asterix 007 "Transmission of Directed Interrogation Messages" edition 1.12 date 2024-07-01 preamble Surveillance data exchange. items 010 "Data Source Identifier" definition Identification of the radar station from which the data is received. group SAC "System Area Code" element 8 raw SIC "System Identification Code" element 8 raw remark Note: - The up-to-date list of SACs is published on the EUROCONTROL Web Site (http://www.eurocontrol.int/asterix). 020 "Type and Properties of the Target Report and Target Capabilities" definition Type and properties of the target report and capabilities of the target. extended TYP "" element 3 table 0: No detection 1: Single PSR detection 2: Single SSR detection 3: SSR + PSR detection 4: Single ModeS All-Call 5: Single ModeS Roll-Call 6: ModeS All-Call + PSR 7: ModeS Roll-Call + PSR SIM "" element 1 table 0: Actual target report 1: Simulated target report RDP "" element 1 table 0: Report from RDP Chain 1 1: Report from RDP Chain 2 SPI "" element 1 table 0: Absence of SPI 1: Special Position Identification RAB "" element 1 table 0: Report from aircraft transponder 1: Report from field monitor (fixed transponder) - TST "" element 1 table 0: Real target report 1: Test target report ERR "" element 1 table 0: No Extended Range 1: Extended Range present XPP "" element 1 table 0: No X-Pulse present 1: X-Pulse present ME "" element 1 table 0: No military emergency 1: Military emergency MI "" element 1 table 0: No military identification 1: Military identification FOEFRI "" element 2 table 0: No Mode 4 interrogation 1: Friendly target 2: Unknown target 3: No reply - ADSB "On-Site ADS-B Information" group EP "ADSB Element Populated Bit" element 1 table 0: ADSB not populated 1: ADSB populated VAL "On-Site ADS-B Information" element 1 table 0: Not available 1: Available SCN "Surveillance Cluster Network Information" group EP "SCN Element Populated Bit" element 1 table 0: SCN not populated 1: SCN populated VAL "Surveillance Cluster Network Information" element 1 table 0: Not available 1: Available PAI "Passive Acquisition Interface Information" group EP "PAI Element Populated Bit" element 1 table 0: PAI not populated 1: PAI populated VAL "Passive Acquisition Interface Information" element 1 table 0: Not available 1: Available spare 1 - ACASVX "ACAS Extended Version" group EP "ACASVX Element Populated Bit" element 1 table 0: ACASVX not populated 1: ACASVX populated VAL "ACAS Extended Version Value" element 4 table 0: Non-Extended Version 1: ACAS Xa Version 1 2: ACAS Xu Version 1 3: Reserved for future versions 4: Reserved for future versions 5: Reserved for future versions 6: Reserved for future versions 7: Reserved for future versions 8: Reserved for future versions 9: Reserved for future versions 10: Reserved for future versions 11: Reserved for future versions 12: Reserved for future versions 13: Reserved for future versions 14: Reserved for future versions 15: Reserved for future versions POXPR "PO Transponder Capability" group EP "POXPR Element Populated Bit" element 1 table 0: POXPR not populated 1: POXPR populated VAL "PO Transponder Capability" element 1 table 0: PO not supported (PPM only) 1: PO supported - POACT "PO Active for Current Plot" group EP "POACT Element Populated Bit" element 1 table 0: POACT not populated 1: POACT populated VAL "PO Active for Current Plot" element 1 table 0: PO not active 1: PO active DTFXPR "Basic Dataflash Transponder Capability" group EP "DTFXPR Element Populated Bit" element 1 table 0: DTFXPR not populated 1: DTFXPR populated VAL "Basic Dataflash Transponder Capability" element 1 table 0: Basic Dataflash not supported 1: Basic Dataflash supported DTFACT "Basic Dataflash Active for Current Plot" group EP "DTFACT Element Populated Bit" element 1 table 0: DTFACT not populated 1: DTFACT populated VAL "Basic Dataflash in Current Plot" element 1 table 0: Basic Dataflash not active 1: Basic Dataflash active spare 1 - IRMXPR "IRM Transponder Capability" group EP "IRMXPR Element Populated Bit" element 1 table 0: IRMXPR not populated 1: IRMXPR populated VAL "Transponder IRM Capability" element 1 table 0: Transponder not IRM capable 1: Transponder IRM capable IRMACT "IRM Active for Current Plot" group EP "IRMACT Element Populated Bit" element 1 table 0: IRMACT not populated 1: IRMACT populated VAL "IRM Active for Current Plot" element 1 table 0: IRM not active 1: IRM active spare 3 - remark Notes: 1. For Mode S aircraft, the SPI information is also contained in I007/230. 2. To bits 3/2 of extension 1 (FOE/FRI): IFF interrogators supporting a three level classification of the processing of the Mode 4 interrogation result shall encode the detailed response information in data item M4E of the Reserved Expansion Field of category 007. In this case the value for FOE/FRI in I007/020 shall be set to “00”. However, even those interrogators shall use I007/020 to encode the information “No reply”. 