What’s SuperNavigation Engine?

Car navigation industry has been boosted by automobile industry and intelligent transportation in the last few years. At present, car navigation system integrates GPS, GIS with modern computer technology to enable real-time vehicle positioning, intelligent navigation, which greatly increase driving convenience while enable drivers to get to the destination precisely.

Car navigation is one of the main GIS applications in mass informationization, SuperNavigation Engine (SNE) is SuperMap’s car navigation platform intended for satellite navigation developers with functions covering from map display, map manipulation, POI query, routing, positioning and navigation, etc. functionality of navigational products is offered in the form of class library by SNE, and a fully functional navigational application system (SuperNavigation) is available in SNE software package. This system is developed in a Win32 programming language, on the architecture of which function extension or customization can be implemented.

Figure 5 SuperNavigation Engine	Figure 6 SuperNavigator

SuperNavigation Engine (SNE) is a professional car navigation engine platform based on SuperMap Universal GIS Core (UGC) and the national standard of electronic map for car navigation application. It offers a full customizable SDK for customizing a car navigation system that can run on multiple operating system and multi CPUs in different IDEs. The basic functions include map display, map operating, POI query, path analysis, position and navigation, etc. It enables all kinds of navigation solution providers and mobile device manufactures to rapidly customize their own navigation applications OEM it into all kinds of terminal navigation products.

SNE is composed of 19 modules divided into three functional levels: fundamental layer, map visual layer and navigational application layer. The relationship is illustrated below, where, universal GIS fundamental modules are rendered with blue, and every other color represents one type of engine:

Figure 7 SNE Architecture

　　◆ Universal GIS fundamental module: Defines fundamental data structure, algorithm, map display flowchart as well as basic navigational element types, etc. this module is compiled as Basci.dll/.lib.

　　◆ Navigational data engine: Universal GIS based data engine development responsible for the management of navigational data in NDF format, including data source read/write, POI index data query, etc. This module is compiled as NdfEngine.sdx/.lib.

　　◆ GDI visual engine: Universal GIS based visual engine development, responsible for the display of SNE map data on Windows system. This module is compiled as WGraphics.uge/.lib.

　　◆ Fast image engine: responsible for reading, displaying ect. of SIT (SuperMap Image Tower) image format. This module is compiled as SuSitEngine100.sdx/.lib.

　　◆ GPS module: Responsible for processing GPS signal reception and protocol interpretation, data reading ect. This module is compiled as GPS.dll/.lib.

　　◆ Routing engine: Responsible for cross layer searching among multi-layer road topology network data to implement optimal routing. This module is compiled as RouteAnalysis.dll/.lib.

　　◆ Navigational engine: Responsible for providing navigation information during traveling and implementing intelligent vehicle navigation, including all route voice tips, 3D roundabout magnification, etc. This module is compiled as GuideEngine.dll/.lib.

Technical Features

Modular Architecture Design

SNE’s modular architecture can assign different functions of the navigation software to different engine modules, every engine can be distributable in the form of class library and logical relationship of each engine is relatively independent. These engines can collaborate with each other and can also be divided flexibly to function independently. This structural model makes it easy to manage the whole system and it is possible for users to customize some of the application engines (GPS module, route analysis module, etc.), therefore, to address various developing needs of car navigation applications.

Cross Platform Development

SNE is developed on Universal GIS architecture, a brand new technical architecture offered by SuperMap. The fundamental of Universal GIS is to separate all GIS functionalities and algorithm from the information technology they are based on by sophisticated software architecture design, thus, making the two parts independent and disengaged from each other. Therefore, the pith of Universal GIS is to establish a universal GIS core (UGC) in order to implement the core functionalities of GIS, which is relatively unable to change or not prone to be affected by rapid technical change. On a basis of UGC, it is easy to be adapted to this change by just implementing or adjusting peripheral modules and user interface, which extends life cycle of the application and reduces a lot of repetitive investment due to technical change. In light of current technical conditions, Universal GIS is an ideal software architecture that supports any existing computing device, operating system, programming language, database as well as data format.

SNE is developed on a basis of concise Universal GIS class library, which fully utilizes cross platform, multiple environment and other technical features of UGC while gives attention to limited hardware resources of Mobile devices, making the core of SNE concise and efficient. Therefore, the navigation application developed on SNE platform can exert technical advantages on different OS, hardware, programming languages or IDEs so that users can focus on maintenance and update of its peripheral functionality.

Figure 8 SNE Integrated Developing Environment

Open Architecture Design

SNE has fully considered users’ needs for customization. Besides splitting or extending of SNE, a number of functions with openness can meet requirements of customization. For example, SNE open workspace file to users so that customizable map color scheme is available to obtain various visual effects; in the routing engine, users are allowed to overload route search classes to implement routing with custom route searching mode.

Multi-threading Map Rendering

Due to large amount of data and limited hardware capability of PDAs, it takes a considerable amount of time for map display or map flashes quite often, which to some extent affects overall performance of the software. To tackle this problem, the map display of SNE employs multiple threading, dual cache techniques.

Figure 9 Multi-threading map rendering (with symbols)	Figure 10 Multi-threading map rendering (without symbols)

Multi-thread refers to multiple threads within a process so that an application can undertake multiple tasks. For a single threaded CPU, only one thread is working at a time. If more tasks are desired to be processed at the same time, multi-threading technique is needed, in which, a time slice is allocated to a thread, allowing switches among different threads according to certain strategies. As every time slice is very short, users feel that multiple tasks are simultaneously executed. Therefore, multi-threading can obviously reduce latency therefore enhance user experiences.

