Auto-Tracking RF Ground Unit for S-Band Critical De Sign Re Vie W

1 ASEN 40 18 Se nior Proje cts Fa ll 2 0 18 Critica l De sig n Re vie w

Auto-Tracking RF Ground Unit for S-Band Team: Trevor Barth, Anahid Blaisdell, Adam Dodge, Geraldine Fuentes, Thomas Fulton, Adam Hess, Janell Lopez, Diana Mata, Tyler Murphy, Stuart Penkowsky, Michael Tzimourakas

Advisor: Professor Dennis Akos Customer: 2

Purpose and Objective 3 Project Motivation

● Ground stations consist of a motorized antenna system used to communicate with satellites ● Current ground stations are expensive and stationary ● Mobile ground stations could be used to provide instantaneous communication with small satellites in remote locations ● Communication is real-time a nd dire ct to the user Current stationary S-Band ground station: $50,000

≈ 4 Project Objective

Mission Statement: The ARGUS ground station is designed to be able to track a LEO sa te llite a nd re ce ive a te le me try downlink using a pla tform tha t is both portable and more affordable than current S-Band ground stations.

● Commercial-off-the-she lf (COTS) whe re possible ● Interface with user laptop (monitor) ● Portable: 46.3 kg (102 lbs), able to be carried a distance of 100 meters by two people 5

CONOPS 6

Under 100 m 7

Under 100 m Within 60 min 8

Under 100 m Within 60 min 9

Under 100 m Within 60 min 10

Under 100 m Within 60 min 11

Under 100 m Within 60 min 12 Functional Requirements

1. 0 The ground station shall be capable of receiving signals from a Low Earth Orbit satellite between 2.2 - 2.3 GHz, in Quadrature Phase Shift Keying (QPSK) modulation with a Bit Error Rate (BER) of 10-5, a bit rate of 2 Mbit/s, and a G/T of 3 dB/K.

2.0 The ground station shall mechanically steer a dish/antenna system to follow a LEO satellite between 200 km to 600 km between 10 ° and 170° local elevation.

3.0 The ground station shall be reconfigurable to be used for different RF bands.

4.0 ARGUS shall weigh less than 46.3 kg (102 lbs) and be capable of being carried a distance of 100 meters by two people.

5.0 The ground station onboard computer shall interface with a laptop using a Cat-5 ethernet ca b le . 13

Design Solution 14 He lica l Ante nna Feed

1.5m Parabolic Reflector

Azimuth/Ele va tion Motors

Transportable Case Tripod 15 Functional Block Diagram 16 Software Flow Chart 17 Antenna Unit Subsystem 18

● Antenna Feed ○ Purpose: Colle ct incoming signa l ○ Model: RFHa m De s ig n H-13 XL ○ Specs: LCHP a t 2 . 1 - 2.6 GHz, 110 ° beamwidth

● Antenna Dish ○ Purpose: Magnify and focus incoming signal ○ Model: RFHa m De s ig n 1. 5 m ○ Specs: Metal mesh, aluminum struts, 6 kg

● Antenna Base ○ Purpose: Support antenna system and motors 1.5 m ○ Model: RFHa m De s ig n ○ Specs: 670mm – 830mm he ight, 30 kg max load 19 Motor System

SPX-01: az/el motors + position sensors + controller

● $655.78 ● 0 .5 deg resolution ● Interfaces with onboard computer ● Manual/auto control ● Designed for continuous tra cking

Az/El motors + position sensors Motor controller Signal Conditioning and Processing 20 21

● Low Noise Amplifie r (LNA) ○ Purpose: Incre a se signa l ga in ○ Model: Minicircuits ZX60-P33ULN+ ○ Specs: 14 . 8 dB Ga in, 0 .38 dB Noise

● Software Defined Radio (SDR) ○ Purpose: Process incoming RF data ○ Model: Ada lm Pluto ○ Specs: 325 MHz to 3.8 GHz Fre que ncy Range , 12 bit ADC, 20 MHz max RX data rate

