add definition]. b. A means shall be provided to operationally inhibit the broadcast of Pressure Altitude information, making it unavailable for transmission. c. A means shall be provided to operationally select the preferred ALTITUDE TYPE that is reported if more than one ALTITUDE TYPE is available. If only one ALTITUDE TYPE is available, then that Altitude shall be indicated in the ALTITUDE TYPE field. Note: The means to operationally inhibit the broadcast of pressure altitude information can be used at the request of ATC, or when altitude is determined to be invalid by the pilot ALTITUDE Field Encoding The ALTITUDE field is a 12-bit (bit 1 of byte 11 through bit 4 of byte 12) field used to encode the altitude of the ADS-B Transmitting Subsystem and shall be encoded as indicated in Table 2-8. MSB Coding (binary) LSB Table 2-8: ALTITUDE Encoding Coding (decimal) Meaning Altitude information unavailable Altitude = feet Altitude = -975 feet Altitude = -25 feet Altitude = ZERO feet Altitude = 25 feet Altitude = 101,325 feet Altitude > 101,337.5 feet

23 NIC Field Encoding The Navigation Integrity Category ( NIC ) field is a 4-bit (bits 5 through 8 of byte 12) field indicatesing the used to allow surveillance applications to determine whether the reported position has an acceptable level of integrity maximum position error in the horizontal plane (NIC = 0 8) or in the horizontal and vertical planes (NIC = 9 11) for the intended use and shall be encoded as indicated in Table 2-9. The value of the NIC parameter shall be the highest value in Table 2-9 consistent with the NIC Input with the exception that if the NIC Input is consistent with a value of 9, 10 or 11 and the ADS-B equipment is not UTC coupled and therefore does not support the timing requirements for the Precision condition ( )), a NIC value of 8 shall be transmitted. Notes: NIC (binary) MSB LSB NIC (decimal) Table 2-9: NIC Encoding Horizontal and Vertical Containment Bounds Comment R C km (20 NM) Unknown Integrity [ km (8 NM) ] R C < RNP-10 or 5 containment radius km (20 NM) R C < km (8 NM) RNP-4 containment radius R C < km (4 NM) RNP-2 containment radius R C < km (2 NM) RNP-1 containment radius R C < 1852 m (1 NM) RNP-0.5 containment radius R C < m (0.6 NM) RNP-0.3 containment radius R C < m (0.2 NM) RNP-0.1 containment radius R C < m (0.1 NM) RNP-0.05 containment radius R C < 75 m and VPL < 112 m e.g., SBAS, HPL, VPL R C < 25 m and VPL < 37.5 m e.g., SBAS, HPL, VPL R C < 7.5 m and VPL < 11 m e.g., GBAS, HPL, VPL (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) (Reserved) 1. The value of the NIC parameter reflects an integrity radius of containment, R C, which provides a maximum position error that is not exceeded with a greater probability than either 1x10-5 per hour of flight (RNP Containment Radius) or 1x10-7 per hour of flight/operation (GNSS Horizontal Protection Limit). 2. The NIC field is closely associated with the SIL field (defined in ). The value of the SIL field is the probability of the true position lying outside the radius of containment, R C, without alerting, including the effects of airborne equipment condition, which airborne equipment is in use, and which external signals are used. The Comment field assumes a SIL value of 2 for NIC values of 1 through 8 and a SIL value of 3 for NIC values of 9 through 11. (Comment: However, SIL is only transmitted in the Mode Status element of the ADS-B message, which is not available in payload type code 0, 2, 4 and higher) Reference to Section 3 of the Implementation Manual on scheduling of UAT ADS-B messages.)

