asterix 002 "Transmission of Monoradar Service Messages" edition 1.1 date 2021-04-01 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: North marker message 2: Sector crossing message 3: South marker message 8: Activation of blind zone filtering 9: Stop of blind zone filtering remark Notes: 1. In application where transactions of various types are exchanged, the Message Type Data Item facilitates the proper message handling at the receiver side. 2. Message Type values 1-127 are reserved for common standard use, whereas the values 128-255 are application dependent. 010 "Data Source Identifier" definition Identification of the radar station from which the data are received. group SAC "System Area Code" element 8 raw SIC "System Identification Code" element 8 raw remark Notes: 1. The defined SACs are listed in Part 1, Table 2 [Ref. 2] 2. The defined SICs are listed in Part 1, Annex B [Ref. 2] 020 "Sector Number" definition Eight most significant bits of the antenna azimuth defining a particular azimuth sector. element 8 unsigned quantity 360/2^8 "°" remark The use of the antenna azimuth as sector number has the advantage of being independent of the number of sectors implemented. 030 "Time of Day" definition Absolute time stamping expressed as UTC time. element 24 unsigned quantity 1/2^7 "s" remark Notes: 1. The time of day value is reset to zero each day at midnight. 2. For time management in radar transmission applications, refer to Part 1, paragraph 5.4 [ Ref.2]. 3. Data Item I002/030 can have various logical meanings. In a particular message, the logical meaning is implicit from its context (e.g. in a North marker message it represents the antenna North crossing time; in a sector message it represents the antenna sector crossing time). 041 "Antenna Rotation Speed" definition Antenna rotation period as measured between two consecutive North crossings or as averaged during a period of time. element 16 unsigned quantity 1/2^7 "s" 050 "Station Configuration Status" definition Information concerning the use and status of some vital hardware components of the radar system. repetitive fx element 7 raw remark Due to the diversity in hardware design and requirement of present and future radar stations, it is felt impractical to attempt to define the individual bits. 060 "Station Processing Mode" definition Details concerning the present status with respect to processing parameters and options. repetitive fx element 7 raw remark NOTES: 1. Typical information conveyed within this Data Item includes inter alia type of polarisation in use, Moving Target Indicator (MTI) in use and/or definition of the range to which MTI is applied, presence of overload conditions and the type of load reduction measures in use. 2. Only the structure of this Data Item is defined, no attempt is made to standardise its contents, in order not to hamper any application or future development. 070 "Plot Count Values" definition Plot count values according to various plot categories, either for the last full antenna scan or for the last sector processed. repetitive 8 group A "Aerial Identification" element 1 table 0: Counter for antenna 1 1: Counter for antenna 2 IDENT "" element 5 table 1: Sole primary plots 2: Sole SSR plots 3: Combined plots COUNTER "" element 10 unsigned integer 080 "Warning/Error Conditions" definition Warning/error conditions affecting the functioning of the radar system itself. repetitive fx element 7 raw remark NOTE: Warning/error condition values 1-63 are reserved for common Standard use, whereas the values 64-127 are application dependent. 090 "Collimation Error" definition Averaged difference in range and in azimuth for the primary target position with respect to the SSR target position as calculated by the radar station. group RE "Range Error" element 8 signed quantity 1/2^7 "NM" AE "Azimuth Error" element 8 signed quantity 360/2^14 "°" remark NOTES 1. LSB of RE is calculated as :math:`2^{16-f}`. 2. A default quantisation unit of 0.022° and a range between -2.8125° and +2.7905° is obtained for a value of f=2 . 100 "Dynamic Window Type 1" definition Signals the activation of a certain selective filtering function and in a polar coordinates system the respective geographical areas. group RS "Rho Start" element 16 unsigned quantity 1/2^7 "NM" < 512 RE "Rho End" element 16 unsigned quantity 1/2^7 "NM" < 512 TS "Theta Start" element 16 unsigned quantity 360/2^16 "°" TE "Theta End" element 16 unsigned quantity 360/2^16 "°" remark The logical meaning of the polar window is defined by its context, given by the Message Type (Data Item I002/000) in the record concerned. SP "Special Purpose Field" definition Special Purpose Field explicit sp RFS "Random Field Sequencing" definition Random Field Sequencing rfs uap 010 000 020 030 041 050 060 070 100 090 080 - SP RFS