This paper describes the features of an extended Kalman filter algorithm designed to support the navigational function of a real-time vehicle performance and emissions monitoring system currently under development. The Kalman filter is used to process global positioning system (GPS) data enhanced with dead reckoning (DR) in an integrated mode, to provide continuous positioning in built-up areas. The dynamic model and filter algorithms are discussed in detail, followed by the findings based on computer simulations and a limited field trial carried out in the Greater London area. The results demonstrate that use of the extended Kalman filter algorithm enables the integrated system employing GPS and low cost DR devices to meet the required navigation performance of the device under development.

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An Extended Kalman Filter Algorithm for Integrating GPS and Low Cost Dead Reckoning System Data for Vehicle Performance and Emissions Monitoring

This thesis is restricted indefinitely. A thesis submitted as fulfilment of the requirements
for the degree of Doctor of Philosophy of the University of London
and for the Diploma of Membership of Imperial College London.

/pdf/high-integrity-map-matching-alogorithms-for-advanced-24yla6vo89.pdf

High integrity map matching alogorithms for advanced transport telematics applications

Towards self-powered sensing using nanogenerators for automotive systems

In this paper we discuss a pilot study where we have mapped urban air pollution using mobile carbon monoxide (CO) sensors. Our objective is to use inexpensive Global Positioning System (GPS) receivers to track the sensors and explore CO variations at a fine geographic scale. The critical issue in data processing is the treatment of the imprecise logs from the GPS. By using knowledge about the route and the geometry of the buildings, we are able to increase the position accuracy significantly, while at the same time showing that certain events, such as CO profiles while crossing roads, can be detected with a high degree of accuracy. Comparisons between data from our own mobile sensors and a fixed sensor site show good agreement in the vicinity of the fixed sensor, while at the same time identifying significant CO peaks within 100 m of this location. Using the mobile sensors to collect data along two of the main roads in the area, we are able to show CO variations along an urban canyon for parallel and perpendicular wind directions. Finally, a number of significant sources of CO were discovered during the course of the study, which suggest possible locations for fixed sensor sites in the future. We conclude by discussing the results in the context of the push towards large sensor networks and mobile communications. The potential for ad hoc mobile sensor networks may be very large.

/pdf/mapping-carbon-monoxide-using-gps-tracked-sensors-41tn801b1v.pdf

Mapping Carbon Monoxide Using GPS Tracked Sensors

The air quality Framework Directive (FWD) and the correspondent Daughter Directives defined the new strategy for air quality management in Europe In general, the new standards are more restrictive than those established by the previous legislation In Portugal, some difficulties can be previewed to achieve those new standards Thus, this paper aims at evaluating the impact of application of the FWD to Oporto Metropolitan Area in what concerns to the most critical air pollutants in the area (PM10 and O3) The specific objectives were: i) to analyse the concentration exceedances between 1999 and 2001; ii) to identify the main emission sources; iii) to evaluate the possibility of a new redistribution of the existing monitoring sites; iv) to contribute to the definition of a new strategy for air quality management The results showed that; i) the standard values for PM10 and O3 were largely surpassed, possibly concluding that the FWD application implies a strong impact on the air quality management strategies; ii) the main emission sources (road traffic and the neighbour stationary sources localised upwind) affect all the Metropolitan area through intra-region pollutant transport; iii) it is safer maintaining the site localisation to avoid previewing exceedances through mathematical correlations; iv) the reduction of PM10 and of ozone precursors must be performed considering new technologies for ‘cleaner production’ and gaseous depuration, a rigorous urban and territory planning, the creation of an efficient public transport network and the definition of strict measures for car maintenance

/pdf/relevant-aspects-of-air-quality-in-oporto-portugal-pm10-and-3m4ilx46u9.pdf

Relevant aspects of air quality in Oporto (Portugal): PM10 and O3.

Integration of GPS and dead reckoning for real-time vehicle performance and emissions

Transport-related environmental problems continue to constitute a major challenge to policy makers at all levels. A key feature of these problems is that they arise from the interaction of human behavioral systems and physical systems. Thus, to improve our understanding of environmental and health problems associated with vehicle emissions it is necessary to combine data on both travel and traffic behavior with environmental data linked to the corresponding spatial and temporal variables. There are currently no such databases available. A new low-cost real-time device is currently under development utilizing the latest developments in environmental monitoring, navigation, communications, data mining and warehousing to capture spatio-temporally referenced data on vehicle and driver performance and the level of emissions and concentrations. Because of the need to acquire data in all environments, there are potential limitations in using a global satellite navigation system such as GPS to determine the spatial and temporal data in built-up areas. Therefore, an augmentation strategy involving differential GPS and new low-cost dead reckoning sensors utilizing micro-electro-mechanical systems technology has been explored. This paper presents a high-level description of the real-time vehicle performance and emissions monitoring system, and details the results of a study carried out to characterize the performance of stand-alone and augmented GPS, and assess whether the required navigation performance is achievable. The study characterized the performance of different types of stand-alone GPS receivers and GPS augmented with differential infrastructure and low-cost dead reckoning sensors. The performance indicators used were satellite visibility, coverage, accuracy and integrity. The results highlight the weaknesses and differences in performance, depending on the type of GPS receiver used and shows that, unlike GPS alone, an integrated system employing GPS and low-cost dead reckoning sensors is capable of meeting the required navigation performance in built-up areas. Furthermore, no significant difference in accuracy between stand-alone GPS and differential GPS has been seen.

M. Walker

Papers

Integration of GPS and dead reckoning for real-time vehicle performance and emissions

Integration of GPS and dead reckoning for real-time vehicle performance and emissions monitoring