24 14 3. VPL refers to the Vertical Protection Limit, which is an indication of the vertical interval within which the actual position of the transmitting participant lies, to a probability of 1 minus HPL refers to the Horizontal Protection Limit A/G STATE Field Encoding The Air/Ground State ( A/G STATE ) field is a 2-bit (bits 1 and 2 of byte 13) field that indicates the format used for representing horizontal velocity by aircraft and ground surface vehicles. The value of this field determines the encoding of the HORIZONTAL VELOCITY field. The A/G STATE shall be composed of two (2) 1-bit fields used as follows (see also Table 2-10): 1. The Vertical Status bit (bit 1 of byte 13) shall be used to reflect the AIRBORNE or ON-GROUND condition as determined in The Subsonic/Supersonic bit (bit 2 of byte 13) shall be used to indicate the scale factor for the velocity information. The Subsonic/Supersonic bit (bit 2 of byte 13) shall only be set to ONE (1) if either the East West velocity OR the North South velocity, exceeds 1022 knots. The Subsonic/Supersonic bit (bit 2 of byte 13) shall be reset to ZERO (0) if the East - West and the North - South velocities, drop below 1000 knots. Table 2-10: A/G STATE Field Encoding MSB A/G STATE Field Encoding LSB Resulting HORIZONTAL VELOCITY Subfield Formats Ownship Conditions Vertical Status (bit 1 of byte 13) Subsonic/Supersonic (bit 2 of byte 13) (decimal) North Velocity or Ground Speed Subfield Meaning East Velocity or Track Angle/Heading Subfield Meaning AIRBORNE condition. Subsonic condition. AIRBORNE condition. Supersonic condition ON GROUND condition <Reserved> North Velocity (LSB = 1 kt) North Velocity (LSB = 4 kts) Ground Speed (LSB = 1 kt) East Velocity (LSB = 1 kt) East Velocity (LSB = 4 kts) Track/Heading Determination of Vertical Status The UAT ADS-B message Transmitting Subsystem shall contain determine the its Vertical Status (i.e., AIRBORNE or ON-GROUND condition) using the following procedures: a. If a UAT ADS-B equipped aircraft Transmitting Subsystem participant has is equipped with automatic means to determine whether it is airborne or on the surfaceground, then such information shall be used to determine the Vertical Status.

25 Note: An automatic means of determining Vertical Status could come from a weight-on-wheels or strut switch, etc. Landing gear deployment is not considered a suitable automatic means. b. If a UAT ADS-B equipped aircraft Transmitting Subsystem participant has no is not equipped with automatic means to determine whether it is airborne or on the surface ground or for other UAT-ADS-B user potential categories of UAT-ADS-B users or usage as listed below, and that participant s Emitter Category is one of the following, then that participant shall set its the Vertical Status shall be set to AIRBORNE: Glider or Sailplane Lighter Than Air Parachutist or Skydiver Ultralight, Hang Glider or Paraglider Unmanned Aerial Vehicle Point Obstacle (includes tethered balloons) Cluster Obstacle Line Obstacle Notes: 1. Because of the unique operating capabilities of Lighter-than-Air vehicles, e.g., balloons, an operational Lighter-than-Air vehicle will always report the AIRBORNE condition unless the ON-GROUND condition is specifically declared in compliance with subparagraph a. above. 2. For the Point, Cluster and Line Obstacles, the Vertical Status reported should be appropriate to the situation. In any case, the Altitude is always included in the ADS-B present in the transmitted message. 15 c. If a UAT ADS-B transmitter is installed in a surface vehicle, the Transmitting Subsystem participant s Emitter Category is one of the following, then that participant shall set its Vertical Status shall be set to the ON-GROUND condition: Surface Vehicle Emergency Vehicle Surface Vehicle Service Vehicle d. If a UAT ADS-B transmitter is installed on a rotorcraft and which Transmitting Subsystem participant is not equipped with automatic means to determine whether it is airborne or on the surfaceground, and that participant s Emitter Category is Rotorcraft, then that participant shall set its it s the Vertical Status shall be set to AIRBORNE. Note: Because of the unique operating capabilities of rotorcraft, i.e., hover, etc., an operational rotorcraft will always report the AIRBORNE condition unless the ON-GROUND condition is specifically declared in compliance with subparagraph a. above. Comment: Not necessary because of the conditions in a)

26 16 e. If a UAT ADS-B transmitter is installed on a light aircraft which and Transmitting Subsystem participant is not equipped with a means to determine whether it is airborne or on the surfaceground, and that participant s Emitter Category is Light Aircraft, then that participant shall set its the Vertical Status shall be set to AIRBORNE,, unless the participant can alternatively determine that it is on the surface ground using Ground Speed information. the following test: If the participant s Ground Speed (GS) is available and is less than an aircraft specific Threshold Level (TL) (what is this?) value, the participant may set its Vertical Status may be set to ON-GROUND. The Ground Speed Threshold Level chosen for an aircraft type must reliably indicate ON-GROUND conditions. Note: The appropriate Ground Speed Threshold Level is chosen to provide, except under unusual operating conditions, a reasonable assurance that the participant will not set the AIRBORNE/ON-GROUND condition to AIRBORNE while taxiing on the airport surface and will not give false indications of being in the ON-GROUND condition while still AIRBORNE. f. If a UAT ADS-B transmitter is installed on aircraft which Transmitting Subsystem participant is not equipped with a means to determine whether it is airborne or on the surfaceground, and that Participant s Emitter Category is not one of those listed in tests items b, c, d, or e above (i.e., the Participant Emitter Category is either: Small, Large, High Vortex Large, Heavy, Highly Maneuverable, or Space/Trans- Atmospheric), then the following tests will be performed to determine the Vertical Status: 1. If the UAT ADS-B Transmitting Subsystem participant s Radio Height (RH) from a radio altimeter parameter is available, and RH < less than 50 feet, and at least Ground Speed (GS) or Airspeed (AS) is available, and the available GS < less than 100 knots, or the available AS < less than 100 knots, then that participant shall set its the Vertical Status shall be set to ON-GROUND. Note: If all three parameters are available, the Vertical Status may be determined by the logical AND of all three parameters. 2. Otherwise, iif Radio Height (RH) is not available, and if the participant s Ground Speed (GS) and Airspeed (AS) are available, and GS < is less than 50 knots and AS < is less than 50 knots, then that participant shall set its Vertical Status to ON-GROUND. 3. Otherwise, the participant shall set its Vertical Status to AIRBORNE Validation of Vertical Status When an automatic means of determining Vertical Status indicates the ON-GROUND condition, then the following additional tests shall be performed to validate the ON- GROUND condition:

