Final Design

Overview of Solution

    The method we use is to set up two infrared transmitters with known position, which are the commercial HTC Vive base stations; the embedded system of the drone will receive and filter the signals and calculate its position based on it. In addition, an inertial measurement unit (IMU) onboard will provide kinetic information. We finally apply a Kalman Filter to fuse information from the two sources, in order to get a better estimation of the position. All processes are done onboard, thus it is decentralized and scalable.

Position Measurement

        The method is as following:

               1. Install two HTC Vive base station at two separate corner of the room.

                2. Each base station do the following things very periodically,  with infrared light at ~850nm:

                        • send out an omnidirectional pulse that last for 100~300µs

                        • send out a 2D plane of light, that rotates and sweeps across the room 

                        • send out an omnidirectional pulse that last for 100~300µs

                        • send out a 2D plane of light, that rotates and sweeps across the room, in another direction

  (Note: The video only shows the sweep of 2D plane. It doesn't show the omnidirectional pulse that marks the beginning of sweep.)

                3. An infrared photodiode can receive the light, and generate signals. 

                    It can measure the time gap between the omnidirectional pulse and the moment when the 2D plane hits the receiver.

                4. While the angular speed of the sweep is constant, given where the sweep starts and the time gap, 

                    we can calculate the plane which both the receiver and the base station exist in. 

                5. First base station sweep in 2 directions, find 2 planes. --> Find the line which the receiver and the first base station exists in.

                6. Second base station sweep in 2 directions, find 2 planes. --> Find the 2nd line which the receiver and the second base station exists in.

                7. The two lines should intersects at a point. The point of the receiver's location.

        This is what the signals look like.

        By identifying which sweep the sweep signal corresponds to, and by calculating the time gap in between the omnidirectional pulse and the sweep            signal , the system is able to calculate its position onboard.

Describe your final design here in more detail than the front page. Use your best figures and material from your presentations and report.

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This page is similar to the executive summary but is in a webpage format.