Navigation system. Marine Navigation Systems

Navigation equipment can be of various types and modifications. There are systems designed for use in the high seas, others are adapted to the wide masses of users using navigators in many ways for entertainment purposes. What are the navigation systems?

What is navigation?

The term "navigation" is of Latin origin. The word "navigo" means "floating on a ship". That is, initially it was actually a synonym for navigation or navigation. But with the development of technologies that facilitate the way vessels navigate the oceans, with the advent of aviation, space technology, the term has significantly expanded the range of possible interpretations.

Today, navigation refers to a process in which a person controls an object based on its spatial coordinates. That is, navigation consists of two procedures - this is the direct control, as well as the calculation of the optimal path of the object's movement.

Types of navigation

Classification of types of navigation is very extensive. Modern experts distinguish its following main varieties:

- Automobile;

- astronomical;

- bionavigation;

- air;

- Space;

- sea;

- radio navigation;

- satellite;

- underground;

- information;

- inertial.

Some of the above types of navigation are closely related - mainly because of the common nature of the technologies involved. For example, car navigation often employs a toolkit specific to satellite navigation.

There are mixed types, in which several technological resources are simultaneously used, such as, for example, navigation and information systems. In them, satellite communication resources can be key. However, the ultimate goal of their involvement will be to supply the target groups of users with the necessary information.

Navigation Systems

The corresponding type of navigation forms, as a rule, a system of the same name. There is, thus, an automobile navigation system, sea, space, etc. The definition of this term is also present in the expert environment. The navigation system, in accordance with a common interpretation, is a collection of different types of equipment (and, if applicable, software) that allow you to determine the position of an object, and also to calculate its route. The toolkit here can be different. But in most cases, systems are characterized by the presence of the following basic components, such as:

- maps (usually in electronic form);

- sensors, satellites and other aggregates for calculating coordinates;

- non-system objects that provide information about the geographic location of the target;

- software and hardware analytical unit that provides inputs and outputs of data, and also links the first three components.

As a rule, the structure of certain systems is adapted to the needs of end users. Individual types of solutions can be accentuated in the direction of the software part, or, conversely, hardware. For example, the navigation system Navitel, popular in Russia, is more of a software. It is intended for use by a wide range of citizens who own various kinds of mobile devices - laptops, tablets, smartphones.

Navigation via satellite

Any navigation system assumes, first of all, the definition of the coordinates of the object - as a rule, geographic. Historically, the human toolkit has been constantly improving in this regard. Today, the most advanced navigation systems are satellite. Their structure is represented by a combination of high-precision equipment, part of which is located on Earth, the other - orbiting. Modern satellite navigation systems are able to calculate not only geographical coordinates, but also the speed of the object, as well as the direction of its movement.

Elements of satellite navigation

The following basic elements are included in the corresponding systems: the constellation of satellites, the ground units for measuring the coordination of orbital objects and the exchange of information with them, end-user devices (navigators) equipped with the necessary software, in some cases - additional equipment for specifying geographical coordinates (GSM tower , Internet channels, radio beacons, etc.).

How Satellite Navigation Works

How does the satellite navigation system work? At the heart of her work is the algorithm for measuring the distance from the object to the satellites. The latter are located in orbit almost without changing their position, and therefore their coordinates relative to the Earth are always constant. In the navigators the corresponding figures are laid. Finding a satellite and connecting to it (or immediately to several), the device determines, in turn, its geographical position. The main method here is to calculate the distance to satellites based on the speed of radio waves. The orbital object sends a request to the Earth with exceptional accuracy in time-an atomic clock is used for this. Having received a response from the navigator, the satellite (or a group of those) determines what distance for such a time interval had a radio wave passed. Similarly, the speed of moving an object is measured - only the measurement here is somewhat more complicated.

Technical difficulties

We determined that satellite navigation is the most perfect method for determining geographic coordinates. However, the practical use of this technology is accompanied by a number of technical difficulties. What, for example? First of all, this is the inhomogeneity of the distribution of the planet's gravitational field - this affects the position of the satellite relative to the Earth. A similar property is also characterized by the atmosphere. Its heterogeneity can affect the speed of radio waves, which can lead to inaccuracies in the corresponding measurements.

Another technical difficulty is that the signal sent from the satellite to the navigator is often blocked by other ground objects. As a result, full use of the system in cities with high buildings is difficult.

Practical use of satellites

Satellite navigation systems find the widest range of applications. In many respects - as an element of various commercial decisions of a civil orientation. It can be both household devices, and, for example, a multifunctional navigation media system. In addition to civil applications, geodesists, cartographers, transport companies, various government services use satellite resources. The satellites are actively used by geologists. In particular, with their help it is possible to calculate the dynamics of motion of tectonic earth plates. Satellite navigators are also used as a marketing tool - with the help of analytics, where there are methods of geography, companies conduct research on their client base, and, for example, send targeted advertising. Of course, navigators and military structures also use navigators - they, in fact, developed the largest navigation systems today, GPS and GLONASS for the needs of the US and Russian armies, respectively. And this is far from being an exhaustive list of areas where satellites can be used.

