Document title: Documentation SFD for NDADS DE RPA_DUCT_ASCII datatype Project: DE NDADS Datatype: RPA_DUCT_ASCII Super-EID: DOCUMENT There may be other documents also identified by this super-EID. NDADS filename: DUCT_FORMAT_DE.SFD TRF entry B46565.txt in NSSDC's controlled digital document library. Feb. 1998. Document text follows: ---------------------- CCSDYDNM000200NSSD0012SMARK001 TYPE_OF_FILE_NAME: DUCT FILES RECORD_TYPE_NAMES: DUCT_1 RECORD_TYPES: RECORD_TYPE_NAME: DUCT_1 MAXIMUM_RECORD_TYPE_LENGTH: 2176 BYTES FIELD_NAME: DATE FIELD_MNEMONIC: DATE FIELD_DESCRIPTION: Year and day number of the year of the record in the form YYDDD. (e.g. 81264 is day 264 of year 1981.) FIELD_RESOLUTI0N: 1 day FIELD_RANGE: MINIMUM_VALUE: 81215 MAXIMUM_VALUE: 83049 FIELD_IDIOSYNCRACIES: None FIELD_SYNTAX: VI4 FIELD_NAME: TIME FIELD_MNEMONIC: TIME FIELD_DESCRIPTION: The universal time (UT) time of the day in milliseconds (ms) of the beginning of the 8 second telemetry frame associated with the data in this record. FIELD_RESOLUTI0N: 1 ms FIELD_RANGE: MINIMUM_VALUE: 0 MAXIMUM VALUE: 86399999 FIELD_IDIOSYNCRACIES: None FIELD_SYNTAX: VI4 FIELD_NAME: Number of Ni values in DUCT_1 record FIELD_MNEMONIC: NOUT FIELD_DESCRIPTION: This is an integer giving the number times the Ni field will be repeated in the record. FIELD_RESOLUTI0N: 1 FIELD_RANGE: MINIMUM_VALUE: 4 MAXIMUM_VALUE: 512 FIELD_IDIOSYNCRACIES: None FIELD_SYNTAX: VI4 FIELD_NAME: Geographic latitude FIELD_MNEMONIC: Glat FIELD_DESCRIPTION: The geographic latitude of the spacecraft in degrees. FIELD_RESOLUTI0N: 0.0001 degrees FIELD_RANGE: MINIMUM_VALUE: -90.0 degrees MAXIMUM_VALUE: 90.0 degrees FIELD_IDIOSYNCRACIES: See RECORD_TYPE_ALGORITHMS FIELD_SYNTAX: VR4 FIELD_NAME: Geographic longititude FIELD_MNEMONIC: Glon FIELD_DESCRIPTION: The geographic longititude of the spacecraft in degrees. FIELD_RESOLUTI0N: 0.001 degrees FIELD_RANGE: MINIMUM_VALUE: -180.0 degrees MAXIMUM_VALUE: 180.0 degrees FIELD_IDIOSYNCRACIES: See RECORD_TYPE_ALGORITHMS FIELD_SYNTAX: VR4 FIELD_NAME: Invariant latitude FIELD_MNEMONIC: Ilat FIELD_DESCRIPTION: The invariant latitude of the spacecraft in degrees. FIELD_RESOLUTI0N: 0.0001 degrees FIELD_RANGE: MINIMUM_VALUE: 0.0 degrees MAXIMUM_VALUE: 90.0 degrees FIELD_IDIOSYNCRACIES: See RECORD_TYPE_ALGORITHMS FIELD_SYNTAX: VR4 FIELD_NAME: Magnetic local time FIELD_MNEMONIC: Mlt FIELD_DESCRIPTION: The magnetic local time of the spacecraft in hours. FIELD_RESOLUTI0N: 0.0001 hours FIELD_RANGE: MINIMUM_VALUE: 0.0 hours MAXIMUM_VALUE: 24.0 hours FIELD_IDIOSYNCRACIES: See RECORD_TYPE_ALGORITHMS FIELD_SYNTAX: VR4 FIELD_NAME: Altitude FIELD_MNEMONIC: Alt FIELD_DESCRIPTION: The altitude of the spacecraft in km. FIELD_RESOLUTI0N: 0.01 km FIELD_RANGE: MINIMUM_VALUE: 200. km MAXIMUM_VALUE: 1012. km FIELD_IDIOSYNCRACIES: See RECORD_TYPE_ALGORITHMS FIELD_SYNTAX: VR4 FIELD_NAME: Wide Band Filter FIELD_MNEMONIC: Wbfilt FIELD_DESCRIPTION: This field is the spectral power/Hz determined by