1. DINO Communication System CDR
Chris Page
Matt Syme
Dotto Manega

2. Purpose of Communications System
Establish two-way communication link between satellite and ground station.
Allow transfer of map and image files from satellite to ground.
Allow transmission of health and status data from satellite to ground.
Allow the satellite radios and flight computer to receive command or schedule lines transmitted by ground station.
Colorado Space Grant
Consortium

3. Agenda Overview of Functional Requirements / Design
Requirements from Subsystems
Overall need of DINO Satellite (Map Size)
(Structures)
(Thermal)
Requirements on Subsystems
Power
C&DH
Software
Structures
Colorado Space Grant
Consortium

4. Agenda Detailed Design (2 additional designs)
Major Components
Radios
TNC
Antennas
Fabrication and Testing Schedule
(Bent Dipole Antenna)
TNC and Radio Testing Schedule
Parts List and Cost
Documentation Progress
Subsystem Plans to Deliver
Colorado Space Grant
Consortium

5. Overview of Functional Requirements
Overall system demands:
Receive schedule
Overall system demands:
Transmit topographical map, health and status, and image information
Antenna
Antenna
Structures demand:
Antennas must be easily deployable, specific area allocated on NADIR plate
Radio2
Receiver
Kenwood TH-D7
Radio1
Transmitter
Kenwood TH-D7
Thermal demand:
Need area of greatest heat dissipation for health and status
Internal
TNC
Internal
TNC
Software Demand:
Shared Serial Port commands
External Terminal Node Controller
(TNC)
C&DH demand:
2 RS-232 Serial Ports for power up and data
Power demand:
Power requirements for TNC and Radios
Colorado Space Grant
Consortium

6. Requirements from Overall System
Must have high data rate to accommodate all transmitted and received information
Transmit from satellite to base station
100 kbytes per topographical map
255 bytes per Health and Status Packet
Image file looking to be thumbnails
Receive from base station
5 kbytes per uploaded schedule
Working Solution
Using external TNC to accomplish 9600 BAUD
Still working on connection between Radios and TNC
Colorado Space Grant
Consortium

7. Requirements : Transmission Time
Using Payload Byte estimates
For 1200 bits/sec (150 bytes/sec), get ≈ 592 bits/sec (74 bytes/sec)
For 9600 bits/sec (1200 bytes/sec), get ≈ 6400 bits/sec (800 bytes/sec)
Calculated Transmission Time based on 1200 BAUD Payload loads
Calculated Transmission Time based on 9600 BAUD Payload loads
Colorado Space Grant
Consortium

8. Maximum Transmission Distance Calculations
Low orbit height from earth = 425km
Maximum distance from base station antenna (horizon) = (with =5o , slant angle) 1.84x106m
For =10o  1.39x106m
For =15o  0.99x106m
These distances play into our free space loss and ultimately our link budget
Diagram Reference:
Vincent L. Pisacane and Robert C. Moore, Eds., Fundamentals of Space Systems. New York: Oxford University Press, 1994.
Colorado Space Grant
Consortium

9. Requirements from Structures
Specific Placement on NADIR plate
Final angle and length of bent dipole antenna must be provided
Pic of NADIR plate
Shade area given
Will have this information for structures after impedance and frequency matching is done (estimated completion is March 31)
Colorado Space Grant
Consortium

10. Requirements from Structures cont.
Final placement points for two antennas on NADIR plate
Interior dimensions and weight of radios and TNC
Placement points for two antennas pictured
Interior dimensions and weight
Radios: Mounted together in one 3CS-sized box
4.9 x 2.3 x 1.2 inches each
170 grams each
TNC: UP-9600 Ultra-miniature Packet Modem
1.0 x 2.5 x 4.75 inches
Upper estimation of 40 grams
Pic of NADIR plate
With antenna placement
Colorado Space Grant
Consortium

