160 likes | 265 Vues
This talk sheds light on the potential of radar-enabled sensor networks for security applications like personnel detection and stealthy sensors. Learn about Doppler sensors, UWB radar range, antenna considerations, sensor traces, and signal detection techniques. The presentation motivates the use of radar for detection applications, emphasizing the benefits and challenges. It also discusses current limitations and future work, such as addressing false alarm rates and exploring collaborative signal processing.
E N D
Towards Radar-Enabled Sensor Networks Prabal Dutta prabal@cs.berkeley.edu http://www.cs.berkeley.edu/~prabal with Anish Arora and Steven Bibyk
For this Talk Radar UWB Radar
I detect a Mag Object I detected a Radar Object Motivating Application – Intrusion Detection
Motivation • Security applications that require • Personnel detection • Stealthy sensors • Low density • The three goals of this talk • Shamelessly proselytize radar • Give you an intuitive appreciation for radar signals • Convince you to consider radar for detection applications
Simplified Theory of Operation – Doppler Sensors • Radar transmits short (wideband) pulses with period T = 1/f • Target with vr = v0 reflects Doppler-shifted pulse f ’ • Electronics “mix” TX and RX pulses and output • Target radial velocity can be estimated • Complication: Moving objects contain many surfaces
Dipole antenna UWB radar sensor Range: 0 – 20 m Power 3.4V – 6.0V @ 1mA 5.5V 1% @ 7.5mA Output LPF Doppler baseband Bias: 1.25V (nominal) Range: 0 – 2.5V (VPP) Wakeup: ~ 30 seconds! Mica Power Board Input: 2.7V – 3.3V Output: 3V – 40V Preset: 3.6V, 5.5V Mica Sensor Board Mica2 Processor Board Sensor Electronics
Used default dipole antenna but it has several issues Null in radiation pattern means a major blind spot Considerable energy reflected by ground Discone addresses Vertical polarization Omni-directional Wideband Antenna Considerations
Orientation issues Gimbal mechanism Rotationally self-righting Horizontally self-righting Transparent body Passes solar radiation Looks really cool! Weather Resistance Water-tight enclosure O-ring seals Overheats in FL sun Enclosure Design
Conclusions and Future Work • We • Motivated the application of a remarkably useful sensor • Showed feasibility of integrating UWB radar with motes • Demonstrated a simple CFAR NP signal detector • Highlighted some challenges with simple SP techniques • Current work limited to • Single (or small number of) node(s) • Simple, local detection (and classification) • UWB Doppler motion sensors • Future work • Address false alarm rates through robust detection • Explore collaborative signal processing • Explore low-complexity classification algorithms • Incorporate UWB rangefinders