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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.<br><br>

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
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
6417
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 [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/RGOWA-S1A10 Date Accessed: 2025-12-14

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
ac_alt Aircraft altitude above WGS-84 ellipsoid, in meters, at ddm_timestamp_utc meter float N/A N/A 1
ac_heading Aircraft heading angle relative to the North, in radians at ddm_timestamp_utc radian float N/A N/A 1
ac_heading_pvt Aircraft heading angle relative to North, in radians at pvt_timestamp_utc radian float N/A N/A 1
ac_lat Aircraft latitude, in degrees North, at ddm_timestamp_utc degrees_north double N/A N/A 1
ac_lon Aircraft longitude, in degrees East, at ddm_timestamp_utc degrees_east double N/A N/A 1
ac_pitch Aircraft pitch angle relative to the aircraft body frame, in radians at ddm_timestamp_utc radian float N/A N/A 1
ac_pitch_pvt Aircraft pitch angle relative to the aircraft body frame, in radians at pvt_timestamp_utc radian float N/A N/A 1
ac_pos_x The X component of the aircraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc. Fill value is -99999999. meter double N/A N/A 1
ac_pos_x_pvt The X component of the aircraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc. Fill value is -99999999. meter double N/A N/A 1
ac_pos_y The Y component of the aircraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc. Fill value is -99999999. meter double N/A N/A 1
ac_pos_y_pvt The Y component of the aircraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc. Fill value is -99999999. meter double N/A N/A 1
ac_pos_z The Z component of the spacecraft WGS84 reference frame ECEF position, in meters, at ddm_timestamp_utc. Fill value is -99999999. meter double N/A N/A 1
ac_pos_z_pvt The Z component of the aircraft WGS84 reference frame ECEF position, in meters, at pvt_timestamp_utc. Fill value is -99999999. meter double N/A N/A 1
ac_roll Aircraft roll angle relative to the aircraft body frame, in radians at ddm_timestamp_utc radian float N/A N/A 1
ac_roll_pvt Aircraft roll angle relative to the aircraft body frame, in radians at pvt_timestamp_utc radian float N/A N/A 1
ac_vel_x The X component of the aircraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc meter s-1 double N/A N/A 1
ac_vel_x_pvt The X component of the aircraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc meter s-1 double N/A N/A 1
ac_vel_y The Y component of the aircraft WGS84 reference frame ECEF velocity, in m/s, at ddm_timestamp_utc meter s-1 double N/A N/A 1
ac_vel_y_pvt The Y component of the aircraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc meter s-1 double N/A N/A 1
ac_vel_z The Z component of the aircraft WGS84 reference frame ECEF velocity , in m/s, at ddm_timestamp_utc. meter s-1 double N/A N/A 1
ac_vel_z_pvt The Z component of the aircraft WGS84 reference frame ECEF velocity, in m/s, at pvt_timestamp_utc meter s-1 double N/A N/A 1
add_range_to_sp 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
add_range_to_sp_pvt 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
ant_temp_nadir The temperature of the LHCP antenna LNA at ddm_timestamp_utc, in degrees C. degree_Celsius short N/A N/A 1
ant_temp_zenith The temperature of the zenith antenna LNA at ddm_timestamp_utc, in degrees C. degree_Celsius short N/A N/A 1
brcs 5 x 40 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 ). meter2 float N/A N/A 1
brcs_ddm_peak_bin_delay_row The zero-based delay row of the peak value in the bistatic radar cross section DDM (brcs). Ranges from 0 to 16. N/A ubyte N/A N/A 1
brcs_ddm_peak_bin_dopp_col The zero-based Doppler column of the peak value in the bistatic radar cross section DDM (brcs). Ranges from 0 to 10. N/A ubyte N/A N/A 1
brcs_ddm_sp_bin_delay_row The zero-based delay row of the specular point delay in the bistatic radar cross section DDM (brcs). N/A float N/A N/A 1
brcs_ddm_sp_bin_dopp_col The zero-based Doppler column of the specular point Doppler in the bistatic radar cross section DDM (brcs). N/A float N/A N/A 1
coherence_metric Root mean square deviation between the power-delay curve of the DDM and the ambiguity function. N/A float N/A N/A 1
coherence_state A value to indicate the degree of coherence 1: With high confidence, state is dominantly coherent 2: State is likely coherent 3: State is likely mixed/weakly diffuse 4: With high confidence, state is dominantly incoherent 5: Uncertain coherence state N/A ubyte N/A N/A 1
coh_int Coherent integration time in seconds s-1 float N/A N/A 1
ddm The netCDF coordinate variable associated with variables that are dimensioned by the 20 NGRx reflectometry channels. It enumerates the zero-justified index range of DDM reflectometry channels. Ranges from 0 to 19. N/A ubyte N/A N/A 1
ddm_ant The antenna that received the reflected GPS signal associated with the DDM. 0 = none 1 = zenith (never used) 2 = nadir_LHCP 3 = nadir_RHCP &lt;none&gt; ubyte N/A N/A 1
ddm_nbrcs_v1 For SP bin, normalized BRCS of the specular point bin. N/A float N/A N/A 1
ddm_noise_floor Noise floor of the DDM, in counts, defined as the median of the average value of the upper-most 5 delay rows from all the LHCP or RHCP DDMs that meet the critera occurred over the surface during the entire flight. The criteria is, the predicted SP of the DDM should be at least 10 delay rows away from the DDM top (i.e., row 39). counts float N/A N/A 1
ddm_pvt_bias The bias in seconds between DDM and PVT timestamps seconds double N/A N/A 1
ddm_snr 10log(Smax/Navg), where Smax = DDM_sp-Navg, DDM_sp is the uncalibrated raw counts in a single DDM bin where indciate the predicted SP, and Navg is the DDM noise floor defined in variable ddm_noise_floor. ddm_snr is in dB, at ddm_timestamp_utc. dB float N/A N/A 1
ddm_snr_flag SNR flag to indicate if the signal peak (DDM peak - Navg) shows a negative value. 0 = signal peak is positive, 1 = signal peak is 0 or a negative value N/A ubyte N/A N/A 1
ddm_timestamp_gps_sec The GPS second of week of ddm_timestamp_utc with nanosecond resolution second double N/A N/A 1
ddm_timestamp_gps_week The GPS week number of ddm_timestamp_utc week ushort N/A N/A 1
ddm_timestamp_utc 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. 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. second double N/A N/A 1
delay_resolution DDM delay bin resolution in chips. N/A float N/A N/A 1
dopp_resolution DDM Doppler bin resolution in Hz. s-1 float N/A N/A 1
eff_scatter 5 x 40 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. meter2 float N/A N/A 1
fresnel_coeff The SQUARE of the left hand circularly polarized Fresnel electromagnetic voltage reflection coefficient at 1575 MHz for a smooth geometrical surface at the specular point location and incidence angle. See UoA document XXX-XXXX Fresnel Coefficient Calculation for more information. N/A float N/A N/A 1
fresnel_major Length of the major axis of the first Fresnel zone meter float N/A N/A 1
fresnel_minor Length of the minor axis of the first Fresnel zone meter float N/A N/A 1
fresnel_orientation First Fresnel zone direction, defined as the angle between the major axis and the North degree float N/A N/A 1
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