ALL ABOUT GPS/GLONASS

The satellite navigation potential have appeared since the start of the first artificial satellite.

Currently, satellite navigation systems are widely used to provide positioning and tracking with fine-resolution for all users at any place and at any time.
Satellite Navigation – is an integrated electro-technical system, consisting of a combination of on-ground and space equipment, navigational maps used to determine the location (latitude and altitude), as well as movement parameters (speed and direction of motion, etc.) for ground-based, water and air objects.

The main elements of the navigation system:

The orbital group, consisting of several (from 2 to 30) satellites that emit special radio signals;
A ground-based management and control system, which includes the units that measuring the satellite current position and sending to them the information received to adjust the information about the orbits;
Client receiving equipment ("satellite navigators"), used to determine the coordinates;
Optional: Informational radio system for the transmission of amendments to the users, that significantly improve the accuracy of positioning.

The principles of navigation systems operation

The principle of navigation systems based on measuring the distance from the antenna on the object (the coordinates of which must be obtained) to the satellites which positions are known with the great accuracy. The location table of all satellites called an almanac, which any receiver should have before the start of measurements. Usually, the receiver retains the almanac in memory since the last shutdown and if it is not outdated - instantly uses it. Each satellite transmits the whole almanac in its signal. Thus, knowing the distances to several satellites, using standard geometric constructions based on the almanac, you can calculate the position of an object in space.
The method of measuring the distance from the satellite to the receiver antenna is based on determining the propagation velocity of radio waves. To implement the possibility of measuring the propagation time of radio waves each satellite of the navigation system emits an accurate time signal using the atomic clock precisely synchronized with the system. The receiver clock is synchronized with the system time. The delay between the time of emanation, contained in the signal, and the time of signal reception is calculated while further reception of signals is on. With this information, the navigation receiver calculates the coordinates of the antenna. The majority of navigation receivers use the Doppler Effect to get the information about the speed. In addition, collecting and processing these data for a certain period of time, makes possible to calculate such parameters as the motion speed (current, maximum, average), distance traveled, etc.
In reality, the work of the system is much more difficult. Here are some problems that require special techniques for dealing with them:
The absence of atomic clocks in most navigation receivers. This defect is usually eliminated with the requirement to obtain the information from not less than three (2-dimensional navigation with a certain height) or four (3-dimensional navigation) satellites; (the availability of a signal from at least one satellite allows to determine the current time with good accuracy).
The heterogeneity of Earth's gravitational field, affecting the orbit;
The heterogeneity of the atmosphere, due to which the speed and direction of radio waves propagation can vary within certain limits;
Echoes from the ground-based objects, which is especially noticeable in the city;
The impossibility to place the high power transmitters on satellites. This is why the reception of their signals is possible only outdoors in a direct line of sight.

Currently working or preparing to deploy the following satellite navigation systems:

NAVSTAR (GPS)-USA.
Global Positioning System (GPS) developed and maintained at the state level in USA.
Currently, the GPS system is the only satellite navigation system, which provides services on a global scale.
The satellite constellation consists of 24 continuously operating satellites.

GLONASS - Russia.
GLONASS - Global Navigation Satellite System was developed in 1978, the orbital grouping will consist of 24 satellites in full force.
The system is currently at the stage of deployment of the satellite constellation and has only 20 satellites in orbit. Belongs to the Russian Ministry of Defense. According to the developers, it has some technical advantages over the NAVSTAR (GPS).

Compass - The Chinese satellite navigation system.
China, the fastest growing country in the world, also began the construction of its own satellite navigation system - Compass.
The currently developing subsystem GNSS, intended for use only in China. The space segment of the Compass satellite navigation systems will consist of 5 satellites in geostationary orbit (GEO) and of 30 satellites in medium Earth orbit.

The European Galileo system.
The European system, which is at the stage of a satellite constellation.
The GALILEO program is created to ensure the Europe's own independent global navigation system and to create a competition, primarily to the GPS.
The negotiations are carried on with Russia on cooperation between the GLONASS and GALILEO. Such countries as Australia, Argentina, Brazil, Japan, Malaysia, Mexico and Norway are also interested in participating in GALILEO.
Full orbital constellation will comprise 30 satellites.

