sample[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Sample index
(Type is String)
-
units:
1
(Type is String)
-
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.
(Type is String)
ddm[
/ddm=
0..3]
(Type is Int16)
-
attributes
-
long_name:
DDM reflectometry channel
(Type is String)
-
units:
1
(Type is String)
-
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.
(Type is String)
spacecraft_id(Type is Int16)
-
attributes
-
long_name:
CCSDS spacecraft identifier
(Type is String)
-
units:
1
(Type is String)
-
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
(Type is String)
spacecraft_num(Type is Int16)
-
attributes
-
long_name:
CYGNSS spacecraft number
(Type is String)
-
units:
1
(Type is String)
-
valid_min:
1
(Type is Int32)
-
valid_max:
99
(Type is Int32)
-
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
(Type is String)
ddm_source(Type is Int16)
-
attributes
-
long_name:
Level 0 data source
(Type is String)
-
valid_range:
0, 3
(Type is Int16)
-
flag_values:
0, 1, 2, 3
(Type is Int16)
-
flag_meanings:
e2es gpss ddmi unknown
(Type is String)
-
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
(Type is String)
ddm_time_type_selector(Type is Int16)
-
attributes
-
long_name:
DDM sample time type selector
(Type is String)
-
valid_range:
0, 3
(Type is Int16)
-
flag_values:
0, 1, 2, 3
(Type is Int16)
-
flag_meanings:
start middle end pvt
(Type is String)
-
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)
(Type is String)
delay_resolution(Type is Float32)
-
attributes
-
long_name:
DDM delay bin resolution
(Type is String)
-
units:
1
(Type is String)
-
comment:
DDM delay bin resolution in chips. One chip is equal to 1/1,023,000 seconds.
(Type is String)
dopp_resolution(Type is Float32)
-
attributes
-
long_name:
DDM Doppler bin resolution
(Type is String)
-
units:
s-1
(Type is String)
-
comment:
DDM Doppler bin resolution in Hz
(Type is String)
ddm_timestamp_utc[
/sample=
0..172634]
(Type is Float64)
-
attributes
-
long_name:
DDM sample timestamp - UTC
(Type is String)
-
standard_name:
time
(Type is String)
-
calendar:
gregorian
(Type is String)
-
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.
(Type is String)
-
units:
seconds since 2023-11-05 00:00:00.499261756
(Type is String)
ddm_timestamp_gps_week[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
DDM sample timestamp - GPS Week
(Type is String)
-
units:
week
(Type is String)
-
comment:
The GPS week number of ddm_timestamp_utc
(Type is String)
ddm_timestamp_gps_sec[
/sample=
0..172634]
(Type is Float64)
-
attributes
-
long_name:
DDM sample timestamp - GPS Seconds
(Type is String)
-
units:
second
(Type is String)
-
comment:
The GPS second of week of ddm_timestamp_utc, with nanosecond resolution
(Type is String)
pvt_timestamp_utc[
/sample=
0..172634]
(Type is Float64)
-
attributes
-
long_name:
PVT timestamp - UTC
(Type is String)
-
standard_name:
time
(Type is String)
-
calendar:
gregorian
(Type is String)
-
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.
(Type is String)
-
units:
seconds since 2023-11-05 00:00:00.499261756
(Type is String)
pvt_timestamp_gps_week[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
PVT timestamp - GPS Week
(Type is String)
-
units:
week
(Type is String)
-
comment:
The GPS week number of pvt_timestamp_utc
(Type is String)
pvt_timestamp_gps_sec[
/sample=
0..172634]
(Type is Float64)
-
attributes
-
long_name:
PVT timestamp - GPS Seconds
(Type is String)
-
units:
second
(Type is String)
-
comment:
The GPS second of week of pvt_timestamp_utc, with nanosecond resolution.
(Type is String)
att_timestamp_utc[
/sample=
0..172634]
(Type is Float64)
-
attributes
-
long_name:
Attitude timestamp - UTC
(Type is String)
-
standard_name:
time
(Type is String)
-
calendar:
gregorian
(Type is String)
-
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.