11. Requirements from Thermal
Need area of radios and TNC that has greatest heat dissipation
Radios
Located at ……. Inside radios
Calculated temperature: 5°C
TNC
Information Still being researched
Area of largest heat dissipation on radios
Colorado Space Grant
Consortium

12. Requirements on Power
Transmitter (Radio1): must have capability to be activated/deactivated by flight computer
Transmit mode
12 V at 1.4 A (16.8 W)
Idle mode
12 V at 90 mA (450 mW)
Receiver (Radio2): must be active concurrently with flight computer
5 V at 90 mA (450 mW)
External TNC: must be active when flight computer is active
12 V at 100 mA (1.2 W)
Power connection on stripped down radio
Colorado Space Grant
Consortium

13. External Terminal Node Controller
Requirements on C&DH
Two RS-232 Serial Ports
1 serial port dedicated to external TNC
9600 baud, 8 data bits, no parity bit, 1 stop bit
Must have hardware flow control (CTS, RTS)
1 serial port shared between radio1 and radio2
Must be able to switch at any time between the two radios
Software flow control only
Radio2
Receiver
Kenwood TH-D7
Radio1
Transmitter
Kenwood TH-D7
Internal
TNC
Internal
TNC
External Terminal Node Controller
(TNC)
Colorado Space Grant
Consortium

14. Requirements on Software
Start up Radio1 (Transmitter) Parameters
Switch the shared serial port to Radio1 immediately after Radio1 is powered on
Must program the following parameters into Radio1:
Select Band: B
Set Mode: Single
Tx Operating Band: 70cm
Tx frequency: ~436MHz
Power Output: 5W (5.5W max)
Squelch: 1 (closest to low)
Radio1
Transmitter
Radio2
Receiver
External Terminal Node Controller
(TNC)
{ "TC 1\r", , TF_junk }, // enter PC command mode (radio commands)
{ "", , TF_junk }, // give time to process before continuing
{ "DTB %x\r", , TF_nul }, // select band(s) for data transfer
{ "DL %d\r", , TF_nul }, // set dual/single band mode
{ "APO 0\r", , TF_nul }, // auto-power-off off
{ "ARO 0\r", , TF_nul }, // auto repeater offset off
{ "CT 0\r", , TF_nul }, // CTCSS subaudible privacy tone off
{ "SV 0\r", , TF_nul }, // auto save mode off
{ "BC %a\r", , TF_dualband }, // select TX operating band
{ "FQ %f,0\r", , TF_dualband }, // set TX frequency and step size
{ "BC %b\r", , TF_nul }, // select RX operating band
{ "FQ %g,0\r", , TF_nul }, // set RX frequency and step size
{ "PC %a,%p\r", , TF_nul }, // set power output for TX band (0=hi,2,3=lowest)
{ "SQ %b,%s\r", , TF_nul }, // set squelch level for RX band
{ "DS 0\r", , TF_nul }, // ignore traffic on non-data
Colorado Space Grant
Consortium

15. Requirements on Software, Continued
Set up Radio2 (Receiver) Parameters
Switch the shared serial port to Radio2 immediately after Radio2 is powered on
Must program the following parameters into Radio2:
Select Band: A
Set Mode: Single
Tx Operating Band: 2m
Tx frequency: ~144MHz
Power Output: 5W (6W max)
Squelch: 1 (closest to low)
Radio1
Transmitter
Radio2
Receiver
External Terminal Node Controller
(TNC)
{ "TC 1\r", , TF_junk }, // enter PC command mode (radio commands)
{ "", , TF_junk }, // give time to process before continuing
{ "DTB %x\r", , TF_nul }, // select band(s) for data transfer
{ "DL %d\r", , TF_nul }, // set dual/single band mode
{ "APO 0\r", , TF_nul }, // auto-power-off off
{ "ARO 0\r", , TF_nul }, // auto repeater offset off
{ "CT 0\r", , TF_nul }, // CTCSS subaudible privacy tone off
{ "SV 0\r", , TF_nul }, // auto save mode off
{ "BC %a\r", , TF_dualband }, // select TX operating band
{ "FQ %f,0\r", , TF_dualband }, // set TX frequency and step size
{ "BC %b\r", , TF_nul }, // select RX operating band
{ "FQ %g,0\r", , TF_nul }, // set RX frequency and step size
{ "PC %a,%p\r", , TF_nul }, // set power output for TX band (0=hi,2,3=lowest)
{ "SQ %b,%s\r", , TF_nul }, // set squelch level for RX band
{ "DS 0\r", , TF_nul }, // ignore traffic on non-data
Colorado Space Grant
Consortium

