OPeNDAP Data Access Form for cyg03.ddmi.s20220526-000000-e20220526-235959.l1.power-brcs.a31.d32.nc
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dataset: cyg03.ddmi.s20220526-000000-e20220526-235959.l1.power-brcs.a31.d32.nc




  • NC_GLOBAL
    • Conventions: CF-1.6, ACDD-1.3, ISO-8601
    • standard_name_vocabulary: CF Standard Name Table v30
    • project: CYGNSS
    • featureType: trajectory
    • summary: CYGNSS is a NASA Earth Venture mission, managed by the Earth System Science Pathfinder Program. The mission consists of a constellation of eight small satellites. The eight observatories comprise a constellation that measures the ocean surface wind field with very high temporal resolution and spatial coverage, under all precipitating conditions, and over the full dynamic range of wind speeds experienced in a tropical cyclone. The CYGNSS observatories fly in 510 km circular orbits at a common inclination of 35\302\260. Each observatory includes a Delay Doppler Mapping Instrument (DDMI) consisting of a modified GPS receiver capable of measuring surface scattering, a low gain zenith antenna for measurement of the direct GPS signal, and two high gain nadir antennas for measurement of the weaker scattered signal. Each DDMI is capable of measuring 4 simultaneous bi-static reflections, resulting in a total of 32 wind measurements per second by the full constellation.
    • program: CYGNSS
    • references: Ruf, C., P. Chang, M.P. Clarizia, S. Gleason, Z. Jelenak, J. Murray, M. Morris, S. Musko, D. Posselt, D. Provost, D. Starkenburg, V. Zavorotny, CYGNSS Handbook, Ann Arbor, MI, Michigan Pub., ISBN 978-1-60785-380-0, 154 pp, 1 Apr 2016. http://clasp-research.engin.umich.edu/missions/cygnss/reference/cygnss-mission/CYGNSS_Handbook_April2016.pdf
    • processing_level: 1
    • comment: DDMs are calibrated into Power (Watts) and Bistatic Radar Cross Section (m^2)
    • creator_type: institution
    • institution: University of Michigan Space Physics Research Lab (SPRL)
    • creator_name: CYGNSS Science Operations Center
    • publisher_name: PO.DAAC
    • publisher_email: podaac@podaac.jpl.nasa.gov
    • publisher_url: \342\200\213http://podaac.jpl.nasa.gov
    • sensor: Delay Doppler Mapping Instrument (DDMI)
    • source: Delay Doppler maps (DDM) obtained from the DDMI aboard CYGNSS observatory constellation
    • version_id: 3.1
    • title: CYGNSS Level 1 Science Data Record Version 3.1
    • ShortName: CYGNSS_L1_V3.1
    • id: PODAAC-CYGNS-L1X31
    • netcdf_version_id: 4.3.3.1 of Dec 10 2015 16:44:18 $
    • history: Fri May 27 21:29:16 2022: ncks -O -a -dsample,0,164111,1 -L1 --cnk_dmn=sample,1000 --cnk_dmn=ddm,4 --cnk_dmn=delay,17 --cnk_dmn=doppler,11 /tmp/qt_temp.b27996 /tmp/qt_temp.f27996 ../../src/produce-L1-files/produce-L1-files production_1@cygnss-data-1.engin.umich.edu 3 2022-05-26 00:00:00 2022-05-27 00:00:00 --allow-partial
    • platform: Observatory Reference: cyg3 (C-SCID=2B)
    • l1_algorithm_version: 3.1
    • l1_data_version: 3.2
    • lna_data_version: 2
    • nadir_ant_data_version: 17
    • nadir_sidelobe_mask_version: -1
    • zenith_ant_data_version: 13
    • ant_temp_version: 1
    • eff_scatter_2d_version: 4
    • eff_scatter_3d_version: 6
    • nbrcs_scatt_1d_version: 9
    • gps_eirp_param_version: 7
    • prn_sv_maps_version: 1
    • land_mask_version: 1
    • near_land_mask_version: 1
    • very_near_land_mask_version: 1
    • open_ocean_mask_version: 1
    • ddm_a2d_version: 1
    • milky_way_version: 1
    • fresnel_coeff_version: 1
    • brcs_uncert_lut_version: 3
    • ddma_les_sel_luts_version: 2
    • mean_sea_surface_version: 1
    • zenith_specular_ratio_gain_version: 19
    • zenith_calibration_params_version: 17
    • anomalous_sampling_periods_version: 1
    • noise_floor_correction_version: 9
    • zenith_sig_i2_q2_correction_version: 4
    • ddm_nbrcs_scale_factor_version: 6
    • eirp_scale_factor_version: 2
    • bin_ratio_qc_version: 1
    • per_bin_ant_version: 1
    • date_created: 2022-05-27T21:29:16Z
    • date_issued: 2022-05-27T21:29:16Z
    • geospatial_lat_min: -42.045N
    • geospatial_lat_max: 42.165N
    • geospatial_lon_min: 0.000E
    • geospatial_lon_max: 360.000E
    • time_coverage_resolution: P0DT0H0M1S
    • time_coverage_start: 2022-05-26T00:00:00.499261785Z
    • time_coverage_end: 2022-05-26T23:59:59.999261635Z
    • time_coverage_duration: P1DT0H0M0S
    • NCO: 4.4.4


sample[ sample= 0 ..164111] (Type is Int32)
  • attributes
    • long_name: Sample index
    • units: 1
    • comment: The netCDF coordinate variable associated with the sample dimension, which enumerates the zero-justified index range of the DDM time instants contained in the file.
ddm[ ddm= 0 ..3] (Type is Int16)
  • attributes
    • long_name: DDM reflectometry channel
    • units: 1
    • comment: The netCDF coordinate variable associated with variables that are dimensioned by the 4 DDMI reflectometry channels. It enumerates the zero-justified index range of DDM reflectometry channels. Ranges from 0 to 3.
