Development and Validation of Parametric Models for Vector Tracking Loops

Abstract

This paper develops parametric models from the existing vector architecture equations to explain the performance benefits of vector tracking loops. A theoretical analysis of the parametric models which are validated with simulation studies shows that internal aiding among loops is the key to the superior performance of the vector tracking architecture. A systematic methodology for comparing scalar and vector architectures with similar design parameters is also presented. From this, the conditions under which both architectures can perform comparably are identified. The analysis results presented in the paper lead to the following important conclusions. First, internal aiding, in addition to being responsible for vector loops' superior performance, allows easy propagation of errors among loops and, therefore, affects the fault tolerance capability of the vector tracking architecture. Second, well designed scalar tracking loops with external Doppler aiding can offer similar performance improvements while avoiding the complexity of the vector architecture.

Integrity monitoring with vector GNSS receivers

“…Further, with multiple GNSS systems on the horizon, the vector architecture holds potential for tracking very weak satellite signals by fusing multi-GNSS signals. This is attributed to its inherent ability to improve tracking thresholds adaptively when more satellites are visible, as concluded in [9]. Hence, in view of these issues, studies of integrity risk in vector tracking are warranted as the literature offers meager information about it.…”

“…This is because tracking loops aid each other in vector receivers [9]. In other words, an individual satellite tracking loop in vector receivers not only applies correction to its own error, but also to those of other loops.…”

“…Therefore, at this point two-dimensional simulation studies with a simple, benign geometry will help gain better insights into the integrity monitoring capability of this architecture. The same user-pseudolite geometry as described in [9] is considered. According to this geometry six pseudolites are evenly distributed around a ground vehicle that is moving along a straight line towards pseudolite 2 (Fig.…”

Position domain joint tracking

“…And so, as pointed out e.g. in [7], the frequency discriminators can additionally be used as measurements:…”

Performance of deeply integrated GPS/INS in dense forestry areas

“…GPS measurements are then derived from NCO signal parameters for each satellite channel that is being tracked. This approach is different from the vector-tracking implementation [1], where signal accumulation results are generally sampled at a 20-ms accumulation point and are then fed into the joint filter that computes the overall navigation and clock solution. Independent signal tracking for individual satellites maintains stochastically independent signal measurements for different satellite channels.…”