DINO Peer Review 3122021 DINO Communication System Peer

DINO – Peer Review 3/12/2021 DINO Communication System Peer Review Zach Allen Chris Page

DINO – Peer Review 3/12/2021 Purpose • Establish two-way communication link between satellite and ground station. – Link must allow transfer of map files from satellite to ground. – Must allow transmission of health and status data from satellite to ground. – Must allow the satellite radios and flight computer to receive command lines transmitted by ground station. Colorado Space Grant Consortium 2

DINO – Peer Review 3/12/2021 Requirements Imposed by other Subsystems • Data Rate: must be high enough to accommodate all data – 20 kbytes per topographical map – 255 bytes per Health and Status Packet – 5 kbytes per uploaded schedule • Antennas – Must be deployable by structures – No deployable ground plane allowed Colorado Space Grant Consortium 3

DINO – Peer Review 3/12/2021 Requirements on Power – Transmitter (Radio 1) • Transmit mode: 12 V at 1. 4 A (16. 8 W) • Idle mode: 12 V at 90 m. A (450 m. W) • Must have capability to be activated/deactivated by flight computer. – Receiver (Radio 2) • • – 5 V at 90 m. A (450 m. W) Must be active concurrently with flight computer External TNC (tentative): 12 V at 200 m. A (2. 4 W) • Must always be active when flight computer is active Colorado Space Grant Consortium 4

DINO – Peer Review 3/12/2021 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 radio 1 and radio 2 • Must be able to switch at any time between the two radios • 9600 baud, 8 data bits, no parity bit, 1 stop bit • Software flow control only Colorado Space Grant Consortium 5

DINO – Peer Review 3/12/2021 Requirements on Software • Set up Radio 1 (Transmitter) Parameters – Switch the shared serial port to Radio 1 immediately after Radio 1 is powered on (every time!) – Must program the following parameters into Radio 1: • • Transmit frequency (TBD, after FCC assigns the frequency) Transmit power (5 Watts) Colorado Space Grant Consortium 6

DINO – Peer Review 3/12/2021 Requirements on Software, Continued • Set up Radio 2 (Receiver) Parameters – Switch the shared serial port to Radio 2 immediately after Radio 2 is powered on (every time!) – Must program the following parameters into Radio 2: • Receive frequency (TBD, after FCC assigns the frequency) • Squelch Colorado Space Grant Consortium 7

DINO – Peer Review 3/12/2021 Requirements on Structures • Mass – Two Transceivers – 170 grams each – 2 x 170 grams = 340 grams total – External TNC – Still determining. Upper limit is 40 g. – Bent Dipole Antenna (transmit antenna) – Duck Antenna (receive antenna) – Approximately 2 feet of coax to feed the antennas Colorado Space Grant Consortium 8

DINO – Peer Review 3/12/2021 Requirements on Structures, Continued • Dimensions – Two Transceivers – 4. 9 x 2. 3 x 1. 2 inches each – Mounted together in one 3 CS-sized box (7. 25 x 4. 75 x 1 inch) – External TNC – Model still being determined – Upper Limit 6. 1 x 7. 3 x 1. 3 inch – Box arrangements TBD – Antennas – Deploy Bent Dipole – Deploy Duck Antenna Colorado Space Grant Consortium 9

DINO – Peer Review 3/12/2021 Subsystem Block Diagram 5 V line voltage 90 m. A 450 m. W (constant) RS-232 Serial 9, 600 bps (during setup only) Antenna Radio 2 Receiver Radio 1 Transmitter 12 V line voltage 1. 4 A 16. 8 W transmitting (450 m. W idle) Kenwood TH-D 7 Internal TNC RS-232 Serial 9, 600 bps (during setup only) External Terminal Node Controller (TNC) RS-232 Serial 9, 600 bps (constant) Legend Power Line Data Line • All Data lines use RS-232 Serial • Transmitter operates at 12 V • Receiver operates at 5 V. • External TNC: 12 V line, allows 9, 600 bps link to ground. • Internal TNC proven to be reliable at 1, 200 bps. 12 V line voltage 400 m. A, 4. 8 W (constant) Colorado Space Grant Consortium 10

