UNIVERSITY OF CALIFORNIA AT SANTA CRUZ BASKIN SCHOOL OF ENGINEERING PROJECT REPORT ARS GROUND STATION, REV. 2 KAYLA CASTILLO HIDALGO JULIE THAO DO WILLIAM YE 09 JUNE 2014 CONTENTS LIST OF FIGURES .................................................................................................................................................... 4 LIST OF TABLES ................................................................................................................................. 5 TEAM INTRODUCTIONS .................................................................................................................... 6 MENTORS/ADVISORS ....................................................................................................................... 6 1. INTRODUCTION ......................................................................................................................... 8 1.1 MOTIVATION .......................................................................................................................................... 8 1.2 PROJECT OVERVIEW ............................................................................................................................ 8 1.2.1 COMMUNICATIONS .................................................................................................... 8 1.2.2 SOFTWARE ................................................................................................................. 9 1.2.3 MICROCONTROLLER .................................................................................................. 9 2. RESEARCH ............................................................................................................................... 10 2.1 ANTENNA .............................................................................................................................................. 10 2.1.1 ANTENNA FUNDAMENTALS ...................................................................................... 10 2.1.2 BEAM ANTENNAS ..................................................................................................... 12 2.1.3 4NEC2 ...................................................................................................................... 13 2.2 SOFTWARE ............................................................................................................................................ 15 2.2.1 SGP4 ALGORITHMS .................................................................................................. 15 2.2.2 CALENDAR CONVERSIONS ........................................................................................ 16 2.3 MICROCONTROLLER .......................................................................................................................... 16 3. DESIGN PHASE ........................................................................................................................ 18 3.1 ANTENNA .............................................................................................................................................. 18 3.1.1 DESIGN SPECIFICATIONS FOR ANTENNA ................................................................... 18 3.1.2 SIGNAL STRENGTH ................................................................................................... 19 3.1.3 HELICAL ANTENNA DESIGN AT 435MHZ.................................................................... 25 3.2 SOFTWARE ............................................................................................................................................ 30 3.2.1 GUI/USER INTERFACE ............................................................................................... 30 3.2.2 ALGORITHM DECISCION ........................................................................................... 31 3.2.3 LIBRARIES ................................................................................................................. 31 3.2.4 DATABASE ................................................................................................................ 33 3.2.5 CENTERING .............................................................................................................. 33 3.2.6 FOOTPRINT .............................................................................................................. 33 ARS GROUND STATION, REV. 2 Page 1 3.2.7 CLICKABLE SATELLITE ............................................................................................... 34 3.3 MICROCONTROLLER .......................................................................................................................... 35 3.3.1 MICROCONTROLLER SPECIFICATIONS ............................................................................. 35 3.3.2 MICROCONTROLLER DESIGN .................................................................................... 35 3.3.3 MICROCONTROLLER PCB .......................................................................................... 37 4. IMPLEMENTATION/INTEGRATION PHASE ................................................................................ 39 4.1 ANTENNA .............................................................................................................................................. 39 4.1.1 MATERIALS ............................................................................................................... 39 4.1.2 CONSTRUCTION ....................................................................................................... 39 4.1.3 TESTING ................................................................................................................... 42 4.2 SOFTWARE & MICROCONTROLLER .............................................................................................. 43 5. RESULTS .................................................................................................................................. 44 5.1 ANTENNA .............................................................................................................................................. 44 5.2 SOFTWARE ............................................................................................................................................ 45 5.3 MICROCONTROLLER .......................................................................................................................... 45 6. CHALLENGES ........................................................................................................................... 46 6.1 ANTENNA .............................................................................................................................................. 46 6.2 SOFTWARE ............................................................................................................................................ 46 6.3 MICROCONTROLLER .......................................................................................................................... 46 7. FUTURE WORK ........................................................................................................................ 48 7.1 COMMUNICATIONS ............................................................................................................................ 48 7.2 SOFTWARE ............................................................................................................................................ 48 7.3 MICROCONTROLLER/MOTOR CONTROLLER ............................................................................ 48 8. APPENDIX ............................................................................................................................... 