Research On Key Technologies Of Network Navigation Services Based On Grid

A Carrier's current position, target position and the path between the two positions are the three basic elements of navigation. From this view point, we define Network Navigation Services as: according to a user's requirements, if necessary, use network computing technologies to get navigation resources over the network together and make the three basic elements' determination, including positioning, target feature retrieval and path planning, can be done through the cooperation of those distributed navigation resources, and then use network transportation to put the results of positioning, target feature retrieval and route planning together to provide navigation services to the user which fulfill his or her requirements.Circling around the concept of Network Navigation Services, we have done research on its key technologies from three aspects: positioning, target feature retrieval and route planning.1. Network Navigation Positioning Services Under network navigation conditions, we can take full advantage of different positioning technologies through the cooperation of distributed positioning resources over the network.There are mainly three cooperation patterns as follows:Cooperation of different positioning technologies Dynamically select different positioning technologies with the changing situation according the user's requirements and provide them with self-adaptive services on demand.Cooperation of different positioning systems using the same technology Continuously Operating Reference System (CORS) is a fast-developing positioning services system which can provide high-precision positioning services for car navigation, car auto-driving, pedestrian navigation, blind navigation and so on. We put forword a Grid-based VCORS technology to realize the coorporation of different CORSs.Cooperation between positioning resources and non-positioning resources in one positioning system We explore how to use Grid to fast resolve multi-session GPS carrier phase base line. we first use the least squares method to reason an adjustment model for the multi-session GPS carrier phase base line, analyzes the model's quality of being decomposable, and decomposes it into several sub computations, and then discuss the grid workflow formed by these sub computations and a way to realize the workflow.2. Network Navigation Target Feature Retrieval Services We use OGSA-DAI from Globus Toolkit 4 to build target feature retrieval services to resolve issues such as the distribution of navigable geospatial databases, diversity of DBMSs and structural heteogeneity. And discuss formalizing navigable geospatial knowledge based on Descrition Logic, use Descrition Logic language to build navigable geospatial knowledge base and describe navigation users' target feature retrieval conditions and obtain the target feature through logic reasoning in the knowledge base, realizing the intellectual retrieval of target features.3. Network Navigation Route Planning ServicesUnder network navigation conditions, we try to provide route planning services for users through the real-time coorperation of distributed road networks, and we propose the dynamic collaborative route planning method for distributed road networks , whose basic process would be as follows: according to the parameters such as start point and target point given by a navigation user, dynamically select certain road networks from distributed road networks which are located around the Internet, let each of the selected road networks make local route planning independently, then integrate all these local route planning results and form a path from the start point to the target point.