spacecraft_id(Type is Int16)
  • attributes
    • long_name: CCSDS spacecraft identifier
    • units: 1
    • comment: The CCSDS spacecraft identifier: 0xF7 (247): CYGNSS 1 0xF9 (249): CYGNSS 2 0x2B ( 43): CYGNSS 3 0x2C ( 44): CYGNSS 4 0x2F ( 47): CYGNSS 5 0x36 ( 54): CYGNSS 6 0x37 ( 55): CYGNSS 7 0x49 ( 73): CYGNSS 8 0x00 ( 0): end to end simulator 0x0E ( 14): engineering model 0x0D ( 15): default 0xFF (255): unknown
spacecraft_num(Type is Int16)
  • attributes
    • long_name: CYGNSS spacecraft number
    • units: 1
    • valid_min: 1
    • valid_max: 99
    • comment: The CYGNSS spacecraft number: Ranges from 1 through 8 and 99. 1 through 8 are on-orbit spacecraft. 99 is the CYGNSS end-to-end simulator
ddm_source(Type is Int16)
  • attributes
    • long_name: Level 0 data source
    • valid_range: 0, 3
    • flag_values: 0, 1, 2, 3
    • flag_meanings: e2es gpss ddmi unknown
    • comment: The source of the Level 0 DDM raw counts and metadata. 0 = End-End Simulator (E2ES) 1 = GPS signal simulator 2 = CYGNSS spacecraft 3 = Source unknown
ddm_time_type_selector(Type is Int16)
  • attributes
    • long_name: DDM sample time type selector
    • valid_range: 0, 3
    • flag_values: 0, 1, 2, 3
    • flag_meanings: start middle end pvt
    • comment: Determines the position of ddm_timestamp_utc relative to the DDM sampling period. Set to <Middle of DDM sampling period> for nominal science operations. Other settings are used for pre-launch testing only. 0 = Start of DDM sampling period (used for pre-launch testing only) 1 = Middle of DDM sampling period 2 = End of DDM sampling period (used for testing pre-launch only) 3 = pvt_timestamp_utc (used for testing pre-launch only)
delay_resolution(Type is Float32)
  • attributes
    • long_name: DDM delay bin resolution
    • units: 1
    • comment: DDM delay bin resolution in chips. One chip is equal to 1/1,023,000 seconds.
dopp_resolution(Type is Float32)
  • attributes
    • long_name: DDM Doppler bin resolution
    • units: s-1
    • comment: DDM Doppler bin resolution in Hz
ddm_timestamp_utc[ sample= 0 ..164111] (Grid of Float64 values)
  • attributes
    • long_name: DDM sample timestamp - UTC
    • standard_name: time
    • calendar: gregorian
    • comment: DDM sample time. The number of seconds since time_coverage_start with nanosecond resolution. Its position relative to the DDM sampling period is determined by ddm_time_type_selector. Some metadata required for DDM calibration are generated relative to pvt_timestamp_utc or att_timestamp_utc. These metadata are interpolated to ddm_timestamp_utc before being used for DDM calibration. Note that the DDM sampling period is not synchronized with the UTC change of second and can occur at any time relative to the UTC change of second.
    • units: seconds since 2022-05-26 00:00:00.499261785
ddm_timestamp_gps_week[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: DDM sample timestamp - GPS Week
    • units: week
    • comment: The GPS week number of ddm_timestamp_utc
ddm_timestamp_gps_sec[ sample= 0 ..164111] (Grid of Float64 values)
  • attributes
    • long_name: DDM sample timestamp - GPS Seconds
    • units: second
    • comment: The GPS second of week of ddm_timestamp_utc, with nanosecond resolution
pvt_timestamp_utc[ sample= 0 ..164111] (Grid of Float64 values)
  • attributes
    • long_name: PVT timestamp - UTC
    • standard_name: time
    • calendar: gregorian
    • comment: The spacecraft position and velocity epoch. The number of seconds since time_coverage_start with nanosecond resolution. This is the timestamp of the position and velocity reported by the DDMI. This is also the timestamp of the most recent GPS pulse per second.
    • units: seconds since 2022-05-26 00:00:00.499261785
pvt_timestamp_gps_week[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: PVT timestamp - GPS Week
    • units: week
    • comment: The GPS week number of pvt_timestamp_utc
pvt_timestamp_gps_sec[ sample= 0 ..164111] (Grid of Float64 values)
  • attributes
    • long_name: PVT timestamp - GPS Seconds
    • units: second
    • comment: The GPS second of week of pvt_timestamp_utc, with nanosecond resolution.
att_timestamp_utc[ sample= 0 ..164111] (Grid of Float64 values)
  • attributes
    • long_name: Attitude timestamp - UTC
    • standard_name: time
    • calendar: gregorian
    • comment: The spacecraft attitude epoch. The number of seconds since time_coverage_start with nanosecond resolution. This is the timestamp of the spacecraft attitude reported by the spacecraft attitude determinination system.
