Exploiting Ultra-Wideband Channel Impulse Responses for Device-Free Localization

Area of Science:

• Wireless communication
• Localization technologies
• Signal processing

Background:

• Device-free localization (DFL) relies on RF sensors, with accuracy and cost influenced by sensor count.
• Radio tomographic imaging (RTI) and multi-static radar (MSR) are key DFL approaches.
• Basic RTI requires numerous sensors for accuracy, increasing costs.

Purpose of the Study:

• To investigate how multipath propagation enhances RTI performance in DFL.
• To evaluate the effectiveness of ultra-wideband (UWB) signals in mitigating multipath effects.
• To compare the localization accuracy of RTI, multipath-assisted (MA)-RTI, MSR, and a combined approach.

Main Methods:

• Utilized ultra-wideband (UWB) channel impulse response (CIR) measurements.
• Modeled multipath effects to improve RTI accuracy and reduce sensor requirements.
• Implemented and compared RTI, MA-RTI, MSR, and a combined approach using a Decawave DW1000 UWB chip.

Main Results:

• Multipath analysis improves RTI performance.
• MA-RTI demonstrates superior accuracy over MSR, with localization errors better than 0.82 m in 50% of cases.
• The combined approach achieved the best localization accuracy, with errors better than 0.64 m in 50% of cases.

Conclusions:

• Exploiting multipath propagation significantly enhances RTI-based DFL systems.
• MA-RTI offers a more accurate and potentially cost-effective DFL solution compared to MSR.
• Combined approaches yield the highest localization precision, paving the way for advanced DFL applications.