A Low SWAP-C Hybrid RF Ranging Software Defined Radio for Complementary PNT
Wilbur L. Myrick, ENSCO, Inc.
Location: Beacon A (Floor 4)
Date/Time: Wednesday, Jul. 11, 11:30 a.m.
The ability to assess the impact of complementary PNT RF ranging measurements with respect to GPS Denied environments is critical to integrated systems and battlefield operations. Inexpensive Sub-1GHz Internet-of-Things (IoT) RF modules are readily available and could support quickly prototyping RF aided complementary PNT systems if these modules provided the necessary measurements for RF ranging. We explore utilizing low cost IoT RF modules as low SWAP-C RF Aided sensors in a complementary PNT architecture even when the necessary measurements for high-precision RF ranging are not available from the IoT module. To facilitate this research we have developed a hybrid (active/passive) RF ranging Software Defined Radio (SDR) architecture that eliminates the need to acquire physical layer RF measurements in the IoT module. We present a prototype low SWAP-C hybrid RF ranging SDR known as a Positioning, Navigation, and Timing (PNT) Sub-1Ghz SDR (PUGS). The PUGS hybrid architecture accommodates low SWAP-C swappable components to explore a variety of configurations when determining the feasibility of using IoT RF modules for RF aided complementary PNT.
The PUGS hybrid architecture decouples the strict timing requirements normally associated with typical RF ranging architectures enabling a low SWAP-C solution for exploring high-precision RF ranging complementary PNT demonstrations. Several features of the initial PUGS prototype include 1) a built-in Multi-Global Navigation Satellite Systems (GNSS) receiver capability, 2) Python based RF ranging protocols, 3) I/Q data capture capability to explore high-precision narrowband RF ranging algorithms, and 4) an accelerometer to support waking up on motion events. I/Q data samples are stored for post processing potentially enabling the generation of complementary PNT RF ranging sensor models. Components of the PUGS architecture as well as RF ranging measurements are discussed based on inexpensive Sub-1GHz LoRa transceivers and RTL-SDRs. It is shown that the PUGS architecture allows the exploration of high-precision RF ranging algorithms on a Sub-1GHz LoRa transceiver without needing the physical layer RF measurements generated by the transceiver. We demonstrate the ability to leverage inexpensive IoT RF modules as RF ranging sensors for supporting complementary PNT architecture exploration based on the PUGS hybrid architecture.