    • units: seconds since 2022-05-26 00:00:00.499261785
att_timestamp_gps_week[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Attitude timestamp - GPS Week
    • units: week
    • comment: The GPS week number of att_timestamp_utc
att_timestamp_gps_sec[ sample= 0 ..164111] (Grid of Float64 values)
  • attributes
    • long_name: Attitude timestamp - GPS Seconds
    • units: second
    • comment: The GPS second of week of att_timestamp_utc, with nanosecond resolution
sc_pos_x[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft position X at DDM sample time
    • units: meter
    • _FillValue: -99999999
    • comment: The X component of the spacecraft WGS84 reference frame Earth-Centered Earth-Fixed (ECEF) position, in meters, at ddm_timestamp_utc
sc_pos_y[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft position Y at DDM sample time
    • units: meter
    • _FillValue: -99999999
    • comment: The Y component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
sc_pos_z[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft position Z at DDM sample time
    • units: meter
    • _FillValue: -99999999
    • comment: The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
sc_vel_x[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft velocity X at DDM sample time
    • units: meter s-1
    • _FillValue: -9999
    • comment: The X component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc
sc_vel_y[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft velocity Y at DDM sample time
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Y component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc
sc_vel_z[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft velocity Z at DDM sample time
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Z component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc
sc_pos_x_pvt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft position X at PVT time
    • units: meter
    • _FillValue: -99999999
    • comment: The X component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc
sc_pos_y_pvt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft position Y at PVT time
    • units: meter
    • _FillValue: -99999999
    • comment: The Y component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc
sc_pos_z_pvt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft position Z at PVT time
    • units: meter
    • _FillValue: -99999999
    • comment: The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc
sc_vel_x_pvt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft velocity X at PVT time
    • units: meter s-1
    • _FillValue: -9999
    • comment: The X component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc
sc_vel_y_pvt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft velocity Y at PVT time
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Y component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc
sc_vel_z_pvt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft velocity Z at PVT time
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Z component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc
nst_att_status[ sample= 0 ..164111] (Grid of Int16 values)
  • attributes
    • long_name: NST attitude status
    • _FillValue: -99
    • valid_range: 0, 22
    • flag_values: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22
    • flag_meanings: ok not_used2 bad too_few_stars quest_failed residuals_too_high too_close_to_edge pix_amp_too_low pix_amp_too_high backgnd_too_high track_failure pix_sum_too_low unused too_dim_for_starid too_many_groups too_few_groups channel_disabled track_blk_overlap ok_for_starid too_close_to_other too_many_pixels too_many_columns too_many_rows
    • comment: Nano Star Tracker attitude status as reported by the ADCS subsystem. Enumeration, with 0 indicating OK, and non-zero indicating an erroneous condition. Values: 0 = ok 1 = not_used2 2 = bad 3 = too_few_stars 4 = quest_failed 5 = residuals_too_high 6 = too_close_to_edge 7 = pix_amp_too_low 8 = pix_amp_too_high 9 = backgnd_too_high 10 = track_failure 11 = pix_sum_too_low 12 = unused 13 = too_dim_for_starid 14 = too_many_groups 15 = too_few_groups 16 = channel_disabled 17 = track_blk_overlap 18 = ok_for_starid 19 = too_close_to_other 20 = too_many_pixels 21 = too_many_columns 22 = too_many_rows
sc_roll[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Spacecraft attitude roll angle at DDM sample time
    • units: radian
    • _FillValue: -9999.00000
    • comment: Spacecraft roll angle relative to the orbit frame, in radians at ddm_timestamp_utc
sc_pitch[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Spacecraft attitude pitch angle at DDM sample time
    • units: radian
    • _FillValue: -9999.00000
    • comment: Spacecraft pitch angle relative to the orbit frame, in radians at ddm_timestamp_utc
sc_yaw[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Spacecraft attitude yaw angle at DDM sample time
    • units: radian
    • _FillValue: -9999.00000
    • comment: Spacecraft yaw angle relative to the orbit frame, in radians at ddm_timestamp_utc
sc_roll_att[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Spacecraft attitude roll angle at attitude time
    • units: radian
    • _FillValue: -9999.00000
    • comment: Spacecraft roll angle relative to the orbit frame, in radians at att_timestamp_utc
sc_pitch_att[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Spacecraft attitude pitch angle at attitude time
    • units: radian
    • _FillValue: -9999.00000
    • comment: Spacecraft pitch angle relative to the orbit frame, in radians at att_timestamp_utc
sc_yaw_att[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Spacecraft attitude yaw angle at attitude time
    • units: radian
    • _FillValue: -9999.00000
    • comment: Spacecraft yaw angle relative to the orbit frame, in radians at att_timestamp_utc
sc_lat[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Sub-satellite point latitude
    • standard_name: latitude
    • units: degrees_north
    • _FillValue: -9999.00000
    • comment: Subsatellite point latitude, in degrees North, at ddm_timestamp_utc
sc_lon[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Sub-satellite point longitude
    • standard_name: longitude
    • units: degrees_east
    • _FillValue: -9999.00000
    • comment: Subsatellite point longitude, in degrees East, at ddm_timestamp_utc
sc_alt[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: Spacecraft altitude
    • units: meter
    • _FillValue: -9999
    • comment: Spacecraft altitude above WGS-84 ellipsoid, in meters, at ddm_timestamp_utc
commanded_sc_roll[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Commanded spacecraft attitude roll angle
    • units: radian
    • _FillValue: -9999.00000
    • comment: Commanded spacecraft attitude roll angle, in radians at ddm_timestamp_utc. This value is updated every 10 seconds from the ENG_HI packet
rx_clk_bias[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: GPS receiver clock bias
    • units: meter
    • _FillValue: -9999.00000
    • comment: The receiver clock bias (in seconds) multiplied by the speed of light as reported by the DDMI, interpolated to ddm_timestamp_utc, in meters.
rx_clk_bias_rate[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: GPS receiver clock bias rate
    • units: meter s-1
    • _FillValue: -9999.00000
    • comment: The receiver clock bias rate (in seconds/second) multiplied by the speed of light as reported by the DDMI, interpolated to ddm_timestamp_utc, in m/s.
rx_clk_bias_pvt[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: GPS receiver clock bias at PVT time
    • units: meter
    • _FillValue: -9999.00000
    • comment: The receiver clock bias (in seconds) multiplied by the speed of light as reported by the DDMI at pvt_timestamp_utc, in meters.
