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Description

The CYGNSS Level 1 Calibrated Raw IF Version 1.0 dataset is produced by the CYGNSS Science Team of the University of Michigan, and it contains the first release, Version 1.0, of the CYGNSS Calibrated Raw Intermediate Frequency (IF) based L1 Product. CYGNSS was launched on 15 December 2016, it is a NASA Earth System Science Pathfinder Mission that was launched with the purpose of collecting the first frequent space‐based measurements of surface wind speeds in the inner core of tropical cyclones. Originally made up of a constellation of eight micro-satellites, the observatories provide nearly gap-free Earth coverage using an orbital inclination of approximately 35° from the equator, with a mean (i.e., average) revisit time of seven hours and a median revisit time of three hours.

This product includes several established signal coherence detectors, including the power-ratio P<sub>ratio</sub>, complex zero-Doppler delay waveform and full entropy E<sub>full</sub>, and a novel fast entropy detector E<sub>fast</sub>. Both entropy detectors are provided with two temporal resolutions: 2 ms and 50 ms. Several scattered signal strength products are included: Signal-to-Noise Ratio SNR, reflected power P<sub>g</sub>, reflectivity Γ, and Normalized Bistatic Radar Cross-Section NBRCS. Each of these products is derived using a coherent integration time of T<sub>c </sub>= 1 ms and incoherent integration times of N<sub>inc</sub> = 1000, 500, 250, 100, 50, and 2 ms. Signal strength time series at the shorter (2 and 50 ms) times provides excellent detection of land-water transitions in heterogeneous scenes. Delay Doppler Maps (DDMs) are also generated with high delay (∆τ = 1/16 chip) and Doppler (∆f= 50 Hz) resolution. This suite of coherence detection methods can be used to detect the presence of small inland water bodies.

Product Summary

Platforms
CYGNSS
Instruments
DDMI
Projects
CYGNSS
Spatial Extent

N: 38.15 S: -38.15 E: 180 W: -180

Spatial Resolution
1000 Meters x 1000 Meters
Location
GLOBAL ,
TROPICS
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2018-08-01
Data Partner
Cyclone Global Navigation Satellite System Mission, NASA Earth Science System Pathfinder, University of Michigan (NASA/ESSP/UMICH/CYGNSS) ,
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2927929087-POCLOUD
Data State
ACTIVE
Number of Files/Granules
1463
Processing Level
1
Published
Updated
Science Keywords
SENSOR COUNTS

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

CYGNSS. (2024). CYGNSS Level 1 Calibrated Raw IF Version 1.0 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/CYGNS-L1R10 Date Accessed: 2026-06-06