one of six comb filters which allow the extension of ionospheric irregularity measurements to a smaller scale size than is possible with the ion density measurements alone. Each filter is sampled 4 times during the 8 second TM frame. Thus the Wbfilt field will be repeated 24 times in a DUCT_1 record. The frequency band, mean scale size, and offset time from the start of the data frame (in ms) of each of the 24 measurements can be summarized as follows: measurement 1 2 3 4 5 6 freq. band(Hz) 630-1700 86-233 1700-4600 233-630 4600-12400 32-86 scale size(m) 6.35 46.5 2.35 17.2 0.87 125 offset time(ms) 32 95 157 220 282 1970 measurement 7 8 9 10 11 12 freq. band(Hz) 630-1700 86-233 1700-4600 233-630 4600-12400 32-86 scale size(m) 6.35 46.5 2.35 17.2 0.87 125 offset time(ms) 2032 2095 2157 2220 2282 3970 measurement 13 14 15 16 17 18 freq. band(Hz) 630-1700 86-233 1700-4600 233-630 4600-12400 32-86 scale size(m) 6.35 46.5 2.35 17.2 0.87 125 offset time(ms) 4032 4095 4157 4220 4282 5970 measurement 19 20 21 22 23 24 freq. band(Hz) 630-1700 86-233 1700-4600 233-630 4600-12400 32-86 scale size(m) 6.35 46.5 2.35 17.2 0.87 125 offset time(ms) 6032 6095 6157 6220 6282 7970 FIELD_RESOLUTI0N: ~0.1% FIELD_RANGE: MINIMUM_VALUE: 10**2 /Hz MAXIMUM_VALUE: 10**-18 /Hz FIELD_IDIOSYNCRACIES: See RECORD_TYPE_ALGORITHMS FIELD_SYNTAX: VR4 FIELD_NAME: Ion density FIELD_MNEMONIC: Ni FIELD_DESCRIPTION: The ion density in ions/cc. This field will be repeated NOUT times in a DUCT_1 record. The time at which a particular ion density measurement was made depends upon its position in the record. The measurements are made uniformly over the 8 second telemetry frame. The Jth ion density field will have been measured at a time of (J-1)*(8.0/NOUT)+TIME ms. FIELD_RESOLUTI0N: 1. ion/cc. FIELD_RANGE: MINIMUM_VALUE: 1000.ions/cc MAXIMUM_VALUE: 6.0E+6 ions/cc FIELD_IDIOSYNCRACIES: A period of negative values in this field often occurs for several records at the beginning or ending of a file as the spacecraft TM is turned on or off. These negative values are not valid data. See also RECORD_TYPE_ALGORITHMS. FIELD_SYNTAX: VR4 RECORD_TYPE_FIELD_RELATIONSHIPS: The order of the fields in an DUCT_1 record is as follows: DATE, TIME, NOUT, Glat, Glon, Ilat, Mlt, Alt, Wbfilt (24 values), Ni (up to 512 values). RECORD_TYPE_ALGORITHMS: The real fields describing spacecraft position in a DUCT_1 record are initialized with a fill value of 9999999.0 and subsequently the geophysical values are inserted. Thus if there is no data available for one of these parameters that particular field will contain the fill data value. The Wbfilt fields will contain values of 0.0 when no data is available. Negative or zero values in the Ni field indicate no data is available. MISCELLANEOUS_TYPE_OF_FILE_ATTRIBUTES: DUCT files are sequential and consist of a single type of variable length record. The Wide band filter field is repeated 24 times followed by NOUT Ni fields. CCSDYDNM000200NSSD0012EMARK001