Mitigating the Effects of Ionospheric Scintillation on GPS Carrier Recovery

Ionospheric scintillation is a phenomenon caused by varying concentrations of charged particles in the upper atmosphere that induces deep fades and rapid phase rotations in satellite signals, including GPS. During periods of scintillation, carrier tracking loops often lose lock on the signal because the rapid phase rotations generate cycle slips in the PLL. One solution to mitigating this problem is by employing decision-directed carrier recovery algorithms that achieve data wipe-off using differential bit detection techniques. Other techniques involve PLLs with variable bandwidth and variable integration times. Since nearly 60% of the GPS signal repeats between frames, this thesis explores PLLs utilizing variable integration times and decision-directed algorithms that exploit the repeating data as a training sequence to aid in phase error estimation. Experiments conducted using a GPS signal generator, software radio, and MATLAB scintillation testbed compare the bit error rate of each of the receiver models. Training-based methods utilizing variable integration times show significant reductions in the likelihood of total loss of lock

Software Radar

This paper describes the design and implementation of a software defined phased radar receiver array developed for MIT Lincoln Laboratory. This receiver array was constructed with the USRP2, an inexpensive software defined radio to allow for scalability to larger receiver arrays. The team worked closely with Lincoln Laboratory staff to conduct time synchronization testing between the receivers in the array in order to characterize the internal oscillator drift of the radios. The team was able to get the receiver array synchronized within less than 2 ns. In addition to building the array, the team implemented radar processing algorithms in Matlab which had the ability to detect a target\u27s range, radial velocity and direction from the receiver with an angular resolution of 20 degrees

EMS Communications

Investigations dealing with the number of fatalities caused by emergency vehicle accidents are growing. The purpose of this project is to investigate communication techniques utilized by emergency medical services, identify areas for improvement, and implement solutions with the goal of reducing response time and emergency vehicle collisions. The project examines the use of active and passive communication including lights, electronic and mechanical sirens, colors, reflective materials, and wireless communications in EMS services and their impact on saving lives. Our results show that the use of mechanical sirens on urban streets can improve response time and safety

The Downtown Area of Jonestown, Texas.

The objective was to assess Jonestown's value and potential using the Quadruple Net Value metrics.Three projects are focused on the city of Jonestown. The first being a Quadruple Net Value Analysis report generated by undergraduate Land and Property Development students. The second is a public sewer feasibility study to generate creative solutions to septic and environmental conditions by undergraduate capstone Civil Engineering students. Finally, a graduate student will complete a transportation plan for the city to address connectivity and walkability.Texas Target Communitie