rx_clk_bias_rate_pvt[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: GPS receiver clock bias rate at PVT time
    • units: meter s-1
    • _FillValue: -9999.00000
    • comment: The receiver clock bias rate (in seconds/second) multiplied by the speed of light as reported by the DDMI, at pvt_timestamp_utc, in m/s.
lna_temp_nadir_starboard[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Starboard antenna LNA temperature
    • units: degree_Celsius
    • _FillValue: -9999.00000
    • comment: The temperature of the starboard antenna low noise amplifier at ddm_timestamp_utc, in degrees C.
lna_temp_nadir_port[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Port Antenna LNA temperature
    • units: degree_Celsius
    • _FillValue: -9999.00000
    • comment: The temperature of the port antenna low noise amplifier at ddm_timestamp_utc, in degrees C.
lna_temp_zenith[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Zenith Antenna LNA temperature
    • units: degree_Celsius
    • _FillValue: -9999.00000
    • comment: The temperature of the zenith antenna low noise amplifier at ddm_timestamp_utc, in degrees C.
ddm_end_time_offset[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: DDM end time offset
    • units: 1e-9 s
    • _FillValue: -9999
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
bit_ratio_lo_hi_starboard[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Starboard low/high bit counter ratio
    • units: 1
    • _FillValue: -9999.00000
    • comment: Bin ratio of the of the starboard antenna defined as (plus_1_cnts + minus_1_cnts) / (plus_3_cnts + minus_3_cnts).
bit_ratio_lo_hi_port[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Port low/high bit counter ratio
    • units: 1
    • _FillValue: -9999.00000
    • comment: Bin ratio of the of the port antenna defined as (plus_1_cnts + minus_1_cnts) / (plus_3_cnts + minus_3_cnts).
bit_ratio_lo_hi_zenith[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Zenith low/high bit counter ratio
    • units: 1
    • _FillValue: -9999.00000
    • comment: Bin ratio of the of the zenith antenna defined as (plus_1_cnts + minus_1_cnts) / (plus_3_cnts + minus_3_cnts).
bit_null_offset_starboard[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Starboard bit count null offset
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
bit_null_offset_port[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Port bit count null offset
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
bit_null_offset_zenith[ sample= 0 ..164111] (Grid of Float32 values)
  • attributes
    • long_name: Zenith bit count null offset
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
status_flags_one_hz[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: 1 Hz Status Flags
    • _FillValue: -9999
    • valid_range: 0, 15
    • flag_masks: 1, 2, 4, 8
    • flag_meanings: milky_way_in_zenith_field_of_view sun_in_zenith_field_of_view sub_sat_pt_over_open_ocean sub_sat_pt_lat_ascending
    • comment: One Hz status flags. These flags apply to all four DDMs. 1 indicates presence of condition. Flag masks: 1 = Milky way in zenith antenna field of view 2 = Sun in zenith antenna field of view 4 = Sub-satellite point over open ocean 8 = Sub-satellite point latitude ascending, i.e. sc_lat has increased since the previous DDM sample
prn_code[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int16 values)
  • attributes
    • long_name: GPS PRN code
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -99
    • valid_min: 0
    • valid_max: 32
    • comment: The PRN code of the GPS signal associated with the DDM. Ranges from 0 to 32. 0 = reflectometry channel idle. 1 through 32 = GPS PRN codes.
sv_num[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Space Vehicle Number
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999
    • comment: The GPS unique space vehicle number that transmitted prn_code.
track_id[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: DDM Track ID
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999
    • comment: A track is a temporally contiguous series of DDMs that have the same prn_code. Each track in the file is assigned a unique track_id starting with one. track_id ranges from 1 to N, where N is the total number of tracks in the file.
ddm_ant[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int16 values)
  • attributes
    • long_name: DDM Antenna
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • _FillValue: -99
    • valid_range: 0, 3
    • flag_values: 0, 1, 2, 3
    • flag_meanings: none zenith nadir_starboard nadir_port
    • comment: The antenna that received the reflected GPS signal associated with the DDM. 0 = none 1 = zenith (never used) 2 = nadir_starboard 3 = nadir_port
zenith_code_phase[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Zenith signal code phase
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The DDMI-measured code phase of the direct GPS signal for prn_code interpolated to ddm_timestamp_utc. 0 <= zenith_code_phase < 1023.0.
sp_ddmi_delay_correction[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Correction to DDMI specular point delay
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
sp_ddmi_dopp_correction[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Correction to DDMI specular point Doppler
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: s-1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
add_range_to_sp[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Additional range to specular point at DDM sample time
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
add_range_to_sp_pvt[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Additional range to specular point at PVT time
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
sp_ddmi_dopp[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDMI Doppler at specular point
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: s-1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
sp_fsw_delay[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Flight software specular point delay
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
sp_delay_error[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Flight software specular point delay error
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
sp_dopp_error[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Flight software specular point Doppler error
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: s-1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
fsw_comp_delay_shift[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Flight software DDM compression delay shift
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
fsw_comp_dopp_shift[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Flight software DDM compression Doppler shift
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: s-1
    • _FillValue: -9999.00000
    • comment: For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
prn_fig_of_merit[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int16 values)
  • attributes
    • long_name: PRN selection figure of Merit
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -99
    • comment: The RCG Figure of Merit (FOM) for the DDM. Ranges from 0 through 15.The DDMI selects the four strongest specular points (SP) for DDM production. It ranks the strength of SPs using an antenna RCG map. The map converts the position of the SP in antenna azimuth and declination angles to an RCG FOM. 0 represents the least FOM value. 15 represents the greatest FOM value.
tx_clk_bias[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: GPS transmitter clock bias
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -9999.00000
    • comment: The GPS spacecraft (sv_num) clock time minus GPS constellation time (in seconds) times the speed of light, in meters.
