1. PSAT PSAT-2 Remote Data & Comms Transponder
2015 Smallsat Cubesat Conference, Utah
Bob Bruninga WB4APR
US Naval Academy Satellite Lab
Ocean Buoys w/ RF Terminals
Title
Name of ParkinsonSAT is in honor of Dr Parkinson of GPS fame and a USNA grad
Shortened to Psat…
GROUND
STATION
A satellite relay channel for Amateur Satellite User data anywhere on earth.
PSAT

2. Ground Terminal Applications Focus (force tracking and text-messaging)
Quicker Student involvement using a Ground Terminal Operational Concept
Ground Terminal Applications Focus (force tracking and text-messaging)
Supports Student Experimenters
School missions/movements
Theater area communications
and Emergency Response Comms
APRS tracking of course, plus remote data sensing, emergency comms drills, And travel/expedition remote data access.
The transponder can also be used by emergency response volunteers such as the
Military Affiliate Radio System (MARS).
Other educational users have access
Education
Force
Multiplier!
APRS Global data network
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3. Solution: Ground Terminal Applications Focus
Supports Student Experimenters world wide OR OR
Mobile and HTradios serve as Ground Terminal Equipment.
GPS gives “tracking” position data. Other sensors give other data OR OR

4. APRS Local & Global Internet linked Data Network
The APRS Internet captures all packets heard by anyone anywhere and makes them available to anyone
This permits Text Messaging between any/all systems also connected to the internet
APRS Global Packet Radio Network
Internet Linked for live Communications
Automatic Packet Reporting System
APRS Global data network
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5. Arctic Buoy Student Experiment
USNA Arctic Buoy deployed March 2012
The APRS piece

6. Example Remote Sensors using APRS Protocol
Very Simple
APRS transmitter
GPS
Typical student “near-space” experiments use the system for Balloon payloads.
COTS amateur radio transponders readily available.

7. Why We Need Psat Satellite Transponders
Transatlantic APRS balloon launched and tracked through terrestrial network
Lost comms over Atlantic Ocean
It could have been picked up by our Psat/Pcsat transponder or the ISS

8. Global Wilderness Areas (90% of Earth)
M0XER-3, 4 and 6
Live Global APRS Balloon Tracking Web Page

9. Hand-Held Satcom via APRS & Psat
Ground Terminal is Walkie-Talkie, and Palm Pilot
“When you have no comms, 1200 baud text/data is great!”
CAPT Chas Richard
To Quote the skipper of the USS Parche.. (red above)
“ *** “
In this photo,
The skipper, Ops bos and Chief Engineer and our Ensign Scrabeck are shown here
Using their handheld PCSAT ground terminal. (which is independent of all the other antennas shown)
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10. MAREA* Rover Projects ( ARRL)
STEM School projects
Excite kids with Robotics
Drive anywhere on Earth!
Via APRS links *

11. Psat APRS Network Architecture
Many of these IGates are tuned to the APRS Satellites too.
Global Volunteer Ground Station Network
Internet Linked for live Telemetry
APRS Global data network
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12. Remote Buoy Baseline Test – Success of 1 min Xmit rate
This chart summarizes the number of packets heard from a floating buoy operating at 5 watts once every 2 minutes.
As many as 11 reports per day were received when both PCSAT1 and PCSAT2 were active at the same time.
Wne PCSAT1 died again, then only the packets via ISS got through. But still, a few per day.
APRS Global data network
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13. Tracking (on Google Earth)
Map.findu.com/wb4apr*
Tactical situational awareness
Since all data is injected live into the internet by volunteer groundstations,
Numerous data mining applications have been developed, especially Google maps and satellite views

14. Findu.com Telemetry Plots
Live Example:
IN addition to position,course, speed, status, text and messages, remote telemetry can also be transmitted.
Such data is automatically archived by the internet system and available at any time from any browser
Even without prior arrangement! This shows a year of ANDE satellite telemetry captured by APRS

