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Description

The Rongowai Level 1 Science Data Record Version 1.0 dataset is generated by the University of Auckland (UoA) Rongowai Science Payloads Operations Centre in New Zealand. This initiative is supported by NASA and the New Zealand Space Agency. The data collection process is conducted using the Next-generation receiver (NgRx) mounted on the Air New Zealand domestic aircraft Q300.

This Level 1 (L1) dataset contains the Version 1.0 geo-located Delay Doppler Maps (DDMs) calibrated into Power Received (Watts) and Bistatic Radar Cross Section (BRCS) expressed in units of meters squared from the Delay Doppler Mapping Instrument onboard an Air New Zealand domestic Q300 (tail number ZK-NFA). 20 DDMs are contained within a typical L1 netcdf corresponding to 10 Left-Hand-Circularly Polarized (LHCP) and 10 Right-Hand-Circularly Polarized (RHCP) channels. Other useful scientific and engineering measurement parameters include the co- and cross-polarized Normalized Bistatic Radar Cross Section (NBRCS) of the specular point, the Leading Edge Slope (LES) of the integrated delay waveform and the normalized waveforms. The L1 dataset contains a number of other engineering and science measurement parameters, including coherence detection and a coherence state metric, sets of quality flags/indicators, error estimates, Fresnel-zone geometry estimates (and thereby the estimated per-sample spatial resolution) as well as a variety of timekeeping, and geolocation parameters.

Each netCDF data files corresponds to a single flight between airports within New Zealand (flight durations typically range between 45 min and 1hr 30min with a median of 7 flights/day) and measurements are reported at 1 second increments. Latency is approximately 1 days (or better) from the last recorded measurement time.

Product Summary

Platforms
Airplane
Instruments
DDMI
Projects
CYGNSS
Spatial Extent

N: -34 S: -47 E: 179 W: 165

Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
2022-10-20
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C2784494745-POCLOUD
Data State
ACTIVE
Number of Files/Granules
7354
Processing Level
1
Science Keywords
WIND VELOCITY/SPEED

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

Rongowai Science Payloads Operations Centre. (2023). Rongowai Level 1 Science Data Record Version 1.0 [Dataset]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/RGOWA-S1A10 Date Accessed: 2026-06-05