sp_lat[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point latitude
    • standard_name: latitude
    • units: degrees_north
    • _FillValue: -9999.00000
    • comment: Specular point latitude, in degrees North, at ddm_timestamp_utc
sp_lon[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point longitude
    • standard_name: longitude
    • units: degrees_east
    • _FillValue: -9999.00000
    • comment: Specular point longitude, in degrees East, at ddm_timestamp_utc
sp_alt[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point altitude
    • standard_name: altitude
    • units: meter
    • _FillValue: -9999.00000
    • comment: Altitude of the specular point relative to the WGS 84 datum in meters, at ddm_timestamp_utc, as calculated on the ground. Note that an approximated DTU10 mean sea surface height model is used to calculate the specular point altitude.
sp_pos_x[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Specular point position X
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -99999999
    • comment: The X component of the specular point position in the ECEF coordinate system, in meters, at ddm_timestamp_utc, as calculated on the ground.
sp_pos_y[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Specular point position Y
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -99999999
    • comment: The Y component of the specular point position in the ECEF coordinate system, in meters, at ddm_timestamp_utc, as calculated on the ground.
sp_pos_z[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Specular point position Z
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -99999999
    • comment: The Z component of the specular point position in the ECEF coordinate system, in meters, at ddm_timestamp_utc, as calculated on the ground.
sp_vel_x[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Specular point velocity X
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter s-1
    • _FillValue: -9999
    • comment: The X component of the specular point velocity in the ECEF coordinate system, in m/s, at ddm_timestamp_utc, as calculated on the ground.
sp_vel_y[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Specular point velocity Y
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Y component of the specular point velocity in the ECEF coordinate system, in m/s, at ddm_timestamp_utc, as calculated on the ground.
sp_vel_z[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Specular point velocity Z
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Z component of the specular point velocity in the ECEF coordinate system, in m/s, at ddm_timestamp_utc, as calculated on the ground.
sp_inc_angle[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point incidence angle
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: degree
    • _FillValue: -9999.00000
    • comment: The specular point incidence angle, in degrees, at ddm_timestamp_utc. This is the angle between the line normal to the Earth's surface at the specular point and the line extending from the specular point to the spacecraft. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
sp_theta_orbit[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point orbit frame theta angle
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: degree
    • _FillValue: -9999.00000
    • comment: The angle between the orbit frame +Z axis and the line extending from the spacecraft to the specular point, in degrees, at ddm_timestamp_utc. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
sp_az_orbit[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point orbit frame azimuth angle
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: degree
    • _FillValue: -9999.00000
    • comment: Let line A be the line that extends from the spacecraft to the specular point at ddm_timestamp_utc. Let line B be the projection of line A onto the orbit frame XY plane. sp_az_orbit is the angle between the orbit frame +X axis (the velocity vector) and line B, in degrees, at ddm_timestamp_utc. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
sp_theta_body[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point body frame theta angle
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: degree
    • _FillValue: -9999.00000
    • comment: The angle between the spacecraft body frame +Z axis and the line extending from the spacecraft to the specular point, in degrees, at ddm_timestamp_utc. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
sp_az_body[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point body frame azimuth angle
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: degree
    • _FillValue: -9999.00000
    • comment: Let line A be the line that extends from the spacecraft to the specular point, at ddm_timestamp_utc. Let line B be the projection of line A onto the spacecraft body frame XY plane. sp_az_body is the angle between the spacecraft body frame +X axis and line B, in degrees, at ddm_timestamp_utc. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
sp_rx_gain[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Specular point Rx antenna gain
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: dBi
    • _FillValue: -9999.00000
    • comment: The receive antenna gain in the direction of the specular point, in dBi, at ddm_timestamp_utc.
gps_eirp[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: GPS effective isotropic radiated power
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: watt
    • _FillValue: -9999.00000
    • comment: The estimated effective isotropic RF power (EIRP) of the L1 C/A code signal within \302\261 1 MHz of the L1 carrier radiated by space vehicle, sv_num, in the direction of the specular point, in Watts, at ddm_timestamp_utc. Variations in GPS transmit power are tracked by the direct signal power measured by the navigation receiver. One second samples are smoothed by a \302\261 10 second running average.
static_gps_eirp[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Static GPS effective isotropic radiated power
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: watt
    • _FillValue: -9999.00000
    • comment: Heritage version of gps_eirp (v2.1 and earlier) that assumed a static value for the power level of the L1 signal transmitted by the GPS satellite, prior to implementation of dynamic gps_eirp monitoring in August 2018.
gps_tx_power_db_w[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: GPS SV transmit power
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: dBW
    • _FillValue: -9999.00000
    • comment: Power input to SV Tx antenna. Referenced from the heritage version of gps_eirp (v2.1 and earlier).
gps_ant_gain_db_i[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: GPS SV transmit antenna gain
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: dBi
    • _FillValue: -9999.00000
    • comment: SV antenna gain in the direction of the specular point. Referenced from the heritage version of gps_eirp (v2.1 and earlier).
gps_off_boresight_angle_deg[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: GPS off boresight angle
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: degree
    • _FillValue: -9999.00000
    • comment: SV antenna off boresight angle in the direction of the specular point
ddm_snr[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDM signal to noise ratio
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: dB
    • _FillValue: -9999.00000
    • comment: 10log(Smax/Navg), where Smax is the maximum value (in raw counts) in a single DDM bin and Navg is the the average per-bin raw noise counts. ddm_snr is in dB, at ddm_timestamp_utc.
ddm_noise_floor[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDM noise floor
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: For non-black-body DDMs: Is equal to the average bin raw counts in the first 45 delay rows of the uncompressed 20 x 128 DDM, in counts, at ddm_timestamp_utc. For black body DDMs: Is equal to the average bin raw counts in all 128 delay rows of the uncompressed 20 x 128 DDM, in counts, at ddm_timestamp_utc.
