Version 3.1   2018/05/27
Table of Contents

Notes on High Altitude Balloon (HAB) Flights
So why is this stuff on Doug Elliott's website
Mission Details  
    Launch Day - new
    Hardware Components
    Radio System for Tracking
Some Discussion Topics -recent updates at end of this section
Contacts and Equipment Details -new
Some Related Links
Webpages for other HAB Info and Teams
Timeline
Configuration Info & Diagrams -new
To Do List  -new
Chase Vehicle Checklist  -new
Ideas for future flights - new
Latest Flight Path Prediction - new

 

Notes on High Altitude Balloon (HAB) Flights

What the heck is that, you say? Here's the scenario, as I understand it: You put a carefully calculated amount of helium or hydrogen into a largish latex balloon, attach a cord from it to a dangling parachute, and another from it to "the payload". The payload is an insulated container that contains some nerdware: a GPS, a radio, a microcomputer or two, maybe a camera or two, a bunch of sensors, and maybe some weird experiments. The payload needs to survive sub freezing temperatures, and a possible water landing.

As the balloon rises from launch, the atmosphere gets less dense, and the balloon, filled at ground level's air pressure, begins to expand. At some point, it bursts, ideally around 100,000 feet (30 Km) and this is where the parachute comes into play (hopefully). Through both the ascent and descent, the sensors are sensing, and values are being recorded by the microcomputer. Also, GPS readings (latitude, longitude, and altitude) are being read, and transmitted over the radio. Radio receivers on the ground receive this information, and it is used to follow the balloon in vehicles, so that the payload can be found (a fairly critical step for mission success) and the stored data can be read out and interpreted. It's nice to retrieve the nerdware as well for reuse, or installation in the team's hall of fame.
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OK, so why is this stuff on Doug Elliott's website?

A team at the University of Western Ontario (UWO) here in London, Ontario came to the London Amateur Radio Club (LARC) looking for assistance with the radio portion of their inaugural HAB flight. Dave McCarter VE3GSO and myself, Doug Elliott VA3DAE volunteered to help out, got excited about the project and got carried away trying to help. So who are these hams?

Dave McCarter
-holder of Canadian Advanced Ham License, call sign VE3GSO
-LARC president
-electronics teacher at Fanshawe College
-Astronomy expert, past London RASC president
-instructor for the LARC Advanced Amateur Radio license course

Doug Elliott
-holder of Canadian Advanced Ham License, call sign VA3DAE
-LARC board member and Education coordinator
-electronics and robotics hobbyist, with Raspberry Pi and Linux experience
-ex-skydiver knowledgable about parachutes
-webmaster/provider of this website
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Mission Details

Launch Day:

-current plan is for Tuesday May 29 - this could change, depending on weather.
-launch location is a 2 hour drive north from London near Orchardville (location constrained by aircraft flight vectors)
-predicted launch time is between 11:00 and 13:00
-latest path forecast is below.  We'll have more accurate forecasts near launch date / time
-chase vehicle 1:
    -driven by Doug Elliott VA3DAE
    -supports direct reception of APRS beacon on 144.39 MHz, and Internet tracking via APRS.fi over date enabled cell phone
    -mave be beaconing chase vehicle position with call sign VA3DAE-2, graphic symbol = van
    -expected to have one additional Ham operator, and multiple UWO staff as passengers
    -van is a Honda Odyssey: driver plus 5 to 7 passengers
    -will be at launch site at or before 11:00, and will follow balloon after launch
-chase vehicle 2:
    -driven by Dave McCarter VE3GSO
    -supports direct reception of beacon on 434.03 MHz via transportable helical antenna mounted on a tripod
    -will not attend launch - will pre-position in the predicted landing area
-additional chase vehicles
    -anyone who can view the APRS.fi website on a cell phone with data plan can follow the balloon and help find it
    -additional chase vehicles should register at launch site to receive communications instructions
-expected flight duration: 3 to 4 hours
-expected APRS tracker battery life: 1.5 days, giving us transmission until about midnight Wednesday if landing doesn't disable antenna

Hardware Components

-Latex weather balloon
    -115 cubic foot volume
    -sensitive to being touched by hands - gloves are mandatory

-Swivel attachment to minimize twist build up

-Parachute - purple. Needs to be highly visible to aid in recovery

-Electronics connected to first Raspberry Pi 3
   -Pi camera, via on onboard connection
   -GPS and Radio Transmitter, via serial
   -Geiger counter, via USB
   -Flight Termination Unit, via GPIO
   -CO2 sensor, via USB

