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Journal of Global Positioning Systems Vol. 10, No. 1, 2011 |
Cover |
Journal of Global Positioning Systems
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JGPS Team Structure, Copyright and Table of Contents |
JGPS Team Structure, Copyright
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Letter from the Guest Editor - Approaching an Ubiquitous Positioning Solution for Indoor Navigation and Location-Based Service |
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Ruizhi Chen
This special issue is a collection of the ten best papers selected from the proceedings of the IEEE conference “Ubiquitous Positioning,
Indoor Navigation and Location-based Service” held in Helsinki, 14-15 Oct. 2010. The selected papers cover several interesting topics
including the visual-aided navigation, multipath mitigation for indoors, indoor pedestrian navigation, PDR (Pedestrian Dead Reckoning)
with EMG (Electromyography) sensors, and indoor positioning using wireless sensor networks. |
1. Low cost vision-aided IMU for pedestrian navigation |
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Chris Hide(1), Terry Moore(1), Tom Botterill(2)
Modern smartphones contain a number of sensors that can be used for navigation when GPS signals are unavailable.
Low cost MEMS gyros and accelerometers are increasingly becoming available in modern devices, however when used
for positioning, they typically result in large errors after very short periods of time. This paper investigates
using measurements from a computer vision algorithm that uses successive frames from a camera approximately looking
at the ground to compute the translation between frames. The measurements can be used to control the drift of
inertial sensor measurements when measurements from GPS are not available. The concept is convenient since it
uses sensors already available on smartphones and pedestrians will naturally hold the smartphone in the required
position when using it for navigation. This paper demonstrates that computer vision measurements can significantly
reduce the drift of inertial-only positioning for pedestrian navigation in areas where GPS is unavailable. Issues
such as computational requirements and operation in low light areas are also discussed. |
2. Visual-aided Two-dimensional Pedestrian Indoor Navigation with a Smartphone |
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Laura Ruotsalainen, Heidi Kuusniemi, Ruizhi Chen
Indoor pedestrian positioning sets severe challenges for a navigation system. To be applicable for pedestrian navigation
the platform used has to be small in size and reasonably priced. Smartphones fulfill these requirements satisfyingly.
GNSS signals are degraded indoors and in order to obtain accurate navigation aiding from other sensors is needed.
Self-contained sensors provide valuable information about the motion of the pedestrian and when integrated with GNSS
measurements a position solution is typically obtainable indoors. The accuracy is however decreased due to errors in
the measurements of the self-contained sensors introduced by various environmental disturbances. When the effect of
the disturbance is constrained using visual-aiding the accuracy can be increased to an acceptable level. This paper
introduces a visual-aided two-dimensional indoor pedestrian navigation system integrating measurements from GNSS,
Bluetooth, WLAN, self-contained sensors, and heading change information obtained from consecutive images. The
integration is performed with an Extended Kalman filter. Reliability information of the heading change measurements
calculated from images using vanishing points is provided to the filter and utilized in the integration. The
visual-aiding algorithm is computationally lightweight taking into account the restricted resources of the smartphone.
In the conducted experiment, the accuracy of the position solution is increased by 1.2 meters due to the visual-aiding. |
3. Vision-based Positioning with a Single Camera and 3D Maps: Accuracy and Reliability Analysis |
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Xun Li, Jinling Wang, Nathan Knight, Weidong Ding
In an effort to supplement the available satelite-based positioning technology and extend such high level positioning
capability to GPS-denied environments, a method of vision-based positioning with the use of single camera and newly
defined 3D maps is proposed. Besides, only natural landmarks are required in the proposed method. Absolute position
and orientation information can be provided in six degree of freedom. Our work here is to address the accuracy and
reliability concerns of such a vision-based navigation system. The main contribution will be the newly defined 3D
map and the adoption of photogrammetric 6DOF pose estimation method to improve positioning accuracy. Dilution of
Precisions (DOPs) are introduced to evaluate positioning precision within the vision-based positioning domain.
Quality control strategies are also applied to detect outliers in the observation and strengthen system reliability |
4. Integrating Low Cost IMU with Building Heading In Indoor Pedestrian Navigation |
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Khairi Abdulrahim(1,2), Chris Hide(1), Terry Moore(1) and Chris Hill(1)
This paper proposes an integration of ‘building heading’ information with ZUPT in a Kalman filter, using a shoe mounted
IMU approach. This is done to reduce heading drift error, which remains a major problem in a standalone shoe mounted
pedestrian navigation system. The standalone system used in this paper consists of only single low cost MEMS IMU that
contains 3-axis accelerometers and gyros. Several trials represented by regular and irregular walking trials were undertaken
inside typical public buildings. The results were then compared with HSGPS solution and IMU+ZUPT only solution. Based on
these trials, an average return position error of below 5 m was consistently achieved for an average time of 24 minutes –
at times as long as 40 minutes - using only a low cost MEMS IMU. |
5. A Novel Pedestrian Dead Reckoning Solution Using Motion Recognition Algorithm with Wearable EMG Sensors |
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Qian Wang(1), Yuwei Chen(2), Xiang Chen(1), Xu Zhang(1), Ruizhi Chen(2) and Wei Chen(1,2)
Navigation applications and location-based services are currently becoming standard features in smart phones with
built-in GPS receivers. However, a ubiquitous navigation solution which locates a mobile user anytime anywhere is
still not available, especially in Global Navigation Satellite System (GNSS) degraded and denied environments.