● Onboard Computer ○ Purpose: Process incoming RF data and control tracking ○ Model: Inte l NUC Kit NUC7I7DNKE ○ Specs: i7 Processor, 16 gb RAM, 5 12 gb SSD 22

Critical Project Elements 23 24

Design Requirements and Sa tisfa ction 25

Antenna Subsystem

F R 1. 0 The ground station shall be capable of receiving signals from a Low Earth Orbit satellite between 2.2 - 2.3 GHz, in Quadrature Phase Shift Keying (QPSK) modulation with a Bit Error Rate (BER) of 10-5, a bit rate of 2 Mbit/s, and a G/T of 3 dB/K.

FR 4.0 ARGUS shall weigh less than 46.3 kg (102 lbs) and be capable of being carried a distance of 100 meters by two people. 26 RF Ham Design Reflector

Mesh Feed Hub

Ribs Feed Support Hardware

1. 5 m ● Meets specified 27 dB at 2.3 GHz requirement; however, fails to meet mobility requirement 27 Modification of Reflector

Current RFHam dish: ● Asse mb ly time 6 + hours ● Single continuous mesh ● Multiple tools

Mod ifica tions: ● Assembly time less than 1 hour ● Split into 12 conne cta b le pieces ● Fewer than 4 tools

Mod ula rity: ● 22 gauge aluminum sheet attaches to ribs ● Petals attach to central hub 28 Modification of Reflector

✔️Meets mobility requirements (FR.4) 29 Antenna Gain Calculation

Pasternack SMA Male to N Male Adapter

ZX60-P33ULN+ MiniCircuits LNA

Pasternack SMA to SMA Cable

Adalm-Pluto SDR 30 Estimated Efficiency

Optima l ARGUS a nte nna is 53.7 % efficient Gain at 53.7% e fficie ncy 28.08 dBi

Gain at 35% e fficie ncy 26.22 dBi

Required gain 26.2 dBi

✔️Meets bandwidth and gain requirements (FR.1) 31

Tracking Hardware Subsystem

FR 2 .0 The ground station shall mechanically steer a dish/antenna system to follow a LEO satellite between 200 km to 600 km between 10° e le va tio n a nd 170 ° e le va tio n. 32 STK: Tracking Rate Verification

DR 2.3 The antenna motor shall be able to move the antenna at a slew rate of 5.0 °/s

● Worst case pass ○ Elliptica l orbit Max of 4.41 °/s ○ Pass directly overhead ○ Retrograde ● Max Rate: 4.41 °/s

Angular Rate (deg/sec) Azimuth Rate (deg/sec) Elevation Rate (deg/sec) 33 Worst Case Pointing Error

Pointing Error

HP𝜽𝜽= 6.5°

𝜽𝜽

Pointing Error = TLE, Error + Motor, Error + Tracking, Error < 3.25°

𝜽𝜽 Motor, Error <𝜽𝜽3.25° - 1. 10𝜽𝜽° - 1. 4 3 ° 𝜽𝜽 TLE, Error, Max = 1. 4 3 ° 𝜽𝜽Motor, Error < 0 .72° Tracking, Error, Max = 1. 10 ° 𝜽𝜽 𝜽𝜽 𝜽𝜽 34 Antenna Motor System ● Specs: ○ Azimuth ■ Ra ng e : 0 ° to 360° ■ Speed: 7.2°/sec ○ Ele va tion ■ Ra ng e : ± 90° ■ Speed: 7.2°/sec ○ Maximum Load: 30 kg ○ Position sensors with accuracy: 0.5°

✔ DR 2.3 The antenna motor shall be able to move the antenna at a slew rate of 5.0 °/s ️

✔ DR 2.4 The antenna motor shall have a pointing accuracy greater than 0.72° ️ 35 Tracking Overview