Electronics connected to second Raspberry Pi 3
   -Pi camera, via onboard connection
   -ozone and methane sensors, via I2C
   -temperature, humidity and pressure sensors, via GPIO
   -ultraviolet sensor, via GPIO
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Radio System for Tracking

The UWO teams original plan was to use radio gear which uses a frequency in the HAM UHF band (434.600 MHz). A low mass radio has been purchased as well as a ground receiver radio. To implement tracking with this system, development work is needed to interface the Raspberry Pi to the payload radio, and to put in place a messaging system that encodes and transmits the relevant GPS data. At the other end, there needs to be a system that receives and interprets these transmissions, ideally in a mobile system that produces map data. This enables the chase vehicle(s) to get close to the landing location, so that the payload can be retrieved. This is critical in order to recover the sensor data which is stored in the payload.

An alternate approach that the hams are recommending is using the existing Ham radio Automatic Packet Reporting System (APRS) for radio tracking purposes. Some of it's attributes are:
    -standardized known working hardware and software components
    -off the shelf availability of units combining GPS, controller, radio and antenna
    -ability to use standard ham radios in chase vehicles, and cell phone web browsers
    -proven performance in other HAB balloon flights
    -compartmentalization: tracking system is independent of payload, and can't be compromised by it
    -ability to use existing network of fixed monitoring ground stations with no additional effort
    -support for online automatic mapping of tracked object location with no additional effort
         -here's one of the websites that can be used: https://aprs.fi/

Unfortunately, the Ham APRS system uses a different frequency - 144.39 MHz which is in the VHF band allocated to Ham radio (Ham VHF Band plan). The radio that the UWO team purchased has the fixed frequency of 434.6 MHz in the Ham UHF band, (designated for digital modes in the Ham UHF band plan) which eliminates all of the advantages listed above, with one exception: This radio has also been used extensively and successfully by other HAB teams. The UWO team is planning to minimize the development effort to support the 434.6MHz radio by adopting the APRS signalling and messaging standards. This will allow the use of some existing software, as described under the discussion topics section below.

Doug the ham is so keen on using the existing VHF Ham APRS system that he has purchased the required radio, antenna, GPS and tracker, and will make it available for this HAB flight. Alexis suggests we proceed with the UHF plan, and use the Ham APRS system as a backup, as a replacement if there are problems getting the UHF system working, or as a parallel self contained tracking system. Doug also has another project in mind for this gear: developing a microprocessor payload that controls a steerable parachute dropped from a kite, drone, or balloon so that it navigates to a predetermined retrieval location.

GPS NOTE: Not all GPS units are suitable for HAB work. Some have altitude limitations. Some also have rate-of-change constraints that the US government imposed at one time to prevent American GPS units from being used in enemy missle guidance systems. Byonics sells 2 different GPS units - one for altitudes up to 60K feet / 18 Km, and a different, slightly more expensive one for altitudes up to 270K feet / 84 Km. Details
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Some discussion topics