3. To bit 6 of extension 1 (XPP): This bit shall always be set when the X-pulse has been extracted, independent from the Mode it was extracted with. 4. To bit 7 of extension 1 (ERR): This bit set to “1” indicates that the range of the target is beyond the maximum range in data item I007/040. In this case – and this case only - the ERR Data Item in the Reserved Expansion Field shall provide the range value of the Measured Position in Polar Coordinates. 5. To Extension 2: The EUROCONTROL Specification for European Mode S Stations Edition 4.0 (EMS 4.0) [Ref. 4] defines new functionalities that can use external data inputs. The possibilities described in EMS 4.0 cover the presence of target information acquired via the on-site ADS-B, the Surveillance Cluster Network or the Passive Acquisition Interface. The second extension provides information – per target – on whether such information is available supporting performance improvements, e.g. Passive Acquisition, and new features, e.g. detection of a potential IC Conflict. 6. To Extensions 3, 4, and 5: The transponder MOPS ED-73F/DO-181F (Minimum Operational Performance Standard [Ref. 2]) defines new optional functionalities: - Basic Dataflash (to reduce BDS registers extractions by groundsystems) - IRM (Interrogation/Reply Monitoring) - Phase Overlay (to convey more data within a single long Roll Call Reply, using Downlink Formats 20 and 21) 7. To Extensions 3 and 4: To populate bits in these extensions, Mode S radars will have to decode/analyse the content of BDS register 1,0 (bits 15, 42 and 44) as per [Ref. 2]. 025 "Data Destination Identifier" definition Identification of the radar station to which the data is sent. group SAC "System Area Code" element 8 raw SIC "System Identification Code" element 8 raw remark Note: - The up-to-date list of SACs is published on the EUROCONTROL Web Site (http://www.eurocontrol.int/asterix). 030 "Warning/Error Conditions" definition Warning/error conditions detected by a radar station for the target report involved. repetitive fx element 7 table 0: Not defined; never used 1: Multipath Reply (Reflection) 2: Reply due to sidelobe interrogation/reception 3: Split plot 4: Second time around reply 5: Angel 6: Slow moving target correlated with road infrastructure (terrestrial vehicle) 7: Fixed PSR plot 8: Slow PSR target 9: Low quality PSR plot 10: Phantom SSR plot 11: Non-Matching Mode-3/A Code 12: Mode C code/Mode S altitude code abnormal value compared to the track 13: Target in Clutter Area 14: Maximum Doppler Response in Zero Filter 15: Transponder anomaly detected 16: Duplicated or Illegal Mode S Aircraft Address 17: Mode S error correction applied 18: Undecodable Mode C code/Mode S altitude code 19: Birds 20: Flock of Birds 21: Mode 1 was present in original reply 22: Mode 2 was present in original reply 23: Plot potentially caused by Wind Turbine 24: Helicopter 25: Maximum number of re-interrogations reached (surveillance information) 26: Maximum number of re-interrogations reached (BDS Extractions) 27: BDS Overlay Incoherence 28: Potential BDS Swap Detected 29: Track Update in the Zenithal Gap 30: Mode S Track re-acquired 31: Duplicated Mode 5 Pair NO/PIN detected 32: Wrong DF reply format detected 33: Transponder anomaly (MS XPD replies with Mode A/C to Mode A/C-only all-call) 34: Transponder anomaly (SI capability report wrong) 35: Potential IC Conflict 36: IC Conflict detection possible - no conflict currently detected 37: Duplicate Mode 5 PIN (refer to the Mode 5 items in the REF) 64: Ambiguous acknowledge, overlapping interrogation windows 65: Ambiguous acknowledge, duplicated request for same Mode S address 66: Ambiguous acknowledge, duplicated request for same track number 67: Reject, unable to process 68: Reject, too many parallel requests (exceeds system parameter for maximum number of requests per scan) 69: Reject, duplicated request remark Notes: 1. It has to be stressed that a series of one or more W/E conditions can be reported per target report. 2. Data conveyed in this item are of secondary importance, and can generally also be derived from the processing of mandatory items. 3. Definitions can be found in SUR.ET1.ST03.1000-STD-01-01 Radar Sensor Performance Analysis. 4. Warning/Error codes of 64 and higher are reserved for Directed Interrogation messages. 