ddm_noise_floor_corrected[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDM noise floor corrected
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The ddm_noise_floor after a correction factor, based on the nadir antenna bin ratio, has been applied.
noise_correction[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDM noise floor correction factor
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The correction factor applied with ddm_noise_floor = (ddm_noise_floor_uncorrected*noise_correction).
inst_gain[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Instrument gain
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The black body noise counts divided by the sum of the black body power and the instrument noise power, in count/W, at ddm_timestamp_utc.
lna_noise_figure[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: LNA noise figure
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: dB
    • _FillValue: -9999.00000
    • comment: The low noise amplifier (LNA) noise figure, in dB, at ddm_timestamp_utc. Estimated from pre-launch characterization of LNA performance as a function of LNA temperature.
rx_to_sp_range[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Rx to specular point range
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -9999
    • comment: The distance between the CYGNSS spacecraft and the specular point, in meters, at ddm_timestamp_utc.
tx_to_sp_range[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Tx to specular point range
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -9999
    • comment: The distance between the GPS satellite and the specular point, in meters, at ddm_timestamp_utc.
tx_pos_x[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Tx position X
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -99999999
    • comment: The X component of the GPS spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
tx_pos_y[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Tx position Y
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -99999999
    • comment: The Y component of the GPS spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
tx_pos_z[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Tx position Z
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter
    • _FillValue: -99999999
    • comment: The Z component of the GPS spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
tx_vel_x[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Tx velocity X
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter s-1
    • _FillValue: -9999
    • comment: The X component of the GPS spacecraft WGS84 reference frame ECEF velocity in meters, at ddm_timestamp_utc
tx_vel_y[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Tx velocity Y
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Y component of the GPS spacecraft WGS84 reference frame ECEF velocity in meters, at ddm_timestamp_utc
tx_vel_z[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: GPS Tx velocity Z
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter s-1
    • _FillValue: -9999
    • comment: The Z component of the GPS spacecraft WGS84 reference frame ECEF velocity in meters, at ddm_timestamp_utc
bb_nearest[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Time to most recent black body reading
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: second
    • _FillValue: -9999.00000
    • comment: The time between ddm_timestamp_utc and the ddm_timestamp_utc associated with the closest (in time) black body reading, in signed seconds. A positive value indicates that the black body reading occurred after ddm_timestamp_utc. A negative value indicates that the block body reading occurred before ddm_timestamp_utc.
fresnel_coeff[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Fresnel power reflection coefficient at specular point
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The SQUARE of the left hand circularly polarized Fresnel electromagnetic voltage reflection coefficient at 1575 MHz for a smooth ocean surface at the specular point location and incidence angle. See UM document 148-0361 Fresnel Coefficient Calculation for more information.
ddm_nbrcs[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Normalized BRCS
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: Normalized BRCS of a 3 delay x 5 Doppler bin box that includes the specular point bin. The specular point bin is in the top (least delay) row and the center Doppler column of the 3 x 5 box.
ddm_les[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Leading edge slope
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: Leading edge slope of a 3 delay x 5 Doppler bin box that include the specular point bin. The specular point bin is in the top (least delay) row and the center Doppler column of the 3 x 5 box.
nbrcs_scatter_area[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: NBRCS scattering area
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter2
    • _FillValue: -9999.00000
    • comment: The scattering area of the 3 x 5 region of the ddm used to calculate ddm_nbrcs.
les_scatter_area[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: LES scattering area
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter2
    • _FillValue: -9999.00000
    • comment: The scattering area of the 3 x 5 region of the ddm used to calculate ddm_les.
brcs_ddm_peak_bin_delay_row[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int16 values)
  • attributes
    • long_name: BRCS DDM peak bin delay row
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -99
    • comment: The zero-based delay row of the peak value in the bistatic radar cross section DDM (brcs). Ranges from 0 to 16.
brcs_ddm_peak_bin_dopp_col[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int16 values)
  • attributes
    • long_name: BRCS DDM peak bin Doppler column
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -99
    • comment: The zero-based Doppler column of the peak value in the bistatic radar cross section DDM (brcs). Ranges from 0 to 10.
brcs_ddm_sp_bin_delay_row[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: BRCS DDM specular point bin delay row
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The zero-based delay row of the specular point delay in the bistatic radar cross section DDM (brcs). Note that this is a floating point value.
brcs_ddm_sp_bin_dopp_col[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: BRCS DDM specular point bin Doppler column
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The zero-based Doppler column of the specular point Doppler in the bistatic radar cross section DDM (brcs). Note that this is a floating point value.
ddm_brcs_uncert[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDM BRCS uncertainty
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: Uncertainty of the BRCS
bb_power_temperature_density[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Black Body Power Temperature Density
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: Counts/Kelvin
    • _FillValue: -9999.00000
    • comment: Raw counts of detected power radiated by the blackbody calibration target, divided by receiver gain and blackbody physical temperature in Kelvins, gives the detected power per unit absolute temperature.
zenith_sig_i2q2[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Zenith Signal I2Q2
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: Raw counts of detected power in direct GPS L1 C/A signal received by zenith navigation antenna and detected by navigation receiver.
zenith_sig_i2q2_corrected[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Zenith Signal I2Q2 Corrected
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The zenith_sig_i2q2 after a correction factor, based on the zenith antenna bin ratio, has been applied.
zenith_sig_i2q2_mult_correction[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Zenith Signal I2Q2 Multiplicative Correction Factor
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The multiplicative correction factor applied with zenith_sig_i2q2_corrected = 10*log10(zenith_sig_i2q2*zenith_sig_i2q2_mult_correction)-zenith_sig_i2q2_add_correction.
zenith_sig_i2q2_add_correction[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: Zenith Signal I2 Q2 additive correction factor
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The additive correction factor applied with zenith_sig_i2q2_corrected = 10*log10(zenith_sig_i2q2*zenith_sig_i2q2_mult_correction)-zenith_sig_i2q2_add_correction.