(Type is String)
-
units:
seconds since 2023-11-05 00:00:00.499261756
(Type is String)
att_timestamp_gps_week[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Attitude timestamp - GPS Week
(Type is String)
-
units:
week
(Type is String)
-
comment:
The GPS week number of att_timestamp_utc
(Type is String)
att_timestamp_gps_sec[
/sample=
0..172634]
(Type is Float64)
-
attributes
-
long_name:
Attitude timestamp - GPS Seconds
(Type is String)
-
units:
second
(Type is String)
-
comment:
The GPS second of week of att_timestamp_utc, with nanosecond resolution
(Type is String)
sc_pos_x[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft position X at DDM sample time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The X component of the spacecraft WGS84 reference frame Earth-Centered Earth-Fixed (ECEF) position, in meters, at ddm_timestamp_utc
(Type is String)
sc_pos_y[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft position Y at DDM sample time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The Y component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
(Type is String)
sc_pos_z[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft position Z at DDM sample time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
(Type is String)
sc_vel_x[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft velocity X at DDM sample time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The X component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc
(Type is String)
sc_vel_y[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft velocity Y at DDM sample time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The Y component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc
(Type is String)
sc_vel_z[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft velocity Z at DDM sample time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The Z component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc
(Type is String)
sc_pos_x_pvt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft position X at PVT time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The X component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc
(Type is String)
sc_pos_y_pvt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft position Y at PVT time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The Y component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc
(Type is String)
sc_pos_z_pvt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft position Z at PVT time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc
(Type is String)
sc_vel_x_pvt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft velocity X at PVT time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The X component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc
(Type is String)
sc_vel_y_pvt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft velocity Y at PVT time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The Y component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc
(Type is String)
sc_vel_z_pvt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft velocity Z at PVT time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The Z component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc
(Type is String)
nst_att_status[
/sample=
0..172634]
(Type is Int16)
-
attributes
-
long_name:
NST attitude status
(Type is String)
-
_FillValue:
-99
(Type is Int16)
-
valid_range:
0, 22
(Type is Int16)
-
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
(Type is Int16)
-
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
(Type is String)
-
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
(Type is String)
sc_roll[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Spacecraft attitude roll angle at DDM sample time
(Type is String)
-
units:
radian
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Spacecraft roll angle relative to the orbit frame, in radians at ddm_timestamp_utc
(Type is String)
sc_pitch[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Spacecraft attitude pitch angle at DDM sample time
(Type is String)
-
units:
radian
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Spacecraft pitch angle relative to the orbit frame, in radians at ddm_timestamp_utc
(Type is String)
sc_yaw[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Spacecraft attitude yaw angle at DDM sample time
(Type is String)
-
units:
radian
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Spacecraft yaw angle relative to the orbit frame, in radians at ddm_timestamp_utc
(Type is String)
sc_roll_att[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Spacecraft attitude roll angle at attitude time
(Type is String)
-
units:
radian
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Spacecraft roll angle relative to the orbit frame, in radians at att_timestamp_utc
(Type is String)
sc_pitch_att[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Spacecraft attitude pitch angle at attitude time
(Type is String)
-
units:
radian
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Spacecraft pitch angle relative to the orbit frame, in radians at att_timestamp_utc
(Type is String)
sc_yaw_att[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Spacecraft attitude yaw angle at attitude time
(Type is String)
-
units:
radian
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Spacecraft yaw angle relative to the orbit frame, in radians at att_timestamp_utc
(Type is String)
sc_lat[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Sub-satellite point latitude
(Type is String)
-
standard_name:
latitude
(Type is String)
-
units:
degrees_north
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Subsatellite point latitude, in degrees North, at ddm_timestamp_utc
(Type is String)
sc_lon[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Sub-satellite point longitude
(Type is String)
-
standard_name:
longitude
(Type is String)
-
units:
degrees_east
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Subsatellite point longitude, in degrees East, at ddm_timestamp_utc
(Type is String)
sc_alt[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
Spacecraft altitude
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
Spacecraft altitude above WGS-84 ellipsoid, in meters, at ddm_timestamp_utc
(Type is String)
zenith_sun_angle_az[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Zenith antenna boresight Sun angle, azimuth
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The azimuth angle of the Sun in the zenith antenna spherical frame, at ddm_timestamp_utc, 0 <= angle < 360 degrees. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
(Type is String)
zenith_sun_angle_decl[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Zenith antenna boresight Sun angle, declination
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The declination angle of the Sun in the zenith antenna spherical frame, at ddm_timestamp_utc, 0 <= angle < 180 degrees. See UM Doc. 148-0336, CYGNSS Science Data Processing Coordinate Systems Definitions.
