A comparison of action cameras available this Christmas

This Christmas you are spoiled for choice as the number of action cameras in the market swells. To help you evaluate the many cameras with many different features, I recommend this review by http://www.actioncameras.co.uk   .

Action Camera Reviews - Camera Comparison Infographichttp://www.actioncameras.co.uk/action-camera-reviews-infographic-best-helmet-cameras/

Looking at the review it is easy to pick out higher resolution and video frame rate models like the Go Pro Hero 3+ Black edition. Battery life is critical. The performances listed are not those that you may expect during a HAB flight and do not include performance with a battery bacpac. The GPS features are nice extras available to the Garmin and Contour cameras though it should be remembered that they only operate below the 18km height limit, so may be inoperative for half of the flight.

 

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Fair winds and following servers: The art of flight prediction

By Lester Haines

source:http://www.theregister.co.uk/2013/12/18/lohan_flight_prediction/

Back in September, the Low Orbit Helium Assisted Navigator (LOHAN) team sent a mighty orb aloft on a test flight of our magnificent Vulture 2 spaceplane’s rocket motor igniter.

The mission was a textbook operation, with the the payload eventually returning to terra firma within a few hundred metres of the awaiting team, at a spot predicted by the impressive Cambridge University Space Flight Landing Predictor.

Since 2008, when Rob Anderson first wrote the predictor, it’s been continually updated to improve performance, and now offers anyone wanting to send a balloon aloft the chance of seeing very quickly indeed just where it’ll burst and where they should head to recover their precious load.

Here’s a prediction from Friday 13 December (.kmz here), showing that a launch from Area 51 in Nevada, with ascent and descent rates of 5m/s and a burst altitude of 30,000m would travel pretty well due east into Utah, where the remains of the balloon could be swiftly recovered by black helicopter squads bearing memory erasure ray guns for anyone unfortunate to have witnessed the landing:

area_51_launch_big

It’s clever stuff, but how does it work? We had a chat with Daniel Richman, who earlier this year followed in the footsteps of Rob Anderson, Fergus Noble, Ed Moore, Jon Sowman, Adam Greig in upgrading the predictor.

Daniel explained:

The US’s National Oceanic and Atmospheric Administration (NOAA) provides (freely) wind forecasts, containing a huge amount of information, but crucially, (horizontal) wind velocity at various levels in the atmosphere. To a close enough approximation, the balloon will move at the same speed as the wind.

Combined with a simple model of how fast the balloon will rise, and how fast it will fall after it has burst, we take the position of the balloon at a certain time, the speed of the wind, and calculate where it will be a short time later using secondary school level maths (“SUVAT”); though the proper name for this is “solving an ordinary differential equation using the Euler method”.

There are a couple of other subtleties: for example, instead of the wind data being provided at certain altitudes, it is provided at certain pressures, and then the actual altitudes of those pressure layers at each point on the Earth is provided separately. So we have to first work out the air pressure corresponding to the altitude of the balloon, and then look up the wind velocity at that pressure level. I assume this is to do with how the forecasting works.

Furthermore, since the velocities are provided at every half-degree of latitude/longitude, we have to interpolate to guess the wind velocity at the position of the balloon. Also there are some little details to do with converting distances in meters to changes in latitude and longitude and so forth.

The current “one-shot” prediction facility, such as the Area 51 example above, went live in 2010, and provided the data for our ill-fated playmonaut’s encounter with the English Channel last December.

According to Daniel, the problem was with the NOOA servers:

For a while we had been using the OpeNDAP servers of the NOAA. Basically, the OpeNDAP server is some Java thing that the NOAA give their forecast data to, and then you can ask it for “all the data in this latitude/longitude range”, which is neat, since it keeps the amount of data we have to download low. Although we are of course very grateful to the free data provided by the NOAA, these servers were becoming – for whatever reason – a bit slow and unstable. Alternatives were investigated, and we found that we could just download the underlying data from a NOAA FTP server.

Going straight to the FTP server has its downsides, as Daniel elaborated when explaining the 2013 predictor update:

Now have to download ~6-7GB, but the server that the predictor now runs on has lots of disk space and gigabit internet, so this isn’t really a problem.