DINO – Peer Review 3/12/2021 Design • Transceivers – Two Kenwood TH-D 7 radios • Radio 1: Downlink, approximately 436 MHz • Radio 2: Uplink, approximately 145 MHz • TNC still under consideration – Timewave PK-96 • Requires removing many electrolytic capacitors – Kantronics KPC 9612+ • Requires removing many electrolytic caps – Paccomm UP-9600 • Already surface mount • Heritage with Citizen Explorer Mission Colorado Space Grant Consortium 11

DINO – Peer Review 3/12/2021 Analysis: Power Requirements • Daytime Operation – Receiver: 0. 45 W (5 V, 90 m. A) always. – TNC: 2. 4 W (12 V, 200 m. A) always. – Transmitter: 16. 8 W (12 V, 1. 4 A) for approx. 8 minutes, otherwise same as Receiver (0. 45 W). • Nighttime Operation – Receiver: 0. 45 W (5 V, 90 m. A) always. – TNC: 2. 4 W (12 V, 200 m. A) always. – Transmitter: 16. 8 W (12 V, 1. 4 A) for approx. 4 seconds, otherwise same as Receiver (0. 45 W). • Safe Mode – Same as nighttime. Colorado Space Grant Consortium 12

DINO – Peer Review 3/12/2021 Analysis: Calculating Transmission Time • We need to find the transmission time in order to find the exact power requirements over the course of one day. • Time needed to send one packet: – 10 bits/byte * 256 bytes/packet 1200 bits/sec = 2. 133 sec/packet • Total transmission time (assuming 25 k. B per pass during daytime): – 2. 133 sec/packet * 25 k. B/pass 256 bytes/packet = 208. 3 sec/pass = ~ 3. 5 minutes (absolute minimum) – May be approx. twice the minimum (resending, errors, etc. ) – This is a realizable amount of time. Colorado Space Grant Consortium 13

DINO – Peer Review 3/12/2021 Antenna/Structure Considerations • • Fit on nadir plate without obstructing cameras Little room for placement inside satellite Deployment of antenna Antenna Structure – Cost – Weight – Material (no outgasing) Colorado Space Grant Consortium 14

DINO – Peer Review 3/12/2021 Antenna Considerations • Noise Factor and Loss • Maximum transmission distance • Radiation Pattern – Gain – Beam width – Efficiency • Link Budget – Carrier – to – Noise Ratio – Energy per bit – to – Noise Ratio (Available to Required) – Margin Colorado Space Grant Consortium 15

DINO – Peer Review 3/12/2021 Noise Factor and Loss • The receivers will determine the noise factor based on criteria like – Bandwidth – Sensitivity • Losses – – Free space loss Polarization loss Pointing, component, and implementation losses Atmospheric loss Colorado Space Grant Consortium 16

DINO – Peer Review 3/12/2021 Maximum Transmission Distance Calculations • Low orbit height from earth = 425 km • Maximum distance from base station antenna (horizon) = (with =5 o , slant angle) 1. 84 x 106 m – For =10 o 1. 39 x 106 m – For =15 o 0. 99 x 106 m • 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 17

DINO – Peer Review 3/12/2021 Up-link (Rubber Duck Antenna) • Targeted Frequency of 145 MHz – Wavelength of approx. 2. 1 m • Why chosen? – Ability to transmit high power and gain from base station – Heritage • Antenna Radiation Patterns – Gain – Beam Width • Link Budget Colorado Space Grant Consortium 18

DINO – Peer Review 3/12/2021 Up-Link (Rubber Duck Antenna): Radiation Patterns • Gain – To be on the safe side, gain was projected to be 0 d. B • Beam Width – Minimal beam width expected. Colorado Space Grant Consortium 19