---- Topic ---- ---- Discussion ----
Radio signal strength / propagation Dave did some calculations, with assumptions, and believes we're OK with the UHF radio. (The VHF radio outputs 1.0 watt, much stronger):
Assuming a full 10mW UHF output, a minimal 1dB loss to the antenna, 3dBi of transmit gain (should be more like 5 dBi), a free space path loss of 102dB (40km line of sight at 434MHz), a receive antenna gain of 12dBi, and a 1.5dB loss in a length of coax to the Ft-817(ground radio receiver), the received signal should be near enough to 20 microvolts, or S7, a nice strong signal, 20dB or more S/N.
Maximum acceleration GPS specs say maximum is 4G, some references warn to expect up to 8G on balloon burst. Some team's photos seem to show simple shock absorbers in support lines
RaspPi software to generate the APRS signalling, and something needed on ground to interpret it, and generate map references Xastir being considered for the payload RaspPi, (http://xastir.org/index.php/Main_Page) and Alexis is already testing it. FLdigi is proposed for the ground receivers - https://sourceforge.net/projects/fldigi/
Some GPS units have altitude limitations, and Byonics sells one specifically for HAB applications The specs for the GPS UWO is using are 50,000 meters, and up to 4G acceleration. See "maximum acceleration" topic higher up in this table. The Byonics HAB GPS is good to 270,000 feet = 84,000 meters.
Payload Retrieval One teams log noted that landing damage and/or awkward orientation may prevent further radio transmissions. They recommended using SPOT satellite location service. Location options:
-hope transmitter keeps working and be ready to do Radio Direction Finding (RDF)
-depend on last GPS transmission. readings are within 2.5 meters, offset by drift between last transmission and landing - up to 60 seconds
-change to a different antenna after, or just before touchdown?
-have a second hardened radio/antenna that's activated just before touchdown?
-generate an audio tone of some sort that can be heard by searchers?
Including data in APRS messages APRS messages can contain what ever data you want (subject to about a 40 character length limitation) in addition to lat, long and alt. Might be able to do some data compression and get most of data transmitted in real time, at once a minute interval of APRS beacons.
double tracking systems Doug Elliott has purchased and will make available a specialized HAM APRS tracking system for HAB applications that includes
    -a 1 watt Radio that transmits on the standard Ham frequency,
    -a 37 inch dipole antenna,
    -a GPS selected for high altitude compatibility, and
    -a controller to connect everything together  ("TinyTrak 3") .
Alexis would like to proceed with development of UHF based tracking, but use Ham APRS system as a fallback, or parallel system. Details on the "MT-1000 HA Combo" near the bottom of this Byonics page.
Batteries Many HAB teams use specific AA batteries with reduced weight and better tolerance of cold weather. From Byonics:
For airborne or more mission critical applications, we recommend using three Energizer “Ultimate Lithium” batteries, which are cold weather tolerant, have significantly higher energy density that batteries of other chemistry, and are roughly 1/3 the weight of Alkaline batteries. Other batteries are fine for ground testing or low altitude, temperate weather operation
Update: Doug has 4 of these AA batteries, bought from Rona.
Timeline I'd be glad to leave the project management stuff of my pre-retirement days behind me, but I think it would be helpful to have a rough and tentative schedule, especially for items that have a long leadtime. Hmm. That probably warrants another section in this webpage - I'm on it.
Things to be careful with -handling latex balloon only with gloves on (Some websites say this isn't actually needed.)
-starting radio transmitters only if antennas or dummy loads connected
-helium safety procedures
-crowd control at launch site: cordon off launch area & have safety officer?
-chase vehicle drivers distracted by radios, cell phones, laptops
Water Landing Possibility There are a lot of lakes, rivers, swamps, etc in Southern Ontario that our payload could end up in.
-should Doug put his canoe on top of his chase vehicle (An Odyssey van) just in case?
-will the payload be waterproof, avoiding damage that might prevent recovery of data
-will the payload float indefinitely on the surface of a lake, or will it sink soon?
Chase vehicle personnel I'm watching European balloons that have sustained ground speeds of 20 to 40 km/hour. Our chase vehicles, being constrained to roads, will likely have to travel twice as far, or twice as fast. This makes me think it's probably mandatory from a safety point of view to have at least 2 people in each chase vehicle, so the driver can concentrate on driving, and navigating.
Chase Coordination The hams will probably want to co-ordinate chase operations using VHF radios.
-Should we use SORT repeaters, simplex...? 
-Should we try to have a ham in each chase vehicle? 
-Should we have someone act as net control, co-ordinating chase vehicles and sending out text message updates to a distribution list frequently?
-should we have a contact information sheet (started below) that has, for all locations and vehicles
    -names of all people expected
    -cell phone numbers
    -ham radio facitities
    -vehicle license plate
    -chase gear present
        -radio receiver > mapper for 434.6 MHz
        -radio receiver > mapper for 144.39
        -Internet browsing ability for APRS.fi map
Zeroing in on payload -trackers may still be transmitting after payload lands - should we be ready to use fox hunt / radio direction finding techniques?
-will the short burst nature of APRS transmissions make it difficult to take bearings.
-need to have compass, protractors, parallel rulers and paper maps ready if we want to try this
-possible future electronics/readio project: capture bearings on short APRS transmissions, and correlate to decoded call sign
What to do when darkness falls? -predetermined meeting place? Probably have to ad lib, depending on balloon path
-do we have a contingency to continue searching on the morning after launch
Standardize map Should we all be using a common map and grid scheme for identifying locations?
-we'll mostly be using electronic mapping, and different ones in different software tools
-suggest standard way of identifying locations using:
    -local place names, like "heading north of Stratford on highway 123"
    -decimal lat/long, like:  my last GPS report was 40.21 degrees North, 80.73 degrees West
Launch Date -Tentative date of Sunday May 27 was scrubbed due to possible thundershowers
-current planned launch date is Tuesday May 29. Location? Arrival time? Is launch site secured for safety?
Expected Flight duration: 3 - 4 hours