Indian Regional Satellite Navigation System.
On May 9, 2006 the government of India has approved the project deployment of Indian Regional Navigation Satellite System (IRNSS). IRNSS constellation will consist of seven satellites in geosynchronous orbits.

Japanese Quasi-Zenith Navigation System (QZSS)
Originally the Japanese QZSS was conceived in 2002 as a commercial system with a set of services for mobile communications, broadcasting and wide use to navigate in Japan and neighboring areas of Southeast Asia.
The Japanese QZSS is primarily intended to improve GPS performance on a national and some neighboring territories.
It is expected that the introduction of QZSS will significantly improve the efficiency of navigation and other tasks and will give the acceleration of the introduction of new applications for navigation, which require greater accuracy and reliability.
The three global satellite navigation systems: GPS, GLONASS and GALILEO will simultaneously operate in the short term.

Technical details of the system operation.

Let’s consider some features of the basic satellite navigation systems (NAVSTAR and GLONASS):
Both systems have a dual purpose - military and civilian, and therefore emit two kinds of signals: one with a lower accuracy in determining the coordinates (≈100 m) for civilian use and the other of high precision (≈ 10-15 m and more accurate) for military applications. To restrict an access to the accurate navigation data there were introduced special interferences that may be taken into account after receiving the keys from the U.S. Department of Defense. Currently, the interferences are canceled and the accurate signals are available for the civilian receivers, but in the case of the decisions of owner’s state bodies, the military code could be re-locked (in the NAVSTAR system this restriction was cancelled only in May 2000 and may be restored at any time).
NAVSTAR satellites are arranged in six planes at an altitude of approximately 20 180 km. GLONASS satellites (code "Hurricane") are located in three planes at an altitude of approximately 19 100 km. The nominal number of satellites in both systems - 24. The NAVSTAR grouping was fully staffed in April 1994, and is fully supported since that time, the GLONASS constellation was fully deployed in December 1995, but it has been significantly degraded since then. It is in active recovery at the moment. Both systems use signals on the basis of so-called "Pseudonoise sequences", the use of which gives them a high noise immunity and reliability at a low power of the transmitters’ emanation.
In accordance with the appointment, each system has two basic frequencies - L1 (standard accuracy) and L2 (high accuracy). For NAVSTAR L1 = 1575,42 MHz and L2 = 1227,6 MHz. The GLONASS uses frequency division signals, i.e. each satellite is working on its frequency and, accordingly, L1 is in the range from 1602.56 to 1615.5 MHz and L2 from 1246.43 to 1256.53. The signal in the L1 is available to all users, the signal in the L2 is only for the military facilities (i.e. can not be decrypted without a special secret key).
Each satellite system, in addition to basic information, transmits the necessary supporting data for continuous operation of the receiving equipment. This category includes a full almanac of the entire satellite constellation, transmitted sequentially within a few minutes. Thus, the start of the receiving device may be fast enough, if it contains an actual almanac (about 1-minute) - this is called a "warm start", but it may take up to 15 minutes, if the receiver has to receive a full almanac – so called "cold start". The need for a "cold start" usually arises when you first start the receiver, or if it hasn’t been used for a long time.

The composition of the GLONASS system

Principles of the GLONASS system operation

The launches of GLONASS satellites

December 25, 2005, the "Proton-K" carrier rocket launched in the orbit one "GLONASS" satellite and two "GLONASS-M" satellites with increased resource exploitation from the Baikonur Cosmodrome.
December 26, 2006, the carrier rocket "Proton-K" held in the orbit three satellites GLONASS-M.
October 26, 2007, the "Proton-K" carrier rocket was launched from the Baikonur and placed into orbit three modified GLONASS-M satellites.
December 25, 2007 the "Proton-M" carrier rocket was launched from the Baikonur and placed into orbit three GLONASS-M satellites. Simultaneously, four satellites launched in 2001-2003, were removed from the grouping.
September 25, 2008, the launch of "Proton" with three satellites GLONASS-M, 1 satellite, launched earlier - at the stage of withdrawal from the grouping.
December 25, 2008, after a successful launch of the "Proton-M" from the Baikonur space center, 3 GLONASS-M spacecrafts had successfully separated from the upper stage and started autonomous flight.
Currently, the orbital grouping consists of 20 satellites, the full constellation of 24 satellites in accordance with the federal target program "Global Navigation System" is going to be launched in 2010.