Az/El angular command

SPX-01

Motor system

External Controller: Az motor Sensor power: Rot2Prog 12V DC El motor Sensor 36 Software Interface

Ena ble se ria l communica tion Input la t/long Ca libra te Se le ct ta rge t Enga ge 37

Tracking Software Subsystem

FR 2.0 The ground station shall mechanically steer a dish/antenna system to follow a LEO satellite between 200 km to 600 km between 10° e le va tio n a nd 170 ° e le va tio n. 38 Tracking Software Demonstration

FR 2 .0 The ground station shall mechanically steer a dish/antenna system to follow a LEO satellite between 200 km to 600 km between 10° e le va tion a n d 17 0 ° e le va tion. 39 Calibration & Manual Control Frames 40 Azimuth and Elevation Calibration

DR 2.2 The pointing control accuracy must be within 3.25° to ma inta in d o wnlink ca p a b ilitie s throughout the entire pass.

● Manual Control Frame - Dither around Sun, find strongest signal strength ● Ca lib ra tio n Fra me - Set current pointing angles to predicted Sun location

Ground Station Sun Azimuth and Point in Predicted Latitude/Longitude ARGUS GUI Elevation Location and Dither (GPS) 41 Upcoming Pass Frame 42 STK: Upcoming Pass Verification

DR 2.2 The pointing control accuracy must be within 3.25° to ma inta in downlink capabilities throughout the entire pass.

ARGUS (Mountain Time) STK (UTC Time)

✔️Ve rifie d 43 Az/El Plot Frame 44 STK: Azimuth/Elevation Verification

DR 2.2 The pointing control accuracy must be within 3.25° to ma inta in downlink capabilities throughout the entire pass.

ARGUS STK 45

Signal Conditioning & Processing

Adalm Pluto SDR Digita l Filte ring Demodulation GUI

● Frequency: ● Lo w P a s s ● QPSK ● FFT Plot 2.2-2.3 GHz ● Bit Plot ● Bit Rate: 2 MHz ● Mixing ● Amplify F R 1. 0 The ground station shall be capable of receiving signals from a ● ADC Low Earth Orbit satellite between 2.2 - 2.3 GHz, in Quadrature Phase Shift Keying (QPSK) modulation with a Bit Error Rate (BER) o f 10 -5, a bit rate of 2 Mbit/s , and a G/T of 3 dB/K. 47 GNURadio Software Demonstration

DR 1.4 The ground station shall be capable of demodulating a signal using the QPSK modulation scheme.

D R 1. 10 The ground station shall be able to receive a data rate of at least 2 million bits per second. 48 Bit Error Rate

FR 1. 0 The ground station shall be capable of receiving signals from a Low Earth Orbit satellite between 2.2 - 2.3 GHz, in Quadrature Phase Shift Keying (QPSK) modulation with a Bit Error Rate (BER) of10 -5, a bit rate of 2 Mbit/s, and a G/T of 3 dB/K.

BER is governed by the system Signa l to Noise Ra tio (SNR)

● Must have SNR ≥ 10.4dB to SNR = 10.4 dB achieve BER of 10-5 ● Current system SNR 17 . 2 1d B ○ BER 8.9e -9 ≅ ○ De te rmine d using ASEN 330 0 link ≅ budget and typical transmit values ✔️Meets Requirement 49

Mobility

FR 4.0 ARGUS shall weigh less than 46.3 kg (102 lbs) and be capable of being carried a distance of 100 meters by two people. 50 Mobility: Mass Estimate

Components Mass Components Mass

Feed 1 k g Tripod 1. 9 k g

Dis h 6 kg SDR 0 . 12 k g

Az/El motors 12 . 8 k g Ele ctro nics 2.2 kg

Motor Controller 2 kg Case 15 . 4 k g

NUC 1. 2 k g Mounting Bracket 1. 6 k g

Total 44.2 kg < 46.3 kg ✔️Meets Mass Requirement (FR 4.0) 51

Risk Management Gain Blocka ge a nd e fficie ncy ca lcula tions fla we d, too little ga in to ge t sa te llite signa l 52

