Improved Wind Measurements with Ultralight StreamSondes

Current dropsondes experience time-lag in changing in windspeeds. Therefore, corrections must be made to acquire the true ambient windspeeds. However, it can be shown that decreasing the terminal velocity of the falling object by increasing its responsiveness to air drag, the magnitude of the wind time-lag corrections become insignificant. Therefore, the uncertainty of wind measurements becomes increasingly dependent on the uncertainty produced by the GNSS (Global Navigation Satellite System) tracking of the object. Skyfora introduces a new dropsonde called a StreamSonde with improvements in both areas.

The StreamSonde incorporates a dual band (L1/L5) GNSS receiver for increased velocity measurement capability. The receiver utilizes GPS L1CA/L5, Galileo E1b/E5a, Beidou B1I/B1C/B2A and optionally NAVIC L5 and QZSS L1C/L1S/L5 signals. Traditional L1 GNSS receivers used in dropsonde applications have position and velocity measurement uncertainties which are typically 2.5x higher than dual-band receivers.

The new instrument design that combines high responsiveness to drag forces with high precision tracking of dual band technology leads to decreased uncertainty in wind measurements. Initial operations conducted in Hurricane Nigel 2023 demonstrate the advantages of the new design and illustrate enhanced windfinding capability in StreamSonde use.