1 / 22

EE 548

EE 548 . Ultra Wideband Radio: Ranging Spring 2006. Approaches to ranging (IEEE 802.15 TG4). The ranging subcommittee has identified 5 different techniques or doing ranging. Time of Arrival Ranging Angle of Arrival Ranging Time Difference of Arrival Ranging Signal Strength Ranging

ziva
Download Presentation

EE 548

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EE 548 Ultra Wideband Radio: Ranging Spring 2006 Spring 2006

  2. Approaches to ranging(IEEE 802.15 TG4) • The ranging subcommittee has identified 5 different • techniques or doing ranging. • Time of Arrival Ranging • Angle of Arrival Ranging • Time Difference of Arrival Ranging • Signal Strength Ranging • Near Field EM Ranging Spring 2006

  3. Ranging: time of arrival Node L Spring 2006

  4. Ranging: critical issues • Detecting the peak of the received signal • Correlating the received signal with the transmitted signal • Mitigation of the effects of noise and jitter Spring 2006

  5. Ranging: why use UWB? • Wide bandwidth and short pulse duration provide • More target information • Improve range accuracy • Improve resilience to passive scatterers (clutter) • Mitigate destructive multipath effects from ground reflection • Enable a narrow antenna beam pattern Spring 2006

  6. Ranging use short duration pulses:traditional RADAR approach Spring 2006

  7. Errors in time of arrival ranging:Cramer-Rao lower bound (CRLB) Spring 2006

  8. CRLB for square pulses Spring 2006

  9. CRLB for square pulses (II) Spring 2006

  10. CRLB for square pulses: example • Assume UWB, • B=10.6-3.1 = 7.5GHz • PSD = FCC max • 2G0=9.86x10-24 joules/Hz • N0=2x10-20 W/Hz, at room temp and 7dB noise figure Spring 2006

  11. Improving the accuracy in TOA ranging • Need to accurately compare received pulse with transmitted pulse to determine time delay • Use correlation techniques • Slide correlation window in time • Look for maximum Spring 2006

  12. Correlation technique for TOA based ranging s(t) T Rectangular pulse of duration T Spring 2006

  13. Output of matched filter for square wave pulse RS(e) 0 T 2T Spring 2006

  14. Early-late gate synchronizer • Exploits correlator output • Measures output at symmetric points in time relative to expected peak value • Then evaluates the difference When the samples are made at points that are symmetric about the peak, DR=0 When there is an unknown delay t, DR is not zero Spring 2006

  15. RS(e) 0 T 2T Effect of unknown delay on the output of early-late gate synchronizer DR t Measurement of DR enables calculation of t Spring 2006

  16. Lower bound on ranging errors Use multiple, repetitive pulses to average out jitter and noise to increase accuracy, at the expense of processing time Spring 2006

  17. Time integrating correlator (TIC) • Received signal s(t) stored • Reference code moved past the analog input signal • Product of received signal and code are summed in a bank of parallel analog integrators • Each correlator uses same code, but shifted in time • When received signal is aligned with proper code, the integrator output reaches as maximum Spring 2006

  18. Pulse pair, offset spreading sequences, and TIC output Spring 2006

  19. UWB ranging is relatively immune to multipath Spring 2006

  20. In-building multipath measurements Spring 2006

  21. Through-wall sensing: RadarVision • Specifications • Size:56 cm x 35.5 cm x 20.3 cmWeight: <4.5 kgEnclosure: High Impact PlasticColor: BlackPower: Removeable/rechargeable lithium ion batteryOperating Time/Charge: >3 HoursRechargeable Time: <4 HoursRange Accuracy: +/- 1 meter (+/- 0.5m typical)Horizontal Field of View: > +/- 60 degreeVertical Field of View: > +/- 45 degreeLine of Sight: 20 meter through Wood, Brick, Gypsum Wall & 20 cm Solid ConcreteShock/Vibration: Drop tested at 2 metersHumidity: 0% to >90% (non-condensing) Liquid: Water resistant (not submersible)Operating Temperature: -10 degree C to +50 degree CStore Temperature: -20 degree C to 60 degree CEmission Type: Coded ultra wideband pulsesPulse Rate: 10 Million pulses per second Transmit Power: 1.5 mWBandwidth: 1-3.5 GHz http://www.radarvision.com/RadarVision2/Rv2.htm Spring 2006

  22. Example locator systemMicro Air Vehicle Collision Avoidance System Spring 2006

More Related