Manufacturing Modifica tions to dish re sult in incorre ct pa ra bola , una ccounte d for blocka ge

TLE Accuracy dependent on source and age of TLE Motor Motor re solution a nd limits ca use e rror in tra cking sa te llite Risk Ma trix Mobility Violate OSHA standards

Calibration Inaccurate calibration of Az/El causes inaccurate pointing and tracking

BER High BER causes data to be erroneous and unusable Severity Full Integration Failure between subsystem interfaces causes entire system failure

1 2 3 4 5

5 Mobility

3 1. Motor Error Full Inte gra tion 2. Ca libra tion

Likelihood 2 Manufacturing BER Dish Ga in

1 TLE Error Risk Mitigation 53

Gain Larger dish gives bigger margin of error

TLE Download most recent TLE’s for testing Motor Buy more precise motors Risk Mitiga tion Mobility Purchase a case with less mass

Calibration Antenna point at strongest signal from sun during calibration

BER LNA, short cable le ngths, spe cific fre que ncy band Severity Full Integration Inte rface s te ste d incre me ntally/thoroughly for prope r function 1 2 3 4 5

4 Mobility

3 Full Integration

2 Manufacturing 1. Motor Error Dish Ga in

Likelihood 2 . Ca libra tion

1 TLE Error BER 54

Verification and Validation 55 Test Plan Component Test: Integration Test: Systems Test: Jan. 15th - F e b . 11t h F e b . 11t h - Ma r . 11t h Ma r . 11t h - April 2 1st Antenna: Antenna System: Antenna System: - Dish manufacturing - Ga in - S-Ba nd sa te llite signa l - Motor calibration - Be a mwidth reception - Fe e d functiona lity Signal Processing Test: Signal Processing Test: Signal Processing: - QPSK demodulation - S-Ba nd signa l - GNURadio - BER processed - Pre dict - Cat5 connection - GPS Motor System Test: Motor System Test: - MTI + Yaogan 6 Hardware: - Rotation rate tracking - Power Transformer - Rotation range - Capacitor Mobility: - Motor Functiona lity - Transport and - Component weights assembly > 100m 56 Signal Processing System Level Test

Equipment Procurement Needed

Laptop Owned

GNURadio Open Source

Possible Measurement Errors

● NUC Processing Speed ● Re configura bility ● Length of test (time) 57 Signal Processing System Level Test

Obje ctive ● Verify NUC Processing speed ● Cat5 data port connection ● GNURadio on S-Band signal

Location ITLL

FR FR 1: BER, QPSK Demodulation, Bandwidth Ve rifie d FR 3: Re configura bility FR 5: Cat5 Connection

Data Needed Compared To Expected

BER Ma tla b e stima tion 8.9E-9

QPSK Signal Matlab generated Matlab generated signa l signa l 58 Antenna Gain/Beamwidth Test

Equipment Procurement Needed

SDR Purchase

Tra nsmit Borrow/Purchase Antenna

Wa ve fo rm Borrow Ana lyze r

Measuring wheel Borrow 59 Antenna Gain/Beamwidth Test

Obje ctive ● Verify antenna gain ● Verify half power beam width (HPBW)

Location Rural location or RF test range

FR Ve rifie d FR 1: Ga in, Be a mwidth

Data Needed Compared To Expected Potential Measurement Issues

Ga in Efficie ncy mode l, 29.5dBi ● Exte rna l signa l noise dish kit spe cs at 2.4GHz ● Signal reflection from ground ● Incorrect feed placement Be a mwidth Idealized estimates, 6.5° ● Pointing accuracy dish kit spe cs 60 Motor System Level Test

