CASSIOPE SPACECRAFT (Swarm-E)
PROCESSED DATA HANDBOOK
RRI Lv1 HDF File
An RRI level 1 HDF file is generated for each RRI turn-on session.
The RRI level 1 HDF files contains 3 objects: A CASSIOPE ephemeris object, an RRI Data object and an RRI Settings object. The attributes of each object are specified below.
| “CASSIOPE Ephemeris” Object Attribute | Description |
| Altitude (km) | WGS-84 altitude (km) |
| Attitude Accuracy (0=Dropout, 1=Rough, 2=Coarse, 3=Moderate, 4=Fine, 9=No data) | Spacecraft attitude quality flag. See the definition of ‘Fine’, ‘Moderate’, ‘Course’, and ‘Rough’ here. |
| Ephemeris MET (seconds since May 24, 1968) | Time of ephemeris data in Mission Elapsed Time (seconds since May 24, 1968 00:00:00 UTC). First time is the anchor for the radio data times. |
| GEI Position (km) | J2000 GEI position (km) |
| GEI Velocity (km per s) | J2000 GEI velocity (km/s) |
| GEO Position (km) | Position in ITRF geographic Cartesian coordinates (km) |
| GEO Velocity (km per s) | Velocity in ITRF geographic coordinates (km/s) |
| GSM Position (km) | Position in Geocentric Solar Magnetospheric coordinates (km) |
| Geographic Latitude (deg) | WGS-84 latitude |
| Geographic Longitude (deg) | WGS-84 longitude |
| MLT (hr) | IGRF MLT (hours) |
| Magnetic Latitude (deg) | IGRF latitude (degrees) |
| Magnetic Longitude (deg) | IGRF longitude (degrees) |
| Pitch (deg) | Spacecraft attitude pitch angle (degrees) |
| Roll (deg) | Spacecraft attitude roll angle (degrees) |
| Yaw (deg) | Spacecraft attitude yaw angle (degrees) |
| “RRI Data” Object Attribute | Description |
| Channel A frequencies (Hz) | Frequency of the RRI numerically-controlled oscillator on Channel A, corresponding to Data Stream 1 and Data Stream 2 |
| Channel B frequencies (Hz) | Frequency of the RRI numerically-controlled oscillator on Channel B, corresponding to Data Stream 3 and Data Stream 4 |
| RRI Packet Numbers | ID of each time-tagged 4×29-sample packet sent out from RRI |
| Radio Data Monopole 1 (mV) | Radio data stream 1. Multiple options exist for what this data represents, see the “Data Format” attribute below for the definition of the available data streams. |
| Radio Data Monopole 2 (mV) | Radio data stream 2. Multiple options exist for what this data represents, see the “Data Format” attribute below for the definition of the available data streams. |
| Radio Data Monopole 3 (mV) | Radio data stream 3. Multiple options exist for what this data represents, see the “Data Format” attribute below for the definition of the available data streams. |
| Radio Data Monopole 4 (mV) | Radio data stream 4. Multiple options exist for what this data represents, see the “Data Format” attribute below for the definition of the available data streams. |
| “RRI Settings” Object Attribute | Description |
| Antenna 1 Gain | Monopole 1 gain setting (Low, Medium, or High) |
| Antenna 2 Gain | Monopole 2 gain setting (Low, Medium, or High) |
| Antenna 3 Gain | Monopole 3 gain setting (Low, Medium, or High) |
| Antenna 4 Gain | Monopole 4 gain setting (Low, Medium, or High) |
| Antenna Configuration | Antenna configuration, Monopole or Dipole |
| Bandwidth A (kHz) | Bandwidth for Channel A, 5 kHz or 30 kHz |
| Bandwidth B (kHz) | Bandwidth for Channel B, 5 kHz or 30 kHz |
| Data Format | Lists the four data streams that are output by RRI. Possibilities are I1, Q1, I2, Q2, I3, Q3, I4, and Q4, where I represents the in-phase signal from a monopole, and Q represents the quadrature output from a monopole. For example, a Data Format of I1Q1I3Q3 in Monopole mode means in-phase and quadrature data are output from monopoles 1 and 3. In Dipole mode this represents I and Q from each dipole. |
| Delta Frequency A (Hz) | For a linear sweep this is the step size in Hz of each frequency step. For a logarithmic sweep this is the starting step size, with each step size being twice the one before it. This has no meaning for fixed frequency. Applies to Channel A. |
| Delta Frequency B (Hz) | For a linear sweep this is the step size in Hz of each frequency step. For a logarithmic sweep this is the starting step size, with each step size being twice the one before it. This has no meaning for fixed frequency. Applies to Channel B. |
| Dwell Time A (s) | Number of seconds to dwell on each frequency of a sweep, Channel A |
| Dwell Time B (s) | Number of seconds to dwell on each frequency of a sweep, Channel B |
| End Frequency A (Hz) | End frequency of a sweep, Channel A. Note that the sweep extends one step past the end of the range, i.e. the sweep returns to the start frequency when f > f_end. |
| End Frequency B (Hz) | End frequency of a sweep, Channel B. Note that the sweep extends one step past the end of the range, i.e. the sweep returns to the start frequency when f > f_end. |
| Start Frequency A (Hz) | Start Frequency for Channel A |
| Start Frequency B (Hz) | Start Frequency for Channel B |
| Sweep Mode A | Sweep mode of Channel A. (Fixed Frequency, Linear Sweep, or Logarithmic Sweep) |
| Sweep Mode B | Sweep mode of Channel B. (Fixed Frequency, Linear Sweep, or Logarithmic Sweep) |
RRI has a sampling frequency of 62500.33933 Hz.
Details of the bandwidth response, calibration, and instrument components can be found in James et al., The e-POP Radio Receiver Instrument on CASSIOPE, Space Science Reviews, 2015, Vol 189 (1), p 155-160.