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Sonde Telemetry Validation

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Mark Jessop edited this page Jul 14, 2026 · 1 revision

Due to an increase in the number of new software uploading telemetry to SondeHub, and wanting to avoid playing whack-a-mole as we find new software uploading invalid telemetry, we have decided to block new software types by default.

We ask that developers contact us, either via email (support@sondehub.org) or via our Discord ( https://sondehub.org/go/discord ) to coordinate testing and validation of the uploaded telemetry data.

Common Issues

Common Telemetry Problems

  • Incorrect date/times, including:

    • GPS vs UTC time issues - the SondeHub convention is to use whatever time is provided by the sonde as-is, unless GPS leap second information is included in the telemetry. For example, Vaisala RS41 sondes transmit GPS time - this is what is uploaded to SondeHub without any conversions.
    • Truncating or rounding of times to the nearest second - many radiosondes transmit fractional seconds, please include these!
    • For sonde types that only transmit HH:MM:SS, issues around addition of the date portion around a day boundary (00:00Z)

  • Excessive floating point precision - we don't need full floating point accuracy! Have a look what other uploaders produce and base the uploaded precision on that.

Common Uploading Problems

  • Excessive uploading of listener position - you only need to upload a stationary listener position every few hours. auto_rx defaults to every 6 hours!
  • Uploading telemetry one-packet-at-a-time - We ask that you queue up telemetry packets and upload as a Gzipped bundle at a minimum of every 15 seconds. For some radiosonde types (DFM, C50) we recommend that uploads occur every 30 seconds for our z-check to work reliably.

Getting JSON data to compare against

We recommend that while testing your new software, that you run 'known good' software such as radiosonde_auto_rx or rdz_ttgo_sonde and compare the decoded data. If there's enough other receivers in your area decoding and uploading data, you may just be able to make use of data from the SondeHub database.

Once a sonde shows up on SondeHub, you can obtain the JSON data for each sonde at the api https://api.v2.sondehub.org/sonde/serial_here e.g. https://api.v2.sondehub.org/sonde/X1234567.

You can also look at the raw uploaded telemetry on the Grafana Radiosonde Dashboards. To access these, locate a radiosonde on Sondehub.org, then look for the 'Plots' button in the sonde information pane on the left of the map. On the dashboard, scroll down and look for the 'logs' pane.

Submitting Data for Validation

To make it easy for us to compare your data with other receivers, we ask that you receive as much of an actual radiosonde flight as you can, and log every JSON object that would have been uploaded to SondeHub, to disk. One-line-per-object is ideal, but a list of objects is also fine. We would like a sample of data for each radiosonde type that you intend to support.

This can be submitted to us either on Discord, or via email. Once we've compared it against existing software, we'll allow your software to upload data into the SondeHub database for the radiosonde types we've received samples for.

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