Journal of the Institute of Navigation 2014 Winter

ljrlove2008

Journal of the Institute of Navigation. Volume 61, Number 3 (Fall 2014)

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Navigation of Ground Vehicles Using Magnetic Field Variations见2楼

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Model-Aided Navigation for a Quadrotor Helicopter: A Novel Navigation System and First Experimental Results见3楼

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Solution Separation Versus Residual-Based RAIM见4楼

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Stability Criteria for GNSS Receiver Tracking Loops见5楼

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A Detailed Analysis of GPS Live-Sky Signals Without a Dish见6楼

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On-the-fly Estimation of Antenna Induced Biases in SFAP Based GNSS Antenna Arrays见7楼

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ljrlove2008

Title: Navigation of Ground Vehicles Using Magnetic Field Variations
Author(s): J. A. Shockley, J. F. Raquet
Abstract: Inexpensive three-axis magnetometers can sense not just heading, but also variations in Earth’s magnetic field. Combined with a magnetic field map, this information can be used for positioning. Pairing the three-axis magnetometer measurements with position information from a ground vehicle creates a magnetic field map containing the variation and localized perturbations in Earth’s magnetic field as a function of position. A magnetometer and the magnetic field map can then be used for navigation. This paper describes how magnetometer measurements can be used to calculate a position update using three different likelihood functions, and it also demonstrates direct incorporation of magnetic field measurements into a map-matching particle filter. These algorithms were tested in three different vehicles under a variety of road conditions and demonstrated meter-level positioning when local magnetic field features are available. Overall the information is sufficient for road level navigation when used as the sole source of navigation information.

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ljrlove2008

Title: Model-Aided Navigation for a Quadrotor Helicopter: A Novel Navigation System and First Experimental Results
Author(s): Philipp Crocoll, Justus Seibold, Georg Scholz, Gert F. Trommer
Abstract: This paper presents a novel navigation system for aiding a classic inertial navigation system with a Vehicle Dynamics Model in a quadrotor application. The navigation system is based on the previously presented Unified Model technique for optimal fusion of the two prediction models. The key point of the approach in this paper is that the required modeling and implementation effort is minimized by incorporating a translational dynamics model only. Even though no rotational vehicle dynamics are modeled, it is shown that the filter is able to estimate roll and pitch angles and even IMU biases with bounded errors. Indoor and outdoor flight experiments confirm that all navigation states except heading angle are significantly improved compared to the single systems. For the first time, this demonstrates in real flight experiments that model-aided navigation allows estimating a full navigation solution for several minutes even without any aiding sensors.

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Title: Solution Separation Versus Residual-Based RAIM
Author(s): Mathieu Joerger, Fang-Cheng Chan, Boris Pervan
Abstract: Future multi-constellation Global Navigation Satellite Systems (GNSS) will offer the possibility to fulfill stringent navigation integrity requirements using Receiver Autonomous Integrity Monitoring (RAIM). This paper presents a detailed comparison of residual-based (RB) and solution separation (SS) RAIM. A complete step-by-step derivation of the two methods, which is currently missing in the literature, is given for the detection of single and multi-measurement faults, starting from common definitions of the integrity and continuity risks. In addition, a parity-space representation of SS RAIM is developed. It is shown that the integrity monitoring performance of SS RAIM can be superior to RB RAIM because SS test statistics are tailored to the fault hypotheses, and to the state of interest. However, for practical reasons of computational efficiency in conventional SS implementations, which are fully detailed in the paper, RB RAIM ultimately provides tighter bounds on integrity risk.

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Title: Stability Criteria for GNSS Receiver Tracking Loops
Author(s): Phillip W. Ward, Troy D. Fuchser
Abstract: This paper analyzes the stability criteria for closed loop tracking in a GNSS receiver using Bode analysis techniques. This defines the stable limits of predetection integration time (T) for a given loop filter design, including its order and noise bandwidth (Bn) in combination with all of the other components involved in the closed receiver tracking loop. The loop filter design used in this paper is based on a traditional analog design converted to digital using the bilinear transform. The shortcomings of this traditional design are briefly described, but the traditional design suffices for small T and ample phase margin. Clearly, a pilot channel in modern GNSS signals permits much longer T than allowed by the original GPS data channels, but the stability assurance must be considered in either case. The methodology applies to both data (Costas) and data-less (pilot) tracking loops. Additional insight is provided using the results of this analysis.

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Title: A Detailed Analysis of GPS Live-Sky Signals Without a Dish
Author(s): Johnathan York, Andrew Joplin, Michael Bratton, David Munton
Abstract: This paper explores a premise that, with appropriate application of digital signal processing techniques, much of the detailed signal analysis typically associated with a dish can instead be done with a standard low-gain GNSS antenna. To do so, the signals of the recently launched GPS IIF satellites are examined, with particular attention on the L5 signal. Notably, using a high-quality non-directional GNSS antenna, we demonstrate observations of: (1) signal bandpass and dispersive characteristics, (2) chip shape, (3) eye and constellation diagrams, and (4) millisecond-level transient events. Such observations are enabled by use of the computationally efficient GNSS Complex Ambiguity Function (GCAF) technique. The methods used to process the GCAF data to produce these results are discussed in detail, with careful attention to the limitations of the techniques. Qualitative comparisons are made to similar dish-based measurements found in open literature.

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Title: On-the-fly Estimation of Antenna Induced Biases in SFAP Based GNSS Antenna Arrays
Author(s): Ying Chieh Chuang, Inder J. Gupta
Abstract: A method for on-the-fly estimation of antenna induced biases in Space-Frequency Adaptive Processing (SFAP) based antenna arrays employed in Global Navigation Satellite System (GNSS) receivers is presented. The method uses real time SFAP weights along with stored antenna array gain and phase data over the frequency band of the incident signals to efficiently estimate the antenna induced biases in GNSS receiver measurements. Using computer simulations, it is shown that the estimated biases are in good agreement with the true antenna induced biases. The same is true in the absence of all interfering signals as well as in the presence of multiple narrowband and wideband interfering signals. As expected, the antenna induced biases vary with the interference environment.

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