27 Note: The Vertical Status can be used by UAT ADS-B transmitters Transmitting Subsystems to select only the TOP antenna when in the ON-GROUND condition. A false indication of the automatic means could therefore impact signal availability. To minimize this possibility, this validation procedure has been established. 17 a.a If one or more of the following parameters is available and satisfy the following requirements: to the UAT ADS-B Transmitting Subsystem participant: Ground Speed (GS), or Airspeed (AS), or Radio Height (RH) from radio altimeter and of the following parameters that are available: GS > of 100 knots or more, or AS > of 100 knots or more, or RH > of 50 feet or more then, the participant s shall set itsit s the Vertical Status shall be set to the AIRBORNE condition b.b Otherwise, the participant s shall set its the Vertical Status shall be set to the ON- GROUND condition HORIZONTAL VELOCITY Subfields The HORIZONTAL VELOCITY Field shall be composed of two components: a. The North Velocity or Ground Speed component shall be represented by an 11-bit subfield from bit 4 of byte 13 through bit 6 of byte 14. b. The East Velocity or Track/Heading component shall be represented by an 11-bit subfield from bit 7 of byte 14 through bit 1 of byte 16. Note: Each component can assume multiple formats depending on the A/G STATE field. Subparagraphs through describe the encoding for each form of each component Encoding as North Velocity Form When the A/G STATE field is set to 0, or 1, the North Velocity or Ground Speed component shall assume the North Velocity format indicated in Table Table 2-11: North Velocity Format Byte 13 Byte 14 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 N/S Sign (MSB) --North Velocity Magnitude-- (LSB)

28 18 a. The N/S Sign subfield (bit 4 of byte 13) shall be used to indicate the direction of the North/South velocity vector as shown in Table Table 2-12: North/South Sign Encoding Coding Meaning 0 NORTH 1 SOUTH b. The North Velocity Magnitude subfield is a 10-bit (bit 5 of byte 13 through bit 6 of byte 14) subfield that shall be used to report the magnitude of the North/South velocity of the UAT ADS-B Transmitting Subsystem. The Range, Resolution and No Data encoding of the North Velocity Magnitude subfield shall be as shown in Table Table 2-13: North Velocity Magnitude Encoding Coding Coding Meaning (Subsonic Scale) Meaning (Supersonic Scale) MSB(binary) LSB (decimal) (A/G STATE = 0) (A/G STATE = 1) N/S Velocity not available N/S Velocity not available N/S Velocity is ZERO N/S Velocity is ZERO N/S Velocity = 1 knots N/S Velocity = 4 knots N/S Velocity = 2 knots N/S Velocity = 8 knots N/S Velocity = 1021 knots N/S Velocity = 4,084 knots N/S Velocity > knots N/S Velocity > 4,086 knots Note: The encoding represents positive figures Positive Magnitude data only. Direction is given completely by the N/S Sign Bit. (Q: Do we really need this note?) Encoding as Ground Speed Form When the A/G STATE field is set to 2, the North Velocity or Ground Speed component shall assume the Ground Speed format indicated in Table Table 2-14: Ground Speed Format Byte 13 Byte 14 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Reserved (MSB) --Ground Speed-- (LSB) a. The 1-bit subfield (bit 4 of byte 13) shall be Reserved and set to ZERO (0). b. The Ground Speed subfield is a 10-bit (bit 5 of byte 13 through bit 6 of byte 14) subfield that shall be used to report the Ground Speed in the of the UAT ADS-B Message Transmitting Subsystem (in knots). The Range, Resolution and No Data encoding of the Ground Speed subfield shall be as shown in Table 2-15.