5. Values 25 to 30 and 32 to 36 have been defined to comply with the Edition 4.0 of the EUROCONTROL Specification for European Mode S Station (EMS) [Ref. 7] and to provide the possibility to report the following information: - Code 25: the maximum number of permitted re-interrogations to acquire the surveillance information has been reached; - Code 26: the maximum number of permitted re-interrogations to extract BDS Registers has been reached; - Code 27: inconsistency detected between the contents of the message and the BDS register overlayed; - Code 28: a BDS swap has been detected and the respective information has been discarded; - Code 29: the track has been updated while being in the zenithal gap (also referred to as “Cone of Silence”); - Code 30: the radar had lost track of an aircraft and subsequently re-acquired it. - Code 31: ??? - Code 32: the transponder has used a wrong Downlink Format. - Code 33 & 34: reporting specific Transponder Anomalies. - Code 35 indicates that a plot has been obtained despite a high probability of an IC Conflict with another interrogator. - Code 36 indicates that a plot is in a configuration that it would be possible to detect an IC Conflict with another interrogator. Currently no potential IC Conflict has been detected. NOTE: Although implementation dependent, the use of this code should be limited to the target acquisition phase. 6. Together with Codes 35 and 36 the possibility to communicate the area within which the detection of an IC Conflict is possible was implemented in the Category 034 Specification [Ref. 8] by means of Message Type 008. 7. The use of this Data Item is implementation specific and shall be described in the ICD of the system generating the Category 048 target reports. 040 "Measured Position in Polar Co-ordinates" definition Measured position of an aircraft in local polar co-ordinates. group RHO "" element 16 unsigned quantity 1/2^8 "NM" < 256 THETA "" element 16 unsigned quantity 360/2^16 "°" remark Notes: 1. In case of no detection, the extrapolated position expressed in slant polar co-ordinates may be sent, except for a track cancellation message. No detection is signalled by the TYP field set to zero in I007/020 Target Report Descriptor. 2. This item represents the measured target position of the plot, even if associated with a track, for the present antenna scan. It is expressed in polar co-ordinates in the local reference system, centred on the radar station. 3. In case of combined detection by a PSR and an SSR, then the SSR position is sent. 4. For targets having a range beyond 256 NM the data item “Extended Range Report” has been added to the Reserved Expansion Field of category 007. The presence of this data item is indicated by the ERR bit set to one in data item I007/020, first extension. The ERR data item shall only be sent if the value of RHO is equal to or greater than 256NM. Please note that if this data item is used, the Encoding Rule to data item I007/040 still applies, meaning that the extra item in the Reserved Expansion Field shall be transmitted in addition to data item I007/040. If the Extended Range Report item in the Reserved Expansion Field is used, it is recommended to set the value of RHO in data item I007/040 to its maximum, meaning bits 32/17 all set to 1. 042 "Calculated Position in Cartesian Co-ordinates" definition Calculated position of an aircraft in Cartesian co-ordinates. group X "X-Component" element 16 signed quantity 1/2^7 "NM" >= -256 <= 256 Y "Y-Component" element 16 signed quantity 1/2^7 "NM" >= -256 <= 256 050 "Mode-2 Code in Octal Representation" definition Reply to Mode-2 interrogation. group V "" element 1 table 0: Code validated 1: Code not validated G "" element 1 table 0: Default 1: Garbled code L "" element 1 table 0: Mode-2 code as derived from the reply of the transponder 1: Smoothed Mode-2 code as provided by a local tracker spare 1 MODE2 "Mode-2 Code in Octal Representation" element 12 string octal remark Note: - Bit 15 has no meaning in the case of a smoothed Mode-2 and is set to 0 for a calculated track. Note: - For radar systems interrogation with various technologies (such as military radars interrogating in Mode S and Mode 5), element I007/REF/GEN07/ALTM2 provides the possibility to transmit an alternative Mode-2 value. If this Data Item carries a Mode-2 value that has been derived from a Mode 5 Reply/Report, then bit-4 in I007/REF/MD5/SF#1 and bit-4 in I007/REF/M5N/SF#1 shall be set to 1. 055 "Mode-1 Code in Octal Representation" definition Reply to Mode-1 interrogation. group V "" element 1 table 0: Code validated 1: Code not validated G "" element 1 table 0: Default 1: Garbled code L "" element 1 table 0: Mode-1 code as derived from the reply of the transponder 1: Smoothed Mode-1 code as provided by a local tracker MODE1 "Mode-1 Code" element 5 raw remark Notes: 1. Bit 7 has no meaning in the case of a smoothed Mode-1 and is set to 0 for a calculated track. 2. The values of the bits for V, G, L, A4, A2, A1, B2 and B1 shall be identical to the values of the corresponding bits in subfield #5 of data item “MD5 – Mode 5 Reports” and in subfield #5 of data item “MD5 – Mode 5 Reports, New Format” in the Reserved Expansion Field. 