Equipment Procurement Needed

Time r Owned 𝝎𝝎 Θ=10° Θ=10° Protractor Borrow Power Supply Borrow 61 Motor System Level Test

PossibleObjective Measurement● Test Errors cable wrap ● Timing accuracy● Show motor control system ● Angle measurement● Test accuracy encoders

Location ITLL

FR Verified FR 2: Slew rate, range of motion

Data Needed Resolution Expected Possible Measurement Errors Rotation Rate 0.5°/s 7.2 °/s ● Timing accuracy Rotation Angle 1° 10°-170° ● Angle measurement accuracy 62 Mobility System Level Test

Equipment Procurement Needed

Sca le Borrow

Measuring Borrow wheel

Stopwatch Borrow/Owned 63 Mobility System Level Test

Objective ● Verify weight requirements ● Demonstrate mobility ● Show assembly is under 60min

Location Business field

FR Verified FR 4: Mass, assembly time

Data Needed Requirement Expected

Weight 46.3 kg 42.6 kg

Assembly Time 60 min 35 min Obje ctive ● Te st ARGUS porta bility 64 ● Re ce ive signa l from sa te llite Full System Test

Location Busine ss Fie ld

FR Ve rifie d All FR 65

Project Planning 66 Organizational Structure 67 Work Breakdown Structure 68 Work Plan

Start Date

Product Procurement 69 Work Plan

Implementing Software

Testing and Calibration 70 Work Plan

Dish Kit Modifying Antenna Gain Testing 71 Work Plan

Fully Integrate System and Full System Test

Design Expo 72 Work Plan Critical Path

Obtaining Products Implementing Software Major Driver: Dish Kit Modifying

Testing and Integration 73 Budget Total: $3419.25

Item Cost ($)

Motor + Controller 782.58

Ele ctronics 113 4 . 10

Dish + Feed 627.67

Tripod 475.0 0

Pe lica n Ca se 400.00

Remaining Funds 1580.65

Total 5000.00 74 References

1. Mason, James. “Development of a MATLAB/STK TLE Accuracy Assessment Tool, in Support of the NASA Ames Space Traffic Management Project.” August, 2009. https://arxiv.org/pdf/1304.0842.pdf 2. Splatalogue, www.cv.nrao.edu/course/astr534/Equations.html. 3. STK, help.agi.com/stk/index.htm#training/manuals.htm?TocPath=Training|_____0. 4. Kilda l, Pe r-Simon. Foundations of Antenna Engineering: a Unified Approach for Line-of-Sight and Multipath. Kilda l Ante nn AB, 2015. 5. “Cables, Coaxial Cable, Cable Connectors, Adapters, Attenuators, Microwave Parts.” Pasternack, www.pasternack.com/. 6. “Tools for Spacecraft and Communication Design.” Amateur Radio in Space, www.amsat.org/tools-for-ca lcula ting- spacecraft-communications-link-budgets-and-other-de sign-issues/. 7. http://www.rfhamdesign.com/index.php 8. Ha mlib rota tor control comma nd libra ry: http://manpages.ubuntu.com/manpages/xenial/man8/rotctld.8.html 9. RF Hamdesign - Mesh Dish Kit 1.5m. “Spe cifica tions She e t”. PDF file . 2 0 18. www.rfhamdesign.com/downloads/rfha mde sign-dish-kit_1m5_kit_spec.pdf. 10. SPX-01 Azimuth & Elevation Rotor Including Control. “SPX-0 1 Spe cifica tions She e t”. PDF file . 2 0 18. www.rfhamdesign.com/downloads/spx-01-spe cifica tions.pdf. 75

Questions? 76

Backup Slides 77 Total List 78 Changes Made Since PDR

Change Reasoning

Purchase and modify dish kit Cost effectiveness due to amount of man hours necessary to build dish from scratch

Purchase motor gimbal Difficulty in a ccura cy a nd e fficie ncy. Out of scope

More precise gain number Specific components chosen, thus, accurately ca lcula te d losse s

Removal of auto-track Out of scope due to difficulty, processing constraints, and strain on motors 79 Requirement Verification Method

1.0 The ground station shall be capable of receiving Verification of conditioning and processing QPSK signals from a Low Earth Orbit satellite between 2.2 - signal in lab setting, power reception test of LEO 2.3 GHz, in Quadrature Phase Shift Keying (QPSK) satellite with integrated system modulation with a Bit Error Rate (BER) of 10 -5, a bandwidth of 2MHz, and a G/T of 3 dB/K.