Different motion sensors and angular sensors have been adopted for augmenting the positioning solutions for such
environments. An electromyography (EMG) sensor, which measures electrical potentials generated by muscle contractions
from human body, is employed in this paper to detect the muscle activities during human locomotion and captures the
human walking dynamics for motion recognition and step detection in a Pedestrian Dead Reckoning (PDR) solution. The
work presented in this paper is a consecutive step of our pilot studies in developing a novel and robust PDR solution
using wearable EMG sensors. The PDR solution includes standing and walking identification, step detection, stride
length estimation, and a position calculation with a heading angular sensor. A situation of standing still is
identified from the EMG signals collected from a walking process, which has standing and walking dynamics, via a
hidden Markov model classifier fed by sample entropy features. Such pre-classified processing reduces the misdetection
rate of step detection. After step detection, two stride length estimation methods are investigated for the PDR
solution. Firstly, a linear stride length estimation method based on statistic models is investigated to improve
the accuracy of the PDR solution. Secondly, five different walking motions are recognized by a motion recognition
algorithm based on some particular EMG features, and a fixed stride length is then set for each walking motion to
propagate the position. To validate the effectiveness and practicability of the methods mentioned above, some field
tests were conducted by a few testers. The test results indicate that the performance of the proposed PDR solution is
comparable to that of a commercial GPS receiver in outdoor test under an open-sky environment. |
6. Positioning in Synchronized Ultra Low-Power Wireless Sensor Networks |
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Ville Kaseva, Timo D. Hämäläinen, Marko Hännikäinen
Wireless Sensor Networks (WSNs) consist of densely deployed, independent, and collaborating low cost sensor
nodes. The nodes are highly resource-constrained in terms of energy, processing, and data storage capacity.
Thus, the protocols used in WSNs must be highly energy-efficient. WSN communication protocols achieving the
lowest power consumption minimize radio usage by accurately synchronizing transmissions and receptions with
their neighbors. In this paper, we show how network signaling frames of state-of-the-art synchronized
communication protocols for low-power WSNs supporting mobile nodes can be used for positioning. We derive
mathematical models for node power consumption analysis. Both centralized and distributed positioning
architectures are modeled. The models provide a tool for estimating what kind of network lifetimes can be
expected when average positioned node speed, the amount of anchor nodes required by the location estimation
algorithm, and the location refresh rate required by the application are known. The presented analysis results
are based on two kinds of node hardware: with and without Received Signal Strength Indicator (RSSI). The
results show that the positioning parameters and used hardware have significant impact on node power consumption
and network lifetime. In the presented results, the network lifetime ranges from over 10 years to 2 months with
different positioning requirements and hardware. |
7. Towards a Rapidly Deployable Positioning System for Emergency Responders |
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Kavitha Muthukrishnan, Stefan Dulman and Koen Langendoen
Ad hoc solutions for positioning and tracking of emergency response teams is an important and safety-critical
challenge. The solutions based on inertial sensing systems are promising, but are subject to drift. Based on
a brief characterization of the errors encountered in inertial-based dead reckoning estimates, we propose a
solution based on a combination of foot-mounted inertial sensors and ultrasound beacons deployed as landmarks
in an ad hoc fashion. This paper targets two important aspects within the context of providing positioning
service for emergency responders namely on how to locate the deployed static beacons (using multidimensional
scaling), and on how to track the responders by using a combination of ultrasound and inertial measurements
(using a Kalman filter). We perform evaluation of both the ultrasonic beacon localization and tracking
algorithm for data collected from real deployments for different trail topologies and our presented algorithms
are benchmarked against an ultra-wideband (UWB) precision location system. Our approach of preventing the drift
in inertial estimates by combining with ultrasound measurements are promising and offers a viable solution to
providing positioning and tracking support to emergency responders. |
8. Multipath Mitigation Based on Deconvolution |
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Kostas Dragunas & Kai Borre
There are many applications which require continuous positioning in combined outdoor urban and indoor
environments. For a long time GNSS has been used in outdoor environments while indoor positioning is
still a challenging task. One of the major degradations that GNSS receivers experience indoors is the
presence of multipath. The current paper analyzes several available multipath mitigation techniques
which would be suitable for indoor applications. Some of these techniques are described in more details.
A few deconvolution based techniques such as the Projection Onto Convex Sets and the Deconvolution Approach
are focused on and some tests are performed to show how they work. It is shown which advantages these
techniques have over the conventional techniques. The wide range of tests show how these techniques
work under ideal conditions, with simulated signals in different environments and in real world using
data from high-end GNSS front-end. |
9. A New Minimal Detectable Bias in Fault Detection for Positioning |
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Nathan L. Knight(1), Jinling Wang(1) and Xiaochun Lu(2)
The Minimal Detectable Bias method of Fault Detection is frequently employed to determine if a position has
integrity. However, to provide integrity the Type I error probability of the statistical tests is required
to be preset. Normally, this probability is set to avoid the unnecessary rejection of measurements or to
satisfy the continuity requirements. In this paper, the Type I error probability is set based on the integrity
requirements by initially setting the Protection Levels equal to the Alert Limit. This new procedure of setting
the Type I error probability is compared with the more conventional approach when there are different continuity
requirements and when multiple biases are considered. From the results of this comparison, it is concluded
that the new procedure increases the availability rates regardless of the continuity requirements and the
number of biases considered. |
Corporate Members of CPGPS |
Corporate Members of CPGPS
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Instructions to Authors |
Instructions to Authors
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CPGPS Team Structure |
CPGPS Management Team (2011) Structure
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