T. Rétornaz 1, J.M. Friedt 1, G. Martin 2 & S. Ballandras 1,2. 6 juillet Senseor, Besançon 2 FEMTO-ST/CNRS, Besançon

Transcription

1 USRP and T. Rétornaz 1, J.M. Friedt 1, G. Martin 2 & S. Ballandras 1,2 1 Senseor, Besançon 2 FEMTO-ST/CNRS, Besançon 6 juillet / 25

2 Radiofrequency circuit : ˆ basic blocks assembled : fragile and large, incompatible with use on the field (outdoor) ˆ dedicated circuit : lengthy and costly manufacturing + hardware debug in parallel to software development USRP (Universal Software Radio Peripheral) provides a flexible set of hardware and software toolset 2 / 25

3 Hardware vs Software Defined Radio Analog Radio Modulator Carrier frequency f(r,l,c) Signal Digital Radio Transmitted signal versatile electronics curves : http ://alexsoft.chez-alice.fr/cours/cm12.htm 3 / 25

4 Software Defined Radio Software Linux LISP, octave, shell... Python gnuradio C++ Hardware independant Library of signal processing Open-Source Hardware USRP CNA CAN Radio waves Open-Hardware Gnuradio : USRP : 4 / 25

5 RFX400 : MHz (275 $) RFX900 : MHz (275 $) RFX1200 : MHz (275 $) RFX1800 : GHz (275 $) RFX2400 : GHz (275 $) USRP & daughterboard 64 MHz BasicRX : MHz (75 $) LFRX : MHz (75 $) TVRX : MHz (100 $) DBSRX : GHz (150 $) IQ demodulator Transmitter 128 MHz IQ modulator XCVR2450 : GHz 700 $ LFTX : MHz (75 $) & GHz (400 $) picture : 5 / 25

6 Graphical User Interface 6 / 25

7 Equivalent Code 7 / 25

8 GNU Radio Applications ˆ A TiVo equivalent for radio, capable of recording multiple stations simultaneously. ˆ Time Division Multiple Access (TDMA) waveforms. ˆ A passive radar system that takes advantage of broadcast TV for its signal source. For those of you with old TVs hooked to antennas, think about the flutter you see when airplanes fly over. ˆ Radio astronomy. ˆ Digital Radio Mundial (DRM). ˆ Software GPS. ˆ Distributed sensor networks. ˆ Distributed measurement of spectrum utilization. ˆ Amateur radio transceivers. ˆ Ad hoc mesh networks. ˆ RFID detector/reader. ˆ Multiple input multiple output (MIMO) processing. exploring-gnuradio.html 8 / 25

9 FM Radio ( Volume ) 9 / 25

10 Slider fast reconfiguration 10 / 25

11 FM Radio in use 11 / 25

12 Spectrum Analyzer 12 / 25

13 Spectrum Analyzer in use 13 / 25

14 Acoustic Sensor 30 cm Piezo-electric materials Quality factor Q 10 4 Length (antenna) = λ 4 17 cm = 75 mm 3 design : - delay line (wideband) - resonator (narrowband) types : T, Pressure, ph,... S11 Sensitive resonator (f ) (T ) T sensor Non-sensitive resonator f 1 f 2 f (Hz) 14 / 25

15 f /T S11 Cold Hot f (Hz) 15 / 25

16 Amplitude (u.a) ton (s) Radio frequency pulse usrp radar mono.py amplitude (%) tsw (s) tlook (s) freq (Hz) Dead time (RF switch : 1.14 µs) t (s) 16 / 25

17 Power (u.a) Spectral distribution Power (u.a) ton = s amplitude = 100 % amplitude = 46 % ton = s amplitude = 28 % ton = s fosc f (u.a) fosc f (u.a) Qsensor Short pulse Long pulse Noise level f (Hz) 17 / 25

18 Short Pulse = Frequency Sweep f osc = MHz f osc = MHz f osc = MHz f (Hz) f (Hz) 18 / 25

19 Reception and Processing of Radar-Echo Qsensor Short pulse Long pulse Noise level Voltage (u.a) Integration time f (Hz) Voltage (u.a) Integration time f (Hz) fft(écho) fft(écho) Σ Σ Time (s) Time (s) 19 / 25

20 Σ (u.a) 0 C 23 C Sensitive mode 433 M f 0 C (f ) (T ) f 23 C 434 M f (Hz) 20 / 25

21 4 f (Hz) f sample 10 Hz Time analysis 4 Burning match under sensor log 4 f ref 1 MHz t (u.a) 4 21 / 25

22 f sensor (Hz) Comparison of methods Short pulse Long pulse t (u.a) 2 hour T ( C) Climatic chamber t (u.a) 22 / 25

23 Pattern of measurements LUSH Socket Long pulse Stop RADAR Init Echo Request freq amplitude ton Short pulse usrp radar mono.py Frequency tuning 50 ms USRP USB Start RADAR Pulse generation Transmit Echo <1 ms Σ FFT 128? T sample 128 points > 6 s f sensor f sample > 800 Hz if f sample = 100 Hz : σ = 150 Hz 23 / 25

24 Long pulse f sample < 0.16 Hz 128 Σ σ = 150 Hz : USRP ISM Band Interval between antenna/sensor > Power comsumption < Mathematical complexity < Short pulse f sample > 800 Hz FFT ISM Band not allowed noise level allowed 24 / 25

25 and perspective ˆ Demonstration of the use of software defined radio for rapid of interrogation ˆ Experimental measurements performed on resonators and delay lines using USRP Further work : ˆ move part of the processing from PC to FPGA (automatic frequency tuning, received power detection) ˆ automatic gain control to tune emitted power as a function of received signal strength References : ˆ J.-M Friedt, T. Rétornaz, G. Martin, T. Laroche, J.-P. Simonnet, E. Carry, S. Ballandras Surface Acoustic Wave Resonators as Passive Buried Sensors 2009 EFTF/IFCS (April 2009). 25 / 25