Simultaneous Localization and Antenna Calibration

Abstract

Cooperative localization fills the gap in scenarios where global navigation satellite system (GNSS) reception is denied or impaired. Position and orientation information is then often provided based on signal round-trip time (RTT) and direction-of-arrival (DoA). Obtaining a meaningful RTT requires calibrated transceiver group delays, and accurate DoA estimation requires antenna calibration. Usually, such calibrations are performed once before operation. However, calibration parameters can change over time, e.g. due to varying temperature of RF components or reconfigurable antenna surroundings. To cope with that, we propose to estimate antenna responses and ranging biases simultaneously with positions and orientations by simultaneous localization and calibration (SLAC). We derive a SLAC algorithm based on Bayesian filtering, which is suitable for arbitrary antenna types. The algorithm is evaluated with measurement data from robotic rovers. We show, that ranging and DoA performance is improved considerably, leading to better position and orientation accuracy with SLAC.