# Functional features of car GPS-navigators, alternative numbering of coordinates, portable GPS-navigators in the car.

What functional features distinguish car GPS navigators from standard portable personal navigation systems? First of all, the main fundamental difference between car GPS-navigators lies in the automatic preparation of the road route, the so-called auto-laying.

## Functional features of car GPS-navigators, alternative numbering of coordinates, portable GPS-navigators in the car.

Without delving into the essence of auto-laying, one may ask why we attribute the addition of only one function to the navigation system to a fundamental difference? Let us clarify this issue in more detail. Determining the route in the road network of a city or a particular country is a difficult mathematical task, since there can be many suitable routes leading to the desired destination.

And the route is needed not anyhow. From the user’s perspective, the ideal solution is to find a route from house X to house Y or from city N to the village of M that satisfies a certain criterion. The most common criteria are:.

Shortest route.
The fastest route combining main and auxiliary roads, taking into account speed limits.
The easiest route with minimizing the number of turns.
With minimal or no major roads.
With maximum use of the main roads.
With or without a minimum number of road sections.
Route with consecutive visits to multiple destinations.
Route with the exception of toll roads.
U-turn route.

Routing according to the specified criteria is a type of classic transportation problem, the mathematical solution of which has been known for a long time, but they have never been offered to an individual consumer before, because their implementation required both high computing power and a special logical structure of electronic cards adapted to solve them . The solution to such problems in today’s automotive GPS navigators indicates their high intellectual “brain” stuffing.

The calculation of the optimal route takes a certain time. The more optimal the route, the more time it takes to calculate it. When determining the route, road restrictions may be taken into account depending on the type of vehicle. Using the appropriate criteria, you can really save both time and money. Along with automatic routing, in automotive GPS-navigators, manual routing is also used when waypoints are selected directly from the electronic map image or entered according to their coordinates.

This method of laying can be successfully used for cards that do not allow auto-laying, in other words, without routers. From the point of view of using routes in practice, we point out two of their modifications. The first starting point of the route is its own current location. In the second modification, the starting point can be any, including the point of its location. It is clear that the first type of route is one of the options for the second. What is the difference then? In the convenience of management.

Situations for the first kind of route arise quite often and unexpectedly. According to him, you must quickly create a new route, the starting point of which is the current location of your car. If the GPS navigator provides for the creation of such a route in the form of a special option or button, then the time spent searching for this place and entering its coordinates is completely eliminated. You can say that this is a trifle. But it is precisely from such small details that the control convenience and the friendly nature of the driver – GPS navigator dialogue are made up. Especially when unnecessary and frequently performed routine operations are eliminated.

For efficient and quick routing, a GPS car navigator must provide the user with the opportunity to find the necessary objects in the system database, which can serve as both a destination and intermediate waypoints. In other words, an expanded base of cartographic data with a powerful information retrieval system should be integrated in car GPS navigators. Most developed automobile GPS navigators use the best technological and functional solutions of navigation systems with cartographic support: panning the map with the cursor, identification of map objects, visual and voice messages.

The second distinguishing feature of car GPS navigators is the provision of driving along the route, navigational support, the “turn-by-turn” mode. This is the main task of the navigation system, and it is performed almost the same in many systems. To do this, the graphic image of the route section, which can be called a traffic pattern, is simplified to a minimum so that a quick glance at the display is enough to recognize the situation and the recommended direction. The movement pattern is always oriented upward, that is, the current direction of movement on the screen is directed vertically. The motion scheme must contain the following elements.

The name of the street you are driving along at the bottom of the screen.
The name of the next street adjacent to the turn from the current street, at the top of the screen.
Turning distance.
Distance to destination.
Direction of current movement.
Direction to destination.

In addition to the name of the current street, the name of the city can be added, which is essential when the city does not have a clearly defined border. In escort mode, the system provides the necessary voice guidance, with one of the commands issued in advance of the turn, allowing the driver to prepare for him, and the second at the start of the turn.

## Alternative numbering of coordinates in car GPS-navigators.

Modern car navigation systems take advantage of the global satellite-based GPS coordinate system in combination with the alternative (stand-alone) method of calculating location coordinates using special sensors or electronic gyroscopes. The question is relevant, why is calculation and reckoning of one’s place used if the coordinates of the place using the GPS satellite system are updated every second?

The fact is that to measure coordinates using GPS, it is necessary to simultaneously receive signals from at least three navigation satellites. This is easily achieved in open areas or avenues 50-80 meters wide with two- and three-story buildings. Under conditions of dense and high-rise urban development and in tunnels, the reception of signals from satellites is interrupted. Here in these cases, the calculation of coordinates also works, constantly providing the driver with accurate and reliable information about his location.

## Using portable GPS in your car.

The use of some portable wearable GPS navigators in a car may have a number of limitations on navigation capabilities. You will have to use only manual routing, and route maintenance will not be supported by cornering graphics. Only the new series of portable GPS navigators are most suitable for use in the car, as they have automatic routing and turn-by-turn mode.

For automatic routing, of course, you must use the appropriate maps. If the navigator used does not have a loaded road map, then the route should be prepared on a personal computer, then it should be loaded into the GPS-navigator’s memory. You can enter a route as a set of individual points. After driving along the desired path and saving the track, you can copy, edit and create a route based on it, which can then be used repeatedly.

If there is a map in the GPS-navigator, route planning is facilitated and control of its passage becomes more visual. What do you need to have more efficient escort along the route? We believe that there must be an audible alarm, and an external antenna will be useful to improve the reception of satellite signals. Although many navigators mounted on the dashboard do an excellent job without it. Particular care must be taken in choosing a device for attaching a GPS navigator. The installation site should provide good screen visibility and not limit the reception of satellite signals.

Based on materials from the book All About GPS Navigators.
Naiman V.S., Samoilov A.E., Ilyin N.R., Sheinis A.I..