Modified FMCW Scheme for Improved Ultrasonic Positioning and Ranging of Unmanned Ground Vehicles at Distances < 50 mm

Area of Science:

• Robotics
• Sensor Technology
• Signal Processing

Background:

• Unmanned Ground Vehicles (UGVs) require precise positioning and obstacle detection for industrial applications.
• Existing ultrasonic ranging systems, particularly frequency-modulated continuous wave (FMCW), face accuracy limitations at short distances (<50 mm).
• Low-resource hardware and narrowband transducers further challenge the performance of standard FMCW systems for close-range sensing.

Purpose of the Study:

• To develop an improved FMCW-based ranging scheme for UGVs.
• To enhance the accuracy and repeatability of distance estimation at ranges below 50 mm.
• To enable more reliable collision avoidance and environmental mapping for UGVs.

Main Methods:

• A modified frequency-modulated continuous wave (FMCW) scheme was proposed.
• The modification involved implementing an ad hoc time-shift of the reference signal.
• Performance was evaluated through numerical simulations and experimental validation.

Main Results:

• The modified FMCW scheme demonstrated significantly improved performance at ranges below 50 mm.
• Accuracy and repeatability at short ranges were dramatically enhanced compared to the standard FMCW approach.
• Performance at greater distances remained unaffected by the modification.

Conclusions:

• The proposed modified FMCW scheme offers a substantial improvement for high-precision ranging applications.
• This advancement is critical for enhancing the safety and functionality of UGVs in close-proximity operations.
• The modified FMCW approach provides a viable alternative to correlation-based methods for short-range sensing.