Outdoor Navigation

Applications
Title	Outdoor Navigation
Author(s)	Rui Barradas Pereira.
Level	Basic
Year of Publication	2011

Outdoor Navigation consists in the navigation in outdoor environments such as natures trails. Outdoor Navigation is use mainly by outdoor enthusiasts (such as hikers, backpackers, geocaching enthusiasts, mountaineers or bikers) and outdoor workers (such emergency workers, wildlife preservation workers, forestry workers, farmers or mining workers).

Outdoor Navigation is somewhat different from Pedestrian Navigation or Road Navigation since it uses the concepts of trails and waypoints instead of a turn by turn navigation. Maps is not always required since individual trails can be loaded on the device or trails can be created from hikes. When present maps are very different from the maps used in Pedestrian Navigation or Road Navigation being more closely related with topographic charts and military charts instead of being street and road oriented.

Application Architecture

Pedestrian Navigation applications are normally implemented using a standalone application running on a mobile device. This mobile device can be GNSS-enable phone with multimedia capabilities or a custom Personal Navigation Device.

Normally the map and database of these applications are local although in some case the local application is supported by an online services that provide database updates, additional dynamic data (such as weather) or even parts of the navigation functionality.

The process normally followed by these applications is:

• The user uses the application to define a destination. Restrictions may be applied on how to get to the destination (e.g. use of public transport).
• The application will guide the user using visual and audio information to its destination.
• If the user diverts from the suggested route the application will recalculate the route.

Variants to this architecture are:

• The more basic pedestrian navigation applications support only outdoor pedonal movements not supporting public transportation.
• These applications can be combined with Location based Information Streams to provide additional information to the user.

These applications are considered non-critical applications.

The precision required by these applications is medium. The current accuracy provided by civilian GPS enough in most situations but not in all since pedestrian are more often in situations with less visible satellites. To support indoor navigation these applications would need a much higher availability than normally given by civilian GPS that might require the use of inertial sensors or other indoor localization techniques.

Application Characterization

Pedestrian Navigation as been wrongly seen as a mode of Road Navigation. But the fact is that the environments where pedestrians move around are generally more difficult than the road environment. Pedestrians normally move in sidewalks where the buildings shadow the GNSS signals, in tree shadowed environments and in indoor three-dimensional environments.

These environments are much more difficult than Road Navigation that even in urban environments will have better satellite visibility. To support indoor navigation these application would have to support inertial sensors integration or other indoor navigation techniques.

In simplified pedestrian applications the maps used for road navigation can be reused but this limits the degree of functionality that the application can provide. Pedestrians move in the sidewalks, not in the roads and can move more freely in the environment since they can use pedestrian streets or pathways and go across open areas.

The mapping of indoor environments is also much more complex and dynamic requiring three-dimensional mapping that is not generally required for road applications.

Also to support public transportation, the routes and the frequency or the timetable of the public transports must be supported making the database and the routing algorithms more complex.

Currently the interface for these applications is supported by the graphical and audio interfaces of mobile phone but these applications would benefit significantly from the used of augmented reality technologies.

Application Examples

Applications and services that fit in this category are:

• Journey Pro by Navitime: Journey is pedestrian navigation application for iPhone and Android.
• Ovi Maps: Nokia free navigation solution that supports pedestrian navigation in the Walk mode.
• Google Maps: Google free map solution that supports pedestrian navigation including public transportation.
• Personal Navigation Devices: Most road oriented personal navigations devices support pedestrian modes although usually the same maps and routing algorithms as for road navigation are used.