Documents

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
gps_ant_gain_db_i SV antenna gain in the direction of the Specular point dBi float N/A N/A 1 N/A
gps_off_boresight_angle_deg SV antenna off boresight angle in the direction of the Specular point degree float N/A N/A 1 N/A
gps_tx_power_db_w Power input to SV Tx antenna dbW float N/A N/A 1 N/A
inst_gain The open-ocean counts divided by the sum of the open-ocean power and the predicted instrument noise power, in count/W, at ddm_timestamp_utc. N/A float N/A N/A 1 N/A
L1a_power_calibration_flag The confidence flag to perform L1a calibration from counts to watts: 0 = high confidence, 1 = low confidence in the L1a power calibration. High confidence when DDM samples using dynamic gain correction <= 65 dB to perform L1a calibration. Note that high gain corrections primarily occur during aircraft ascent, descent or manoeuvres rather than straight and level flight and thus are flagged. N/A float N/A N/A 1 N/A
L1a_power_ddm 5 x 40 array of DDM bin power, Watts. watt float N/A N/A 1 N/A
L1a_xpol_calibration_flag The confidence to compensate the L1a calibrated power. 0 = high confidence, 1 = low confident in the L1a cross-pol calibration High confidence when 1) off-boresight angle <= 60 deg and 2) x-pol ratio > 14 dB N/A float N/A N/A 1 N/A
lna_noise_figure The LNA noise figure, in dB, at ddm_timestamp_utc. Estimated from pre-launch characterization of LNA performance as a function of LNA temperature. Default value = 3 for early stage L1 product. dB float N/A N/A 1 N/A
LOS_flag Indicate the line-of-sight status between the tracked satellite and NGRx. 0 = LOS does not exist 1 = LOS exists N/A float N/A N/A 1 N/A
nbrcs_cross_pol_v1 For SP bin, cross polarization ratio of the LHCP NBRCS to RHCP NBRCS. db float N/A N/A 1 N/A
nbrcs_scatter_area_v1 For SP bin, the scattering area of the ddm region used to calculate ddm_nbrcs. meter2 float N/A N/A 1 N/A
norm_refl_waveform Normalized GNSS reflected waveform. N/A float N/A N/A 1 N/A
prn_code 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. PRN = 28 is the unhealthy GPS PRN. N/A ubyte N/A N/A 1 N/A
pvt_timestamp_gps_sec The GPS second of week of pvt_timestamp_utc with nanosecond resolution. second double N/A N/A 1 N/A
pvt_timestamp_gps_week The GPS week number of pvt_timestamp_utc week ushort N/A N/A 1 N/A
pvt_timestamp_utc The aircraft 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 NGRx. This is also the timestamp of the most recent GPS pulse per second. second double N/A N/A 1 N/A
quality_flags1 First group of the Per-DDM quality flags. 1 indicates presence of condition. Flag bit mask details refer to ATBD. <none> uint N/A N/A 1 N/A
raw_counts 5 x 40 array of DDM bin raw counts multiplies the first scale factor. These are the uncalibrated power values produced by the NGRx. N/A uint N/A N/A 1 N/A
rx_clk_bias The receiver clock bias (in seconds) multiplied by the speed of light as reported by the NGRx, interpolated to ddm_timestamp_utc, in meters. meter float N/A N/A 1 N/A
rx_clk_bias_pvt The receiver clock bias (in seconds) multiplied by the speed of light as reported by the NGRx at pvt_timestamp_utc, in meters. meter float N/A N/A 1 N/A
rx_clk_drift The receiver clock bias rate (in seconds/second) multiplied by the speed of light as reported by the NGRx, interpolated to ddm_timestamp_utc, in m/s. meter s-1 float N/A N/A 1 N/A
rx_clk_drift_pvt The receiver clock bias rate (in seconds/second) multiplied by the speed of light as reported by the NGRx, at pvt_timestamp_utc, in m/s. meter s-1 float N/A N/A 1 N/A
rx_to_sp_range The distance between the aircraft and the Specular point, in meters, at ddm_timestamp_utc. meter double N/A N/A 1 N/A
sample 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. N/A ushort N/A N/A 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 N/A N/A 1 N/A
sp_az_body Let line A be the line that extends from the aircraft to the specular point, at ddm_timestamp_utc. Let line B be the projection of line A onto the aircraft 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. degree float N/A N/A 1 N/A
sp_az_enu Let line A be the line that extends from the aircraft to the specular point at ddm_timestamp_utc. Let line B be the projection of line A onto the receiver ENU frame East-North plane. sp_az_enu is the angle between the +E axis (the East vector) and line B, in degrees, at ddm_timestamp_utc. degree float N/A N/A 1 N/A
sp_delay_error For diagnostic use only. See UoA document XXX-XXXX Rongowai L1 netCDF Diagnostic Variables for more information. N/A float N/A N/A 1 N/A
sp_dist_to_coast_km Distance from the norminal specular point to the nearest coastline, in kilometers. Positive value represents the SP locates on land. Negative value represents the SP locates on ocean. kilometer float N/A N/A 1 N/A
sp_dopp_error For diagnostic use only. See UoA document XXX-XXXX Rongowai L1 netCDF Diagnostic Variables for more information. s-1 float N/A N/A 1 N/A
sp_d_snell_angle The Snell angle along both az and el for both incidence and scattering directions degree float N/A N/A 1 N/A
sp_fsw_delay For diagnostic use only. See UoA document XXX-XXXX Rongowai L1 netCDF Diagnostic Variables for more information. N/A float N/A 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's surface at the specular point and the line extending from the specular point to the aircraft. degree float N/A N/A 1 N/A
sp_lat Specular point latitude, in degrees North, at ddm_timestamp_utc degrees_north double N/A N/A 1 N/A
sp_lon Specular point body frame azimuth angle degrees_east double N/A N/A 1 N/A
sp_ngrx_delay_correction For diagnostic use only. See UoA document XXX-XXXX Rongowai L1 netCDF Diagnostic Variables for more information. N/A float N/A N/A 1 N/A
sp_ngrx_dopp For diagnostic use only. See UoA document XXX-XXXX Rongowai L1 netCDF Diagnostic Variables for more information. s-1 float N/A N/A 1 N/A
sp_ngrx_dopp_correction For diagnostic use only. See UoA document XXX-XXXX Rongowai L1 netCDF Diagnostic Variables for more information. s-1 float N/A 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. Fill value is -99999999. meter double N/A 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. Fill value is -99999999. meter double N/A 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. Fill value is -99999999. meter double N/A N/A 1 N/A
sp_rx_gain_copol The co-pol active receive antenna gain in the direction of the Specular point, in dBi, at ddm_timestamp_utc. dBi float N/A N/A 1 N/A
sp_rx_gain_xpol The cross-pol active receive antenna gain in the direction of the Specular point, in dBi, at ddm_timestamp_utc. dBi float N/A N/A 1 N/A
sp_surface_type Surface type of the specular point, surface type from the latest LINZ database, where -1 = ocean, 1 = artifical, 2 = barely vegetated, 3 = inland water, 4 = crop, 5 = grass, 6 = shrub, 7 = forest N/A float N/A N/A 1 N/A
sp_theta_body The angle between the aircraft body frame +Z axis and the line extending from the spacecraft to the specular point, in degrees, at ddm_timestamp_utc. degree float N/A N/A 1 N/A
sp_theta_enu The angle between the aircraft body reference frame +up axis and the line extending from the aircraft to the specular point, in degrees, at ddm_timestamp_utc. degree float N/A 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 double N/A 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 double N/A 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 double N/A N/A 1 N/A
static_gps_eirp 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. watt float N/A N/A 1 N/A
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