060 "Mode-2 Code Confidence Indicator" definition Confidence level for each bit of a Mode-2 reply as provided by a monopulse SSR station. group spare 4 QA4 "" element 1 table 0: High quality pulse A4 1: Low quality pulse A4 QA2 "" element 1 table 0: High quality pulse A2 1: Low quality pulse A2 QA1 "" element 1 table 0: High quality pulse A1 1: Low quality pulse A1 QB4 "" element 1 table 0: High quality pulse B4 1: Low quality pulse B4 QB2 "" element 1 table 0: High quality pulse B2 1: Low quality pulse B2 QB1 "" element 1 table 0: High quality pulse B1 1: Low quality pulse B1 QC4 "" element 1 table 0: High quality pulse C4 1: Low quality pulse C4 QC2 "" element 1 table 0: High quality pulse C2 1: Low quality pulse C2 QC1 "" element 1 table 0: High quality pulse C1 1: Low quality pulse C1 QD4 "" element 1 table 0: High quality pulse D4 1: Low quality pulse D4 QD2 "" element 1 table 0: High quality pulse D2 1: Low quality pulse D2 QD1 "" element 1 table 0: High quality pulse D1 1: Low quality pulse D1 065 "Mode-1 Code Confidence Indicator" definition Confidence level for each bit of a Mode-1 reply as provided by a monopulse SSR station. group spare 3 QA4 "" element 1 table 0: High quality pulse A4 1: Low quality pulse A4 QA2 "" element 1 table 0: High quality pulse A2 1: Low quality pulse A2 QA1 "" element 1 table 0: High quality pulse A1 1: Low quality pulse A1 QB2 "" element 1 table 0: High quality pulse B2 1: Low quality pulse B2 QB1 "" element 1 table 0: High quality pulse B1 1: Low quality pulse B1 070 "Mode-3/A Code in Octal Representation" definition Mode-3/A code converted into octal representation. group V "" element 1 table 0: Code validated 1: Code not validated G "" element 1 table 0: Default 1: Garbled code L "" element 1 table 0: Mode-3/A code derived from the reply of the transponder 1: Mode-3/A code not extracted during the last scan spare 1 MODE3A "Mode-3/A Reply in Octal Representation" element 12 string octal remark Notes: 1. Bit 15 has no meaning in the case of a smoothed Mode-3/A code and is set to 0 for a calculated track. For Mode S, it is set to one when an error correction has been attempted. 2. For Mode S, bit 16 is normally set to zero, but can exceptionally be set to one to indicate a non-validated Mode-3/A code (e.g. alert condition detected, but new Mode-3/A code not successfully extracted). 3. For radar systems interrogation with various technologies (such as military radars interrogating in Mode S and Mode 5), element I007/REF/GEN07/ALTM3 provides the possibility to transmit an alternative Mode-3/A value. If this Data Item carries a Mode-3/A value that has been derived from a Mode 5 Reply/Report, then bit-3 in I007/REF/MD5/SF#1 or bit-3 in I048/REF/M5N/SF#1 shall be set to 1. 080 "Mode-3/A Code Confidence Indicator" definition Confidence level for each bit of a Mode-3/A reply as provided by a monopulse SSR station. group spare 4 QA4 "" element 1 table 0: High quality pulse A4 1: Low quality pulse A4 QA2 "" element 1 table 0: High quality pulse A2 1: Low quality pulse A2 QA1 "" element 1 table 0: High quality pulse A1 1: Low quality pulse A1 QB4 "" element 1 table 0: High quality pulse B4 1: Low quality pulse B4 QB2 "" element 1 table 0: High quality pulse B2 1: Low quality pulse B2 QB1 "" element 1 table 0: High quality pulse B1 1: Low quality pulse B1 QC4 "" element 1 table 0: High quality pulse C4 1: Low quality pulse C4 QC2 "" element 1 table 0: High quality pulse C2 1: Low quality pulse C2 QC1 "" element 1 table 0: High quality pulse C1 1: Low quality pulse C1 QD4 "" element 1 table 0: High quality pulse D4 1: Low quality pulse D4 QD2 "" element 1 table 0: High quality pulse D2 1: Low quality pulse D2 QD1 "" element 1 table 0: High quality pulse D1 1: Low quality pulse D1 085 "Mode 5, Extended Mode 1 and X-Pulse" compound SUM "Subfield #1: Mode 5 Summary" group M5 "" element 1 table 0: No Mode 5 interrogation 1: Mode 5 interrogation ID "" element 1 table 0: No authenticated Mode 5 ID reply 1: Authenticated Mode 5 ID reply DA "" element 1 table 0: No authenticated Mode 5 Data reply or Report 1: Authenticated Mode 5 Data reply or Report (i.e any valid Mode 5 reply type other than ID) M1 "" element 1 table 0: Mode 1 code not present or not from Mode 5 reply 1: Mode 1 code from Mode 5 reply M2 "" element 1 table 0: Mode 2 code not present or not from Mode 5 reply 1: Mode 2 code from Mode 5 reply M3 "" element 1 table 0: Mode 3 code not present or not from Mode 5 reply 1: Mode 3 code from Mode 5 reply MC "" element 1 table 0: Mode C altitude not present or not from Mode 5 reply 1: Mode C altitude from Mode 5 reply spare 1 PMN "Subfield #2: Mode 5 PIN/National Origin/Mission Code" group spare 2 