Intelligent Transportation Systems

This paper presents a cost benefit study of a Cooperative High-Accuracy LOcation (C-HALO) service as a nationwide service capable of providing decimeter level positioning accuracy to enable several new applications across various industries. We survey and summarize work by others quantifying the benefits reaped from enabling applications that require C-HALO. However, benefits to the economy from enabling C-HALO for Intelligent Transportation Systems (ITS) have not been quantified in the literature. This study estimates these benefits. We also provide an order of magnitude rough estimate of...

This paper presents a methodology for assessing the accuracy gap between the current level-of-service provided by the US GPS constellation and DGPS, and the level-of-service envisaged by new Cooperative High-Accuracy LOcation (C-HALO) services that achieve decimeter accuracy. We present a novel GIS-based Hidden-Markov Model (HMM) predictive framework to estimate the fraction of roads with low satellite visibility counts that we call as the “dark area”, where C-HALO cannot be realized. Out of the total area of San Francisco (121 sq.km), 0.3 to 4% of the San Francisco streets are predicted...

The paper describes algorithms required to enable the crowd sourcing of indoor building maps, i.e., where GPS is not available. Nevertheless to enable crowd sourcing we use the 3-axis accelerometers and the 3-axis magnetometers available in many smart phones and the piezometer in a Nike running shoe. Volunteers carry the sensors while walking around in buildings, and use some application on their smart phone to send the data to a mapping server. We present the algorithms to obtain walking trajectories from the data by dead reckoning, and to estimate indoor maps with multiple walking...

This chapter discusses how a wireless sensor network can be built for real-time estimation purposes. The finite capacity of a wireless network in delivering information means that a real-time estimation process has finite accuracy too. Improving accuracy requires faster sampling and more communication; however, faster communication is not always a possibility due to scalability issues and the limited capacity of a network. In fact, in networks where the wireless medium is shared amongst many nodes, the increase in the amount of communication may even have a negative impact on the capacity...