Lockheed Martin UAV Challenge Automated Aerial Reconnaissance Abstract
Lockheed Martin UAV Challenge Automated Aerial Reconnaissance Abstract Modern warfare has seen a shift in location to more urban settings. Urban structures are the new terrain for soldiers. These structures can be a large hindrance to military operations because they block large lines of sight. To better equip the modern solider a new system needs to be implemented. This new system should allow soldiers to see around urban structures which will provide them an advantage over their opponent. Problem Statement In 2008, students began designing and building an unmanned aerial vehicle (UAV) to address this need. The work addressed here is the continued development and improvements made to the work of the original group to better meet the needs of the client, Lockheed Martin. The Electrical and Computer Engineering members of the multidisciplinary team focused on three main areas of improvement in order to meet the program’s requirements: Communication • Increase range • Decrease effect of interference Power Supply • Decrease weight • Increase flight time • Improve launch safety Autopilot • Allow for autopilot takeover of manual control • Tune control system • Develop point of interest orbit functionality Project Requirements FR 01 -The UAV shall be capable of flying at a cruising speed of 40 -50 knots. FR 02 -The UAV shall be capable of flying for 1 hour. FR 03 -The UAV shall be capable of resolving a 6 inch target 100 feet below the aircraft. FR 04 -The UAV shall be capable of vertical or near vertical launch from a pneumatic rail system. FR 05 -The UAV shall be capable of climbing to an altitude of 100 feet. FR 06 - The UAV shall be capable of clearing a 40 foot tall obstacle, 20 feet downrange from launch. FR 07 -The UAV shall not be very noticeable to a ground observer. NFR 01 - The UAV shall use an electric motor. NFR 02 - The UAS shall fit into the back of a Military Humvee (5’x 2. 5’x 1. 5’). NFR 03 - The UAV shall only fly under moderately calm, clear conditions. NFR 04 - The UAS shall be capable of autonomously navigating through GPS waypoints. Power Supply To keep the total aircraft system weight below ten pounds, a custom power supply was designed. The new power supply quadruples flight time and provides the correct voltage (12 V or 5 V) to each avionics component through switching voltage regulators. This redesign allowed us to integrate a throttle cutoff into the system. The new throttle cutoff prevents the propeller from spinning while on the launcher, thereby eliminating any accidental throttle-up from occurring until the plane leaves the launch rail. Together with the throttle cut-off, the launch control system was integrated into a single control box. The power supply redesign reduced weight, simplified the launch system, increased flight time, and made the system significantly safer. Communication System The video system is made up of 8 components that work together to transmit video from the UAV and display it at the ground station. All of this is done while remaining within FCC radio regulations. The block diagram to the right describes the layout of the video transmission system and how the signal flows from the camera to the video screen. The OSD board overlays the video signal with the call letters of the licensed HAM radio operator to meet FCC regulations. The transmitting antenna is a halfwave dipole and is located in the fuselage to remove the need for extra wires in the wing. A 12 element Yagi antenna receives the signal, which is then changed from 435 MHz to 44 MHz by the downconverter, and then demodulated by the IF Converter. The demodulated video signal can then finally be displayed on any TV or computer with an NTSC composite video input. Autopilot The autopilot is a commercial, off-the-shelf system designed by Micro. Pilot. It uses various sensors and feedback control loops to achieve fully autonomous flight. Each of the feedback control loops have three gain values associated with them which determine the timing and magnitude of the changes made to the aircraft’s control components. In order to maintain stability in flight, each gain value must be carefully tuned to fit the aircraft’s design. This tuning is done manually through a series of trial and error test flights. On the ground, the operator uses Micro. Pilot’s Horizon software to set way-points for the aircraft or to vary its speed and altitude. Once a potential ground threat is identified, the operator can simply drag and drop a way-point for the aircraft to circle, and the camera will automatically focus on the center of its flight path, providing a clear image of the ground target. Time and Monetary Budgets Design Item Video Transmitter Base station antenna Down converter IF Converter OSD Board Cost $179 $50 $75 $62 $139 Power Supply/Launch System Batteries Total Design Cost $300 $885 630 Total Hours Tim Jacobs Jason Ekstrand Dan Jason Matt Stemper Repair Expense Autopilot Replacement RX Antenna Replacement Camera Lens Replacement Camera Replacement Total Repair Cost $2, 500 $55 $78 $190 $2, 823
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