Currently, the composition of the orbital grouping does not ensure a 100% availability of GLONASS services on the territory of country, but the number of GLONASS satellites visible above the horizon in Russia usually equals three or more. As the sellers of the Glospace navigation devices claimed - only three visible GLONASS satellites are enough to determine the location and the fourth gives clarification on height. Hence it is easy to conclude that the system is quite suitable for the orientation of ground-based users (drivers, mushroom pickers, hikers, etc.) right now, although the air navigation can still be a problem.
The "GLONASS-M" satellites will be in the orbital constellation at least until 2015. The flight tests of the new-generation "GLONASS-K" non-sealed satellites with improved performance (increased to 10 years warranty period and the third L-range frequency for civilian users) should begin in 2010. This satellite will be lighter than its predecessor by a half (about 850 kg against 1415 kg in "GLONASS-M").
Later, after the deployment of the orbital constellation of 24 satellites, it will need to make one launch of two "GLONASS-K" satellites on the "Soyuz" carrier rocket a year, which will significantly reduce operating costs.

From January 1, 2006 all newly commissioned vehicles, including aircrafts, ships, ground transportation, survey equipment and spacecrafts - must necessarily be equipped with the GLONASS satellite navigation system equipment or with the combined GLONASS/GPS receivers.

According to the decision of the Government of Russia from June 9, 2005 the in-use vehicles should be equipped with GLONASS receivers. According to the representatives of the "Russian Space Agency", these measures are reasonable and are designed to protect the market of global satellite navigation custom hardware. On the other hand, these systems are primarily aimed at addressing the problems of national security, because the global satellite navigation system plays a critical role in ensuring the application of precision long-range weapons. However, the future of the GLONASS system appears far from cloudless light.
The fear is the lack of competitive domestic GLONASS receivers on a market, as well as specific plans for the deployment of its mass production.

The importance of GLONASS for the economy of the country.

The use of GLONASS/GPS is widely spread both in military and civilian spheres. With the ability to receive an instant information on the whereabouts of your children, relatives and friends with the use of personal tracking devices, you can always be assured of their safety. The ability to receive messages about the whereabouts of vehicles for commercial enterprises is also essential. Possession of such information in real time helps to save money, minimize working time due to operational traffic management with advanced software and hardware tools.
Satellite navigation helps to determine the exact geographical location of objects. It is very important especially for the field of transport - air, sea, road, and rail. In the world’s largest metropolitan areas the more or less free traffic on the highways is based on satellite navigation software. Only through the optimization of traffic lights and traffic management - the time and money savings are not less than 20 percents. The situation with traffic jams is exactly the same. Traffic jams are the huge, tremendous loss of time and resources for individuals and companies. One hour of a downtime per employee in a traffic jam on a daily basis turns into hundreds of millions and billions of rubles of losses on a country scale. Accordingly, the effective control of traffic jams is crucial in terms of improving Russia's economic development as a whole.
If we talk about the areas of special-purpose of satellite navigation, such as: geodesy, mapping, exploration, cadastral works, etc. - the use of GLONASS and GPS-technology allows you to save huge money.
The signals of satellite navigation systems are used for time synchronization in many advanced industries. The works on the use of satellite navigation technologies for scientific research are conducted.
Private firms are willingly investing in satellite navigation. And that means that it is profitable and necessary for them. Business does not like throwing money down the drain.
In short, navigation is the basic component of the infrastructure of the modern economy, capable to "save" millions, tens and hundreds of millions, billions of rubles a year across the state, stimulating the growth and development of a large number of companies and organizations. By increasing the tax base. The country's economy requires satellite navigation just as it requires cellular communication, fast internet and good roads. The better the roads, the better the economy works. The greater the number of people and vehicles using the navigation on the everyday level, the higher the efficiency of people and companies, the subjects of the economy.

The problems of the introduction of GLONASS.

