asterix 240 "Radar Video Transmission" edition 1.3 date 2015-05-13 preamble Surveillance data exchange. items 000 "Message Type" definition This Data Item allows for a more convenient handling of the messages at the receiver side by further defining the type of transaction. element 8 table 1: Video Summary message 2: Video message remark Notes: 1. In applications where transactions of various types are exchanged, the Message Type Data Item facilitates the proper report handling at the receiver side. 2. All Message Type values are reserved for common standard use. 3. The list of items present for the two message types is defined in the following table. Table: Message Types :: Type Item 001 002 I240/000 M M I240/010 M M I240/020 X M I240/030 M X I240/040 X O(1) I240/041 X O(1) I240/048 X M I240/049 X M I240/050 X O(2) I240/051 X O(2) I240/052 X O(2) I240/140 O O (1) - Either Item I240/040 or I240/041 shall be present in each Video Message (2) - Either Item I240/050 or I240/051 or I240/052 shall be present in each video message 010 "Data Source Identifier" definition Identification of the system from which the data are 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 "Video Record Header" definition Contains a message sequence identifier. element 32 unsigned integer remark Note: - The Message Sequence Identifier is used by the receiving application to detect lost messages. 030 "Video Summary" definition Contains an ASCII string (free text to define stream meta data). repetitive 8 element 8 string ascii 040 "Video Header Nano" definition Defines a group of video cells corresponding to a video radial: all cells have the same size in azimuth and range and are consecutive in range. group STARTAZ "Start Azimuth of the Cells Group" element 16 unsigned quantity 360/2^16 "°" >= 0 < 360 ENDAZ "End Azimuth of the Cells Group" element 16 unsigned quantity 360/2^16 "°" >= 0 < 360 STARTRG "Starting Range of the Cells Group, Expressed in Number of Cells" element 32 unsigned integer CELLDUR "Video Cell Duration in Nano-seconds" element 32 unsigned quantity 1 "ns" 041 "Video Header Femto" definition Defines a group of video cells corresponding to a video radial: all cells have the same size in azimuth and range and are consecutive in range. group STARTAZ "Start Azimuth of the Cells Group" element 16 unsigned quantity 360/2^16 "°" >= 0 < 360 ENDAZ "End Azimuth of the Cells Group" element 16 unsigned quantity 360/2^16 "°" >= 0 < 360 STARTRG "Starting Range of the Cells Group, Expressed in Number of Cells" element 32 unsigned integer CELLDUR "Video Cell Duration in Femto-seconds" element 32 unsigned quantity 1 "fs" 048 "Video Cells Resolution & Data Compression Indicator" definition This Data Item defines the bit resolution used in the coding of the video signal amplitude in all cells of the video group as well as an indicator whether data compression has been applied. group C "Data Compression Indicator" element 1 table 0: No compression applied 1: Compression applied spare 7 RES "Bit Resolution" element 8 table 1: Monobit Resolution (1 bit) 2: Low Resolution (2 bits) 3: Medium Resolution (4 bits) 4: High Resolution (8 bits) 5: Very High Resolution (16 bits) 6: Ultra High Resolution (32 bits) remark Note: - When the Data Compression Indicator (C) is set, shows that a data compression technique has been applied. The actual algorithm used and the related parameters have to be specified in a relevant ICD (Interface Control Document). 049 "Video Octets & Video Cells Counters" definition This Data Item contains the number of “valid” octets (i.e. nonempty octets) used in the coding of the video signal amplitude and the number of “valid” cells in the video group. group NBVB "Number of 'valid' Octets" element 16 unsigned integer NBCELLS "Number of 'valid' Cells" element 24 unsigned integer 050 "Video Block Low Data Volume" definition Contains a group of video cells corresponding to a video radial; all cells have the same size in azimuth and range and are consecutive in range. This item shall be used in cases where a low data volume, up to 1020 bytes, will be transmitted. repetitive 8 element 32 raw remark Notes: 1. The first cell in the block is always the closest to the sensor and the following cells are in increasing range order. 2. To get the range in meters of the cell at position “NU_CELL” in the data stream, the following formula shall be used: D = CELL_DUR(in seconds) * (START_RG + NU_CELL - 1) * c/(2.) where c = 299 792 458 m/s: light celerity. 051 "Video Block Medium Data Volume" definition Contains a group of video cells corresponding to a video radial; all cells have the same size in azimuth and range and are consecutive in range. This item shall be used in cases where a medium data volume, up to 16320 bytes, will be transmitted. repetitive 8 element 512 raw remark Notes: 1. The first cell in the block is always the closest to the sensor and the following cells are in increasing range order. 2. To get the range in meters of the cell at position “NU_CELL” in the data stream, the following formula shall be used: D = CELL_DUR(in seconds) * (START_RG + NU_CELL - 1) * c/(2.) where c = 299 792 458 m/s: light celerity. 052 "Video Block High Data Volume" definition Contains a group of video cells corresponding to a video radial; all cells have the same size in azimuth and range and are consecutive in range. This item shall be used in cases where a high data volume, up to 65024 bytes, will be transmitted. repetitive 8 element 2048 raw remark Notes: 1. The first cell in the block is always the closest to the sensor and the following cells are in increasing range order. 2. The maximum value of REP that should be used is 254, in order to keep the maximum size of the field at 64kbytes. 3. To get the range in meters of the cell at position “NU_CELL” in the data stream, the following formula shall be used: D = CELL_DUR(in seconds) * (START_RG + NU_CELL - 1) * c/(2.) where c = 299 792 458 m/s: light celerity. 140 "Time of Day" definition Absolute time stamping expressed as UTC. element 24 unsigned quantity 1/2^7 "s" remark Note: - The time information, shall reflect the exact time of an event, expressed as a number of 1/128 s elapsed since last midnight. RE "Reserved Expansion Field" definition Expansion explicit re SP "Special Purpose Field" definition Special Purpose Field explicit sp uap 010 000 020 030 040 041 048 049 050 051 052 140 RE SP