170 likes | 270 Views
Fishfinders. Thomas J Kramer EECS 725. What is a Fishfinder ?. From Wikipedia: “an instrument used to locate fish underwater by detecting reflected pulses of sound energy”. Generally meant to be used on a boat, and usually come with a graphical display.
E N D
Fishfinders Thomas J Kramer EECS 725
What is a Fishfinder? • From Wikipedia: “an instrument used to locate fish underwater by detecting reflected pulses of sound energy”. • Generally meant to be used on a boat, and usually come with a graphical display. • Used in both recreational and commercial applications.
Example: Garmin ECHOMAP Plus 73sv Image obtained from Bass Pro Website: https://www.basspro.com/shop/en/garmin-echomap-plus-73sv-chartplotter-fishfinder-combo
Why Sonar over Radar? Sound in Liquid Water (fresh) Light in Liquid water First image from: J(2007) Light Absorption by Water Molecules and Inorganic Substances Dissolved in Sea Water. In: Light Absorption in Sea Water. Springer, New York, NY Second image from: http://phasordesign.com/uwacoustics/
Design Considerations: • Same as normal radar systems, but with the addition of a transducer known as a hydrophone. • Water proof, pressure proof. • Center Frequency. • Temperature and Depth. (affects speed of the wave) • Motion of the boat. • User Interface (Not everyone is a Radar Engineer).
Interpreting the Fish Finder: Obtained from: https://www.fishfinders.info/how-to-read-a-fish-finder-screen
Active areas of research: • Fish detection using Machine Learning Techniques: Vision based real-time fish detection using convolutional neural network • Fish Tracking tags (like RFID tags): Development of a sonar-responding acoustic tag for fish behavior observation • General Sonar Research: Feasibility of Second Harmonic Imaging in Active Sonar: Measurements and Simulations
Radar Assisted Cruise Control Thomas J Kramer EECS 725
What is Radar Assisted Cruise Control? • From Wikipedia: “a cruise control system for road vehicles that automatically adjusts the vehicle speed to maintain a safe distance from vehicles ahead”. • Can be used in normal cars (manually operated) or in self driving cars (automatically operated). • Can also be supplemented with laser or cameras. However, only radar can be guaranteed to work in all weather conditions. • Allows the speed of the vehicle to slow down due to changes in speed in the car in front.
Example: Mazda Radar Cruise Control • Uses millimeter wave radar on the front of the car. • User can manually set how many car lengths behind to maintain. • Displays the approximate distance to the car in front. Image obtained from Mazda’s website: https://www.mazda.com/en/innovation/technology/safety/active_safety/mrcc/
Example: Mazda Radar Cruise Control Image obtained from Youtube: “Adaptive Cruise Control Test - 2016 Mazda CX-9 | It can slow you down!“ by CharlestonCarVideos
Design Considerations • Beamwidth – only want returns from our lane (12 ft width), and out to a far enough distance (~60 ft or several car lengths). • Target Masking – A large target (metal wall along a turn) can mask a smaller target (car) with its range sidelobes. • Operation speeds – highway speeds or down to 0 mph. • Responsiveness – need to adjust more quickly if car in front slams on brakes, need to track range. • Predictability– normal traffic and stop and go traffic will require different response patterns.
Spectrum Sharing • One car with radar assistance may utilize an entire approved band, but multiple cars will begin to have interference. • Sharing spectrum adds additional design requirements, which could degrade the performance of the radar. • Sense and avoid, waveform diversity, and distributed networks are solutions to address this concern. • Also must consider other sources of interference in band (Communications, Internet of Things).
Cognitive Radar • Cognitive Radar is one way to handle spectrum sharing issues as well as target characterization. Figure from: Haykin, S.:‘Cognitive radar: a way of the future’,IEEE Signal Process.Mag., 2006
Active Areas of Research • W-Band Radar Designs: A 77 GHz Frequency Doubling Two-Path Phased-Array FMCW Transceiver for Automotive Radar • All-Direction Detection: RCS characteristics of street curbs and the applications in automotive radar classification • All-Weather Lane Detection: Environment classification and hierarchical lane detection for structured and unstructured roads • Paper above is for optical, but Radar is a natural solution for all weather scenarios. • Combined Radar and Comm Waveforms: Dual-Beam Transmit from Shared Aperture with Constant Envelope Constraint
Any Questions? Thomas J Kramer EECS 725