Ultra-Wideband (UWB) Ranging and Communications as a PNT Aiding Source in Orolia VersaPNT Systems
Garrett Payne, Orolia Defense & Security
Location: Ballroom B
Date/Time: Thursday, Jun. 15, 9:35 a.m.
The VersaPNT is a robust Position, Navigation, and Timing (PNT) solution that utilizes GPS/GNSS signals, inertial measurement sensors, timing oscillators, and can be configured to use external PNT sensors. We propose adding ultra-wideband (UWB) technology as additional sensor inputs for ranging, positioning, and communicating between VersaPNT systems. UWB technology, utilizing the unlicensed 7.5 GHz bandwidth between 3.1 – 10.6 GHz, has been tested and proven for short-range communications and ranging. UWB signals are ideal for these applications due to their low radiated power limits, low power requirements, and simple transceiver implementation. An UWB transceiver will be treated as an additional sensor input into the VersaPNT that will be used as an aiding source with the other sensor inputs for assured PNT.
UWB ranging consists of transmitting UWB signals between two (or more) devices to determine the distance between the devices. UWB ranging typically utilizes Time-Of-Arrival (TOA) methods to determine the Line of Sight (LOS) path between devices. For example, consider two devices that are within LOS of each other. Device 1 transmits signal at time T1, which is received by Device 2 at time T2. The signal propagated through the air for the total time of transmission (T2 – T1), and the LOS distance between the devices can be calculated using this information and knowing the speed of light. Due to the large bandwidths available in the frequency domain, UWB signals have very short pulses, offering very precise timing for ranging applications. The high-precision oscillators within the VersaPNT systems will help provide very accurate timestamps with the UWB pulses, resulting in accurate timing synchronization across systems.
UWB ranging is demonstrated technology that has been used commercially for indoor and outdoor positioning and locating services. The technology has been used for asset and personnel tracking in warehouses, vehicle collision-avoidance, and even swarm ranging. Transceivers for UWB signals are cheap and commercially available, allowing this technology to be used easily and widespread. UWB ranging is advantageous for positioning due to its low power requirements, low probability of interference, large bandwidth for multitudes of signals, and precise timing pulses. The main limitation of UWB ranging is that the range for use is limited to within 50 meters due to the low power signals. This severely limits the use case of UWB technology, but the technology would still be applicable for units positioned closely and in possible swarm configurations.
Since UWB ranging has been proven with cheap, commercial transceivers, we propose integrating UWB ranging into the capabilities of the VersaPNT. UWB ranging would allow VersaPNT systems within close range (<50 meters) to determine their relative location precisely and with very low probability of interference. Communication protocols will also be tested and implemented for VersaPNT systems to broadcast out PNT information within the large bandwidth signals. Transceiver hardware can easily be integrated into the existing VersaPNT chassis due to their low SWAP, and software can be written and added into the system easily for control and range processing. The high-precession oscillators within the VersaPNT systems will help achieve the very precise timing needed for ranging. The FlexFusion navigation software will also be modified to include ranging estimates in the fusion engine that is calculating the PNT solution in real time, improving the accuracy of the ranging between systems.