DINO – Peer Review 3/12/2021 Up-Link (Rubber Duck Antenna): Link Budget Form courtesy of Dr. Stephen Horan, New Mexico State University. Colorado Space Grant Consortium 20

DINO – Peer Review 3/12/2021 Down Link • Targeted Frequency of 436 MHz – Wavelength of approx. 0. 7 m • Primary consideration – Bent Dipole • Helix design still in simulation • Next consideration is phased, 4 element antenna array Colorado Space Grant Consortium 21

DINO – Peer Review 3/12/2021 Down-Link (Bent Dipole Antenna) • Antenna Radiation Patterns – Gain – Beam Width • Link Budget • Simulations (NEC) – Design – Radiation Pattern – 3 D view of Radiation Pattern Colorado Space Grant Consortium 22

DINO – Peer Review 3/12/2021 Down-Link (Bent Dipole Antenna): Radiation Patterns • Gain – 6. 58 d. B (NEC Simulation 12 -8) • Transmitted Power – 36. 9 d. Bm (5 W) • Beam Width – 120 o – Filled requirement of 90 o Colorado Space Grant Consortium 23

DINO – Peer Review 3/12/2021 Down-Link (Bent Dipole Antenna): Link Budget Form courtesy of Dr. Stephen Horan, New Mexico State University. Colorado Space Grant Consortium 24

DINO – Peer Review 3/12/2021 Down-Link (Bent Dipole Antenna): Simulation Design Colorado Space Grant Consortium 25

DINO – Peer Review 3/12/2021 Down-Link (Bent Dipole Antenna): Simulation Radiation Pattern Colorado Space Grant Consortium 26

DINO – Peer Review 3/12/2021 Down-Link (Bent Dipole Antenna): 3 D View of Radiation Pattern 6. 58 0. 286 -14 Colorado Space Grant Consortium 27

DINO – Peer Review 3/12/2021 Antenna Deployment After Deployment Bent Dipole Monopole Note: placement of monopole will need to be simulated and tested for best results Before Deployment Colorado Space Grant Consortium 28

DINO – Peer Review 3/12/2021 Commands – After Antenna Deployment TNC power activated 1 Software switches serial port to Radio 2 power activated 2 3 4 Radio 1 power activated 5 Software programs Radio 2 Software switches serial port to Radio 1 6 Software programs Radio 1 7 Colorado Space Grant Consortium System Ready 29

DINO – Peer Review 3/12/2021 Antenna Test Plan • Testing to be done either at Ball Aerospace or CU Antenna Lab – Test for resonant frequency • By measuring reflection S parameters – Antenna Radiation Pattern Measurements • Gain • Beam width • Efficiency – Power transmitted to power received – Transfer files to and from spacecraft CDH system Colorado Space Grant Consortium 30

DINO – Peer Review 3/12/2021 Radio/TNC Test Plan • 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 properation. – 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 31

DINO – Peer Review 3/12/2021 Parts list and Cost • Rubber duck – Bought through distributor – Cost of between $20 -$50 • Bent dipole – Metal selections considered • Copper: ~0. 68 pounds • Aluminum: ~0. 2 pounds – Estimated cost of $30 for each prototype • All design and manufacturing will be done by Space Grant Colorado Space Grant Consortium 32

DINO – Peer Review 3/12/2021 Parts List and Cost • Transmitter (Radio 1): $360. 00 • Receiver (Radio 2): $360. 00 • External TNC • Initial cost: $595. 00 • Custom Firmware: $80 Colorado Space Grant Consortium 33

DINO – Peer Review 3/12/2021 Issues and Concerns • Link Budget Issues – Need to verify noise figure and thermal noise for link budgets. – Need to verify link range • Bent Dipole Issues – Gain and beam width only simulated, prototype must be built and tested. – What will be the margin of error between angle needed to angle achieved when deployed Colorado Space Grant Consortium 34

DINO – Peer Review 3/12/2021 Issues and Concerns • External 9600 baud TNC interface still in question – Fall-back is 1200 baud Colorado Space Grant Consortium 35