A team of Ph.D., masters, and undergraduate researchers at the Autonomous Networks Research Group (ANRG) have been working over the last 2 years to design and build a multi-robot testbed, referred to as the Intelligent Robotic IoT System (IRIS) Testbed. The motivation behind the IRIS effort is to create a testbed to experiment with algorithm designs that can empower autonomous exploration of buildings or exploration on the landscapes of Mars where GPS is not available. To coordinate as a team, the robots in the IRIS testbed are equipped with radios to communicate with one another as well as various sensors. The robots find the position between one another using a technique called Time Difference of Arrival (TDoA). In TDoA, a single robot node calculates the difference in time between the reception of an ultrasound signal (traveling at the speed of sound) and a radio frequency signal (traveling at the speed of light) which are both transmitted simultaneously by another node. By calculating the time difference, a robot can determine its distance from the node transmitting the pings within +/- 5cm as well as the orientation of the robot. Using distances from several nodes at known locations, the robot can infer its own position through a process of triangulation.