Đang chuẩn bị liên kết để tải về tài liệu:
Introduction to GPS The Global Positioning System - Part 9

GPS Integration GPS đã tìm thấy đường vào nhiều ứng dụng, chủ yếu là một kết quả về tính chính xác, sẵn sàng toàn cầu, và chi phí-hiệu quả. Thật không may, tuy nhiên, có tồn tại một số tình huống trong đó một phần của tín hiệu GPS có thể bị che khuất trong phạm vi thu GPS có thể không  "seeÂ" đủ các vệ tinh để định vị. Ví dụ trong những tình huống được định vị trong các hẻm núi đô thị và khai thác mở hố sâu. Tuy nhiên, vấn đề tắc nghẽn tín hiệu này. | 9 GPS Integration GPS has found its way into many applications mainly as a result of its accuracy global availability and cost-effectiveness. Unfortunately however there exist some situations in which part of the GPS signal may be obstructed to the extent that the GPS receiver may not see enough satellites for positioning. Examples of those situations are positioning in urban canyons and deep open-pit mining. This signal-obstruction problem however was successfully overcome by integrating GPS with other positioning systems. In fact reported results showed that the performance of the integrated system is better than either system alone. Augmenting GPS is not limited to sensor integration. As shown below GPS can be augmented with computer-based tools such as GIS for efficient data collection and analysis. 9.1 GPS GIS integration A geographic information system GIS is a computer-based tool capable of acquiring storing manipulating analyzing and displaying spatially referenced data 1 . Spatially referenced data is data that is identified 117 118 Introduction to GPS according to its geographic location e.g. features such as streets light poles and fire hydrants are linked by geography . Spatial or geographic data can be obtained from a variety of sources such as existing maps satellite imagery and GPS. Once the information is collected a GIS stores it as a collection of layers in the GIS database see Figure 9.1 . The GIS can then be used to analyze the information and decisions can be made efficiently. For example the decision to build a new road can be made by studying the effect of one feature such as traffic volume. GPS is used to collect the GIS field data efficiently and accurately 2 . With GPS the data is collected in a digital format in either real-time or postprocessed mode. A number of GPS GIS systems that provide centimeter- to meter-level accuracy are now available on the market. Most of these systems allow the user to enter user-defined attributes for each .