The first problem lies in the very GLONASS satellite constellation. Nobody is going to invest money in the NAP (Consumer Navigation Equipment) while the system is not working fully and guaranteed. Thus, there is still time until 2010.
The second problem is the designing of the GLONASS-chips. There are no such chips in Russia today. Domestic design centers are not able to compete with the foreign developers who are working on 0,09-0,065 micron and below design standards. It is important to get the GLONASS receiver type to the "System in Package" (SiP) standard. The world's leading electronic companies have been working with GPS-chips based on the very-large-scale integrated circuit (VLSI) of the «System on Chip» (SoC) type long enough.
Today, the GLONASS / GPS satellite navigation receiver (SNR) requires low power consumption (several tens of milliwatts), high performance and low cost that can not be obtained by the development of SNR based on circuits of programmable logic, which are used by many Russian companies. The existing GLONASS / GPS-receivers have large dimensions, which do not allow the developers to create the NAP device for mobile applications.
The third problem of GLONASS/GPS-receivers is that the Russian design-centers don’t have their own GLONASS/GPS navigation processors that constitute the basis of any receiver. All the western companies extensively use so-called IP blocks. They are essential for all advanced radio-electronic companies, which are engaged in the development of electronics.
The fourth problem – production. Roscosmos’ companies (RIRV, FGUP RNII KP, FGUP NII KP) would unlikely overpower the production of mass civil GLONASS products, unnatural for them. Also today, none of the former Russian Rosprom factories are unable to establish the mass production (from 500 000 units per month) of GLONASS equipment (mobile navigation terminals, browsers, etc.) because they do not meet modern requirements of microelectronics, a high percentage of spoilage (10%), poor quality, etc. The proposed GLONASS equipment on the Russian market has a high price that can not be compared with the price of GPS-equipment.
The fifth problem is system-defined. Today, GLONASS/GPS-receivers are needed not only to show the user’s location, but they are important for mobile applications (mobile phones, PDA). The relevant task is the integration of GLONASS receivers with a GSM / TETRA / WiMAX-modems that can transmit data obtained from satellite navigation systems GLONASS and GPS into the active monitoring centers. There are no such so-called "active monitoring centers" of the federal scale, which represent a closed architecture, network and telecommunication equipment with special software, capable to process a large number of requests for assistance in real-time, such as military convoys or echelons for the Defense Ministry, Emergencies Ministry and other huge databases departments of mobile navigation terminals. Non of the system integrators in Russia has an experience of integration of such "active monitoring centers" for the Defense Ministry, the FSB, the Foreign Ministry, the Interior Ministry or for the Emergencies Ministry.
Sixth problem is the lack of navigational maps and databases market. As before, the search for any qualitative spatial data is almost insoluble problem. It is easier to do everything all over again. This is due to the lack of metadata, the lack of renovation of state topographic maps and rigid state policies on property rights and copyrights to the state cartographic base. Furthermore, the existing secrecy is continued to impede the development. Also the problems of the Federal cartography and geodesy fund are acutely raised (mandatory, fee, copyrights and proprietary rights of third parties).
The official digital maps are available only in Roskartographya companies (GIS centers), however, you still won’t find any specific nomenclature, object composition, data format and the most important indicators for assessing - the quality and price on the GIS-Centers sites.
The seventh reason holding back the progress in the industry is the lack of mechanism for quality improvement of the legislative, regulatory and legal documentation.

Conclusion: Many countries in the world are vitally interested in the appearance of the powerful alternative to the American GPS system. If such an alternative appears, without a doubt, it will be useful in dozens of countries in different regions.

But it is important to understand that nobody needs the GLONASS in the form of satellites flying in their orbits and broadcast their signals into the void. The world needs complete solutions, that is, in addition to satellites, our potential partners - GLONASS buyers - waiting for the equipment that catches both the GLONASS and GPS satellite signals, the software that works on this equipment, the technology of creation of navigational maps and updating them, navigation services (and also the telematics and vehicle tracking systems). If GLONASS will "come out" on the world stage as a complete solution, as an alternative satellite navigation system that offers a complete infrastructure, then we have every chance not just to strengthen our influence in the world, but also to get a very profitable industry capable of producing high-tech and, most importantly, relevant products in the global market. The industry that gives an income not only from oil, gas or platinum group metals export. But the industry that is selling the product of the “brain work” of Russian engineers and programmers abroad. This is exactly the "changing the export structure with the expansion of the high-tech production" or "the shift of the economy from the rough to the innovative rails".