Group 3 (2005)

Student Members:
David A. Hague
John Lima
Eric M. Scanlon

Faculty Advisor:
Dr. Dayalan Kasilingam

Project Title:
RADAR Obstacle Detection System for DARPA Grand Challenge Vehicle

Project Description (provided by group):
The Departments of Electrical and Computer Engineering of the University of Massachusetts Dartmouth has entered a competition sponsored by, The Defense Advanced Research Projects Agency (DARPA) called the Grand Challenge 2005. The Defense Advanced Research Projects Agency (DARPA) seeks to promote innovative technical approaches that will enable the autonomous operation of unmanned ground combat vehicles.

The scope of team 3 project is to develop a RADAR Obstacle Detection System to be mounted on an off road (DARPA) vehicle. This system will feed a navigation system which will attempt to make intelligent decisions on the vehicle's next move based on incoming sensor data.

The final design for the Long Range Obstacle Detection System consists of a Continuous-wave RADAR that is responsible for transmitting and receiving a signal, which will allow us to detect objects in the path of the DARPA vehicle. In order to detect objects, we must send a pulse and be capable of receiving that same time delayed pulse. By measuring the delay between the transmitted and received pulse, we can calculate the range of the obstacle. A Continuous-Wave RADAR can implement this pulsing technique by using Frequency Shift Keying. What this means is when the low part of the pulse wave is transmitted, a lower frequency sinusoid wave will be transmitted. When the high part of the pulse wave is transmitted, a higher frequency wave will be transmitted. This will allow us to pulse with continuous-wave RADAR. In order to pulse the RADAR, a Pulse Generator is used to develop a pulse train which in turn drives the modulator on the radar transceiver.

In order to measure the time delay, the received signal must be passed through our two-stage amplifier in order to make the signal compliant with the hardware we used. Then the two pulse trains go through comparators to digitize the signals. We then used a Binary counter driven by an oscillator to count the delay between pulses. When a pulse is transmitted, the counter starts counting. When a signal is received, the counter stops counting. This binary number will be sent to the microprocessor. The microprocessor will use a look up table to match that binary number with a specific range. This range will then be sent via a TCP/IP port to the DARPA Vehicle's CPU for necessary decision making.