-about 1.5 - 2 hours ascent,
-about 1.5 - 2 hours descent


Flight Height, in Kilometers


20 22 24 26 28 30 32
Average ascent or descent rate in Meters per second 3 1.9 2 2.2 2.4 2.6 2.8 3
4 1.4 1.5 1.7 1.8 1.9 2.1 2.2
5 1.1 1.2 1.3 1.4 1.6 1.7 1.8
6 0.9 1 1.1 1.2 1.3 1.4 1.5
7 0.8 0.9 1 1 1.1 1.2 1.3
8 0.7 0.8 0.8 0.9 1 1 1.1










Values in chart = number of hours for ascent, or for descent

             

Contact and Equipment Details

(work in progress)

 
   "Location" Person      Car License Ham Callsign Cell Phone / Text 434.6 MHz mapper 144.39 MHz Mapper APRS.fi mapper Fox Hunt / RDF
Launch Point only UWO Person 1 ?              
  UWO Person 2 ?              
Chase-1 Doug Elliott - driver VA3DAE VA3DAE 519-630-8925 no yes yes yes-144.39
  Tom Pillon - shotgun   VE3HOR          
  UWO?   VE3abc          
Chase-2 Dave McCarter VE3GSO VE3GSO 519-319-1437 yes no yes yes-144.39 ?
  Shotgun - UWO ?              
Chase-3 ? Alexis Pascual - UWO xxx.111   519-xxx-yyyy no no yes no
                 
Chase-4 > UWO person? yyy.222   519-aaa-bbb no no yes no
                 
                 
                 
                 


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Some related links

-Byonics - providers of the TinkTrak family of trackers: Byonics
       -their HAB kit:MT-1000 HA Combo: GPS, controller, 1W frequency agile programmable VHF transceiver, and dipole antenna, for U$D 220.
       -manual for above.

-A combined High Altitude GPS / controller / radio:  https://www.highaltitudescience.com/products/stratotrack-aprs-transmitter
       -manual for the above unit, with lots of related info: manual 
       -products from same company: product page includes some interesting kits, & "train" with swivel
       -tutorials from same company: tutorials
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Webpages for other HAB Info and Teams

Wikipedia

Naval Academy Amateur Radio BALLOON Experiments

UK: RaspPi, same Radio, schematics

Amateur Radio High Altitude Ballooning (ARHAB)

How to launch a HAB

University of Regina  Canada Wide High Altitude Balloon Experiment

The Global Space Balloon Challenge (547 teams in 67 countries)
   -antenna theory page says you need to survive 8G's at burst - our GPS has 4G maximum?
   -has forum, tutorials, etc
   -suggests RaspPi camera for economical high quality video and stills

Brown University "Owen"  360 degree camera with 4K resolution

University of Saskatchewan 

Launch with us - semi-commercial launches? 

First Canadian Stratospheric Balloon Launch from Timmins in 2013 

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Rough and Tentative Timeline

"Subject to change is an understatement"

  --- Date ---   --- Milestone ---     --- Responsible ---
         Person
done Development complete on 434.6 MHz payload transmitter  
Development complete on 434.6 MHz ground receiver, decoder and map generator
  End-to-end testing complete on 434.6 MHz tracking system  
done End-to-end testing complete on 144.39 MHz tracking system  
done Go/nogo decision on inclusion of 434.6 MHz tracking system - it's in  
done Go/nogo decision on inclusion of 144.39 MHz tracking system - it's in  
done Testing complete on payload sensors and data acquisition  
done Construction, integration, packaging and testing of payload electronics  
done Construction and testing of payload container and connection cords.  
  Testing complete on parachute deployment system  
done Chase vehicle plan decided and documented  
  Chase vehicle equipment tested  
  Chase rehearsal completed?  
  Tethered test flight completed?  
done Launch date and location finalized. It's never final, but May 29 is current target. Location is near Orchardville  
  Launch day safety plan developed, and documented  
Launch day safety plan reviewed.
  Launch day time line decided and documented - tentatively Tuesday May 29  
done Launch approvals and notifications prepared  
done Launch approvals and notifications reviewed  
done Launch approvals and notifications submitted. Still need launch day communications with NavCan.  
done Helium tank ordered  
done Helium tank picked up  
  Launch day materials gathered and pre-packed  
  Publication of data extracted from recovered payload,  
  Publication of flight data extracted from APRS.fi Elliott
  Publication of data analysis  
  Publication of Mission Summary  
  Formulation and publication of future HAB plans  
     

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Configuration Information

Full Byonics Tracker Config

which will be included in payload, with external vertical dipole antenna 37 inches long.