PIN "PIN Code" element 14 raw spare 3 NAT "National Origin" element 5 raw spare 2 MIS "Mission Code" element 6 raw POS "Subfield #3: Mode 5 Reported Position" group LAT "Latitude in WGS 84" element 24 signed quantity 180/2^23 "°" >= -90 <= 90 LON "Longitude in WGS 84" element 24 signed quantity 180/2^23 "°" >= -180 < 180 GA "Subfield #4: Mode 5 GNSS-derived Altitude" group spare 1 RES "Resolution with which the GNSS-derived Altitude (GA) is Reported" element 1 table 0: GA reported in 100 ft increments 1: GA reported in 25 ft increments GA "GNSS-derived Altitude of Target, Expressed as Height Above WGS 84 Ellipsoid" element 14 signed quantity 25 "ft" >= -1000 EM1 "Subfield #5: Extended Mode 1 Code in Octal Representation" group V "" element 1 table 0: Code not validated 1: Code validated G "" element 1 table 0: Default 1: Garbled code L "" element 1 table 0: Mode-1 code derived from the reply of the transponder 1: Mode-1 code not extracted during the last scan spare 1 EM1 "Extended Mode 1 Code in Octal Representation" element 12 string octal TOS "Subfield #6: Time Offset for POS and GA" element 8 signed quantity 1/2^7 "s" XP "Subfield #7: X Pulse Presence" group spare 3 X5 "X-pulse from Mode 5 Data Reply or Report" element 1 table 0: X-pulse set to zero or no authenticated Data reply or Report received 1: X-pulse set to one (present) XC "X-pulse from Mode C Reply" element 1 table 0: X-pulse set to zero or no Mode C reply 1: X-pulse set to one (present) X3 "X-pulse from Mode 3/A Reply" element 1 table 0: X-pulse set to zero or no Mode 3/A reply 1: X-pulse set to one (present) X2 "X-pulse from Mode 2 Reply" element 1 table 0: X-pulse set to zero or no Mode 2 reply 1: X-pulse set to one (present) X1 "X-pulse from Mode 1 Reply" element 1 table 0: X-pulse set to zero or no Mode 1 reply 1: X-pulse set to one (present) 090 "Flight Level in Binary Representation" definition Flight Level converted into binary representation. group V "" element 1 table 0: Code validated 1: Code not validated G "" element 1 table 0: Default 1: Garbled code FL "Flight Level" element 14 signed quantity 1/2^2 "FL" remark Notes: 1. When Mode C code / Mode S altitude code is present but not decodable, the “Undecodable Mode C code / Mode S altitude code” Warning/Error should be sent in I007/030. 2. When local tracking is applied and the received Mode C code / Mode S altitude code corresponds to an abnormal value (the variation with the previous plot is estimated too important by the tracker), the “Mode C code / Mode S altitude code abnormal value compared to the track“ Warning/Error should be sent in I007/030. 3. The value shall be within the range described by ICAO Annex 10 4. For Mode S, bit 15 (G) is set to one when an error correction has been attempted. 5. For radar systems interrogating with various technologies (such as military radars interrogating in Mode S and Mode 5), element I007/REF/GEN07/ALTFL provides the possibility to transmit an alternative Flight Level value. If this Data Item carries a Flight Level value that has been derived from a Mode 5 Reply/Report, then bit-2 in I007/REF/MD5/SF#1 and in bit-2 in I007/REF/M5N/SF#1 shall be set to 1. 100 "Mode-C Code and Code Confidence Indicator" definition Mode-C height in Gray notation as received from the transponder together with the confidence level for each reply bit as provided by a MSSR/Mode S station. group V "" element 1 table 0: Code validated 1: Code not validated G "" element 1 table 0: Default 1: Garbled code spare 2 MODEC "Mode-C Reply in Gray Notation" element 12 raw spare 4 QC1 "" element 1 table 0: High quality pulse C1 1: Low quality pulse C1 QA1 "" element 1 table 0: High quality pulse A1 1: Low quality pulse A1 QC2 "" element 1 table 0: High quality pulse C2 1: Low quality pulse C2 QA2 "" element 1 table 0: High quality pulse A2 1: Low quality pulse A2 QC4 "" element 1 table 0: High quality pulse C4 1: Low quality pulse C4 QA4 "" element 1 table 0: High quality pulse A4 1: Low quality pulse A4 QB1 "" element 1 table 0: High quality pulse B1 1: Low quality pulse B1 QD1 "" element 1 table 0: High quality pulse D1 1: Low quality pulse D1 QB2 "" element 1 table 0: High quality pulse B2 1: Low quality pulse B2 QD2 "" element 1 table 0: High quality pulse D2 1: Low quality pulse D2 QB4 "" element 1 table 0: High quality pulse B4 1: Low quality pulse B4 QD4 "" element 1 table 0: High quality pulse D4 1: Low quality pulse D4 remark Notes: 1. For Mode S, D1 is also designated as Q, and is used to denote either 25ft or 100ft reporting. 2. For Mode S, bit-31 (G) is set when an error correction has been attempted. 