49 8.1 BLOCK DIAGRAMS .............................................................................................................................. 49 8.2 GRAPHS .................................................................................................................................................. 50 8.3 TABLES ................................................................................................................................................... 53 8.4 MICROCONTROLLER PCB SCHEMATICS ...................................................................................... 57 8.5 ANTENNA CONSTRUCTION ............................................................................................................. 59 8.5.1 PARTS ....................................................................................................................... 59 8.5.2 DRAWINGS/SCHEMATICS ............................................................................................... 62 8.6 BUDGET .................................................................................................................................................. 68 9. REFERENCES............................................................................................................................ 69 ARS GROUND STATION, REV. 2 Page 2 ANTENNA ................................................................................................................................ 69 SOFTWARE .............................................................................................................................. 69 MICROCONTROLLER ................................................................................................................ 70 ARS GROUND STATION, REV. 2 Page 3 LIST OF FIGURES FIGURE 1: RADIO LINK OF A SATELLITE [1] ...................................................................................................... 8 FIGURE 2: PROJECT SYSTEM OVERVIEW.. ........................................................................................................ 9 FIGURE 3: RADIATION PATTERN [2] .............................................................................................................. 10 FIGURE 4: HELICAL ANTENNA [4] .................................................................................................................. 13 FIGURE 5: EXAMPLE OF 4NEC2 EDITOR ......................................................................................................... 14 FIGURE 6: 4NEC2 GENERATING PATTERNS .................................................................................................... 15 FIGURE 7: MICROCONTROLLER OVERVIEW.. ................................................................................................. 16 FIGURE 8: PROFESSOR PETERSEN'S 70CM (HELICAL) AND 2M (YAGI) ANTENNAS .......................................... 18 FIGURE 10: RECEIVED POWER FOR FO-29 ..................................................................................................... 23 FIGURE 11: RECEIVED POWER FOR VO-52 ..................................................................................................... 23 FIGURE 12: RECEIVED POWER FOR AO-7 ....................................................................................................... 24 FIGURE 13: RECEIVED POWER FOR AO-73 ..................................................................................................... 24 FIGURE 14: RADIATION PATTERN .................................................................................................................. 26 FIGURE 16: GRAPH OF ANTENNA GAINS ....................................................................................................... 28 FIGURE 17: GRAPH OF IMPEDANCE [RE] ....................................................................................................... 28 FIGURE 18: GRAPH OF IMPEDANCE [IM] ....................................................................................................... 29 FIGURE 19: SOLIDWORKS MODEL OF PROPOSED HELICAL ANTENNA ............................................................ 29 FIGURE 20: 3D VIEW. .................................................................................................................................... 32 FIGURE 21: 2D VIEW . ................................................................................................................................... 32 FIGURE 22: MICROCONTROLLER STATE MACHINE ......................................................................................... 37 FIGURE 23: PCB ........................................................................................................................................... 38 FIGURE 24: IN BETWEEN "T" SUPPORTS ........................................................................................................ 40 FIGURE 25: 3D PRINTED WIRE SUPPORTS ..................................................................................................... 40 FIGURE 26: BULKHEAD FITTING .................................................................................................................... 40 FIGURE 28: CONNECTING WIRE TO COAX VIA BNC ........................................................................................ 41 FIGURE 27: BULKHEAD FITTING ATTACHED TO GROUND PLANE.................................................................... 41 FIGURE 30: S11 OF HELICAL ANTENNA .......................................................................................................... 43 FIGURE 31: GRAPH OF THEORETICAL VS. MEASURED IMPEDANCE ................................................................ 44 FIGURE 33: FREQUENCY SWEEP OF GAIN ...................................................................................................... 50 FIGURE 34: FREQUENCY SWEEP OF IMPEDANCE [RE] .................................................................................... 51 FIGURE 35: FREQUENCY SWEEP OF IMPEDANCE [IM] ................................................................................... 52 FIGURE 36: MOTOR CONTROL CIRCUIT SCHEMATIC ...................................................................................... 57 FIGURE 37: PCB ............................................................................................................................................ 58 FIGURE 38: PVC "T" FITTING ......................................................................................................................... 59 FIGURE 39: 90° ELBOW PVC FITTING ............................................................................................................. 59 FIGURE 40: 1/2" MALE ADAPTER .................................................................................................................. 60 FIGURE 41: BULKHEAD FITTING .................................................................................................................... 60 FIGURE 42: 3D PRINTED WIRE SUPPORT ....................................................................................................... 61 FIGURE 43: BNC CONNECTOR ....................................................................................................................... 61 FIGURE 44: DRAWING OF STRUCTURE SUPPORT ........................................................................................... 62 FIGURE 45: DRAWING OF IN BETWEEN STUCTURE SUPPORT ........................................................................ 63 FIGURE 46: DRAWING OF IN BETWEEN STRUCTURE SUPPORT ...................................................................... 