2.0 The ground station shall mechanically steer a Slew rate and pointing accuracy testing of integrated dish/antenna system to follow a LEO satellite gimbal/antenna assembly, tracking satellite during between 200 km to 600 km between 10 ° elevation pass monitoring signal strength and 170° elevation.

3.0 The ground station shall be reconfigurable to be used All band specific components are accessible and for different RF bands. interfaced with industry standard connectors

4.0 ARGUS shall weigh less than 46.3 kg (102 lbs) and be Weight budgeting, mobility and assembly capable of being carried a distance of 100 meters by demonstrations two people.

5.0 The ground station onboard computer shall interface Passage of required data between laptop and NUC with a laptop using a Cat-5 ethernet cable. 80

Reconfigurability

FR 3.0 The ground station shall be reconfigurable to be used for different RF bands. 81 Reconfigurability to Other Frequency Bands

Components Dependent Reason Reconfigurable Solution upon Frequency

Feed Picks up specific band and made for specific Modular ring clamp makes it possible focal length to diameter ratio; diameter to swap out feed at other band, depends on frequency provided F/D ratio is similar

SDR SDR has maximum frequency and sampling Change defined frequency window rate, upgrade may be required at higher and sampling rate according to new frequencies. band OR insert new SDR using the same connections

Pa ra b o lic d ish ma te ria l Must use material smaller than 1/10th of None needed; current mesh is valid wavelength u p t o 11 G H z

LNA Made for specific frequency bands Replace LNA to accommodate new band 82

Laptop Interface

FR 5.0 The ground station onboard computer shall interface with a laptop using a Cat -5 ethernet cable. 83 Power Budget

Component Voltage Max Power Draw

Motor Assembly 24 VAC, 50/60 Hz 45.6 W

NUC Computer 19 V 120 W

LNA 3.0 V 0.5 W

*All other components powered through USB connections to NUC computer 84 Power Components

● 120-24 VAC Transformer ○ Used for providing 24 VAC to pointing motors ○ Rated for 100 W (45.6 W required) ○ Verification: Multimeter reading of input and output for voltage and frequency ● 120 VAC to 3.3 VDC AC-DC Converter ○ 3.3 VDC required for LNA ○ Rated for 9.9 W (0.5 W required) ○ Verification: Multimeter reading of DC output 85 GPS Module

● Purpose: ○ Determine precise location of ground station use d for ca libra tion a nd timing ● Model: ○ Globa lsa t BU-353 ● Specs: ○ Stationary Accuracy of +/- 3 meters ○ $30 86 Low Noise Amplifier

● Purpose: ○ Incre a se signa l ga in ● Model: ○ Minicircuits ZX6 0 -P33ULN+ ● Specs: ○ G a in : 14 . 8 d B ○ Noise: 0.38 dB ○ Max Power Draw: 0.2 Watts ○ $94.95 87 Software Defined Radio

● Purpose: ○ Process incoming RF data ● Model: ○ Ada lm Pluto ● Specs: ○ Up to 20 MHz Bit Rate ○ 12 b it AD C ○ Fre que ncy Range : 325 MHz to 3.8 GHz ○ $ 10 0 88 Onboard Computer

● Purpose: ○ Process incoming RF data and control tracking ● Model: ○ Intel NUC Kit NUC7I7DNKE ● Specs: ○ Inte l i7 Proce ssor ○ 3.6 GHz Clock Spe e d ○ $750 89 BER Equation

Using QPSK Modula tion, BER is ca lcula te d by:

● Va ryin g SNR (E/N) g ive s BER

https://e n.wikipe dia .org/wiki/Pha se -shift_keying#Bit_error_rate_2 90 BER Confidence Level Calculation

https://www.keysight.com/main/editorial.jspx?ckey=1481106&id=1481106&nid=-1114 3 . 0 . 0 0 &lc =e n g &c c =U S 91 What is QPSK Modulation?