(Type is String)
zenith_ant_bore_dir_x[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Zenith antenna boresight ECI direction, X
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The X component of the Earth-Centered Inertial (ECI) direction unit vector of the zenith antenna boresight at ddm_timestamp_utc
(Type is String)
zenith_ant_bore_dir_y[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Zenith antenna boresight ECI direction, Y
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The Y component of the ECI direction unit vector of the zenith antenna boresight at ddm_timestamp_utc
(Type is String)
zenith_ant_bore_dir_z[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Zenith antenna boresight ECI direction, Z
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The Z component of the ECI direction unit vector of the zenith antenna boresight at ddm_timestamp_utc
(Type is String)
rx_clk_bias[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
GPS receiver clock bias
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
rx_clk_bias_rate[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
GPS receiver clock bias rate
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
rx_clk_bias_pvt[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
GPS receiver clock bias at PVT time
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The receiver clock bias (in seconds) multiplied by the speed of light as reported by the DDMI at pvt_timestamp_utc, in meters.
(Type is String)
rx_clk_bias_rate_pvt[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
GPS receiver clock bias rate at PVT time
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
lna_temp_nadir_starboard[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Starboard antenna LNA temperature
(Type is String)
-
units:
degree_Celsius
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The temperature of the starboard antenna low noise amplifier at ddm_timestamp_utc, in degrees C.
(Type is String)
lna_temp_nadir_port[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Port Antenna LNA temperature
(Type is String)
-
units:
degree_Celsius
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The temperature of the port antenna low noise amplifier at ddm_timestamp_utc, in degrees C.
(Type is String)
lna_temp_zenith[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Zenith Antenna LNA temperature
(Type is String)
-
units:
degree_Celsius
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The temperature of the zenith antenna low noise amplifier at ddm_timestamp_utc, in degrees C.
(Type is String)
ddm_end_time_offset[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
DDM end time offset
(Type is String)
-
units:
1e-9 s
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
bit_ratio_hi_lo_starboard[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Starboard high/low bit counter ratio
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
bit_ratio_hi_lo_port[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Port high/low bit counter ratio
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
bit_null_offset_starboard[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Starboard bit count null offset
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
bit_null_offset_port[
/sample=
0..172634]
(Type is Float32)
-
attributes
-
long_name:
Port bit count null offset
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
status_flags_one_hz[
/sample=
0..172634]
(Type is Int32)
-
attributes
-
long_name:
1 Hz Status Flags
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
valid_range:
0, 15
(Type is Int32)
-
flag_masks:
1, 2, 4, 8
(Type is Int32)
-
flag_meanings:
milky_way_in_zenith_field_of_view sun_in_zenith_field_of_view sub_sat_pt_over_open_oceansub_sat_pt_lat_ascending
(Type is String)
-
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
(Type is String)
prn_code[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int16)
-
attributes
-
long_name:
GPS PRN code
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-99
(Type is Int16)
-
valid_min:
0
(Type is Int32)
-
valid_max:
32
(Type is Int32)
-
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.
(Type is String)
sv_num[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Space Vehicle Number
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The GPS unique space vehicle number that transmitted prn_code.
(Type is String)
track_id[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
DDM Track ID
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
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.
(Type is String)
ddm_ant[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int16)
-
attributes
-
long_name:
DDM Antenna
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
_FillValue:
-99
(Type is Int16)
-
valid_range:
0, 3
(Type is Int16)
-
flag_values:
0, 1, 2, 3
(Type is Int16)
-
flag_meanings:
none zenith nadir_starboard nadir_port
(Type is String)
-
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
(Type is String)
zenith_code_phase[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Zenith signal code phase
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_ddmi_delay_correction[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Correction to DDMI specular point delay
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
sp_ddmi_dopp_correction[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Correction to DDMI specular point Doppler
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
s-1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
add_range_to_sp[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Additional range to specular point at DDM sample time
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
add_range_to_sp_pvt[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Additional range to specular point at PVT time
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
sp_ddmi_dopp[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
DDMI Doppler at specular point
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
s-1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
sp_fsw_delay[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Flight software specular point delay
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
sp_delay_error[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Flight software specular point delay error
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
sp_dopp_error[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Flight software specular point Doppler error
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
s-1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
fsw_comp_delay_shift[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Flight software DDM compression delay shift
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
fsw_comp_dopp_shift[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Flight software DDM compression Doppler shift
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
s-1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information.
(Type is String)
prn_fig_of_merit[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int16)
-
attributes
-
long_name:
PRN selection figure of Merit
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-99
(Type is Int16)
-
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.
