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Loran-C Receiver

Loran-C Receiver. Team Deathstar September 7, 2004. Capstone Fall 2004. Group Members. Matt Anderson (ECE) Chris Birschbach (ECE) Christy Corner (EE) Matt Hayman (EE) Erin Mowbray (ECE). Background: What is Loran-C?.

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Loran-C Receiver

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  1. Loran-C Receiver Team Deathstar September 7, 2004 Capstone Fall 2004

  2. Group Members • Matt Anderson (ECE) • Chris Birschbach (ECE) • Christy Corner (EE) • Matt Hayman (EE) • Erin Mowbray (ECE)

  3. Background: What is Loran-C? • Loran-C is a navigation system that was developed by the US Coast Guard. • The system is comprised of transmission stations located around the world. • The Loran-C signal is transmitted from these stations at specified intervals. • By measuring the time delay between transmissions a user can determine their position relative to the towers.

  4. Loran-C Signal

  5. Loran-C Signal continued • The Loran-C signal is transmitted on a 100kHz carrier.

  6. Project Purpose • Our group will design a receiver that will be able to capture and decode the Loran-C signal maintained by the United States Coast Guard. • Our system will consist of three main parts: the antenna/receiver, processing unit and personal computer.

  7. Project Funding • Undergraduate Research Opportunities Program (UROP) Grant. • Amount: $1750

  8. Tentative Budget

  9. Project Objectives • Capture a clean copy of the Loran-C signal • Determine Time Delays • Convert to a Latitudinal & Longitudinal coordinates.

  10. Outline of Approach • The system will consist of the following subsystems: • Antenna Receiver • Analog-to-digital converter • Motorola 68K processor • Memory • FPGA • Serial Interface • PC • Power

  11. Subsystems Diagram Processing Unit A/D Converter Antenna/Receiver FPGA Processor PC RAM

  12. Antenna Receiver Subsystem • The antenna/receiver will consist of a loop antenna with a active Butterworth filter to capture and amplify the fundamental signal received by the antenna. • This segment of the project serves the main purpose of capturing the Loran-C signal with minimal noise and preparing it for processing.

  13. Analog-to-Digital Converter Subsystem • The A/D converter will sample the analog signal. • Sampling rate will be 1MHz. • The digital data will be sent to the FPGA .

  14. FPGA Subsystem • The FPGA has a state machine for detecting the third zero crossing of the Loran-C signal. (Generates an interrupt) • It functions as a counter to measure the delay between pulses. • It includes an interrupt controller for the processor.

  15. Processor Subsystem • Upon generation of an interrupt, the processor stores the counter data from the FPGA into RAM. • Performs operations on the counter data to determine time delays and stores the delays in RAM. • The microcontroller sends the time delay data to the serial interface with the PC.

  16. RAM Subsystem • Holds the time delay and counter data for processing and transmission.

  17. Serial Interface Subsystem • The communication interface between the PC and the processor. • Consists of a serial shift register & RS-232 logic level converter.

  18. PC Subsystem • Displays the time delays. • Performs intensive conversion calculations to convert data into Latitudinal and Longitudinal coordinates. • Displays the Latitudinal and Longitudinal coordinates.

  19. Power • Transform, rectify, and regulate voltage from standard 120V/60Hz outlet to required DC voltages. (Or purchase power supply) • Include portable power sources (battery or car adapter) if time permits

  20. Tasks • Antenna Design • Filtering • PCB design • Memory interface • FPGA design • PC programming • PC interface • A/D interface • Processor programming • Power • Users Manual

  21. Schedule

  22. Division of Labor • Matt A • Power • Memory interface • Microprocessor Programming • Chris B • PC programming • Microprocessor programming • User’s Manual • Christy C • Antenna/Filtering • Verilog Design • User’s Manual • Matt H • Antenna/Filtering • PCB • Microprocessor Programming • PC programming • Erin M • Verilog Design • User’s Manual • PC interface

  23. Risks and Backup • Receiving a clean copy of the signal (Can generate a fake signal) • Baud rate generation for PC/processor communication • Buffer overflow (Sample slower) • Size and complexity of the state machine. (Can shift tasks from the FPGA to the processor to compensate.) • RS-232 Communication on PC (Manually entering data into the conversion program)

  24. Above and Beyond • If time permits we shall include a LCD display on our receiver that displays the Loran-C time delays. • Portable power sources. • Cup Holders

  25. Questions and Comments

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