1.0 The ground station shall be capable of receiving signals from a Low Earth Orbit satellite between 2.2 - 2.3 GHz, in Quadrature Phase Shift Keying (QPSK) modulation with a Bit Error Rate (BER) of 10 -5, and a G/T of 3 dB/K.

● QPSK Modulation is a method of encoding bits within a wa ve form ● Slice tra nsmitte d signa l into four pa rts by va rying pha se ; ○ 45°, 13 5 °, 18 0 °, 225° ● Shape of wave indicates what pair of bits are being transmitted ● Piece received signal back together 92 QPSK Modulation

Sending the letter “A”: Transmission: 01000001

● Bit stream broken up into 2 parts ○ Odd Bits = Inphase Component (I) ○ Even Bits = Quadrature Phase Component (Q) ● 2 waves created composed of 4 periods ○ Certain shape of cosine = 0 ○ Certain shape of sine = 1 ● Waves combined with 2 bits per period of transmitted signal 93 QPSK Modulation

Reception:

● Fina l wa ve is re ce ive d containing 2 bits per Pe riod ● Results in 2 times faster data rate ● Or half the BER with same data rate

Received the letter “A”: 01000001 94 GNURadio Software Diagram

Adalm Pluto SDR Filtering Demodulation GUI 95 TLE Predicted Error

● In the absence of truth data Two Line Element text files can be propagated and compared to the positions assumed to be the most accurate, the epoch. ● The positions of the satellite are then propagated and compared to the origina l position 96 Bit Error Rate & QPSK Verification

● Purpose: Ensure received bit stream will be accurate and software can successfully demodulate QPSK signals. ● Procedure: ○ Cre a te QPSK modula te d signa l in MATLAB of a t le a st 460,518 bits to give 99% confidence ○ Add noise to signa l (a ssume Additive White Ga ussia n) using signal to noise ratio of 17.21 ○ Write to file ○ Read file using GNURadio and Demodulate ○ Write output bit stream to file and compare to original b it s tre a m in MATLAB 97 Controller Interface

Rot2Prog motor controller (back)

Azimuth motor connector: Elevation motor connector: USB computer control Motor drive (2 pins) Motor drive (2 pins) connector: built-in tracking Impulse sense (2 pins) Impulse sense (2 pins) interface or popular tracking programs 98 Reflector Design Choice

○ 3 Materials and Dish Styles Explored

Aluminum Ribs with Aluminum Mesh 3D Printed Hexagonal Design Carbon Fiber Panels

Difficult to Manufacture Over Budget ❌ ❌Not Time Efficient ❌ Not Cost/Time Effective Difficult to Verify ❌ ❌Heavy ❌ 99 Dish Wind Loading Estimation ● Based on information by RF Ham Design spec sheet ● 1.5 Me te r dish with 2 .8 mm Me s h 10 0 Antenna Efficiency

Feed Blockage Efficiency Efficiency 10 1 Feed Loss Sources

Phase Efficiency

Polarization Sidelobe Efficiency

Spillover Efficiency

Illumination Efficiency 10 2 Feed Efficiency 1 1 10 3 Blockage Loss 10 4 Antenna Surface Efficiency

Assume surface errors ϵ have Gaussian distribution with an rms of σ. Surface efficiency is then

Varying the error-to-wavelength ratio results in the following efficiency distribution: 10 5 Signal to Noise Ratio (SNR) Verification