16. Requirements on Software, Continued
External TNC Parameters
Packet Size: 256
Data Bits / Byte: 8
Set RF BAUD Rate: 9600
No callsign needed
{ "TC 0\r", , TF_nul }, // enter TNC command mode
{ "", , TF_junk }, // absorb all the init text
{ "P %z\r", , TF_cmd }, // set packet size
{ "AW 8\r", , TF_cmd }, // data bits / byte
{ "RES 1\r", , TF_cmd }, // ACK packet delay time (100msec)
{ "FR 1\r", , TF_cmd }, // frame retry delay (1 sec)
{ "DW 10\r", , TF_cmd }, // clear channel delay wait
{ "PP OFF\r", , TF_cmd }, // P-persistent CSMA off
{ "CR ON\r", , TF_cmd }, // add CR to sent packets
{ "AU OFF\r", , TF_cmd }, // don't add line feed to each CR rec'd
{ "MAX 2\r", , TF_cmd }, // send a maximum of N frames at a time
{ "MYC %c\r", , TF_cmd }, // set my callsign
{ "F OFF\r", , TF_cmd }, // show all rec'd packets
{ "X ON\r", , TF_cmd }, // XON/XOFF enabled
{ "HB 1200\r", , TF_cmd }, // set RF data baud rate
{ "CONOK OFF\r", , TF_cmd }, // don't accept connection requests
{ "TXU ON\r", , TF_cmd }, // send packets in unconnected mode
{ "E OFF\r", , TF_cmd }, // echo of xmit data & cmds off
{ "", , (TF_type)(TF_junk | TF_stop) }, // absorb junk & stop };
Radio2
Receiver
Radio1
Transmitter
External Terminal Node Controller
(TNC)
Colorado Space Grant
Consortium

17. Commands after Antenna Deployment1 2 3 4
TNC power activated
Radio2 power activated
Software switches serial port to Radio2
Software programs Radio2 5 6 7
Radio1 power activated
Software switches serial port to Radio1
Software programs Radio1
System Ready
Colorado Space Grant
Consortium

18. Design, Fabrication, and Testing
Detailed Design
Major Components
Radios
TNC
Antennas
Additional Design #1
Additional Design #2
Fabrication and Testing Schedule
(Bent Dipole Antenna)
TNC and Radio Testing
Colorado Space Grant
Consortium

19. Comm. System Block Diagram
All Data lines will use the RS-232 Serial Port
Transmitter operates at 12 V
Receiver operates at 5 V.
External TNC operates at 12 V, allows 9,600 bps link to ground.
Internal TNC proven to be reliable at 1,200 bps.
Antenna
Antenna
5 V line voltage
90 mA
450 mW
(constant)
Radio1
Transmitter
Kenwood TH-D7
12 V line voltage
1.4 A
16.8 W transmitting
(450 mW idle)
Radio2
Receiver
Kenwood TH-D7
RS-232 Serial
9,600 bps
(during setup only)
RS-232 Serial
9,600 bps
(during setup only)
Internal
TNC
Internal
TNC
Legend
External Terminal Node Controller
(TNC)
Power Line
Data Line
RS-232 Serial
9,600 bps
(constant)
12 V line voltage
400 mA, 4.8 W
(constant)
Colorado Space Grant
Consortium