I wrote the new code to download and decompress (the downloaded files are in the GRIB2 format; the compression method itself is actually a variant of JPEG) this data in advance; it runs every six hours to download the new forecast from the NOAA.

The download takes about an hour, and is mainly limited by the fact that it takes about an hour for the NOAA to upload it to their FTP servers.

The download in advance means that when you push ‘Run prediction’, instead of waiting a minute for data to download, it starts instantly. Furthermore, we decompress the data into a 18GB binary file (referenced in my original email) purely because this means it’s very quick and easy for the predictor to access the data (essentially, the binary file is a giant 5 dimensional array of double precision floats, “double dataset_array_t[65][47][3][361][720]”).

By quick, I mean that the calculating stage itself now takes between 20 milliseconds and 2 seconds (depending on whether the wind data has to be read from disk or is stored in the page cache) instead of tens of seconds to load it from several files.

The long-term aim for the predictor is “to rewrite the underlying prediction code – the bit that does the actual calculation – to add features like predictions for balloons that achieve float, and so forth”.

The “floater” option will certainly prove useful for LOHAN team members Dave Akerman and Anthony Stirk, who have a penchant for drifting across European airspace on long-range missions.

Back at LOHAN headquarters meanwhile, as well as one-shot predictions, we’ve been availing ourselves of all this hard work to examine seasonal wind conditions for the eventual launch of our Vulture 2.

Our intended launch is at 40°25’20.49″N, 5°18’0.27″W, and we’d rather like the balloon to pass within gliding distance of the Vulture 2‘s landing site* at 40°45’15.06″N, 5°25’3.90″W, or at the very least stay within our designated operational areas (dark blue primary, light blue extended secondary):

A map of central Spain showing our Vulture 2 landing areas

Here are some predictions from between April and October (.kmz here)…

Google Earth grab showing all the predicted flight paths

…which become a bit clearer when broken down:

The flight predictions shown monthly on a montage of Google Earth grabs

As you can see, the predictor demonstrated that September is the best month for the job, confirming our research on historical wind data showing predominantly south-westerly winds for pretty much the whole month.

Of course, should the wind direction not play ball, we can always shift the launch location to optimise the balloon’s flight path, and with the improved predictor, we’re confident it’ll perform as expected. ®

Wind Visualiser

map

Cameron Beccario has developed a really great web site that visualises the surface wind forecast around the world. The visualisation uses US National weather surface data for wind forecasts at 1000 hPa or approximately 100m above ground level. More information from the visualisation can be found at http://earth.nullschool.net/about.html

The visualisation, which is updated every 3 hours, can be found at http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-7.95,54.15,3000  (1000hPa / ground level)

http://earth.nullschool.net/#current/wind/isobaric/250hPa/orthographic=-3.24,-301.69,989   (250 hPa / jet stream)

The lengths others go to, to return your payload box

Source http://www.wthr.com/story/24081143/2013/11/27/purdue-weather-balloon-found-in-ohio

WEST LAFAYETTE, Ind –

A group of Purdue University students whose camera-equipped weather balloon vanished during the Midwest’s recent tornado outbreak has got their balloon back along with some amazing footage thanks to an Ohio farmer.

The image that allowed the farmer to trace the launch team

The image that allowed the farmer to trace the launch team

Purdue technology and engineering students launched the high-altitude balloon the day before Nov. 17’s deadly tornado outbreak. But howling jet stream winds swept it eastward and it crashed in a northeastern Ohio field near the town of Kalida.

The storm-tossed balloon also lost its Purdue contact information.

https://www.youtube.com/watch?v=i0mpU2U8tQo

But the farmer who found it geared up its camera and saw footage of the students who launched it sporting Purdue sweatshirts.

The farmer was able to track down the students, who got their balloon back Monday night along with footage looking down on menacing clouds during the tornado outbreak.