Dual cache refers to a technique that images are firstly created on RAM, and then they will be presented from the memory to the screen. By using the dual cache technique, screen flash can be effectively minimized and visual effect is therefore enhanced.

Efficient Indexing Algorithm

Point of Interest (POI) has rich attribute information with massive data. A number of indexing methods are available for attribute data accessibility. The data structure of indexing is tight, the algorithm of indexing has been optimized, and the index data expanding problem is avoided efficiently while real time query of millions of POI can be supported. Five basic POI query modes are provided in SNE.

Hierarchical Fast Search

For any navigation software, the precision and efficiency of routing are important performance indicators of an overall system. The routing engine of SNE is based on the road network model specified by the national standard of Application Storage Format for Digital Map in Vehicle Navigation System. By using multi scale, multi mode and adaptive seamless hierarchical fast search techniques, real-time analysis of large scale road network (million grades) is achievable with the most matches between the analysis result with actual road status.

Dead Reckoning

Positioning technology is a foundation of intelligent navigation, whose precision and real-time ability directly concerns the usability and overall performance of an car navigation application. Dead reckoning refers to a process of estimating current position of a vehicle based upon a previous traveling track if it is unable to receive GPS signal or the signal is too weak to pick up within a certain period. GPS and DR are combined together in SNE to ensure precise and continuous positioning and navigation in various signal situations.

Dynamic 3D Synthesis Magnification of Road Junction

For conventional navigation software, road junction magnification adopts either 2D road view or static 3D texture presentation. The former method fails to have a good visual effect while the latter fails to provide a large number of magnified images and thus increases overall size of the software. In contrast, OpenGL is employed by SNE to dynamically synthesize 3D magnification of a road junction in real time according to actual road status, resulting in a vivid effect and enhancing users’ visual experience.

Figure 11 Dynamic 3D junction guiding	Figure 12 3D Junction guiding in full screen mode

Smart Driving Tip Synthesis

When you are on the move, frequent driving tips may divert your attention. SNE adopts smart driving tip synthesis to avoid this problem. According to road and vehicle status, road junction mode is automatically analyzed while unnecessary data is filtered out, and driving tips are then synthesized to offer a more precise, humanized and safer navigation message.

Rapid Application Development

SNE offers a professional data compiling service, helping users cope with massive original data in effectively reducing developing difficulty; SNE offers a complete application framework for customization, based on which, from functionality to user interface can all be customized, and professional navigation software can be rapidly produced. With our user manuals, sample codes as well as developing guidelines, developers can get quickly started and master navigation application development.

Main Functionality

Basic Map Operation

SNE delivers a complete map display and operation functions for navigation applications, including rich map visual effects for map display, extensible vector symbol library, conventional/multi-threading map zooming, panning, full extent displaying, rotation, etc.

SIT is SuperMap’s exclusive fast image pyramid technique, capable of handling massive image data compression and presentation. SIT is introduced into SNE for real-time GB level image presentation.

Figure 13 Visual effect of SIT

POI Search

Five basic POI index query methods: full text, address, alphabet, telephone and around are available on SNE. Users are allowed to combine these indexes to achieve advanced user-defined search.

Figure 14 POI Index query mode

Routing

Routing engine of SNE complies with national standard for road network model with hierarchical fast search technique for real-time analysis of large scale road network status. Its main features include:

Million grade real-time road network analysis
Support for complex traffic rule related to time, car model, lane, etc.
Road avoiding option available for avoiding traffic jam or accident spot
Preset five route searching options: fastest route, shortest route, and highway priority, avoid highways, recommended route (high level road and landscape road preferred). Below is a comparison between Fastest route and Avoid Highway route with the same starting point and finishing point.

Figure 15 Fastest route	Figure 16 Avoid highway route

User defined route search option for flexible routing
Consider the impact of both search speed and precision on route plan, four route search strategies are available including synthesis search (synthesize multiple level networks searching), fast search (speed searching with upper level of road networks), precise search (route searching with all level of networks), and realized search (route searching with consideration of real time transport information)

Provide two route recovery modes with consideration of the road complexity impact on the result of route recovery: simplified route recovery mode – roads inside complex junctions (crossroads, loop island etc.) are not recovered; precise route recover mode – all roads are recovered.

GPS / DR Positioning

Vehicle positioning is the base of intelligent navigation. Its precision directly impacts the usability and performance of navigation software. SNE combines GPS and Dead Reckoning technology to ensuring the availability of positioning and navigation in various signal situations.

With the combination of GPS and DR, on one hand, the precise positioning when GPS signal is strong will correct the error of DR, which avoids accumulating errors of DR; on the other hand, when the GPS signal temporarily unavailable, the corrected DR will ensure the vehicle positioning in certain time period.

Rectifying Deviation and Matching

Rectifying deviation and Matching is the technology to match the output vehicle position data of GPS/DR with detailed road data in digital map, after making sure that vehicle position does not deviate or in stillness, match the vehicle position to the most possible matching road. By combining intelligent map matching and GPS/DR, the positioning information can synchronize ambient information to correct deviation, which enhances the overall accuracy of the positioning.

Voice Guidance

SNE voice navigation adopts intelligent synthesis technology, which employs real human voice.