64 FIGURE 47: DRAWING OF BASE OF ANTENNA; INCLUDES DETAILS ABOUT BULKHEAD FITTING ..................... 65 FIGURE 48: PVC "T" FITTING ......................................................................................................................... 66 FIGURE 49: 90 DEGREE PVC FITTING ............................................................................................................. 66 FIGURE 50: BULKHEAD MALE ADAPTER ........................................................................................................ 66 FIGURE 51: SCREW PLACEMENTS OF SHEET METAL TO WOOD ..................................................................... 67 FIGURE 52: FINISHED 70CM HELICAL ANTENNA ............................................................................................ 67 ARS GROUND STATION, REV. 2 Page 4 LIST OF TABLES TABLE 1: GENERAL UPLINK SATELLITE INFORMATION ................................................................................... 21 TABLE 2: GENERAL DOWNLINK SATELLITE INFORMATION ............................................................................. 21 TABLE 3: UPLINK BUDGET FOR SO-50 ........................................................................................................... 21 TABLE 4: DOWNLINK BUDGET FOR SO-50 ..................................................................................................... 21 TABLE 5: DESIGN PARAMETERS FOR HELICAL ANTENNA ............................................................................... 26 TABLE 6: MICROCONTROLLER COMPARISON BETWEEN ATMEGA8L & PIC182553 ......................................... 35 TABLE 7: ANTENNA IMPEDANCE; THEORETICAL VS. MEASURED ................................................................... 44 TABLE 8: UPLINK BUDGET FOR SO-50 ........................................................................................................... 53 TABLE 9: DOWNLINK BUDGET FOR SO-50 ..................................................................................................... 53 TABLE 10: UPLINK BUDGET FOR FO-29.......................................................................................................... 53 TABLE 11: DOWNLINK BUDGET FOR FO-29 ................................................................................................... 54 TABLE 12: UPLINK BUDGET FOR VO-52 ......................................................................................................... 54 TABLE 13: DOWNLINK BUDGET FOR VO-52 ................................................................................................... 54 TABLE 14: UPLINK BUDGET FOR AO-7 ........................................................................................................... 55 TABLE 15: DOWNLINK BUDGET FOR AO-7 ..................................................................................................... 55 TABLE 16: UPLINK BUDGET FOR AO-73 ......................................................................................................... 55 TABLE 17: DOWNLINK BUDGET FOR AO-73 ................................................................................................... 56 TABLE 18: FINAL BUDGET ............................................................................................................................. 68 ARS GROUND STATION, REV. 2 Page 5 TEAM INTRODUCTIONS KAYLA CASTILLO HIDALGO, KK6JGU ELECTRICAL ENGINEERING TEAM LEAD ANTENNA DESIGN JULIE THAO DO, KK6JHF COMPUTER ENGINEERING DOCUMENTATION MICROCONTROLLER DESIGN WILLIAM YE, KK6JGV COMPUTER ENGINEERING FINANCES/PARTS PROCUREMENT SOFTWARE DESIGN MENTORS/ADVISORS PAUL NAUD STEPHEN PETERSEN, AC6P JOHN VESECKY, AE6TL ARS GROUND STATION, REV. 2 Page 6 ABSTRACT The purpose of this project is to design and build an Amateur Radio Station that will be able to track and communicate with satellites operating on HAM radio (amateur radio) frequencies. This service will be available to those on campus with a radio license and for future students who wish to improve upon the design of ARS rev.1 and rev 2. ARS GROUND STATION, REV. 2 Page 7 1. INTRODUCTION 1.1 MOTIVATION The ARS Ground Station project Rev. 1 was proposed last year but remains incomplete to this day. Although the previous ARS Ground Station team was unsuccessful in completing the project,, they provided this year’s project with the necessary foundation to continue towards the completion of a working ground station. There are multiple motivations that spur on this project; in cases of emergencies where phone lines or communication goes down, we wanted an alternative way of reaching out for help other than depending on normal means of communication such as cell phone or internet networks. Furthermore, this will allow those who already possess a HAM license to have access to our ground station, which in turn may spark the interest of others who wish to partake in amateur radio. 1.2 PROJECT OVERVIEW An amateur radio satellite ground station is a terminal located on earth designed for communication with amateur radio satellites. Ground stations communicate with satellites by transmitting and receiving radio waves. Figure 1 demonstrates the radio link between the ground station, the satellite, and the desired recipient. The ARS Ground Station will be able to communicate over operating Amateur Radio Service satellites that are in orbit: SO-50, FO-29, VO-52, AO- 7, and AO-73 (see Operating Satellites section for further information on satellites). These satellites, along with the ground station, allow a HAM licensed FIGURE 1: RADIO LINK OF A SATELLITE [1] user to transmit a signal (i.e. a voice message) to another HAM licensed user within the range of the satellite’s coverage. In order to build the ground station, there are three main subsystems that need to be engineered: communications (antenna/radio), software, and microcontroller motor control. Together, these subsystems will work together to produce a working ground station. Figure 2 displays the system project overview and details how each subsystem works with one another. 1.2.1 COMMUNICATIONS On the communications side of this project are the antenna and radio. For this ground station, the IC-910H radio will be used to transmit and receive the communication signals. Attached to the IC- 910H will be two antennas: a 70cm band antenna and a 2m band antenna. Each antenna will be able to transmit and receive to the desired satellite. ARS GROUND STATION, REV. 2 Page 8 1.2.2 SOFTWARE The goal of the software is to be able to track orbiting satellites and communicate between the IC- 910H radio and the microcontroller. This is done so that users are able to operate the ARS station easily and reliably. The main parts of the software tracks and projects paths of satellites using the SGP4 algorithm while the User Interface displays the necessary data. 1.2.3 MICROCONTROLLER The microcontroller is designed as a USB Virtual COM Port that interfaces the software and the rotor controller. It is controlled by the JavaScript software, and rotates the antennas to the correct azimuth and elevation angle. FIGURE 2: PROJECT SYSTEM OVERVIEW. Using the computer software program, the user is able to select an ARS satellite to track. The software interfaces with the IC-910H radio as well as the microcontroller to properly configure the settings needed to locate the satellite. Once the settings are established, the microcontroller shifts the motor and the antenna to point towards the satellite. Once the connection is established, the user is able to communicate over the satellite. ARS GROUND STATION, REV. 2 Page 9