Jordan Truesdell
Tracking Methods
 Visual
 Audio Direction Finding
 Radio Direction Finding
 Global Positioning System
Radio Direction Finding
 Rocket payload - RF Beacon
 Transmitter
 Battery
 Antenna
 Tracking Kit - Receiver
 RF receiver
 Antenna
 Attenuator
Radio Direction Finding
 Non-rocketry trackers
 Falconry
 Hunting Dogs
 Wildlife tracking
 Fox Hunting / HAM RDF
 Rocketry trackers
 Walston Retrieval Systems
 Big Red Bee - Beeline
 Altus Metrum - Telemetrum
Radio Direction Finiding
 Antenna usage
 Directional / high gain Yagi
 Offset attenuators
 Body shielding
GPS Coordinate Transmission
 Child/Animal Locators
 Typically use SMS (text message) to send GPS
coordinates via cell towers
 Can use MURS RF frequencies with custom receiver
(Garmin Astro)
 Cell Phones
 Use Android software to send telemetry
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SMS or Bluetooth to RF link
 Use iOS “Find iPhone” application
 Satellite Location Services (SPOT Tracker)
GPS using HAM Radio
 Rocket payload - GPS receiver
 GPS receiver
 APRS encoder/Transmitter
 Battery
 Antenna
 Tracking Kit - Receiver
 RF receiver & Antenna
 APRS Decoder
 GPS Mapper or Locator
GPS using HAM Radio
 Most trackers use 70cm (430MHz) amateur band
 Large frequency band
 Small antenna requirements (1/4 wave whip)
 Available to Technician class amateurs
 Technician Test
 $15, available from NRV Am. Radio Club or VT Am. Radio Assn
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NRV Meeting 8/26 @ C’burg Library, 7:30pm
Next Exams: VT 9/18, 7pm, TBD || NRV 10/13, 2pm, Radford Library
26 of 35 multiple choice questions from pool of ~350
Study the question pool with books or online
Study guides available for iOS and Android
GPS using HAM Radio
 My Tracking Devices
Big Red Bee – Beeline GPS (~$260)
Baofeng - UV-5R
(Amazon, $33-40)
iOS device Tablet and/or phone
with APRS software
APRS Software
 APRS (Amateur Packet Radio Service) transmits data
at 1200 baud (bits per second), similar to old modems
 Two useful iOS applications
 PacketPad
 Simplest interface, listens through the mic for AX.25 packets
and decodes the data.
 Results are saved and can be cut and pasted into other apps
 PocketPacket
 Primarily Internet based (will receive APRS-IS), but has an
acoustic modem option
 Shows location overlaid on Google Maps
 Allows detailed data from screen markers
There’s got to be a better way
 Acoustic capture of data packets is a hit-or-miss proposition
 Most APRS Terminal Node Controllers (TNC) are difficult to find,
expensive, require a computer, or all three
 Direct wire connectors are generally not made for this application; one
possible schematic is:
Capture & Tracking: PocketPacket
Disable APRS-IS
Enable Audio Modem
Locate your transmitter
and Go get the rocket, or…
Get Specific Location
Information
Capture & Tracking: PacketPad
 I prefer to use PacketPad during the flight
 Shows record of all received transmissions
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Verification of packet info receipt & decoding
Log of received values (in case it does disappear)
Coordinates are listed as DDMM.MM[N/S]/DDDMM.MM[E/W]
Yes – Degrees, Minutes, and Hundredths of minutes
Using FreeGPS, enter the data:
Or copy/paste the data into Google Earth, editing the string
for Google formatting:
Note: Google Earth/Maps chose a close address and did
NOT show the actual location on the map accurately
GPS Tracking Prep
 Arm GPS at prep bench and acquire signal
 Beeline GPS battery is 750 mAh@3.7V, lasts 10 hours
 A “cold” start GPS may take up to 20 minutes to lock
 Turn on receiver and listen for tones
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Sounds like an audio modem or fax machine preable
After lock, transmission is every 2 seconds
Data includes callsign, lat/long, altitude
 Factors which affect transmission
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Antenna size and type
Antenna orientation (polarization)
Payload bay material – no conductive materials (i.e. Carbon Fiber)
GPS Flight Example
 Goldfinger – L2 Flight / J357
 Predicted Altitude ~6000’
 Beeline GPS onboard
 Audio acquired on bench and verified
receiving/decoding while armed on pad ready
for launch
Beeline GPS rode in upper payload bay, installed
into a plastic “spice jar” with a lanyard on the
cap which held it to the recovery harness
GPS Flight Example
 GPS lock was lost during boost, regained near apogee
 Data was copied out of PacketPad and into Google Earth
 Recovery was made ~ ½+ mile away from the launch site.
 Drove to within 100 yards of the landing site
 An anomalous data point had us searching ~ 150 yards
from actual touchdown. Use of real-time recovery data
should be verified.
 0.01’ at N37° is between 15-20 meters
GPS Flight Example - Landing
Data point shown had us
searching along the treeline
on the east of the road.
Re-acquisition of data
point, or real-time mapping
(like PocketPacket or
GPS/APRS handheld
transmitter) would have
made the search even
easier!
GPS Flight Example
Download of GPS data in KML (Keyhole Markup Language) allows visualization
of flight using Google Earth:
GPS Flight Example
 Review of flight data from KML file can reveal flight
statistics:
Latitude Longitude Altitude
1957m – 135m)
x3.28 = 5976 feet
-78.064633,38.398550,00135
-78.064633,38.398552,00135
-78.064640,38.398567,00137
-78.064695,38.398725,00142
-78.064853,38.399163,00147
-78.065155,38.399715,00151
-78.067125,38.401113,00425
-78.068147,38.401733,00750
-78.062005,38.397657,01957
-78.061900,38.397588,01942
.....
<!-<!-<!-<!-<!-<!-<!-<!-<!-<!--
-78.054227,38.399550,00119
-78.054228,38.399550,00118
-78.054228,38.399552,00118
-78.054227,38.399552,00118
<!-<!-<!-<!--
Liftoff @
Altitude
Increase
55410
55425
55440
55455
55470
55485
55500
55515
55530
55545
Time
sats:10 UTC 17:46:59 -->
sats:10 UTC 17:47:00 -->
sats:10 UTC 17:47:01 -->
sats:10 UTC 17:47:02 -->
sats:7 UTC 17:47:03 -->
sats:5 UTC 17:47:04 -->
sats:7 UTC 17:47:06 -->
sats:7 UTC 17:47:07 -->
sats:10 UTC 17:47:18 -->
sats:10 UTC 17:47:19
Lost GPS
Lock
Apogee @ Altitude Decrease
59610
59625
59640
59655
sats:11
sats:11
sats:11
sats:11
UTC
UTC
UTC
UTC
17:51:57
17:51:58
17:51:59
17:52:00
-->
-->
-->
-->
Questions