When the GNSS receiver on-board a Spire satellite is powered on, it continuously tracks multiple dual-frequency GNSS satellite signals simultaneously from the POD antenna. These signals are primarily used for the purpose of precise orbit determination, which is necessary for neutral atmospheric radio occultation inversion. However, the pseudorange and carrier phase measurements measured by the receiver are also used to derive an estimate of the ionospheric total electron content (TEC) along the line-of-sight to each GNSS satellite. During post-processing, the TEC is computed for each signal “arc” (i.e. the period when the Spire receiver is continuously tracking a particular GNSS satellite) by forming a linear combination of phase measurements from dual GNSS frequencies. The phase TEC measurements are then “leveled” to the analogous combination of the pseudorange measurements for a more accurate measurement. Receiver and transmitter differential code biases are removed when possible. 


The computed TEC values are stored in standard NetCDF format along with ancillary information including the transmitter and receiver positions. These data sets are packed in a NetCDF format, following conventions derived from data products created by CDAAC. Read more about this format here.


Available Data

podTec NetCDF (*.nc) files


Data Statistics

Coverage: Global

Time Resolution: 1 sec



Scintillation indices are indicators for ionospheric turbulence and are subdivided into two classifications: amplitude scintillation (S4), and phase scintillation (σɸ). Both provide indicators for "space weather" in the upper atmosphere. For example, large S4 values from a GNSS link may indicate ionospheric "storms" consisting of electron density gradients (e.g., Equatorial Spread F). This could lead to loss-of-lock on GNSS receivers, jeopardizing a receiver's ability to provide robust and accurate Position, Navigation, and Timing (PNT). Continuous monitoring of scintillation indices is key for understanding GNSS link health, and is a first step toward predicting potential GNSS regional outages.


Spire's CubeSats feature an advanced scintillation monitoring capability and can measure both amplitude and phase scintillation (S4 and σɸ). Combined with both a large constellation (~100 CubeSats) and diverse orbital planes, Spire's constellation is prepared to contribute critical ionospheric data, particularly over Equatorial regions.


These data sets are packed in a NetCDF format, following conventions derived from data products created by CDAAC. Read more about this format here.


Available Data

scnLv1 NetCDF (*.nc) files

Data Statistics

Coverage: Global

Time Resolution: 1 sec



Magnetometer data is collected continuously on Spire spacecraft as part of our Attitude Control and Determination (ADCS) system. The sensor used is based on magneto-inductive technology to deliver high-performance resolution and repeatability with high gain, high sample rates, low hysteresis, and no need for temperature calibration.

Available Data

Magnetic field vector (x, y, z + unix timestamp). Unit: nT



Data Statistics

Coverage: Global

Time Resolution: 4 Hz or 0.1 Hz

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