starboard_gain_setting[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: The Nadir-Starboard Gain Setting
    • units: dB
    • _FillValue: -9999
    • comment: The Nadir-Starboard Gain Setting (dB, 0=Automatic)
port_gain_setting[ sample= 0 ..164111] (Grid of Int32 values)
  • attributes
    • long_name: The Nadir-Port Gain Setting
    • units: dB
    • _FillValue: -9999
    • comment: The Nadir-Port Gain Setting (dB, 0=Automatic)
ddm_kurtosis[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Float32 values)
  • attributes
    • long_name: DDM kurtosis
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999.00000
    • comment: The kurtosis of the DDM noise floor. For diagnostic use only. See UM document 148-0347 DDM RFI Algorithm for more information.
quality_flags[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Per-DDM quality flags 1
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • _FillValue: -9999
    • valid_range: 0, 2147483647
    • flag_masks: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824
    • flag_meanings: poor_overall_quality s_band_powered_up small_sc_attitude_err large_sc_attitude_err black_body_ddm ddmi_reconfigured spacewire_crc_invalid ddm_is_test_pattern channel_idle low_confidence_ddm_noise_floor sp_over_land sp_very_near_land sp_near_land large_step_noise_floor large_step_lna_temp direct_signal_in_ddm low_confidence_gps_eirp_estimate rfi_detected brcs_ddm_sp_bin_delay_error brcs_ddm_sp_bin_dopp_error neg_brcs_value_used_for_nbrcs gps_pvt_sp3_error sp_non_existent_error brcs_lut_range_error ant_data_lut_range_error bb_framing_error fsw_comp_shift_error low_quality_gps_ant_knowledge sc_altitude_out_of_nominal_range anomalous_sampling_period invalid_roll_state
    • comment: First group of the Per-DDM quality flags. 1 indicates presence of condition. More quality flags can be found in quality_flags_2. Flag bit masks: 1/0x00000001 = poor_overall_quality. The logical OR of the following flags. If any one of the following flags are set then poor_overall_quality will be set: large_sc_attitude_err black_body_ddm ddmi_reconfigured spacewire_crc_invalid ddm_is_test_pattern channel_idle low_confidence_ddm_noise_floor sp_over_land sp_very_near_land large_step_noise_floor large_step_lna_temp direct_signal_in_ddm low_confidence_gps_eirp_estimate rfi_detected brcs_ddm_sp_bin_delay_error brcs_ddm_sp_bin_dopp_error gps_pvt_sp3_error sp_non_existent_error brcs_lut_range_error ant_data_lut_range_error bb_framing_error fsw_comp_shift_error low_quality_gps_ant_knowledge sc_altitude_out_of_nominal_range anomalous_sampling_period invalid_roll_state incorrect_ddmi_antenna_selection(quality_flags_2) sp_in_sidelobe(quality_flags_2) fatal_nst_outage(quality_flags_2) low_zenith_ant_gain(quality_flags_2) poor_bb_quality(quality_flags_2) poor_quality_bin_ratio(quality_flags_2) 2/0x00000002 = s_band_powered_up Set if S-band transmitter is powered up. 4/0x00000004 = small_sc_attitude_err Set if the absolute value of the spacecraft roll is between 1 and 30 degrees, the pitch is between 1 and 10 degrees, or the yaw is between 1 and 5 degrees. 8/0x00000008 = large_sc_attitude_err Set if the absolute value of the spacecraft roll is greater than or equal to 30 degrees, the pitch is greater than or equal to 10 degrees, or the yaw is greater than or equal to 5 degrees. 16/0x00000010 = black_body_ddm Set if the black body load was selected during the DDM sampling period. 32/0x00000020 = ddmi_reconfigured Set if the DDMI was reconfigured during the DDM sampling period. 64/0x00000040 = spacewire_crc_invalid Set if the DDM CRC transmitted from the DDMI to the spacecraft computer was not valid. 128/0x00000080 = ddm_is_test_pattern Set if the DDM is a test pattern generated by the DDMI. 256/0x00000100 = channel_idle Set if this reflectometry channel was not tracking a PRN. 512/0x00000200 = low_confidence_ddm_noise_floor Set if the difference between this DDM noise floor and the previous DDM noise floor is greater than 10 percent. 1024/0x00000400 = sp_over_land Set if the specular point is over land. Referenced using a map with 0.1 degree lat/lon bins. Coastline features or islands smaller than bin size may not be properly captured. 2048/0x00000800 = sp_very_near_land Set if the specular point is within 25 km of land. Referenced using a map with 0.1 degree lat/lon bins. 4096/0x00001000 = sp_near_land Set if the specular point is within 50 km of land. Referenced using a map with 0.1 degree lat/lon bins. 8192/0x00002000 = large_step_noise_floor Set if the difference between this DDM noise floor and the previous DDM noise floor is greater than 0.24 dB. 16384/0x00004000 = large_step_lna_temp Set if the LNA temperature rate of change is greater than 1 degree C per minute. 32768/0x00008000 = direct_signal_in_ddm Set if the absolute value of the difference between direct signal code phase and the DDM signal code phase is less than or equal to four. 65536/0x00010000 = low_confidence_gps_eirp_estimate Set when there is low confidence in the GPS effective isotropic radiated power estimate. 131072/0x00020000 = rfi_detected Set when the kurtosis of the DDM noise floor deviates from pure Gaussian by more than 1.0. 262144/0x00040000 = brcs_ddm_sp_bin_delay_error Set if the calculated specular point bin zero-based delay row is less than 4 or greater than 8. 524288/0x00080000 = brcs_ddm_sp_bin_dopp_error Set if the calculated specular point bin zero-based Doppler column is less than 4 or greater than 6. 1048576/0x00100000 = neg_brcs_value_used_for_nbrcs Set if any bin in the 3 x 5 brcs area used to calculate ddm_nbrcs has a negative value. 2097152/0x00200000 = gps_pvt_sp3_error Cannot calculate GPS SV position/velocity/time from SP3 file. 4194304/0x00400000 = sp_non_existent_error Specular point does not exist. 8388608/0x00800000 = brcs_lut_range_error Unable to index into BRCS uncertainty lookup table. 16777216/0x01000000 = ant_data_lut_range_error Unable to index into antenna data lookup table. 33554432/0x02000000 = bb_framing_error Insufficient black body data for calibration. 67108864/0x04000000 = fsw_comp_shift_error Flight software telemetry encoding error of the fsw_comp_delay_shift and fsw_comp_dopp_shift variables. Corrected in FSW version 4.5. 134217728/0x08000000 = low_quality_gps_ant_knowledge Not enough data is available to properly calibrate the NBRCS for this sample's GPS satellite. 268435456/0x10000000 = sc_altitude_out_of_nominal_range The spacecraft's altitude is out of nominal altitude range. Nominal altitude is defined as between 490 km to 550 km. 536870912/0x20000000 = anomalous_sampling_period Set when an anomaly was observed on the CYGNSS or GPS satellite while this sample was taken. These samples have produced data that do not align with typical CYGNSS results. See up to date list at: https://docs.google.com/spreadsheets/d/1AFAZanVGDApLSnJQAAdPfOKoJQs0jnB8ZvIuD1Z5mAc/edit?usp=sharing 1073741824/0x40000000 = invalid_roll_state The spacecraft\342\200\231s reported roll angle is more than 1 degree from the commanded roll.