(Type is String)
tx_clk_bias[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
GPS transmitter clock bias
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The GPS spacecraft (sv_num) clock time minus GPS constellation time (in seconds) times the speed of light, in meters.
(Type is String)
sp_lat[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point latitude
(Type is String)
-
standard_name:
latitude
(Type is String)
-
units:
degrees_north
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Specular point latitude, in degrees North, at ddm_timestamp_utc
(Type is String)
sp_lon[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point longitude
(Type is String)
-
standard_name:
longitude
(Type is String)
-
units:
degrees_east
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Specular point longitude, in degrees East, at ddm_timestamp_utc
(Type is String)
sp_alt[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point altitude
(Type is String)
-
standard_name:
altitude
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_pos_x[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Specular point position X
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
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.
(Type is String)
sp_pos_y[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Specular point position Y
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
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.
(Type is String)
sp_pos_z[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Specular point position Z
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
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.
(Type is String)
sp_vel_x[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Specular point velocity X
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
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.
(Type is String)
sp_vel_y[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Specular point velocity Y
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
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.
(Type is String)
sp_vel_z[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Specular point velocity Z
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
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.
(Type is String)
sp_inc_angle[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point incidence angle
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_theta_orbit[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point orbit frame theta angle
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_az_orbit[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point orbit frame azimuth angle
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_theta_body[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point body frame theta angle
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_az_body[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point body frame azimuth angle
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
sp_rx_gain[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Specular point Rx antenna gain
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
dBi
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The receive antenna gain in the direction of the specular point, in dBi, at ddm_timestamp_utc.
(Type is String)
gps_eirp[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
GPS effective isotropic radiated power
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
watt
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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 CYGNSS spacecraft, in Watts, at ddm_timestamp_utc.
(Type is String)
gps_tx_power_db_w[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
GPS SV transmit power
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
dBW
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
GPS Tx power in dBW
(Type is String)
gps_ant_gain_db_i[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
GPS SV transmit antenna gain
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
dBi
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
SV antenna gain in the direction of the specular point
(Type is String)
gps_off_boresight_angle_deg[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
GPS off boresight angle
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
degree
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
SV antenna off boresight angle in the direction of the specular point
(Type is String)
direct_signal_snr[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Zenith (direct) signal to noise ratio
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
dB
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
10log(zenith signal power/zenith signal noise) in dB, at ddm_timestamp_utc.
(Type is String)
ddm_snr[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
DDM signal to noise ratio
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
dB
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
ddm_noise_floor[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
DDM noise floor
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
inst_gain[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Instrument gain
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
lna_noise_figure[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
LNA noise figure
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
dB
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
rx_to_sp_range[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Rx to specular point range
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The distance between the CYGNSS spacecraft and the specular point, in meters, at ddm_timestamp_utc.
(Type is String)
tx_to_sp_range[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Tx to specular point range
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The distance between the GPS satellite and the specular point, in meters, at ddm_timestamp_utc.
(Type is String)
tx_pos_x[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Tx position X
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The X component of the GPS spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
(Type is String)
tx_pos_y[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Tx position Y
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The Y component of the GPS spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
(Type is String)
tx_pos_z[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Tx position Z
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter
(Type is String)
-
_FillValue:
-99999999
(Type is Int32)
-
comment:
The Z component of the GPS spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc
(Type is String)
tx_vel_x[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Tx velocity X
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The X component of the GPS spacecraft WGS84 reference frame ECEF velocity in meters, at ddm_timestamp_utc
(Type is String)
tx_vel_y[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Tx velocity Y
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The Y component of the GPS spacecraft WGS84 reference frame ECEF velocity in meters, at ddm_timestamp_utc
(Type is String)
tx_vel_z[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
GPS Tx velocity Z
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter s-1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
The Z component of the GPS spacecraft WGS84 reference frame ECEF velocity in meters, at ddm_timestamp_utc
(Type is String)
bb_nearest[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Time to most recent black body reading
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
second
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
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.
(Type is String)
radiometric_antenna_temp[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Antenna Temperature (TA) at specular point
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
K
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The top-of-atmosphere radiometric brightness temperature of the Earth at 1575 MHz and left hand circular polarization, averaged over the nadir antenna pattern in which the specular point lies, in Kelvins.
