SAE Aero Telemetry System Catherine Kanama ECE 499 Advisor: Prof. Shane Cotter March 15, 2017 Project Summary The main objective of this project is to provide the SAE Aero team with a telemetry system needed to compete at the SAE Aero Advanced class competition. The advanced class involves building an aircraft that simulates a large cargo plane carrying a payload and dropping “humanitarian aid packages” from 100ft onto a target site. The telemetry system is made up of two main subsystems, the data acquisition system (DAS) and the first-person view system (FPV). The system uses flight data from sensors on the plane to provide valuable in-flight information about the state of the aircraft and improve accuracy of dropping the package on the target. The data collected will also be used for flight testing and structural optimization of the plane. Each of the systems has minimum functional requirements laid out in the competition rules. Additional components are allowed to enhance reliability or functionality but increase weight and complexity. The data acquisition system will be used to wirelessly transmit the sensor readings from the plane to the ground station and record when the package is dropped. The first-person view system will be used to stream video from an onboard camera in real time to a screen on the ground station. The data acquisition system and first person view system will be physically separate so that they can be easily tested and debugged, mounted and removed from the fuselage of the aircraft easily. Table of Contents Project Summary .......................................................................................................................... 1 List of Figures ................................................................................................................................ 3 List of Tables ................................................................................................................................. 3 1. Introduction ........................................................................................................................... 4 2. Background ............................................................................................................................ 6 3. Design Requirements ............................................................................................................. 8 3.1. SAE Advanced Class Competition Requirements....................................................... 9 3.2. 2017 Union College Trivium Aircraft Requirements ................................................ 10 4. Design Alternatives .............................................................................................................. 12 4.1. First Person View System ............................................................................................ 12 4.1.1. Analog vs Digital Video Transmission ................................................................... 12 4.1.2. Video Transmitter/Receiver Model ........................................................................ 12 4.1.3. Camera Alternatives................................................................................................ 13 4.1.4. Camera Placement .................................................................................................. 14 4.2. Data Acquisition System .............................................................................................. 15 4.2.1. Communication Protocol Alternatives .................................................................... 15 4.2.2. Transmitter/Receiver............................................................................................... 17 5. Final Design Implementation ............................................................................................. 19 5.1. First Person View System ............................................................................................ 19 5.1.1. Transmitter/Receiver............................................................................................... 19 5.1.2. Camera .................................................................................................................... 19 5.1.3. RCA Converter ....................................................................................................... 19 5.1.4. Power Supply .......................................................................................................... 19 5.2. Data Acquisition System .............................................................................................. 20 5.2.1. Microcontroller ....................................................................................................... 20 5.2.2. Transmitter/Receiver............................................................................................... 21 5.2.3. Airspeed Sensor ...................................................................................................... 21 5.2.4. Altitude Sensor........................................................................................................ 21 5.2.5. GPS Tracking and On-Board Storage ..................................................................... 21 5.2.6. User Interface .......................................................................................................... 22 5.2.7. Power Supply .......................................................................................................... 22 5.3. Telemetry System Placement on the Trivium............................................................ 23 6. Performance Estimates and Results .................................................................................. 24 6.1. First Person View ......................................................................................................... 24 6.2. Data Acquisition System .............................................................................................. 25 7. Discussion and Conclusion .................................................................................................. 26 8. User’s Manual ...................................................................................................................... 27 8.1. First Person View ......................................................................................................... 27 8.2. Data Acquisition System .............................................................................................. 28 9. References............................................................................................................................. 30 10. Cost Analysis .................................................................................................................... 32 11. Appendices ........................................................................................................................ 32 11.1. Battery Calculations ................................................................................................. 32 11.2. Arduino Code ............................................................................................................ 33 List of Figures Figure 1: SAE Aero Competition Advanced Class Scoring Method [1] ........................................ 8 Figure 2: SAE Aero Competition DAS and FPV requirements [1] ................................................ 9 Figure 3: Telemetry System Block Diagram based on minimum requirements ........................... 11 Figure 4: Boscam FPV (Left) and AKK FPV (Right) .................................................................. 13 Figure 5: Camera Placement Location Options ............................................................................ 15 Figure 6: Block Diagram showing SPI Connection [9] ................................................................ 16 Figure 7: Block diagram showing I2C connection [10]................................................................ 17 Figure 8: Block Diagram of FPV implementation ........................................................................ 20 Figure 9: FPV system.................................................................................................................... 