110 "Height Measured by a 3D Radar" definition Height of a target as measured by a 3D radar. The height shall use mean sea level as the zero reference level. group spare 2 3DH "3D-Height" element 14 signed quantity 25 "ft" 120 "Radial Doppler Speed" definition Information on the Doppler Speed of the target report. compound CAL "Subfield #1: Calculated Doppler Speed" group D "" element 1 table 0: Doppler speed is valid 1: Doppler speed is doubtful spare 5 CAL "Calculated Doppler Speed" element 10 signed quantity 1 "m/s" RDS "Subfield #2: Raw Doppler Speed" repetitive 1 group DOP "Doppler Speed" element 16 unsigned quantity 1 "m/s" AMB "Ambiguity Range" element 16 unsigned quantity 1 "m/s" FRQ "Transmitter Frequency" element 16 unsigned quantity 1 "MHz" 130 "Radar Plot Characteristics" definition Additional information on the quality of the target report. compound SRL "Subfield #1: SSR Plot Runlength" element 8 unsigned quantity 360/2^13 "°" SRR "Subfield #2: Number of Received Replies for (M)SSR" element 8 unsigned integer SAM "Subfield #3: Amplitude of Received Replies for (M)SSR" element 8 signed quantity 1 "dBm" PRL "Subfield #4: PSR Plot Runlength" element 8 unsigned quantity 360/2^13 "°" PAM "Subfield #5: PSR Amplitude" element 8 signed quantity 1 "dBm" RPD "Subfield #6: Difference in Range Between PSR and SSR Plot" element 8 signed quantity 1/2^8 "NM" APD "Subfield #7: Difference in Azimuth Between PSR and SSR Plot" element 8 signed quantity 360/2^14 "°" remark Notes: 1. The total range covered is therefore from 0 to 11.21 °. 2. Negative values are coded in two's complement form. 3. The total range covered is therefore from 0 to 11.21 °. 4. Negative values are coded in two's complement form. 5. Negative values are coded in two's complement form. 6. The covered range difference is +/- 0.5 NM. 7. Sending the maximum value means that the difference in range is equal or greater than the maximum value. 8. Negative values are coded in two's complement form. 9. The covered azimuth difference is +/-360/2 7 = +/- 2.8125 °. 10. Sending the maximum value means that the difference in range is equal or greater than the maximum value. 140 "Time of Day" definition Absolute time stamping expressed as Co-ordinated Universal Time (UTC). element 24 unsigned quantity 1/2^7 "s" < 86400 remark Notes: 1. The time of day value is reset to 0 each day at midnight. 2. Every radar station using ASTERIX should be equipped with at least one synchronised time source 161 "Track Number" definition An integer value representing a unique reference to a track record within a particular track file. group spare 4 TN "Track Number" element 12 raw 170 "Track Status" definition Status of monoradar track (PSR and/or SSR updated). extended CNF "Confirmed Vs. Tentative Track" element 1 table 0: Confirmed Track 1: Tentative Track RAD "Type of Sensor(s) Maintaining Track" element 2 table 0: Combined Track 1: PSR Track 2: SSR/Mode S Track 3: Invalid DOU "Signals Level of Confidence in Plot to Track Association Process" element 1 table 0: Normal confidence 1: Low confidence in plot to track association MAH "Manoeuvre Detection in Horizontal Sense" element 1 table 0: No horizontal manoeuvre sensed 1: Horizontal manoeuvre sensed CDM "Climbing/Descending Mode" element 2 table 0: Maintaining 1: Climbing 2: Descending 3: Unknown - TRE "Signal for End_of_Track" element 1 table 0: Track still alive 1: End of track lifetime (last report for this track) GHO "Ghost Vs. True Target" element 1 table 0: True target track 1: Ghost target track SUP "Track Maintained with Track Information from Neighbouring Node B on the Cluster, or Network" element 1 table 0: No 1: Yes TCC "Type of Plot Coordinate Transformation Mechanism" element 1 table 0: Tracking performed in so-called 'Radar Plane', i.e. neither slant range correction nor stereographical projection was applied 1: Slant range correction and a suitable projection technique are used to track in a 2D reference plane, tangential to the earth model at the Radar Site co-ordinates spare 3 - 200 "Calculated Track Velocity in Polar Co-ordinates" definition Calculated track velocity expressed in polar co-ordinates. group GSP "Calculated Groundspeed" element 16 unsigned quantity 1/2^14 "NM/s" HDG "Calculated Heading" element 16 unsigned quantity 360/2^16 "°" remark Notes: - The calculated heading is related to the geographical North at the aircraft position. 210 "Track Quality" definition Track quality in the form of a vector of standard deviations. group SIGX "Standard Deviation on the Horizontal Axis of the Local Grid System" element 8 unsigned quantity 1/2^7 "NM" SIGY "Standard Deviation on the Vertical Axis of the Local Grid System" element 8 unsigned quantity 1/2^7 "NM" SIGV "Standard Deviation on the Groundspeed Within the Local Grid System" element 8 unsigned quantity 1/2^14 "NM/s" SIGH "Standard Deviation on the Heading Within the Local Grid System" element 8 unsigned quantity 360/2^12 "°" remark Notes: 1. The standard deviation is per definition a positive value, hence the range covered is : 0 <= Sigma(X) < 2 NM 2. The standard deviation is per definition a positive value, hence the range covered is : 0 <= Sigma(Y) < 2 NM 3. The standard deviation is per definition a positive value, hence the range covered is: 0 <= Sigma (V) < 56.25 Kt 4. The standard deviation is per definition a positive value; hence the range covered is: 0 <= sigma (H) < 22.5 degrees. 