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

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. © CSIR 2006 www.csir.co.za

Outline Project Concept The Universal Software Radio Peripheral (USRP) The USRP Basic Layout Test Application Overview Implementation (FPGA) Results Further Development Conclusion © CSIR 2006 www.csir.co.za

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. © CSIR 2006 www.csir.co.za

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. © CSIR 2006 www.csir.co.za

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 © CSIR 2006 www.csir.co.za

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. © CSIR 2006 www.csir.co.za

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 © CSIR 2006 www.csir.co.za

Daughterboard Functionality ● Basic RX, 0.1-300 MHz receive ● Basic TX, 0.1-200 MHz transmit ● LFRX, DC-30 MHz receive ● LFTX, DC-30 MHz transmit ● TVRX, 50-860 MHz receive ● DBSRX, 800-2400 MHz receive ● RFX1800, 1500-2100 MHz Transceiver ● RFX2400, 2250-2900 MHz Transceiver © CSIR 2006 www.csir.co.za

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) © CSIR 2006 www.csir.co.za

Implementation (FPGA) Ram Control module PRI counter TX Chain module Delay counter Window counter RX Chain module RX Buffer TX enable © CSIR 2006 www.csir.co.za

Results (1) Fed back output showing the USRP capturing the transmitted pulse © CSIR 2006 www.csir.co.za

Results (2) Raw received data showing the PRI triggered marker samples © CSIR 2006 www.csir.co.za

Results (3) Echo recorded from a stationary object Echo spectrum © CSIR 2006 www.csir.co.za

Further Development (1) Development of a USRP and GNU Radio based active radar prototype USRP with transceiver board, front end, and host computer Target © CSIR 2006 www.csir.co.za

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 © CSIR 2006 www.csir.co.za

Further Development (3) Development of a passive coherent location prototype using the USRP TV receiver daughterboard FM / TV transmitter © CSIR 2006 www.csir.co.za

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. © CSIR 2006 www.csir.co.za

References GNU Radio – GNU FSF Project. 15 November 2006 [accessed online at http://www.gnu.org/software/gnuradio/ on 4 December 2006] Ettus Research LLC. 20 November 2006 [accessed online at http://www.ettus.com/ on 4 December 2006] © CSIR 2006 www.csir.co.za