An Interactive Radar Demonstration for Children

Transcription

1 An Interactive Radar Demonstration for Children Team 5: Nur Syuhada Zakaria Andy Myrick Steve Hughey Andrew Renton Sponsor: MIT Lincoln Laboratory Facilitator: Dr. Radha

2 Outline Introduction and goals Syue Design setup, hardware and software Andy Analysis and theory Steve Risk analysis, project management and budget Andrew

3 Introduction RADAR Radio Detection And Ranging Reflection principle Electromagnetic theory

4 Goals Demonstrate the principles of radar Real time processing Display Doppler effect and range vs. time Visually stimulating and interactive A portable system to be displayed in the MIT Museum

5 Design Setup CRT monitor - bottom shelf Can-tennas - middle shelf Processing hardware (microcontroller) - top shelf in a Plexiglass enclosure Each of the three units will be modular - allowing various placements

6 Design Setup

7 Hardware Pre-existing RF components Arduino MEGA 2560 R3 PICASO CRT for VGA output

8 VCO: ZX C-S+ Attenuator: VAT-3+ Low noise amplifier: ZX60-272LN+ Splitter: ZX Mixer: ZX05-43MH+ RF components have approximately 2.4 GHz operating frequency Manufacturer: All have a 50Ω impedance The + denotes RoHS compliance

9 Arduino MEGA 2560 R3 16 MHz ATmega 2560 µ-controller 54 Digital I/O pins 256KB Flash memory, 8KB SRAM, 4KB EEPROM USB programming and power Automatic (software) reset

10 PICASO GFX2 Graphics Processor VGA/SVGA Display Graphics Controller RGB 65K Custom resolutions Easy to use built in graphics functions: lines, images, bitmaps, etc Low power consumption

11 Software Data processing Arduino FFT Peak detection Communicates range and velocity information via serial port Image processing PICASO Display range and velocity versus time VGA output

12 Target Detection Velocity detection Doppler frequency shift proportional to target velocity Relatively simple implementation Range detection Phase shift causes beat note with frequency proportional to target distance Requires frequency modulated carrier signal More difficult to resolve than velocity Both can be achieved at once, but this introduces ambiguity to the signal.

13 Chirping Frequency of transmitted signal modulated by triangle wave Reflected signal returns to radar after a time Δt Heterodyning the received signal with the transmitted signal yields a beat note with the instantaneous beat frequency Beat frequency relates to target range linearly

14 Speed Detection Simulation The parameters of our radar give the following linear relation between beat frequency and target relative velocity: The graph to the right shows a peak at 256 Hz Thus, the target is moving at 16 m/s. Spectrum of mixed signal with target velocity 16 m/s and AWGN

15 Range Detection Simulation The peak frequency in the mixed signal corresponds to the target s range via the following linear relation R = cf b 8f m f where f b is the peak beat frequency, f m is the modulation frequency, and f is the frequency sweep This 900 Hz peak corresponds to a distance of 2 m Spectrum of mixed signal with target distance 2 m and AWGN

16 Risk Analysis and Considerations Time Safety Structural integrity Maintenance Power use

17 Project Management Andrew Signal processing and communications programming Andy Graphics programming & structure design/fabrication Steve Algorithmic analysis and programming Syue Graphics programming & structure design/fabrication

18 Timeline Syue Steve Andy Andrew Arduino Programming A/D Conversion 2/15::2/19 2/15::2/19 Signal Processing 2/20::2/26 2/20::3/4 2/20::2/26 2/20::3/4 Serial Communication Visual design/ coding Graphics Controller 3/5::3/19 3/5::3/19 2/27::3/12 2/27::3/12 Ancillary Design Cart and Housing 3/13::3/19 3/13::3/19 Power Supply 3/13::3/19 3/13::3/19 Analog Design 2/15::2/19 2/15::2/19

19 Budget $250 for microcontroller and associated costs (attachments, evaluation board, etc.) $55 for PICASO Graphics Controller $55 for Arduino Mega $100 for cart construction $31.50 for movable AV cart $150 for additional unforeseen costs

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