Documents

USER'S GUIDE

ANOMALIES

GENERAL DOCUMENTATION

PUBLICATIONS

DATA CITATION GUIDELINES

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
sc_lat Subsatellite point latitude, in degrees North, at ddm_timestamp_utc degrees_north float -9999 N/A 1 N/A
sc_lon Subsatellite point longitude, in degrees East, at ddm_timestamp_utc degrees_east float -9999 N/A 1 N/A
sc_pitch Spacecraft pitch angle relative to the orbit frame, in radians at ddm_timestamp_utc radian float -9999 N/A 1 N/A
sc_pitch_att Spacecraft pitch angle relative to the orbit frame, in radians at att_timestamp_utc radian float -9999 N/A 1 N/A
sc_pos_x The X component of the spacecraft WGS84 reference frame Earth-Centered Earth-Fixed (ECEF) position, in meters, at ddm_timestamp_utc meter int -99999999 N/A 1 N/A
sc_pos_x_pvt The X component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc meter int -99999999 N/A 1 N/A
sc_pos_y The Y component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc meter int -99999999 N/A 1 N/A
sc_pos_y_pvt The Y component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc meter int -99999999 N/A 1 N/A
sc_pos_z The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc meter int -99999999 N/A 1 N/A
sc_pos_z_pvt The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc meter int -99999999 N/A 1 N/A
sc_roll Spacecraft roll angle relative to the orbit frame, in radians at ddm_timestamp_utc radian float -9999 N/A 1 N/A
sc_roll_att Spacecraft roll angle relative to the orbit frame, in radians at att_timestamp_utc radian float -9999 N/A 1 N/A
sc_vel_x The X component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc meter s-1 int -9999 N/A 1 N/A
sc_vel_x_pvt The X component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc meter s-1 int -9999 N/A 1 N/A
sc_vel_y The Y component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc meter s-1 int -9999 N/A 1 N/A
sc_vel_y_pvt The Y component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc meter s-1 int -9999 N/A 1 N/A
sc_vel_z The Z component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc meter s-1 int -9999 N/A 1 N/A
sc_vel_z_pvt The Z component of the spacecraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc meter s-1 int -9999 N/A 1 N/A
sc_yaw Spacecraft yaw angle relative to the orbit frame, in radians at ddm_timestamp_utc radian float -9999 N/A 1 N/A
sc_yaw_att Spacecraft yaw angle relative to the orbit frame, in radians at att_timestamp_utc radian float -9999 N/A 1 N/A
spacecraft_id 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 1 short N/A N/A 1 N/A
spacecraft_num 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 1 byte N/A 1 to 99 1 N/A
sp_alt 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. meter float -9999 N/A 1 N/A
sp_az_body 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. degree float -9999 N/A 1 N/A
sp_az_orbit 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. degree float -9999 N/A 1 N/A
sp_calc_method Method used for Specular Point Calcualtion: 0 = Ocean, uses DTU10 for altitude 1 = Land, uses SRTM for altitude N/A byte -99 N/A 1 N/A
sp_code_phase TBD N/A float -9999 N/A 1 N/A
sp_ddmi_delay_correction For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information. 1 float -9999 N/A 1 N/A
sp_ddmi_dopp For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information. s-1 float -9999 N/A 1 N/A
sp_ddmi_dopp_correction For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information. s-1 float -9999 N/A 1 N/A
sp_delay_error For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information. 1 float -9999 N/A 1 N/A
sp_doppler TBD Hz float -9999 N/A 1 N/A
sp_dopp_error For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information. s-1 float -9999 N/A 1 N/A
sp_fsw_delay For diagnostic use only. See UM document 148-0372 CYGNSS L1 netCDF Diagnostic Variables for more information. 1 float -9999 N/A 1 N/A
sp_inc_angle The specular point incidence angle, in degrees, at ddm_timestamp_utc. This is the angle between the line normal to the Earth&#039;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. degree float -9999 N/A 1 N/A
sp_land_confidence Meaning of each confidence value: 0 = Lowest confidence, land SP wrong 1 = Land SP probably wrong, but low SNR is the cause 2 = Land SP probably OK, despite low SNR 3 = Highest confidence, land SP OK N/A byte -99 N/A 1 N/A
sp_land_valid 0 if the specular point calculated in Scott&#039;s correction function is invalid, 1 if it is valid, and fill value if Scott&#039;s specular point correction was not attempted. N/A byte -99 N/A 1 N/A
sp_lat Specular point latitude, in degrees North, at ddm_timestamp_utc degrees_north float -9999 N/A 1 N/A
sp_lat_one_ms Specular point latitude, in degrees North, at ddm_timestamp_utc degrees_north float -9999 N/A 1 N/A
sp_lon Specular point longitude, in degrees East, at ddm_timestamp_utc degrees_east float -9999 N/A 1 N/A
sp_lon_one_ms Specular point longitude, in degrees East, at ddm_timestamp_utc degrees_east float -9999 N/A 1 N/A
sp_pos_x The X component of the specular point position in the ECEF coordinate system, in meters, at ddm_timestamp_utc, as calculated on the ground. meter int -99999999 N/A 1 N/A
sp_pos_y The Y component of the specular point position in the ECEF coordinate system, in meters, at ddm_timestamp_utc, as calculated on the ground. meter int -99999999 N/A 1 N/A
sp_pos_z The Z component of the specular point position in the ECEF coordinate system, in meters, at ddm_timestamp_utc, as calculated on the ground. meter int -99999999 N/A 1 N/A
sp_rx_gain The receive antenna gain in the direction of the specular point, in dBi, at ddm_timestamp_utc. dBi float -9999 N/A 1 N/A
sp_theta_body 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. degree float -9999 N/A 1 N/A
sp_theta_orbit 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. degree float -9999 N/A 1 N/A
sp_vel_x 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. meter s-1 int -9999 N/A 1 N/A
sp_vel_y 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. meter s-1 int -9999 N/A 1 N/A
sp_vel_z 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. meter s-1 int -9999 N/A 1 N/A
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