quality_flags_2[ sample= 0 ..164111] [ ddm= 0 ..3] (Grid of Int32 values)
  • attributes
    • long_name: Per-DDM quality flags 2
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • _FillValue: -9999
    • valid_range: 0, 1024
    • flag_masks: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512
    • flag_meanings: incorrect_ddmi_antenna_selection high_signal_noise noise_floor_cal_error sp_in_sidelobe negligible_nst_outage minor_nst_outage fatal_nst_outage low_zenith_ant_gain poor_bb_quality poor_quality_bin_ratio
    • comment: Second group of the Per-DDM quality flags. 1 indicates presence of condition. The first group of quality flags can be found in quality_flags. Flag bit masks: 1/0x00000001 = incorrect_ddmi_antenna_selection The wrong (port or starboard) antenna was selected. 2/0x00000002 = high_signal_noise The signal is in the highest noise group, but there are still some OK noise rows. Samples are suspect, but may contain quality data. Flag only used for land applications. 4/0x00000004 = noise_floor_cal_error The signal is off or is very near the top rows of the full DDM. A proper noise floor cannot be computed. Flag only used for land applications. 8/0x00000008 = sp_in_sidelobe The specular point is in the sidelobe causing low confidence in the antenna gain. 16/0x00000010 = negligible_nst_outage Minor star track outage with negligible impact on attitude knowledge 32/0x00000020 = minor_nst_outage Minor star track outage with small but acceptable impact on attitude knowledge 64/0x00000040 = fatal_nst_outage Star track outage with unacceptable impact on attitude knowledge 128/0x00000080 = low_zenith_ant_gain Zenith antenna gain is less than -6 dB 256/0x00000100 = poor_bb_quality The distance between the surrounding BB samples > 1350 seconds OR the absolute value of the time to the nearest BB > 350 seconds. 512/0x00000200 = poor_quality_bin_ratio Bin ratio on the nadir or zenith antenna is associated with degraded performance.
raw_counts[ sample= 0 ..164111] [ ddm= 0 ..3] [ delay= 0 ..16] [ doppler= 0 ..10] (Type is Int32)
  • attributes
    • long_name: DDM bin raw counts
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: 1
    • _FillValue: -9999
    • comment: 17 x 11 array of DDM bin raw counts These are the uncalibrated power values produced by the DDMI.
power_analog[ sample= 0 ..164111] [ ddm= 0 ..3] [ delay= 0 ..16] [ doppler= 0 ..10] (Type is Float32)
  • attributes
    • long_name: DDM bin analog power
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: watt
    • _FillValue: -9999.00000
    • comment: 17 x 11 array of DDM bin analog power, Watts. analog_power is the true power that would have been measured by an ideal (analog) power sensor. power_digital is the power measured by the actual 2-bit sensor, which includes quantization effects. power_analog has been corrected for quantization effects.
brcs[ sample= 0 ..164111] [ ddm= 0 ..3] [ delay= 0 ..16] [ doppler= 0 ..10] (Type is Float32)
  • attributes
    • long_name: DDM bin bistatic radar cross section
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter2
    • _FillValue: -9999.00000
    • comment: 17 x 11 array of DDM bin bistatic radar cross section, m^2. The specular point is located in DDM bin round(brcs_ddm_sp_bin_delay_row), round(brcs_ddm_sp_bin_dopp_col).
eff_scatter[ sample= 0 ..164111] [ ddm= 0 ..3] [ delay= 0 ..16] [ doppler= 0 ..10] (Type is Float32)
  • attributes
    • long_name: DDM bin effective scattering area
    • coordinates: ddm_timestamp_utc sp_lat sp_lon
    • units: meter2
    • _FillValue: -9999.00000
    • comment: 17 x 11 array of DDM bin effective scattering area, m^2. This is an estimate of the true surface scattering area that contributes power to each DDM bin, after accounting for the GPS signal spreading function. It is calculated by convolving the GPS ambiguity function with the surface area that contributes power to a given DDM bin as determined by its delay and Doppler values and the measurement geometry. The specular point bin location matches the specular point bin location in brcs.

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OPeNDAP Hyrax (1.16.8-383)
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