1. Low Cost Radar and Sonar using Open Source Hardware and Software
Lance Williams
Radar Remote Sensing Group
University of Cape Town

2. Project Goal To create a Radar/Sonar application using the USRP
and GNU Radio, and examine its effectiveness as a
monostatic and netted Radar/Sonar node.
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3. Outline Project Concept The Universal Software Radio Peripheral (USRP)
The USRP Basic Layout
Test Application Overview
Implementation (FPGA)
Results
Further Development
Conclusion
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4. Project Concept: Reducing Cost
There is increasing demand on telecom networks for more capability and coverage.
More specialized DSP chips performing mixing, filtering
and analog to digital conversion.
Performance lost can possibly be regained by using
alternative radar types, configurations and processing
techniques.
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5. Project Concept: Recovering Performance
Netted radar may recover performance lost by using non-ideal components.
Synchronized nodes show an improvement in certain performance metrics over a monostatic system.
Netted radar: counter stealth, more robust tracking, more information for target classification.
Cheaper nodes make larger, better performing netted radars more viable.
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6. Project Concept: Open Source Hardware and Software
Universal Software Radio Peripheral: A software defined
radio hardware solution. A single hardware interface to
many different RF channel types. Re-configurability
enables applications like FM radio, TV, GPS, Radar and
Sonar.
GNU Radio: A flexible open source software application building frame-work that serves for developing small scale RF software systems, quick prototyping, and for educational purposes
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7. The Universal Software Radio Peripheral
usb 2.0 via Cypress FX2
Altera Cyclone FPGA
4 14 bit DAC's capable of 128 M samples/sec
4 12 bit ADC's capable of 64 M samples/sec
Interchangeable daughterboard front-ends.
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8. The USRP Basic Layout FPGA Cypress FX2 usb controller ADC ADC ADC ADC
Receive
Daughterboard
Receive
Daughterboard
ADC
ADC
DAC
DAC
Transmit
Daughterboard
Transmit
Daughterboard
DAC
DAC
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9. Daughterboard Functionality
● Basic RX, MHz receive
● Basic TX, MHz transmit
● LFRX, DC-30 MHz receive
● LFTX, DC-30 MHz transmit
● TVRX, MHz receive
● DBSRX, MHz receive
● RFX1800, MHz Transceiver
● RFX2400, MHz Transceiver
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10. Test Application Overview
SONAR system using ultrasonic tranducers
Emits chirp signals centred at 40 kHz
2 kHz bandwidth
1 millisecond pulse lengths (Variable)
16 ms pulse repetition interval (Variable)
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11. Implementation (FPGA)
Ram
Control
module
PRI counter
TX Chain module
Delay counter
Window counter
RX Chain module RX
Buffer TX
enable
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12. Results (1)
Fed back output showing the USRP capturing the transmitted pulse
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13. Results (2) Raw received data showing the PRI triggered marker samples
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14. Results (3) Echo recorded from a stationary object Echo spectrum
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15. Further Development (1)
Development of a USRP and GNU Radio based active radar prototype
USRP with transceiver board, front end, and host computer
Target
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16. Further Development (2)
Development of a small scale netted radar prototype using the USRP and GNU radios existing support for IP interconnectivity and distributed clocks.
Target
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17. Further Development (3)
Development of a passive coherent location prototype using the USRP TV receiver daughterboard
FM / TV transmitter
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18. Conclusion USRP modifications have proved successful.
The system design within the USRP has been kept flexible in order to create radar application with little firmware modification.
The GNU Radio software has been used to produce a basic front-end and perform data gathering.
The standard USRP contains features that will be needed for netted Radar/Sonar prototypes.
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19. References
GNU Radio – GNU FSF Project. 15 November 2006 [accessed online at on 4 December 2006]
Ettus Research LLC. 20 November 2006 [accessed online at on 4 December 2006]
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