(Type is String)
fresnel_coeff[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Fresnel power reflection coefficient at specular point
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
ddm_nbrcs[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Normalized BRCS
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
ddm_les[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
Leading edge slope
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
nbrcs_scatter_area[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
NBRCS scattering area
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter2
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The scattering area of the 3 x 5 region of the ddm used to calculate ddm_nbrcs.
(Type is String)
les_scatter_area[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
LES scattering area
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter2
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
The scattering area of the 3 x 5 region of the ddm used to calculate ddm_les.
(Type is String)
brcs_ddm_peak_bin_delay_row[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int16)
-
attributes
-
long_name:
BRCS DDM peak bin delay row
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-99
(Type is Int16)
-
comment:
The zero-based delay row of the peak value in the bistatic radar cross section DDM (brcs). Ranges from 0 to 16.
(Type is String)
brcs_ddm_peak_bin_dopp_col[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int16)
-
attributes
-
long_name:
BRCS DDM peak bin Doppler column
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-99
(Type is Int16)
-
comment:
The zero-based Doppler column of the peak value in the bistatic radar cross section DDM (brcs). Ranges from 0 to 10.
(Type is String)
brcs_ddm_sp_bin_delay_row[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
BRCS DDM specular point bin delay row
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
brcs_ddm_sp_bin_dopp_col[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
BRCS DDM specular point bin Doppler column
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
ddm_brcs_uncert[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Float32)
-
attributes
-
long_name:
DDM BRCS uncertainty
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
Uncertainty of the BRCS
(Type is String)
quality_flags[
/sample=
0..172634]
[
/ddm=
0..3]
(Type is Int32)
-
attributes
-
long_name:
Per-DDM quality flags
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
valid_range:
0, 536870911
(Type is Int32)
-
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
(Type is Int32)
-
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
(Type is String)
-
comment:
Per-DDM quality flags. 1 indicates presence of condition. Flag bit masks:
1/0x00000001 = poor_overall_quality. The logical OR of:
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
sc_altitude_out_of_nominal_range
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.
2048/0x00000800 = sp_very_near_land
Set if the specular point is within 25 km of land.
4096/0x00001000 = sp_near_land
Set if the specular point is within 50 km of land.
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
The directional gain pattern of the GPS transmit antenna, and hence the value of its gain in the direction of the specular point, is less well known for some GPS satellites than others. This flag indicates that Level 1 calibration was based on a GPS antenna gain value with a higher than normal uncertainty. The impact on retrieved wind speed values is typically less than 1 m/s, so this is considered a non-fatal flag.
268435456/0x10000000 = sc_altitude_out_of_nominal_range
The spacecraft's altitude is out of nominal altitude range. Nominal altitude is defined as between 450 km to 550 km.
(Type is String)
raw_counts[
/sample=
0..172634]
[
/ddm=
0..3]
[
/delay=
0..16]
[
/doppler=
0..10]
(Type is Int32)
-
attributes
-
long_name:
DDM bin raw counts
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
1
(Type is String)
-
_FillValue:
-9999
(Type is Int32)
-
comment:
17 x 11 array of DDM bin raw counts These are the uncalibrated power values produced by the DDMI.
(Type is String)
power_digital[
/sample=
0..172634]
[
/ddm=
0..3]
[
/delay=
0..16]
[
/doppler=
0..10]
(Type is Float32)
-
attributes
-
long_name:
DDM bin digital power
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
watt
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
comment:
17 x 11 array of DDM bin digital power, Watts. See power_analog for more information.
(Type is String)
power_analog[
/sample=
0..172634]
[
/ddm=
0..3]
[
/delay=
0..16]
[
/doppler=
0..10]
(Type is Float32)
-
attributes
-
long_name:
DDM bin analog power
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
watt
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
brcs[
/sample=
0..172634]
[
/ddm=
0..3]
[
/delay=
0..16]
[
/doppler=
0..10]
(Type is Float32)
-
attributes
-
long_name:
DDM bin bistatic radar cross section
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter2
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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).
(Type is String)
eff_scatter[
/sample=
0..172634]
[
/ddm=
0..3]
[
/delay=
0..16]
[
/doppler=
0..10]
(Type is Float32)
-
attributes
-
long_name:
DDM bin effective scattering area
(Type is String)
-
coordinates:
ddm_timestamp_utc sp_lat sp_lon
(Type is String)
-
units:
meter2
(Type is String)
-
_FillValue:
-9999.00000
(Type is Float32)
-
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.
(Type is String)