Notes
-call sign = VA3DAE
-path = WIDE2-1
-Auto TX Rate = 60 seconds
-status text: "UWO Balloon"


The Direct Receive path

Direct Beacon Path details

from Onboard Balloon tracker to Vehicle Radio > Laptop /Map display

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To Do List

scribbles to compensate for Doug being old and forgetful...

Done? Due Date For Whom                Description     
  May 26 Elliott document Laptop receiver/mapper set up for McCarter  
y   Elliott waterproof APRS tracker & document installation requirements  
y   Elliott deliver APRS tracker to Alexis for inclusion in payload  
y   Alexis Publish Launch time and location  
y   Alexis Publish chase vehicle strategy - are we recruiting ASAP?  
    Alexis Publish chase vehicle coordination communications strategy  
y   Alexis Publish predicted flight path twice daily and/or method to generate it  
    Elliott Get independent APRS tracker working in van?  
  May 27 Alexis Publish procedure to be followed when payload is found  
  Alexis Publish procedure to be followed if payload not located by darkness on May 29
  May 29 Elliott Test APRS tracker at launch site  
    McCarter preposition chase vehicle (ideally with assistant) near predicted landing point  
    Alexis Communicate actual launch time  
    Chasers Find the payload, & return it to London untouched (unless it has water inside?)  
    Elliott Download beacon history from APRS.fi  
May 30
         
         
         

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Stuff to go in the chase vehicle


-Tom Pillon, to help with Ham operations
-several UWO staff
-bottled water and snacks
-857, signalink, laptop, GPS, handhelp GPS, cabling, work surface?
-canoe paddles, lifejackets, ropes, etc
-Binoculars
-fox hunt gear
-rubber boots
-work gloves
-painter pole with large hook
-pruning and wire saws
-change of clothes
-maps to mark bearings on, compass, parallel rulers, protractor, etc
-multiple charged up HT's
-multiple charged up Cell phones
-chargers for cell phones, HT's
-hand held GPS
-notebook, pens, pencils, erasers
-contact information list
-12V power splitter
-large battery pack
-hat, sunscreen, rain gear?
-slingshot, weight, chalk cord
-orange marker tape
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Ideas for future flights

-write chase vehicle software that combines two technologies:
   - fox hunt techniques that do rapid 360 degree scanning for strong signals (boxes with compass rosette LEDs)
   - APRS client software that tell us what call sign did the last transmission
  to have a box that zeroes in on our payload callsign, and flashes one of, say, 8 LEDs to tell you what direction it came from

-involve Joe O'Neill, a professional expert commercial drone operator, to see if he could take part in the chase, and provide an aerial viewpoint. If the balloon lands in a forest with heavy foliage, this may be the only way we see it. His drones already have GPS, and we might be able to put an APRS client and or beacon on drone?

-have a bunch of ham chase vehicles, each with their own APRS tracker, so they show up on APRS.fi maps, and can do payload approaches from different directions.

-do a lot more pre-flight testing.

-use custom software in the onboard APRS beacon (Byonics device supports this) to:
   -go to beaconing every 15 seconds if the altitude is below some threshold, which takes into account the ground altitude in the predicted landing area
   -switch to a different internal antenna after landing which is less likely to be damaged (or alternate between them)
   -transmit useful data in the beacon, possibly including:
       -climb rate - could be calculated from altitude values, and time delta
       -ground speed - simple calculation from previous and currrent locations
       -some sensor readings - probably need to encode and compress them to fit into telemetry data space in beacon
       -remaining battery capacity - simple analog to digital conversion
       -software status on all microprocessors, Raspberry PI's, beacon's PIC, etc

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Latest Flight Path Prediction

Using the online prediction software at: http://predict.habhub.org/
and these launch parameters:
      lat/long = 44.07.61  -80.8353
      altitude = 300 meters
      time = 17:00  UTC (= 13:00 local)
      date = 29 May 2018
      ascent rate = 3.55
      burst altitude = 26500
      descent rate = 4.57

Latest Landing point prediction made on: May 29 / 00:15. Forecasted landing: Between Arthur and Fergus
Start
= red circle, near Orchardville,  End = green circle. Star = predicted balloon bust location

flight path

73,
  Doug

                                                       
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