Effective-Height Analysis of UWB Antenna Arrays for TDoA and PDoA Estimation
Authors:
Tobias Lafer, Michael Gadringer, Ulrich Muehlmann, Franz Teschl, Klaus Witrisal
Abstract:
State-of-the-art low-power ultra-wideband (UWB) chipsets commonly rely on phase-difference of arrival (PDoA)
and time-difference of arrival (TDoA) measurements for performing angle-of-arrival (AoA) estimations. But in
real-world scenarios, the TDoA and PDoA measurements suffer from AoA-dependent phase and delay biases
introduced by the receiver antennas. If not properly compensated, the accuracy of the final AoA estimates
reduces. To assess such antenna influences, we extend effective-height-based analysis methods from standalone
antennas to antenna arrays for simulation and measurement. Each antenna element is modelled as an LTI system,
with its effective height as AoA-dependent transfer function. The obtained effective heights of the single
antenna elements consider coupling effects between the antenna elements as well as objects in their vicinity.
The proposed simulation and measurement procedures were applied to two different antenna pairs, one composed
of directional antennas and one composed of omnidirectional antennas. We compare impulse responses as well as
PDoA and TDoA estimates obtained from simulations and measurements to discuss influences of the measurement
system as well as modelling uncertainties in the simulation. We found that effective heights and PDoAs
correlate rather well between simulation and measurement for the investigated antennas. However, substantial
differences were observed between simulated and measured TDoAs, which require further investigation.
