PDA based in-vehicle navigation system
MAP DATABASE
A first step toward location intelligence is acquiring the right set of spatial data to include in any navigation system. The data gathered will form the basis for all subsequent navigation and location intelligence analysis and reporting, so many factors are important to consider: quality, vintage and coverage to name a few. The geographical database, which describes the road network, contains geometrical as well as attributive data. In order to harmonize the content and the formatting of these data, databases have been created in various formats like international ISO standard, the GDF - Geographic Data File. This standard defines how roads have to be described in order to be correctly interpreted by navigation systems. A road database consists of an inventory of features, topology and attributes. Most of this information can be collected using different surveying techniques. The following steps are usually used to gather geo-information:
- Positioning of features in a spatial reference system. This geo-referencing operation is based on land survey techniques (GPS, theodolite) and aerial techniques (photogrammetry, remote sensing)
- Building the topology of objects (road network, nodes, crossings)
- Capturing attributes and information such as the direction of traffic, a signpost, a street name etc.
Collecting and managing all the geo-information and its related attributes in a map database requires a good co-ordination in the field surveying process. The whole process is monitored in order to reach the desired quality of the database. The merging of different information (aerial imagery, GPS, maps) can affect the database if the quality of the original data is poor. New techniques for capturing geo-information are developed with the target to warrant accuracy and reliability in dynamic applications.
NAVIGATION SOFTWARE
Navigation software is core component of overall navigation solution. So the functionalities, visual output, voice commands, user interface should be designed in a way to support a comfortable and hassle free journey. Some recommended guidelines are:
- Use simple displays for complex and critical information
- Present textual information by vocal announcement
- Simple guidance instructions
- Use symbols to present guidance information
- Glances to display should not be longer
- Avoid flashing or moving graphics elements
- Minimize visual clutter
- Use maximum contrast between display elements
- Keep backgrounds simple and muted
- Group information logically considering frequency and sequence of use.
- Consider user's behaviour and needs.
- Let user set pace and initiate interaction
- Prioritize information
- Restrict information when necessary
- Voice prompts should use easily recognizable sounds
- Voice commands should have similar duration, intensity, and quality
Looking into above parameters, Transport Hi-Tech Consultants developed EasyNav Navigation system on PDA platform with the help of Space Machine Inc. Silicon Valley, USA.