"This thesis documents the design and implementation process for the next generation of the WPI Precision Personnel Location (PPL) system hardware. The driving goal of the new hardware was to support a new method of radio frequency location developed at WPI referred to as Transactional Array Reconciliation Tomography (TART). This new method is based on a time of arrival (TOA) technique as opposed to the previous Singular Value Array Reconciliation Tomography (SART), which uses time difference of arrival (TDOA). The use of a TOA method requires additional timing information and necessitates a bidirectional (transmit and receive) multicarrier transaction. The design of the new transceiver that can function as both a mobile locator and a static reference unit is the main focus of this thesis. This redesign also addressed previous hardware issues that have been exposed through extensive use in real world testing."

"The Precision Personnel Locator project is an ongoing research project funded by the Department of Justice, the goal of which is to provide sub-meter accuracy tracking and location of first responders inside of buildings with no pre-existing infrastructure, especially in emergency situations. The PPL system consists of wearable, battery-powered Locator devices that transmit a multi-carrier “ranging signal” waveform and Reference Units that receive this ranging signal and relay the information to a Base Station for location estimation processing and display. This thesis describes the design and implementation of a subset of the Locator devices’ functionality, including: the digital generation of the ranging signal waveform; the coordination of the transmissions of many Locator devices using time-sharing methods to prevent overlap of the signals; and finally, the gathering of environmental data such as temperature and movement of the wearer and the relaying of this data back to the Base Station. To perform these tasks, two subsystems were designed and implemented as printed circuit boards. The first of these is the Data Channel, which is a low power, general-purpose communications platform that is capable of controlling the transmissions of the Locator devices with support for up to 100 Locators transmitting every second, and it can control the power of the Locator devices by switching portions of the system off when they are not in use. It also includes sensors to measure the ambient temperature, movement of the device, and a “distress button” that a first responder can press to trigger a distress signal to be transmitted to the outside of the building. The second subsystem is the Digital Waveform Generator, which consists of a Field-Programmable Gate Array (FPGA) and Digital-to-Analog Converter (DAC) that are capable of generating waveforms of up to 200 MHz bandwidth. The new Locator hardware can operate on battery power for many days. The two subsystems were successfully tested and will serve as an important step towards the goal of developing a deployable location and tracking system."