DINO – Peer Review 4 December 2015 DINO Communication System Peer Review Zach Allen Chris Page.
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Transcript of DINO – Peer Review 4 December 2015 DINO Communication System Peer Review Zach Allen Chris Page.
Colorado Space Grant Consortium 2
DINO – Peer Review April 18, 2023
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 3
DINO – Peer Review April 18, 2023
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 4
DINO – Peer Review April 18, 2023
Requirements on Power
– Transmitter (Radio1)• Transmit mode: 12 V at 1.4 A (16.8 W)• Idle mode: 12 V at 90 mA (450 mW)• Must have capability to be activated/deactivated by flight
computer.
– Receiver (Radio2)• 5 V at 90 mA (450 mW)
• Must be active concurrently with flight computer
– External TNC (tentative): 12 V at 200 mA (2.4 W)• Must always be active when flight computer is active
Colorado Space Grant Consortium 5
DINO – Peer Review April 18, 2023
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• 9600 baud, 8 data bits, no parity bit, 1 stop bit• Software flow control only
Colorado Space Grant Consortium 6
DINO – Peer Review April 18, 2023
Requirements on Software
• Set up Radio1 (Transmitter) Parameters– Switch the shared serial port to Radio1 immediately
after Radio1 is powered on (every time!)– Must program the following parameters into Radio1:
• Transmit frequency (TBD, after FCC assigns the frequency)• Transmit power (5 Watts)
Colorado Space Grant Consortium 7
DINO – Peer Review April 18, 2023
Requirements on Software, Continued
• Set up Radio2 (Receiver) Parameters– Switch the shared serial port to Radio2 immediately
after Radio2 is powered on (every time!)– Must program the following parameters into Radio2:
• Receive frequency (TBD, after FCC assigns the frequency)• Squelch
Colorado Space Grant Consortium 8
DINO – Peer Review April 18, 2023
Requirements on Structures
• Mass– Two Transceivers
– 170 grams each
– 2 x 170 grams = 340 grams total
– External TNC– Still determining. Upper limit is 40g.
– Bent Dipole Antenna (transmit antenna)– Duck Antenna (receive antenna)– Approximately 2 feet of coax to feed the antennas
Colorado Space Grant Consortium 9
DINO – Peer Review April 18, 2023
Requirements on Structures, Continued
• Dimensions– Two Transceivers
– 4.9 x 2.3 x 1.2 inches each
– Mounted together in one 3CS-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 10
DINO – Peer Review April 18, 2023
Subsystem Block Diagram
• 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 voltage1.4 A16.8 W transmitting(450 mW idle)
5 V line voltage90 mA450 mW(constant)
12 V line voltage400 mA, 4.8 W(constant)
RS-232 Serial9,600 bps(during setup only)
RS-232 Serial9,600 bps(during setup only)
RS-232 Serial9,600 bps(constant)
Radio1Transmitter
Kenwood TH-D7
Radio2Receiver
Kenwood TH-D7
External Terminal Node Controller(TNC)
InternalTNC
InternalTNC
Antenna
Power LineData Line
Legend
Antenna
Colorado Space Grant Consortium 11
DINO – Peer Review April 18, 2023
Design
• Transceivers– Two Kenwood TH-D7 radios
• Radio1: Downlink, approximately 436 MHz
• Radio2: 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 12
DINO – Peer Review April 18, 2023
Analysis: Power Requirements
• Daytime Operation– Receiver: 0.45 W (5 V, 90 mA) always.– TNC: 2.4 W (12 V, 200 mA) 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 mA) always.– TNC: 2.4 W (12 V, 200 mA) 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 13
DINO – Peer Review April 18, 2023
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 kB per pass during
daytime):– 2.133 sec/packet * 25 kB/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 14
DINO – Peer Review April 18, 2023
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 15
DINO – Peer Review April 18, 2023
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 16
DINO – Peer Review April 18, 2023
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 17
DINO – Peer Review April 18, 2023
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 18
DINO – Peer Review April 18, 2023
Up-link (Rubber Duck Antenna)
• Targeted Frequency of 145 MHz– Wavelength of approx. 2.1m
• 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 19
DINO – Peer Review April 18, 2023
Up-Link (Rubber Duck Antenna): Radiation Patterns
• Gain– To be on the safe side, gain was projected to be 0dB
• Beam Width– Minimal beam width expected.