20. Radio Consideration
Considered Three Models: ICOM IC-ID1, Kenwood TH-D7 and Stanford Quakesat Flight Radio
ICOM IC-ID1
Kenwood TH-D7
Stanford Quakesat Flight Radio
PROS
Built in TNC w/high Baud rate
Operates in two frequency bands
Requires no actual programming:
USB interface
Third cost of IC-ID1
unlike the Kenwood Radio
1.2 GHz allows for smaller antenna
Fair amount of experience from other missions
CONS
Expensive (~$1,600 per radio)
Restrictive baud rate (maximum of 9.6 Kbps)
Research still in progress regarding
Only Operates within one band of frequencies:
Requires a larger antenna
size, weight power, interface, etc.
communication would be half duplex
Uses an RS-232 interface
Would need to modify ground equipment to use
Decided on Kenwood TH-D7 because of familiarity and BAUD rate would be sufficient for our purposes
Colorado Space Grant
Consortium

21. TNC Consideration PK-96: 9600 baud PROS: CONS: Great technical support
Already have this particular TNC here
Not extremely expensive: $220.
CONS:
High power consumption
Must replace existing capacitors and chips to reach the specifications we want
Colorado Space Grant
Consortium

22. TNC Consideration cont.
KPC-9612+
PROS:
Power Consumption: 5.5V to 45mA (.25W to 1.1W)
Fast data transfer
Up to 38.4Kb/s which can be modified with a crystal change that will bump it up to 56Kb/s
However faster data transfer rates are limited by the radio we use
CONS:
Communications with the company
Unable to contact via phone
takes about 1-2 weeks
Contains electrolytic capacitors
Colorado Space Grant
Consortium

23. TNC Consideration cont.
Ultra-miniature Packet Modem (UP9600): 9600 baud
PROS:
Very low power consumption: 9V to
30-60mA (0.27W to 0.72W)
Customizable Firmware available
Small size: 2.5” x 4.75”
CONS:
Price: $595.
Have had troubles customizing PacComm TNC’s in the past
Colorado Space Grant
Consortium

24. TNC Recommendation The PacComm UP9600 Meets all specifications
Uses by far the least amount of power
Surface mount design saves us time by not having to modify any parts
The only downfall:
The Price: $595.
Colorado Space Grant
Consortium

25. Antenna Considerations
Receive Antenna
Monopole
Targeted Frequency: 145MHz (2m)
Transmit Antenna
Bent Dipole
Targeted Frequency: 436MHz (70cm)
Base Station Characteristics: Yagi
Power: 25W (safe figure)
Gain: 15dBi
Circular Polarization
Colorado Space Grant
Consortium

26. Antenna Considerations: Monopole
Link Budget Form courtesy of Dr. Stephen Horan, New Mexico State University.
Colorado Space Grant
Consortium

27. Antenna NEC Simulation: Monopole
Notes
Getting highest gain and radiation pattern on sides as expected
Gain ~1.08dBi
Colorado Space Grant
Consortium

28. Antenna Considerations: Bent Dipole
Link Budget Form courtesy of Dr. Stephen Horan, New Mexico State University.
Colorado Space Grant
Consortium

29. Antenna NEC Simulation: Bent Dipole
Notes
Gain has decreased to ~6dBi due to replacement of bent dipole antenna to comply with structures
Issues with being able to simulate full structure of NADIR plate
Colorado Space Grant
Consortium

30. Fabrication and Testing Schedule: Bent Dipole
Bent Dipole Antenna
Ready for testing
Impedance matching (simulated a SWR of 1.86:1)
Have approval to use Network Analyzer in CU Transmission Lab
Next step is to schedule time with Professor Kuester
Connect to transceiver to test for frequency
Vertical and Horizontal Planes and Gain measurements
Colorado Space Grant
Consortium