220 "Aircraft Address" definition Aircraft address (24-bits Mode S address) assigned uniquely to each aircraft. element 24 raw 230 "Communications/ACAS Capability and Flight Status" definition Communications capability of the transponder, capability of the on-board ACAS equipment and flight status. group COM "Communications Capability of the Transponder" element 3 table 0: No communications capability (surveillance only) 1: Comm. A and Comm. B capability 2: Comm. A, Comm. B and Uplink ELM 3: Comm. A, Comm. B, Uplink ELM and Downlink ELM 4: Level 5 Transponder capability 5: Not Assigned 6: Not Assigned 7: Not Assigned STAT "Flight Status" element 3 table 0: No alert, no SPI, aircraft airborne 1: No alert, no SPI, aircraft on ground 2: Alert, no SPI, aircraft airborne 3: Alert, no SPI, aircraft on ground 4: Alert, SPI, aircraft airborne or on ground 5: No alert, SPI, aircraft airborne or on ground 6: Not Assigned 7: Unknown SI "SI/II Transponder Capability" element 1 table 0: SI-Code Capable 1: II-Code Capable spare 1 MSSC "Mode-S Specific Service Capability" element 1 table 0: No 1: Yes ARC "Altitude Reporting Capability" element 1 table 0: 100 ft resolution 1: 25 ft resolution AIC "Aircraft Identification Capability" element 1 table 0: No 1: Yes B1A "BDS 1,0 Bit 16" element 1 raw B1B "BDS 1,0 Bits 37/40" element 4 raw remark Note: - This item shall be present in every ASTERIX record conveying data related to a Mode S target. If the datalink capability has not been extracted yet, bits 16/14 shall be set to zero. 240 "Aircraft Identification" definition Aircraft identification (in 8 characters) obtained from an aircraft equipped with a Mode S transponder. element 48 string icao remark Notes: 1. This data item contains the flight identification as available in the respective Mode S transponder registers. 250 "Mode S MB Data" definition Mode S Comm B data as extracted from the aircraft transponder. repetitive 1 group MBDATA "Mode S Comm B Message Data" element 56 raw BDS1 "Comm B Data Buffer Store 1 Address" element 4 raw BDS2 "Comm B Data Buffer Store 2 Address" element 4 raw remark Notes: 1. For the transmission of BDS Register 2,0, Data Item I007/240 is used. 2. For the transmission of BDS Register 3,0, Data Item I007/260 is used. 3. In case of data extracted via Comm-B broadcast, all bits of fields BDS1 and BDS2 are set to 0; in case of data extracted via GICB requests, the fields BDS1 and BDS2 correspond to the GICB register number. 260 "ACAS Resolution Advisory Report" definition Currently active Resolution Advisory (RA), if any, generated by the ACAS associated with the transponder transmitting the report and threat identity data. element 56 raw remark Notes: 1. Refer to ICAO Draft SARPs for ACAS for detailed explanations. 400 "Directed Interrogation Request Number" definition Directed interrogation request number group PRI "Priority of Command" element 1 table 0: Normal Priority, surveillance function has priority 1: High Priority, Directed interrogation has priority over surveillance RN "Request Number" element 15 raw remark Notes: 1. The Request Number is created by the client, which directs the sensor to perform an interrogation. 2. The sensor will use the same request number for all subsequent messages related to the respective directed interrogation. 3. The sensor will not accept a request numbere which is currently processed. 4. In some cases (e.g. overlapping of directed interrogation windows with partially equal mode combinations) the sensor cannot determine which request number to assign to target reports due to ambiguity. In this case one matching request number will be used and the sensor has to generate an "ambiguous acknowledge" message when accepting the command. 5. A value of 0 for the Request Number will cause an Interrogation reject by the sensor. Therefore, the Request Number shall always be greater than or equal to 1. 410 "Directed Interrogation Message Type" definition Directed interrogation message type element 8 table 0: Acknowledge 1: Reject 2: Interrogation Finished 3: Interrogation Completed 4: Target Report 5: Interrogation Request Type A 6: Interrogation Request Type B 7: Interrogation Request Type C 8: Selective BDS-Register Request remark Notes: 1. Using the Acknowledge the sensor will confirm the receipt of the directed interrogation command. 