● Purpose: De te rmine if signa ls received from orbit are distinguishable from noise floor ● Procedure: ○ Track transmitting LEO satellite ○ Perform fourier transform on signa ls ○ Compare signal power to average noise floor power ○ Compare actual SNR to SNR range for acceptable bit error rate ○ Pure tone transmit. Low power. Sinusoid 10 6 RFHamDesign Predicted Gain 10 7 Antenna Radiation Pattern 10 8 Gain Verification

Two possibilities: ● Anechoic chamber test ● Far-fie ld ra dia tion te st

Estimated Far-Fie ld dista nce :

Anechoic chamber not feasible 10 9 Motor Modeling

∑ Newton’s 2nd law for rotational motion

Torque proportional to current, C by constant a

Friction opposes torque, proportional to ang vel by constant b 110 Transfer Function Modeling

● Commanding position: PID control

● Commanding angular rate: PID control 111 PID Block Diagram 112 Simulink and Arduino Controls 113 Signal Reception

● According to ASEN 3300 Lab 11 link budget, current signal to Ca lcula tion Assumptions: noise ra tio figure is 17.21dB prior ● TX Antenna Gain: 6.0 dBi ● TX Pointing Error: ± 6° (-12 dB loss) to a mplifica tion ● TX Power: 5 Watts ● Chosen LNA has a gain of 14 dB ● RX Diameter: 1.5 m and a noise figure of 0.4 dB ● RX Antenna Efficiency: 50% ● RX Be a mwid th: 9 ° ○ Signa l to noise ra tio will ● RX Pointing Accuracy: 0.5° barely be reduced by ● Range: 400 km a mplifica tion ● Fre que ncy: 2.3 GHz 114 Control Interface 1. Connect controller to computer via USB 2. Ena ble communica tion to controlle r with TCP using Ha mlib’s rotcld libra ry

Example Linux command: “rotctld -m 202 -s 19200 -r /dev/ttyUSB0”

Model Baud Port

1. Input current lat/long 2. Pe rform ma nua l sun ca libra tion 3. Select satellite to track 4. Engage tracking 115 Requirements & Their Satisfaction

Requirement Satisfaction

1. 0 The ground station shall be capable ● The dish, LNA, and SDR are designed to handle signals of receiving signals from a Low Earth between 2.2-2.3 GHz Orbit satellite between 2.2 - 2.3 GHz, ● The software is capable of QPSK demodulation of the in Quadrature Phase Shift Keying signal, as well as handling signals with high bandwidth (QPSK) modulation with a Bit Error ● The MATLAB s imula tio n sho we d the BER will b e we ll Rate (BER) of 10-5, a bit rate of 2 below 10-5 Mbit/s , and a G/T of 3 dB/K. ● The dish is designed with a minimum gain of 27 dBi, which satisfies the G/T requirement

2.0 The ground station shall ● The software is capable of tracking a LEO satellite from 0° mechanically steer a dish/antenna to 90° e le va tio n system to follow a LEO satellite ● The motors will use PID control to ensure that they are between 200 km to 600 km pointing as close to the desired position as possible between 10° elevation and 170° elevation. 116 Requirements & Their Satisfaction

Requirement Satisfaction

3.0 The ground station shall be ● Components can be swapped out; dish reconfigurable to be used for different RF needs no adjustment bands.

4.0 ARGUS shall weigh less than 46.3 kg ● The mass estimate is 45.32 kg, which is (102 lbs) and be capable of being carried less than the requirement. ● The carrying case and dish disassembly a distance of 100 meters by two people. will a llo w fo r e a sy tra nsp o rt.

5.0 The ground station onboard computer ● Linux Secure Shell with X11 Forwarding sha ll inte rfa ce with a la p to p using a Ca t-5 ethernet cable. 117 Disassembled and Packaged System 118 Disassembled and Packaged System