Davin Huston, Continuing Lecturer and Faculty Advisor from the university said,

  • “We had placed a handheld APRS radio in the payload.  As the balloon gained altitude the temperature drop caused the battery to fail which caused us to lose tracking ability.  The battery was fine once we charged it back in our lab.

The label got washed away in the heavy rains, it would have been still attached.  Next time we are going to laminate the labels Smiling face with smiling eyes.
The flight plan was almost dead on for our estimates.  It’s twin balloon, launched an hour earlier, landed 10 miles south of this one.”

Go Pro Hero 3 + takes to the skies

Go Pro Hero 3 plus takes to the skies in a weather balloon

hero-3-plus

In a flight over the Grand Canyon earlier this month, HABist John Flaig put the new Go Pro Hero 3+ to the test.

Highlights of the flight can be found at:

http://nearspaceballooning.com/

and

http://nearspaceballooning.com/launch6.asp

and

http://nearspaceballooning.com/photos_launch6.asp

This is what John said about the camera’s performance.

The Grand Canyon taken by a Go Pro hero 3+

The Grand Canyon taken by a Go Pro Hero 3+

“The quality with the Hero 3+ is visibly much better than the Hero 2.  In the dark it does perform marginally better. We shot in 2.7k using ProTune so I’ll have to see what it looks like once it’s gone through the professional video editing software.”

After testing the camera for the flight,John said, “In testing so far, the battery life is not long enough, even with the bacpac, to get 3-4 hours recording at the highest quality settings. I also had to get a 64gb card and an external battery (Anker Astro Mini 3000mAh) to record for longer. I’d also add that the resolution seems better. The sun looks more natural and the camera seems to handle contrast better. You can also use a smart phone App to manage the camera settings instead of relying on the clunky in-camera controls.

It should be possible to get about 2.5 hours of 1080p with the BacPac. They have the improved battery life. I found this helpful forum post a few weeks ago:

 

http://snowheads.com/ski-forum/viewtopic.php?t=93605

More of John’s work can be seen at http://nearspaceballooning.com/

HAB weather balloon trans Atlantic crossing attempt fails

UK HABer Anthony Stirk and US HABer Jim N2NXZ  launched their attempt to cross the Atlantic yesterday evening (UK time) with a 1600g Hwoyee balloon. The balloon will be using a small tube in the bottom to prevent burst at sunrise.

 In his own words, Anthony said,
“Balloon will be carrying two UKHAS format 70cms telemetry transmitters as follows :
$$$$$N2NXZ-1 434.550Mhz 50 Baud RTTY 7N2 500 shift
$$$$$N2NXZ-2 434.445Mhz  50 Baud RTTY 7N2 500 shift
ta1
These are not equipped with TCXO’s so this frequency may be +/- some arbitrary amount. In additional N2NXZ-2 is equipped with a Euro/Azores frequency (144.800Mhz) APRS transmitter which will transmit below 300 meters and then is geofenced so it won’t transmit until ~ 400km from Azores, or > -15 longitude subject to normal euro legislation geofencing, call sign will be N2NXZ-12 with country prefix in comments i.e CU/N2NXZ-12.
Finally there will be a 50mW 10 meter CW beacon on 28.219 Mhz which is transmitting N2NXZ/BLN/6 and repeats every 10 seconds @ 10 wpm.
The current winds are taking it down towards Southern Spain, most likely in range of the Azores : http://nstar.org/GFS/10mb/10mb.048.png but this is subject change. Once its launched hopefully we should get an idea of its velocity and be able to make some guesses as to when it should appear.
We welcome listeners in the Nova Scotia area, as always live chat here : http://webchat.freenode.net/?channels=highaltitude and a tracking guide here : http://ukhas.org.uk/guides:tracking_guide   “
By the morning of Friday 4th December the balloon was over New Brunswick.
ta2
6th December 2013
The following update was made on the UKHAS web site
“It looks like the balloon didn’t make it as there has been no contact. We’d like to thanks everyone for trying especially members of Associacao de Radioamadores dos Açores (CU2ARA) for taking the time to set up a receiving station in the Azores. Was great to see an antenna on the map there and we will be sending more your way soon!

Cheers,
Anthony M0UPU”