Colorado Space Grant Consortium 20
DINO – Peer Review April 18, 2023
Up-Link (Rubber Duck Antenna): Link Budget
Forward 145 MHz Link UnitsTransmitter (Tx)
1 Tx Power, Pt 43.9 dBm2 Tx Component Line Losses, Ltl 3.0 dB 3 Tx Antenna Gain (Peak), Gt 15.0 dBi4 Tx Pointing Loss, Ltp 1.0 dB5 Tx Radome Loss, Ltr 0.0 dB
6 EIRP (1-2+3-4-5) 54.9 dBm
PropagationTransmission Frequency, f 145.0 MHzLink Range, R 1700.0 kmPropagation Factor, n 1.0
7 Free Space Loss, Ls 140.3 dB8 Atmospheric Absorption, Lpa 0.0 dB9 Precipitation Absorption, Lpp 0.0 dB
10 Total Propagation Loss (7+8+9) 140.3 dB
Receiver (Rx)11 Rx Antenna Gain (Peak), Gr 0.0 dBi12 Rx Polarization Loss, Lrpol 3.0 dB13 Rx Pointing Loss, Lrp 0.0 dB14 Rx Radome Loss, Lrr 0.0 dB15 Rx Component Line Losses, Lrl 1.0 dB16 Rx Implementation Losses, Lri 1.0 dB
17 Received effective carrier power -90.4 dBm(6-10+11-12-13-14-15-16)
Noise18 Standard Thermal Noise, kT -174.0 dBm/Hz19 Rx Noise Bandwidth, W 44.8 dBHz20 Rx Noise Figure, NF -1.3 dB
21 Effective Noise Power (18+19+20) -130.4 dBm
Result22 Available CNR (17-21) 40.1 dB23 Data Rate 39.8 dBHz24 Available Eb/No (22+19-23) 45.0 dB25 Implementation Losses 3.0 dB26 Required Eb/No 14.2 dB25 Margin (24-25-26) 27.8 dB
Link Budget Form courtesy of Dr. Stephen Horan, New Mexico State University.
Colorado Space Grant Consortium 21
DINO – Peer Review April 18, 2023
Down Link
• Targeted Frequency of 436 MHz– Wavelength of approx. 0.7m
• Primary consideration– Bent Dipole
• Helix design still in simulation• Next consideration is phased, 4 element
antenna array
Colorado Space Grant Consortium 22
DINO – Peer Review April 18, 2023
Down-Link (Bent Dipole Antenna)
• Antenna Radiation Patterns– Gain– Beam Width
• Link Budget• Simulations (NEC)
– Design– Radiation Pattern– 3D view of Radiation Pattern
Colorado Space Grant Consortium 23
DINO – Peer Review April 18, 2023
Down-Link (Bent Dipole Antenna): Radiation Patterns
• Gain– 6.58 dB (NEC Simulation 12-8)
• Transmitted Power– 36.9 dBm (5W)
• Beam Width– 120o
– Filled requirement of 90o
Colorado Space Grant Consortium 24
DINO – Peer Review April 18, 2023
Down-Link (Bent Dipole Antenna): Link Budget
Link Budget Form courtesy of Dr. Stephen Horan, New Mexico State University.
Colorado Space Grant Consortium 25
DINO – Peer Review April 18, 2023
Down-Link (Bent Dipole Antenna): Simulation Design
Colorado Space Grant Consortium 26
DINO – Peer Review April 18, 2023
Down-Link (Bent Dipole Antenna): Simulation Radiation Pattern
Colorado Space Grant Consortium 27
DINO – Peer Review April 18, 2023
Down-Link (Bent Dipole Antenna): 3D View of Radiation Pattern
6.58
0.286
-14
Colorado Space Grant Consortium 28
DINO – Peer Review April 18, 2023
Antenna Deployment
Before Deployment
After Deployment
Note: placement of monopole will need to be simulated and tested for best results
BentDipole Monopole
Colorado Space Grant Consortium 29
DINO – Peer Review April 18, 2023
Commands – After Antenna Deployment
Radio2 power activated Software switches serial port to Radio2
Software programs Radio2
Radio1 power activated Software switches serial port to Radio1
Software programs Radio1
TNC power activated
12 3
4
56
7
System Ready
Colorado Space Grant Consortium 30
DINO – Peer Review April 18, 2023
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 31
DINO – Peer Review April 18, 2023
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 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
DINO – Peer Review April 18, 2023
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 33
DINO – Peer Review April 18, 2023
Parts List and Cost
• Transmitter (Radio1): $360.00• Receiver (Radio2): $360.00• External TNC
• Initial cost: $595.00• Custom Firmware: $80
Colorado Space Grant Consortium 34
DINO – Peer Review April 18, 2023
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