Windsond now adds support for OziExplorer. Since before, Google Earth could be used to visualize the movement of sondes during soundings and to see the predicted landing locations. Now OziExplorer can be used as an alternative. OziExplorer has better support for offline maps which can help if operating without an internet connection.
OziExplorer is a commercial mapping application, also available in a free version with limitations, and a trial version. The support starts with Windsond software 1.52. Enable the support in the Settings dialog.
The company behind Windsond has changed name in the process of incorporation. The company is now known as Sparv Embedded AB instead of Kiwi Embedded. The company logo is new but operation continues as before and all agreements, warranties etc naturally continue to be honoured.
The current enclosure is a regular styrofoam cup, meant to hold hot or cold beverages thanks to the insulating properties. This works surprisingly well for a weather sonde, both in terms of aerodynamic properties, low weight, insulation and access to interior. The very low cost is also a bonus. The circuit board is designed to lock in place inside, for a snug fit.
Still, a commercial product can do better. Even lower weight is achievable. Replacing the battery and balloon tether thread can become easier. The insulation can be improved, allowing operation at higher altitude. The size can be reduced to about 50%.
These CAD renderings give an idea of how Windsond will look once large-scale production is started. Apart from the advantages listed above, the product name is printed on the side and grooves on the top eases opening the sonde for service. The sensor boom with thermometer and hygrometer is shown in green. The telemetry antenna sticks out below the sonde. Barometer, GPS and other components are protected inside the enclosure, as they are today.
Below is the verbatim report of Windsond during a big ballooning event.
Wind measurements during Swiss National Hot Air Balloon Championship (SMHL 2014) in Bischofszell, May 28th – June 1st. 31 balloon teams from 6 European nations started at the Swiss National Hot Air Balloon Championship (SMHL 2014). For more details of the competition see www.smhl.ch.
Claude Weber (Luxemburg) leaded the competition as Event Director and Daniel Gerstgrasser was consulting meteorologist. We did at least one wind measurement for the task setting of each flight. All wind measurement were done with windsondes .We started the measurements typically two hours before the task briefing. Daniel Gerstgrasser presented the results of the wind measurements in his meteo report to the pilots during the briefings. For some flight we also measured the wind after the briefing near the launch fields of the hot air balloons and the pilots have been invited to consult this data. Most of the pilots used this opportunity.
Claude Weber and Daniel Gerstgrasser have been very impressed by the good quality of the wind measurements.
The new Windsond website marks the introduction of a logotype for Windsond. The unassuming and stylish dandelion seed represents floating with the winds, low weight and ease of use. Like the dandelion seed, the Windsond radiosonde is its own parachute. Many thanks to my friend the game and graphics designer Martin Magni for the logo work!
Windsond was used during the Australian National Balloon Championships on April 22-27. The organizer released at least one sonde before each morning and evening flight to get the most up-to-date data to plan fun and challenging tasks for the pilots. In total 15 soundings were made, up to 9700 ft AGL. All sondes were recovered – with one exception closer than 10 m from the reported GPS landing co-ordinates.
The people operating Windsond during the competition reports the following:
In summary the use of windsond was very well received by pilots, event directors and the event professional meteorologist. Readings correlated well with forecast conditions above 5000 ft agl and provided detailed information on conditions below 5000 ft where winds were more difficult to forecast due to localised drainage. To operate the system was simple and intuitive, with an average turn around from launch to return of 45 minutes to 1 hour for reading to around 7500 ft agl with data, maps and recovery of the windsond (up to 10 km from launch). Recovery was often straightforward thanks to the remote cut down feature, allowing us to accurately target landing adjacent to access roads thanks to the live tracking & rolling updated predicted landing points. By the end of the week we could confidently land it within 100 m of a road and the reported landing locations were within 10 m of the actual landing location. We made 15 soundings in total up to a maximum altitude of 9727ft agl and all sonds were recovered. We’ll definitely be using windsonds again in the future.
One of the soundings proved problematic, when the altitude reported by the sonde GPS suddenly reported a big drop in altitude although the sonde was still rising. This fooled the sonde to believe the balloon had burst and the sonde was falling, causing it to behave as though going through a landing. The sonde stopped updating the GPS position to save power, as it usually does after a landing. The sonde could still be recovered.
This was clearly a software bug. The altitude reported by the GPS system has proved to be inaccurate in general, and in this rare case particularly unreliable. That’s why all sondes also are equipped with a barometric pressure sensor, which the system usually trusts more than GPS. I’m now modifying the algorithm to inspect air pressure change instead of GPS altitude change also in this case, to avoid such errors in the future.
The Windsond software has matured a lot over the winter. For example, the software can now generate a range of different file formats for the weather data. The settings dialog of this is pictured below. All generated files can be viewed within the application, even while the sounding is still progressing.
Here’s a quick breakdown of the major changes:
- Better curve smoothing algorithm that preserves air layer transitions
- Altitude axes start at the current ground altitude
- Support generating nine different weather data formats
- Select generated data formats in the Settings dialog and inspect the result in the Report panel.
- Dewpoint and lapse rate are plotted
- Plot history of sensor readings and GPS/pressure altitude
- Winds are reported starting at 10m height
- Bugfix in improving cut-down altitude accuracy when using the default cut-down altitude
- Name of launch site can be entered by hand or selected in list
The software update is available without charge to all customers.
In Abu Dhabi, I visited the International Exhibition for Security and National Resilience (ISNR) on April 1. (No, it’s not an April fool.) This is a big trade show held every two years at the grand National Convention Centre in Abu Dhabi, UAE. The 400 exhibitors cover topics such as security, surveillance, terror prevention and counter-measures, emergency services like ambulance and fire-fighting, etc.
At the show I met with several interesting companies where Windsond would serve a valuable role. The small size and ease of deployment of Windsond makes it possible to gather local wind profiles in scenarios where this was previously unpractical. My goal is to continue exploring such alternative use cases in cooperation with these companies. I extend a thank you to exhibitors and fellow visitors from all over the world for the friendly reception!