International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 15 (2016) pp8501-8506
© Research India Publications. http://www.ripublication.com
8501
GPS PROTOCOLS
Michal Sustek, Miroslav Marcanik, Milan Oplustil, Zdenek Urednicek
Faculty of Applied Informatics, Tomas Bata University in Zlin,
Zlin, Czech Republic.
Abstract
The contribution describes the basic principles of
measurement and the use of global positioning systems,
focusing on the most widely used system NAVSTAR,
including used protocols. It deals NMEA protocols-which
today ranks among the most widespread GPS system, RINEX-
which is an interpretation of "raw" data, these systems, and
RTCM-which is an alternative for NMEA with the difference
that is much used in the GLONASS system.
Keywords: GPS;protocols; NMEA; RINEX;RC-104.
INTRODUCTION
The need to know its place and purpose of humanity was
already known at the time of nomadic tribes, even though it
was not the exact coordinates, but rather about the features
and layout of the new territory to be able to survive. With the
increasing development and demarcation of borders of
individual states are at the forefront seceded and precise
geographic coordinates, and it's no surprise that over time,
methods of identifying and mapping increasingly refined.
Nowadays, because there is a large geographic area
Navigation Satellite Systems (GNSS), in which it is possible
to include the most common navigation system NAVSTAR
GPS, but also GLONASS (Russia) and GALILEO (European
Union).
In positioning systems are distinguished two methods for
aiming points, these are the absolute and relative, both of
which can be used in static and kinematic mode. In the static
application, the receiver is during the measurement due to the
earth's surface at rest. On the other hand, in the kinematic
applications is the antenna relative to the surface of the earth
in motion. The accuracy of static methods and speed of
kinematic measurements contributed to the development of
technologies whose combination leads to rapid positioning. It
is a method of Rapid Static and Stop & Go. Another
development from the perspective of hardware receivers led to
the creation of options "real-time" measurement techniques.
Due to the mass spread of GPS technology, it is not surprising
that they constitute a resource of information that must be
processed. The problem may be a transmission with a device
to the software that was created by another manufacturer. It
leads to the need for at least some of the protocols to
standardize. Among the most used include NMEA, RTCM
SC-104, and RINEX.
GPS HISTORY
The GPS system has its roots in the 60s of the 20th century.
The primary purpose for which the system was designed in
the effort to obtain a universal, highly accurate and easily
accessible positioning and navigation system, which at that
time replaced the myriad specific devices. The main problem
with these devices is their cost and limited use. Based on these
facts, the US Navy and Air Force began independently to
study the possibility of using a radio signal that would be sent
from the satellites and the possibility of its use for navigation.
Navy sponsored two research programs. These were Transit
and Timation. On the other hand, the Air Force participated in
a similar program 621B System. In 1973, there was a
compromise that united researcher programs under a single
program known as GPS. The first phase of the GPS had a set
budget to $ 100 million. [3]
Between 1978 and 1985 there was a total of 11 satellites
launched, but one of them was destroyed in a failed launch.
The initial service of life which has been determined by these
satellites was only three years, but the most of them worked
over 10 years. In the 80 years was sent into orbit by an
additional 23 satellites. Currently, this system consists of 24
satellites. Like a number of other technologies, it was the first
major test for the deployment of GPS in military operations in
the Persian Gulf. The system enabled the orientation in rough
desert terrain with great precision. It is said that one of two
things that stood for victory in this war conflict was just a
GPS (the other was night vision). It is, therefore,
understandable that in addition to the Gulf War, the system
was deployed in countless other military operations.
GPS METHODOLOGY
The GPS has two basic measurement methodology, these are
absolute (autonomy) and relative (differential) positioning.
Both of these methods can be used for static and kinematic
positioning application. Under static positioning, the receiver
during the measurement due to the earth's surface at rest, on
the other hand in kinematic applications, the antenna relative
to the surface of the earth in motion. The accuracy of static
methods and speed of kinematic measurements contributed to
the development of technologies whose combination leads to
rapid positioning. It is a method of Rapid Static and Stop &
Go. Another development from the perspective of hardware
receivers led to the creation of options "real-time"
measurement techniques (RTK).
Statistic Method
The relative measurement method allows determining the
differences between GPS coordinates of the satellite system
and the reference point. The various distances to the satellites
must be determined simultaneously from the examined and
the reference point. Under static measurements are determined
vectors connectors points of interest (in figure 1). The static