Here are minutes of our telecon on Tuesday July 25, my apologies for the delay! -- as well as work done since then -- please just reply with (or let me know) any corrections -- thanks! :
Attendees: Arnold Gaertner (NRC), Alexy Decrooq (student at ISAE-SUPAERO + MITACS Globalink summer student at UVic), & me
The past two weeks have primarily been spent doing the very hard work needed to make the telemetry system _much_ more consistently reliable. We began by moving to using Yorke's DNT900 settings, which improved things, and allowed data transfer between Mt. Doug to UVic (5 km) with simple dipole antennas on both sides, but we still suffered _far_ too often from lost data and dropped+reconnected connections at that distance. Two things helped a lot (but still not nearly enough): 1) adding 1000 uF capacitor filters, again at Yorke's suggestion, to the power supplies for the DNT transceivers, which prevented the large keying transients from the transceivers from causing resets of the GPS receiver; and 2) only transmitting one data string per second, rather than 10x per second (as trying to do the latter causes occasional overwrites). But we still do not have the level of consistent, effectively "bulletproof" reliability that we absolutely require from our telemetry at long distances, even with those improvements. I then tried completely separating the power supply for the DNTs from that of the rest of the system (except, of course, from the main battery), and adding more filter capacitors upstream of the new 5V power supplies dedicated to the DNTs, but that did not help (it didn't hurt of course, except for the time taken, but didn't help at all). What surprisingly did help a lot (but still not enough) was reducing some mechanical pressure on the GPS serial inputs to the main board, which were apparently causing poor electrical connection of the GPS serial data input. But we _still_ definitely require the reliability improvement that will come from having a backup redundant data telemetry connection at a separate frequency: we still do suffer far too often (even rarely is far too often -- the telemetry needs to be completely rock-solid at all times even from 50 km) from occasional dropped connections. For that, a pair of antennas arrived this past Thursday for our 144 MHz backup boards (based on Radiometric SHX1's):
http://projectaltair.org/HyperNews/get/AUX/2017/08/07/18.39-72077-SHX1transceivers.JPG
and I've purchased a large Yagi tuned to 144 MHz for use as part of the ground station:
https://cdn3.volusion.com/rcmqs.fsseg/v/vspfiles/photos/JETSJTBM270-2.jpg?1393496786
I have additionally been working on my 433 MHz backup boards (based on HopeRF RFM23BP's), however have been suffering with interrupt pin problems on the latter. So we'll be focusing on the 144 MHz boards as backup for now.
Students Alexy Decrooq and Kyle Jordan, as well as software expert Layth Holubeshen, are all working on getting the code that runs the balloon flight path predictor running inside of AIFCOMSS:
http://projectaltair.org/HyperNews/get/AUX/2017/07/10/18.55-39312-IFCOMSSwithPredictor1.png http://projectaltair.org/HyperNews/get/AUX/2017/07/10/18.55-56749-IFCOMSSwithPredictor2.png
into good shape such that it is easier to install, and additionally working on relatively easy and reproducible instructions on how to install it (on Windows, Mac, and Linux platforms). We're greatly looking forward to adding those instructions as a README at https://github.com/ProjectALTAIR/AIFCOMSSwithCUPredictorTest, as well as making any changes to the code itself to make it easier to install. After that's done, we will work on updating and improving the flight prediction code itself -- and also, after that, seeing if we can successfully simulate some form of station-keeping over a region of land, using the actual wind forecasts and data from NOAA, and also reasonable values for drag, propulsive thrust, battery power (as well as some battery recharging with future lightweight solar panels), etc etc.
Machinist Chris Secord has been very busy welding the 12" diameter aluminum sphere that will function as our pre- and post-flight photometry cross-check device -- here's a photo of him at work plasma arc welding on the small rings to hold each of the photodiode mounts in place:
http://projectaltair.org/HyperNews/get/AUX/2017/07/24/21.17-71704-isSecordWeldingSphere.JPG
The plasma welder he was using did not have sufficient power to weld the the short (~1") length of 6" diameter tube onto the input port (for mechanical mount purposes) top ring on (that plasma welder is for fine work); so the machine shop just purchased a new gas tungsten arc welder with greater power. That new welding machine arrived late last week. When he finishes this weld job tomorrow, we'll then prime the interior with white powder coat, and then use our Avian-B paint to paint over the powder coat (Avian-B sticks far better over a powder coat than directly on aluminum, since Avian-B does not contain etch primer). The sphere should be coated and completed in the next couple of weeks.
ALTAIR-Victoria is fully assembled, and its light sources are functioning nominally:
http://projectaltair.org/HyperNews/get/AUX/2017/06/26/19.25-55880-ALTAIRwithGear.JPG
however: only the light sources themselves have been tested so far -- they need to be tested in concert with the photodiode readout; with the telemetry; with the orientation, GPS, and environmental monitoring; with the onboard data storage; with the propulsion and its monitoring data; etc., etc., etc. Much of the software to combine all that functionality, and resultantly _very_ large number of possible error conditions, still needs to be written. Thus, there remains an enormous amount to do -- including, of course, drop testing, long-range telemetry testing, etc. -- before seriously thinking about a flight ...