Modern navigation systems

Which navigation systems are currently operating or under deployment? Let's start with the one that appeared on the global public market earlier than other navigation systems - GPS. Its developer and owner is the US Department of Defense. Devices that support communication via GPS satellites are the most common in the world. Mainly because, as we said above, this American navigation system was launched on the market earlier than its modern competitors.

GLONASS is actively gaining popularity. This is the Russian navigation system. It belongs, in turn, to the Ministry of Defense of the Russian Federation. It was developed, according to one version, approximately in the same years as GPS - in the late 80's - early 90's. However, the public market was withdrawn quite recently, in 2011. More and more manufacturers of hardware navigation solutions are implementing GLONASS support in their devices.

It is assumed that the global navigational system "Beidou", being developed in the PRC, can seriously compete with GLONASS and GPS. True, at the moment it functions only as a national one. According to some analysts, by 2020, when a sufficient number of satellites will be introduced into orbit - about 35, the status of the global satellite can be obtained. The development program for the Beidou system is relatively young; it started only in 2000, and the first satellite was launched by Chinese developers in 2007th.

Try to keep up and Europeans. The navigation system GLONASS and its American analogue in the foreseeable future may well come into competition with GALILEO. The Europeans plan to deploy a grouping of satellites in the required number of units of orbital objects by 2020.

Among other promising projects for the development of navigation systems can be noted Indian IRNSS, as well as Japanese QZSS. Regarding the first widely publicized information about the intentions of developers to create a global system yet. It is assumed that IRNSS will serve only the territory of India. The program is also quite young - the first satellite was put into orbit in 2008. The Japanese satellite system is also expected to be used mainly within the national territories of the developing country or neighboring countries.

Positioning accuracy

Above we noted a number of complexities that are relevant for the functioning of satellite navigation systems. Among the main things that we called - the location of satellites in orbit, or their movement along a given trajectory, is not always characterized by absolute stability for a number of reasons. This predetermines the inaccuracy of calculating geographic coordinates in navigators. However, this is not the only factor that influences the correctness of positioning with the help of a satellite. What else affects the accuracy of calculating coordinates?

First of all, it's worth noting that the same atomic clocks that are installed on satellites are not always absolutely accurate. They are possible, although very small, but still affecting the quality of the navigation error systems. For example, if a mistake is made at the level of tens of nanoseconds when calculating the time for which the radio wave moves, an inaccuracy in determining the coordinates of the ground object can be several meters. At the same time, modern satellites have equipment that makes it possible to conduct calculations even taking into account possible errors in the work of atomic clocks.

Above we noted that among the factors affecting the accuracy of navigation systems - the heterogeneity of the Earth's atmosphere. It will be useful to supplement this fact with other information concerning the influence of near-Earth regions on the work of satellites. The fact is that the atmosphere of our planet is divided into several zones. The one that is actually on the border with the open space - the ionosphere - consists of a layer of particles having a certain charge. They, when encountering radio waves sent by a satellite, can reduce their speed, as a result of which the distance to the object can be calculated with an error. Note that with this kind of source of communication problems, the developers of satellite navigation are working: in the algorithms of the orbital equipment, as a rule, various kinds of correcting scenarios are built, taking into account the peculiarities of the passage of radio waves through the ionosphere.

Clouds and other atmospheric phenomena can also affect the accuracy of navigation systems. Water vapor present in the corresponding layers of the Earth's air envelope, as well as particles in the ionosphere, affect the speed of radio waves.

Undoubtedly, as for the domestic use of GLONASS or GPS in the structure of such units as, for example, a navigation media system whose functions are largely entertaining, small inaccuracies in the calculations of coordinates are not critical. But with the military use of satellites, the corresponding calculations should ideally correspond to the real geographic location of the objects.

Features of marine navigation

Having talked about the most modern type of navigation, we will make a short digression into the history. As you know, the very term in question, first appeared in the environment of seafarers. What are the characteristics of marine navigation systems?

Speaking about the historical aspect, it is possible to note the evolution of the instruments at the disposal of seamen. One of the first "hardware solutions" was a compass, which, according to some experts, was invented in the XI century. The process of mapping as a key navigation tool has also been improved. In the 16th century, Gerard Mercator began to draw maps based on the principle of applying a cylindrical projection with equal angles. In the XIX century, a log was invented - a mechanical unit capable of measuring the speed of sea-going vessels. In the twentieth century, the arsenal of navigators appeared radar, and then space communications satellites. The most modern navigational systems today function, thus, reaping the fruits of man's exploration of the cosmos. What is the specificity of their work?

Some experts believe that the main feature of the modern marine navigation system is that the standard equipment installed on the ship has a very high resistance to wear and water. This is quite understandable - it is impossible that a ship that went into open swimming thousands of kilometers from the land, was in a situation where the equipment unexpectedly refused. On the ground, where the resources of civilization are available, everything can be mended, in the sea - it is problematic.

What other noteworthy characteristics does the naval navigation system have? The standard equipment, in addition to the mandatory requirement of durability, usually contains modules adapted to fixing certain parameters of the environment (depth, water temperature, etc.). Also, ship speed in marine navigation systems in many cases is calculated not by satellites, but by standard methods.