15. Dual Hop Operations with PCSAT-1 and PCSAT2:
This was the longest 2 hop DX via PCSAT1 and PCSAT2
APRS Global data network
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16. APRS Global data network
All on MHz
1990
With all APRS transponder satelites on the same frequency, there can be multiple hops!
Trans-Atlantic communications possible through satellite-to-satellite communications
See live downlink on and
APRS Global data network
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17. APRS Global data network
Huge reduction from transponders on PCSAT’s 1,2, ANDE and RAFT missions
Psat USNA-0601
Earlier reductions to 5” cubesat on RAFT (2006)
4:1
Read TITLE
First by a factor of 4 on RAFT (which were deployed from ISS in 2006)
And now by a factor of 18 or more for our CUBESAT design.
Now reduced 18:1 in volume/mass for 4” cubesat 2009
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18. APRS Global data network
A single 3” Square card
AX.25
MHz
Mission: Remote Data Relay, Data Exfiltration, Remote Sensor Relay
Benefit: Support Space Education on the ground through space applications and student experimental access
Hardware: VHF simplex data Xsponder MHz
Size/Mass: < 10 cu.in (1 PCB 3.4” square), <0.1kg
Power: < 1W orbit average, 5 volts.
Integration Requirement: Simply, on/off (or *)
Structure Impact: Needs 19” thin wire whip antenna (1 cu.in)
Benefit to Spacecraft: High visibilty to worldwide educational institutions, fosters collaboration, orders of magnitude greater student experimental access to space systems (ground segment). * Independent back-up telemetry command/ control channel, RS232 serial data, 16 on/off discretes, backdoor reset capability. Worldwide Telemetry Beacon access via global station network.
Here is a summary for potential as an AUX payload on Falconsat-6
APRS Global data network
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19. APRS Global data network
A single 3” Square card
AX.25
MHz
$5000
New Board Layout –
Standard Comm board
$250
Here is a summary for potential as an AUX payload on Falconsat-6
APRS Global data network
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20. Psat-1 Transponder & Aux Payload
75% Payload Space Available! (only 50% shown here)
18 cu.in for Transponder
External 19” whip antenna
68 cu.in for Aux Payload (SPMS?)
Aux payload gets 4” external panel
Aug payload gets .5 kg – self contained
1 to 3W average power for aux payload
The mechanical design allows for the additional clean integration of more than half of the volume for an AUX payload.
The challenge is getting the Moments of intertia maximized along the Z axis for a stable sun pointing spin.
Full sun power is 5.5 Watts, 1 to 3 watts is available for auxilliary payloads.
APRS Global data network
Vandegriff
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21. PSAT-1 Unique Power Attitude and spin
Uses only one Z coil for attitude Control
Fires only within +/- 20 deg of Equator
Solar Panel angle better than 95% power
Higher reliability
Passive Spin maintenance
Differential Radiation Spin

22. Plenty of Room for more cards
For Maximum MOI about Z
Batteries to outside for MOI & Shielding
Stainless steel belt around everything
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23. APRS Global data network
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24. APRS Global data network
When we find the time we are really looking forward to understanding our Solar Radiative Spin system.
APRS Global data network
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25. PSAT: Aux PSK31 Transponder Payload
Flew on PCSAT2 on ISS but astronaut broke off HF antenna
Flew on RAFT but took 1 kW uplink and negative power budget
Now Operational since May 2015 launch of PSAT and BRICsat
Both transponders built at Brno Univ, Czech Republic.
28 MHz
SSB uplinks
FM downlink
APRS Global data network
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26. PSAT Nitinol Wire Whip Antennas
APRS Global data network
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27. Wrapping Antennas to one Burn Resistor
2 Orthogonal UHF whips
One VHF whip
One 6’ HF whip
3rd Enable Switch
APRS Global data network
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28. APRS Ground Station Network
Many of these IGates are tuned to the APRS Satellites too.
Global Volunteer Ground Station Network
Internet Linked for live Telemetry
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29. APRS Global data network
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30. APRS FOCUS: “Network Centric” & Remote Sensor Experiments
Communications Mission Background APRS is everywhere * (Remote Data Relay)
FOCUS:
“Network
Centric”
&
Remote Sensor Experiments
APRS
The APRS transponder is an education multiplier giving student access to space with ground system experiments
Zoom in on Colorado Springs and you can see 50 “remote sensors/tactical assets” within 50 miles!
This shows the popularity of the Remote Data Reporting mission for experimenters (amateur radio operators and students)
300 stations In 35 miles
35 mi
Find any station, Any map, Anywhere-

31. APRS Terrestrial Data Relay Network
Supports over 20,000+ terrestrial users and experimenters.
Read the 1st bullet… then … this map shows the number of USA users and experimenters that use our AX.25 data channel terrestrially…
but any of these users can switch to our uplink with a click turn of their frequency knob.
As an example, The Mars Society was an educational arctic outpost that has used our system
… Read last bullet
But stops at the shoreline and has huge holes in the wilderness
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32. There are terrestrial network holes everywhere
Just like cell coverage,
Maybe 70% of USA users are actually out of range of the terrestrial network in rural areas
And the terrestrial user does not know when the next
APRS satellite is in view…