Mark Lenckowski has completed the stabilized pole for the new 10-meter-high drop test setup at Victoria:
http://projectaltair.org/HyperNews/get/AUX/2016/12/19/15.28-91194-MeterStabilizedPole_1.jpg http://projectaltair.org/HyperNews/get/AUX/2016/12/19/15.28-81425-MeterStabilizedPole_2.jpg
As you can see (faintly), he affixed side-struts and guy wire to the PVC pole, to prevent it from bending in either of the two transverse directions, so it can now be raised to vertical, from horizontal, without bending or breaking. Mark is now working on some carabiner-type attachments for the end of the pole, and he should have those finished in about a week or so.
The survey-tripod-mounted device to cross-check yaw-pitch-roll information from the gondola (e.g., on days before/after flights) is mostly constructed now, thanks to Mark Lenckowski -- photo at:
http://projectaltair.org/HyperNews/get/AUX/2016/08/31/18.15-24048-wPitchRollCalibDevice.jpg
and all that remains to be done is a small fitting between the device and the bottom of the payload. The purchased hardware in it includes both the survey tripod (http://www.cpotools.com/cst-berger-60-alwi20-o-aluminum-tripod-with-quick-release--orange-/cstn60-alwi20-o,default,pd.html), two adjustable angle mounts (http://www.thorlabs.com/thorproduct.cfm?partnumber=AP180), and a rotation mount (https://www.thorlabs.com/thorproduct.cfm?partnumber=RP01). That last fitting to attach (temporarily, pre- or post-flight) the upper adjustable angle mount to the payload feet will be completed here in the next couple weeks.
We're currently revising the draft initial contractual agreement from our colleagues at Globalstar Canada regarding 2 initial SPOT Trace devices (and their service plans) for the educational side-project for the upcoming NATO SPS application, in which classrooms in elementary and high schools could launch company-donated SPOT Traces using party balloons (or a more environmentally-friendly version thereof), and track them to learn more about winds at different levels in Earth's atmosphere.
Another next step, software-wise, is to establish telemetry communication between ALTAIR-Victoria:
http://projectaltair.org/HyperNews/get/AUX/2017/04/17/18.41-75359-assembledpayload1.JPG
and the Betelgeuse test-box:
http://projectaltair.org/HyperNews/get/AUX/2016/08/17/20.30-68004-Betelgeuse1.jpg http://projectaltair.org/HyperNews/get/AUX/2016/08/17/20.30-53104-Betelgeuse2.jpg
and to update the control and monitoring software to incorporate the telemetered info, and also implement onboard SD card data storage, as well as storage of the telemetered info.
Houman will send Cordell and/or us updated sections of his master's thesis soon -- that information will be extremely useful to us going forward. Also, Susana and Nathan, it would be very helpful for us all to get the JHU students' final writeup when you have a chance.
Our next grant application will be a NATO "Science for Peace and Security" application, together with Australian colleague partners.
That's all I remember, please send things that I forgot. Next telecon tomorrow, at the usual 4:00 pm Eastern time.
Cheers, talk to you all tomorrow! justin
On Tue, 25 Jul 2017 00:09:46 GMT, Justin Albert wrote:
> Hi! > > Telecon tomorrow (July 25 in North America, July 26 in Australia) at the > regular time: 4:00 pm Eastern (1:00 pm Pacific, 10 am Hawaii, 22.00 > European, 6 am Eastern Australia). Discussion items include: > flight/telescope plans and tests; construction, drop testing, and other > tests of the new gondolas/payloads; light sources and light source > modelling; goniometric and pre- and post-flight calibration; propulsion > work; nanosat bus and payload solid models; computing/website; grant > applications; and recap of schedules. > > Here's how to connect: > > 1) Open Skype on your computer (note that of course, you should first install Skype, http://www.skype.com , on your machine if you haven't already). > 2) In the "Contacts" menu, add me ( jalbertuvic ) as a contact, if you haven't already. > 3) Just wait for me to Skype-call you at the usual time (4 pm Eastern, 1 pm Pacific). > 4) If there is any trouble, or if you don't get a Skype-call for some reason and would like to join, just send me an e-mail (jalbert@uvic.ca). > > Here's the tentative agenda: > > I) Flight & telescope plans, and upcoming tests > II) Construction, drop tests, and other forms of tests of the new gondolas and payloads here in Victoria. > III) Diffused light source, and its modelling, pre- and post-flight calibration, and goniometric calibrations > IV) Nanosat solid models & Houman's thesis > V) Computing/website, including new flight control and simulation progress. > VI) Grant applications > VII) AOB > > Talk to you all tomorrow, thanks! > justin
Attachments:
http://projectaltair.org/HyperNews/get/AUX/2016/05/22/18.23-24702-12inAlSphere.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/04/06/16.53-58615-SideView.pdf
http://projectaltair.org/HyperNews/get/AUX/2016/04/06/16.53-48539-TopView.pdf
http://projectaltair.org/HyperNews/get/AUX/2017/06/26/19.25-55880-ALTAIRwithGear.JPG
http://projectaltair.org/HyperNews/get/AUX/2016/08/17/20.30-99000-AvianBTestHemisphere.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/08/17/20.30-68004-Betelgeuse1.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/08/17/20.30-53104-Betelgeuse2.jpg