31. TNC and Radio Testing Schedule
Incremental Testing is important to track bugs
Test TNC on bench first, connected directly to another TNC
Connect TNC to flight radios. Make transmissions of ASCII character strings. Verify proper operation.
Test to make sure that received packets get properly decoded and sent out of TNC serial port.
Install Radios and flight antenna prototypes into metal DINO model
Connect a computer running the flight software to the TNC in the DINO model
Attempt communication link between ground station and DINO flight model.
Colorado Space Grant
Consortium

32. External Terminal Node Controller
Additional Design #1
Antenna
Antenna
Idea #1: use relays for radios in case of radio malfunction
Issues: increased complexity (i.e. software)
Concerns: a need to eliminate magnetic fields and moving parts (considering solid state MOSFET device)
5 V line voltage
90 mA
450 mW
(constant)
Radio2
Receiver
Kenwood TH-D7
Radio1
Transmitter
Kenwood TH-D7
12 V line voltage
1.4 A
16.8 W transmitting
(450 mW idle)
RS-232 Serial
9,600 bps
(during setup only)
RS-232 Serial
9,600 bps
(during setup only)
Internal
TNC
Internal
TNC
relays
Legend
Power Line
Data Line
External Terminal Node Controller
(TNC)
RS-232 Serial
9,600 bps
(constant)
12 V line voltage
400 mA, 4.8 W
(constant)
Colorado Space Grant
Consortium

33. External Terminal Node Controller
Additional Design #2
Antenna
Antenna
Idea #2: use relays for TNC in case of external TNC malfunction
Issues
Dependent on TNC to Radio procedure
Increased complexity
5 V line voltage
90 mA
450 mW
(constant)
Radio2
Receiver
Kenwood TH-D7
Radio1
Transmitter
Kenwood TH-D7
12 V line voltage
1.4 A
16.8 W transmitting
(450 mW idle)
RS-232 Serial
9,600 bps
(during setup only)
RS-232 Serial
9,600 bps
(during setup only)
Internal
TNC
Internal
TNC
relays
Legend
Power Line
Data Line
External Terminal Node Controller
(TNC)
RS-232 Serial
9,600 bps
(constant)
12 V line voltage
400 mA, 4.8 W
(constant)
Colorado Space Grant
Consortium

34. Logistics Parts List and Cost Documentation Progress
Subsystem Plans to Deliver
Colorado Space Grant
Consortium

35. Parts List and Cost Bent dipole Monopole Transmitter (Radio1): $360.00
Estimated cost of $10 for each prototype
All design and manufacturing will be done by Space Grant
Monopole
Cost estimates ≈ $40
Transmitter (Radio1): $360.00
Receiver (Radio2): $360.00
External TNC
Initial cost: $595.00
Custom Firmware: $80
Miscellaneous (i.e. coax cable)
Colorado Space Grant
Consortium

36. Documentation Progress
Documentation Needed
Progress
TNC data sheets
Have some data sheets from website
Radio TH-D7 data sheets and users guide
We have all of this information
TNC to Radio procedure
Currently waiting on confirmation
Link Budget Paper
Rough copy done
Bent Dipole Antenna fabrication procedures
Rough copy
Antenna testing procedures
TNC and Radio testing procedure
Overall comm. system testing procedures
Colorado Space Grant
Consortium

37. Comm. Team’s Plan to Deliver
One main issue
Waiting on procedure to connect the external TNC to the radios.
Once done, tasks go as follows
Purchase TNC
Test TNC
Modify TNC
Test Radios and Antennas
Modify Radios to connect to TNC
Integrate Radios and TNC
Give Structures final Box Requirements for Radio and TNC
Task to give structures and mechanisms final antenna requirements will occur after testing of antennas
Approximately at the end of April
Colorado Space Grant
Consortium

38. DINO Communications Team CDR
Questions / Comments
Colorado Space Grant
Consortium