A Fully Integrated Stepped Frequency Ranging Sensors for Aiding Pedestrian Inertial Navigation

Pedestrian navigation systems that track the position of a person are useful in indoor, underground or mountainous areas where Global Positioning Systems (GPS) are unavailable. A common solution to GPS-denied personal navigation is based on MEMS inertial sensors such as accelerometers and gyroscopes and this is potentially attractive for pedestrian navigation because it does not require prior knowledge of the environment.;However, state-of-the art MEMS accelerometers and gyroscopes do not provide acceptable accuracy; this problem is due to accumulated integration error from uncertain sensor bias. To overcome this issue, an array of RF sensors is possible solution in conjunction with the inertial sensors to enhance accuracy as ranging aiding systems. Two types of RF sensors are utilized a Zero Velocity Update (ZUPT) technique that continuous wave (CW) radar to measure the vertical component of velocity; and a Shoe Ranging Sensor (SRS) that uses bidirectional signaling to measure the distance between the two shoes. A present commercial RF radar is generally aimed for over longer range (>>1m) and coarse accuracy (>1cm). This is not appropriate for pedestrian target. Even though, there was a commercial component based solutions for short distance (<1m), it used all commercial components for prototype and they are not suitable for low power application (few mW).;This dissertation proposes a fully integrated CMOS Shoe Ranging Sensor (SRS) using a hybrid Stepped Frequency Continuous Wave–Continuous Wave (SFCW-CW) ranging method for aiding pedestrian indoor navigation. The coarse-fine ranging techniques with CMOS integrated transceiver are used to realize millimeter-accurate ranging with small size, low power and light weight. Low IF architecture with integrated VCO and PLL is used for RF receiver. A developed RF transceiver can be used for the basic building block-receiver, transmitter and frequency synthesizer- of both the scalar and the vector inter-shoe ranging methods. Radio system specifications are derived according to required ranging accuracy. The ranging measurement in fixed position is performed in frequency 6 GHz to 7 GHz in 21 steps using aforementioned hybrid SFCW and CW method. Wideband microstrip Vivaldi antennas are used for receiver and transmitter. A custom prototype in a 0.13 μm CMOS shows maximum 1.5 cm RMS error accuracy while consuming 58mW from a 1.2 V supply and occupying an active area 1.42 mm x 2.2 mm. As a results, chip-scale ranging sensor dramatically can reduce power (<1/8) and size compared to commercial components type of radar even chip-scale sensor includes an integrated Phase Locked Loop (PLL) which is not included in former research.