2. After the sensor has completed the interrogation, i.e. the interrogations are transmitted, the sensor will report an Interrogation Finished message. 3. When no further targets for a directed interrogation are expected, an Interrogation Completed message will be issued by the interrogator. 4. Although each Directed Interrogation should result in exactly one target report, cases may occur resulting in error conditions. These potential error conditions are signalled with item I007/030. 415 "Required Interrogation Modes" definition Directed Interrogation MIPs compound - - - - - RIM "Subfield #1: Required Interrogation Modes" group spare 7 LO "Lockout Override" element 1 table 0: No lockout override 1: Lockout override MSPROB "Probability of Reply If Mode S UF11 or Combined Modes Are Used" element 3 table 0: 1 1: 1/2 2: 1/4 3: 1/8 4: 1/16 M5FORMAT "Mode 5 Format" element 5 raw M4CS "Mode 4 Code Selection" element 2 table 0: Code A 1: Code B 2: Defined by sensor M5S "M5_SUPERMODE_S" element 1 raw SM5S "M5_SUPERMODE_S" element 1 raw SM54 "M5_SUPERMODE_4" element 1 raw SM5C "M5_SUPERMODE_C" element 1 raw SM53 "M5_SUPERMODE_3A" element 1 raw SM52 "M5_SUPERMODE_2" element 1 raw SM51 "M5_SUPERMODE_1" element 1 raw spare 1 M5 "MODE_5" element 1 raw RCMA "MODE S ROLL_CALL" element 1 raw RCMC "MODE S ROLL_CALL" element 1 raw CMC "COMBINED_C" element 1 raw CM3A "COMBINED_3A" element 1 raw MS "MODE_S" element 1 raw M4S "M4_SUPERMODE_" element 1 raw SMC "SUPERMODE_C" element 1 raw SM3A "SUPERMODE_3A" element 1 raw SM2 "SUPERMODE_2" element 1 raw SM1 "SUPERMODE_1" element 1 raw MCO "MODE_C_ONLY" element 1 raw M3O "MODE_3A_ONLY" element 1 raw MCS "MODE_C_S" element 1 raw M3S "MODE_3A_S" element 1 raw MD "MODE_D" element 1 raw MC "MODE_C" element 1 raw MB "MODE_B" element 1 raw M4 "MODE_4" element 1 raw M3A "MODE_3A" element 1 raw M2 "MODE_2" element 1 raw M1 "MODE_1" element 1 raw MIPT "Subfield #2: MIP Table" element 8 raw 420 "Directed Interrogation Window" definition Geographical window defined in polar co-ordinates group RS "Rho-Start" element 16 unsigned quantity 1/2^8 "NM" < 256 RE "Rho-End" element 16 unsigned quantity 1/2^8 "NM" < 256 TS "Theta-Start" element 16 unsigned quantity 360/2^16 "°" TE "Theta-End" element 16 unsigned quantity 360/2^16 "°" remark Notes: 1. When present, this window defines the area which should be interrogated and for which the target reports are expected. 2. The sensor shall use this window to determine the azimuth range for the directed interrogation. 3. The sensor may use this window to tag the extracted targets within this window with the request number. 4. In case multiple request windows overlap, the sensor may respond with an Ambiguous Acknowledge. It shall be noted, that internally generated expectation windows for directed interrogations related to targets/tracks may also lead to Ambiguous Acknowledge Responses. 5. The target window is meant within a NE related coordinated system with the point of origin at the radar head. 440 "Directed Interrogation BDS Register Request" definition Directed Interrogation BDS Register Request repetitive 1 group BDS1 "Comm B Data Buffer Store 1 Address" element 4 raw BDS2 "Comm B Data Buffer Store 2 Address" element 4 raw remark Notes: 1. A Directed Interrogation BDS request will only be performed once. If it is not successful it will not be repeated automatically but has to be re-ordered. 450 "Directed Interrogation Result" definition Directed Interrogation Result compound TR "Subfield #1: Truncation" group spare 4 N "Interrogation Was Not Executed" element 1 raw T "Interrogation Scheduler Has Truncated the All Call Request" element 1 raw A "Interrogation Scheduler Has Activated the Request At Least Once" element 1 raw C "Interrogation Scheduler Has Activated the Request During All Its Validity" element 1 raw M4 "Subfield #2: Mode 4 Interrogations" element 8 raw M5 "Subfield #3: Mode 5 Interrogations" element 8 raw MS "Subfield #4: Mode S All Call Interrogations" group spare 6 LO "Lockout" element 2 table 0: No Lockout used by Interrogation Scheduler 1: Lockout used by Interrogation Scheduler 2: Lockout-Override applied NB "Number of Mode S All Calls Performed for the Request" element 8 raw MX "Subfield #5: Mark X Interrogations" element 8 raw SMS "Subfield #6: Selective Mode S Interrogations" element 8 raw REF "Reserved Expansion Field" explicit re SPF "Special Purpose Field" explicit sp uaps variations downlink 010 025 410 140 400 020 040 070 090 130 220 240 250 161 042 200 170 210 030 080 100 110 120 230 260 055 050 065 060 450 085 - - SPF REF uplink 010 025 410 140 400 040 220 161 042 200 415 420 440 - - - - - - SPF REF case 410 0: downlink 1: downlink 2: downlink 3: downlink 4: downlink 5: uplink 6: uplink 7: uplink 8: uplink