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This article discusses theoretical and practical aspects of direct position estimation (DPE) of global navigation satellite system (GNSS) receivers. DPE is an alternative approach to the well-established positioning method, where time delays and Doppler shifts to the visible satellites are estimated to solve for a geometrical problem to compute the receiver's position. In contrast, DPE infers position...
This paper addresses the problem of acquiring weak high-order binary offset carrier (BOC) signals in the context of high-sensitivity global navigation satellite system (HS-GNSS) receivers. The use of high-order BOC modulations provides an improvement over conventional BPSK modulation in terms of positioning accuracy, at the cost of secondary peaks appearing in the correlation function. The acquisition...
Based on the Ziv-Zakai methodology to bound estimators, we derived an estimation bound able to predict the mean square error degradation due to model mismatches. In this article, we build upon this result to provide a performance comparison between mean and median estimators in the presence of outliers. The latter is well known to be statistically more robust than the mean in the presence of outliers...
The problem of localizing one impulse radio (IR) Ultra-wideband (UWB) transmitter from the signals received at several anchors is assessed. In the direct position estimation (DPE) approach the target position is estimated in one step from the received signals from all anchors, while in two steps positioning (2SP) estimation, the times of arrival (TOAs) at different anchors are estimated in a first...
This paper derives the Ziv-Zakai lower bound (ZZLB) for the time of arrival (TOA) estimation in the presence of one interfering pulse from which no a priori knowledge is available. The bound is obtained by including the interference in the system model but only the transmitted pulse as a candidate for the likelihood ratio (LR) test. A compact ZZLB expression that depends on the time delay and amplitude...
The aim of this paper is to derive a Ziv-Zakai lower bound (ZZLB) for the time of arrival (TOA) estimation in single-path (SP) additive white Gaussian noise (AWGN) channels and in the presence of multiuser interference (MUI). Time-hopping pulse position modulated (TH-PPM) ultra-wideband (UWB) signals are considered. Following a classical approach and extending it for the scenario under consideration,...
In this paper we consider the impact of MUI (multiuser interference) on coherent TOA (time of arrival) estimation. We consider TH-PPM (time-hopping pulse position modulation). We propose estimators based on the ML (maximum likelihood) criterion together with interference cancellation. We propose algorithms for SP (single-path) and MP (multipath) communication channels. We report simulation results...
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