Autonomous Obstacle Avoidance with Nano-Drones and Novel Depth Sensors
- Type: Master Thesis, Semester Project
- Professor: Prof. Dr. L. Benini
UWB Two-way Ranging (TWR). Figure 2a illustrates the classical single-sided two-way ranging (SS-TWR), the simplest scheme, where an Initiator requests a ranging measurement by sending a poll message; the responder answers after a fixed delay TRESP with a response message containing the timestamps marking the receipt of the poll message. The Initiator receives the message and, having the timestamps, it computes the time of flight τ and estimates the distance from the responder as d = τ × c, where c is the speed of light. Two-way ranging, as the name suggests, involves a sequential pairwise exchange between the Initiator and every Responder. Thus, if an Initiator has to estimate its distance from N nodes, N cycles of ranging are required and therefore 2 × N messages.
UWB Concurrent Ranging. The project aims at developing a novel approach to ranging in which, instead of separating the pairwise exchanges necessary to ranging, these are overlapping in time (Figure 2b). Its mechanics are extremely simple: when the single (broadcast) poll sent by the initiator is received, each responder sends back its response as if it were alone, effectively yielding concurrent replies to the initiator. This concurrent ranging technique enables the initiator to range with N nodes at once by using only 2 packets, i.e., as if it were ranging against a single responder. This significantly reduces latency and energy consumption, increasing scalability and battery lifetime, but causes the concurrent signals from different responders to “fuse” in the communication channel, potentially yielding a collision at the initiator.
- 20% Literature / familiarization with UWB
- 30% Bare-metal / FreeRTOS C programming
- 30% Signal processing / machine learning
- 20% Evaluation
- Strong interest in embedded systems
- Experience with data acquisition and analysis
- Experience with low-level C programming
 Corbalán, Pablo, and Gian Pietro Picco. "Ultra-wideband concurrent ranging." ACM Transactions on Sensor Networks (TOSN) 16.4 (2020): 1-41.