20 Figure 10:Block Diagram of Implemented DAS .......................................................................... 22 Figure 11: Completed DAS .......................................................................................................... 22 Figure 12: Telemetry System Placement on the plane.................................................................. 23 Figure 13: FPV Video Quality ...................................................................................................... 24 Figure 14: FPV Football Field Range Test ................................................................................... 24 Figure 15: Recorded Altitude from Test Flight ............................................................................ 26 Figure 16: Recorded Flight Path from Test Flight ........................................................................ 26 List of Tables Table 1: Requirements generated by the 217 Union SAE Aero Team ......................................... 10 Table 2: Boscam vs AKK Specifications...................................................................................... 13 Table 3: Airy 3g vs CrazyPony ..................................................................................................... 14 Table 4: XBee Modules Comparison ............................................................................................ 18 Table 5: Altitude Sensor Test Results ........................................................................................... 25 Table 6: Cost Analysis .................................................................................................................. 32 1. Introduction The Union College Aero Team has competed in the SAE Aero Design competition since 2004. The advanced class involves building an aircraft that simulates a large cargo plane carrying a payload and dropping “humanitarian aid packages” from 100ft onto a target site. Last year the Flying Dutchmen participated in the Advanced class for the first time and placed 4th out of more than 40 schools from different countries in the flight round, this year we will also be participating in the Advanced class with the Trivium aircraft. The advanced class involves simulating a large cargo plane carrying a payload and dropping “humanitarian aid packages” from 100ft onto a target site. The scoring is based on accuracy of dropping the package. [1] The main aim of this project is to implement a telemetry system which includes the data acquisition system (DAS) and first person view system (FPV). The purpose of the telemetry system is to guide the pilot when dropping the package. Knowing the airspeed, altitude, and pressure readings will provide extremely useful data which will be used for calculating when to drop the payload and therefore increasing the accuracy. Both systems need to meet the design specifications set by the SAE Aero 2017 competition rules. I will also work on improving the video interface so that data such as altitude, speed and wind direction is also displayed on the screen. In addition to that, I will also implement a fuel monitoring system that will be used to provide data that can help improve flight performance and keep track of gas usage. The purpose of the telemetry system is to guide the pilot when dropping the package. Knowing the airspeed, altitude, and pressure readings will provide extremely useful data which will be used for calculating when to drop the payload and therefore increasing the accuracy. The telemetry system will consist of sensors, transmitters, receivers, memory storage and an onboard camera. The interface for each individual component is manageable. However, connecting all the components together in a synchronous manner will require some research, as well as trial and error in coding and testing. 2. Background One of the main challenges of flying RC aircrafts is the fact that you are physically separated from the aircraft you are controlling. This separation limits your access to the status of the plane to only the current clear a range of sight. Due to this problem, wireless telemetry systems have been very popular because they allow the user to monitor the plan wirelessly by providing altitude, airspeed, motor rpm, battery voltage, fuel status and even GPS tracking data. [2] Most prebuilt telemetry systems are standalone units which consist of a transmitter and sensor package on the aircraft and a receiver on the handheld controller. These units use several different ways including radio frequency, Bluetooth and even Wi-Fi to transmit the data. The data is usually displayed on a handheld controller rarely logged or recorded in any form. According the SAE competition restrictions, the telemetry system needs to log all data on the ground station, therefore we need to implement our own telemetry system in order to participate in the competition. [1] Our telemetry system also needs to be robust enough to survive small crashes and hard landings without falling apart. This means that the system also needs to be constructed such that it can be easily rebuilt and modified. Using a flexible design can easily will make the system easily movable or mounted onto the any aircraft. Thus, allowing us to quickly reassemble the system to accommodate any last-minute fuselage design fixes or alterations. The sensors should also be easily available and replaceable in the event of a crash and this should be a simple process. The main environmental concern for the system is the power source of the aircraft, a lithium- polymer battery. The rules mandate the use of a lithium-polymer battery, more specifically a 6 cell lithium-polymer battery. [1] If the battery were to become damaged at any point then it will not only become dangerous, but it will also pose an environmental risk as well. The lithium in the battery could ignite and result in a combustion reaction that would be dangerous to the surroundings. To minimize the effects of a battery malfunction, the batteries will be placed in a fire proof case and replaced after each flight to allow time for cooling.
 In an effort to make the aircraft more environmental friendly we plan on using bamboo composite sheets instead of wood composite sheets. Bamboo has same structural properties as composite wood therefore will not affect structural qualities of the aircraft. Also, bamboo is not a tree, it’s a grass, and has the ability to grow back faster making it more sustainable and environmental friendly. [3] Also, using bamboo instead of wood composite will help the team gain innovation design points. [1] There are several safety issues associated with this project. There is a 6-cell battery operating close to 1000 Watts and a motor that is being rotating at approximately 6000 rpm. When using the 6- cell battery it will draw close to 40 A or more of current to reach a power of 880 Watts. This amount of current and power could be fatal if not handled properly. If the two battery leads short out, the battery it could be destroyed and likely ignite. Therefore, all the wires used in the system need to be properly insulated, labelled and color coded 3. Design Requirements The design requirements for the telemetry system are based on two main sources, SAE International 2017 Collegiate Design Series: Design Aero East and West Rules and the 2017 Union Aero team. [1] Both sets of requirements aim to improve the accuracy of hitting the target and increasing innovation design points for the team. As seen in Figure 1, the scoring is based on a “Zone Multiplier” ranging from 0 to 1 depending on how the close the package is dropped on the target [1] Figure 1: SAE Aero Competition Advanced Class Scoring Method [1] 3.1. SAE Advanced Class Competition Requirements The SAE International 2017 Collegiate Design Series: Design Aero East and West Rules clearly layout the requirements of a telemetry system which consists of a data acquisition system(DAS) and first person view(FPV). Figure 2 below shows the different requirements outlines in the competition rule book. [1] Figure 2: SAE Aero Competition DAS and FPV requirements [1]