Since time immemorial we human beings have always yearned to explore beyond our daily environments to find out what lies elsewhere, normally from a sense of need but sometimes from sheer curiosity! In this quest we have needed to look for methods to pinpoint where we are, determine where we’re headed and decide how to get back to the starting point. At first this navigation and orientation tapped into natural features such as the lie of the land, the sun, the stars, moss growing on tree trunks …. but little by little we have dreamed up increasingly sophisticated techniques and tools: maps, lighthouses, timers and chronometers, right up to today’s latest satnav systems such as GPS, GLONASS, Galileo and BeiDou, all of which have helped us to achieve ever-higher levels of precision.
On 4 October 1957 the world woke up to the breaking news that the Soviet Union had placed the earth’s first artificial satellite in orbit, Sputnik 1. It was an 83-kg, radio-signal-emitting aluminum sphere with a 58-cm diameter and 4 long antennae pointing at the earth. Analyzing these radio signals, scientists gleaned important information on the ionosphere but the launch grabbed headlines well beyond the mere scientific sphere. It was a watershed moment in the so-called Cold War and served as the starting pistol for the Space Race, a parallel competition between the two Cold War rivals. This first launch was followed by many others, initially in the military sphere and then in the civil, for purposes of communications, earth observation and also for navigation.
American engineers were able to estimate the Sputnik orbit by measuring the signal’s Doppler effect from an earth station. A little later they had the brilliant idea of switching this round: ascertaining the position of the station by measuring the Doppler effect of the signal of a satellite with a known orbit. This idea enabled them to solve the problem of determining the position of a submarine passively, i.e. without the submarine itself having to emit any position-revealing signal. This is how the Transit program came into being, the forerunner of today’s GPSs. And all this happened astonishingly quickly. The first satellites of the Transit system were launched between 1961 and 1962 and the system was up and running by 1964… only 7 years after the Sputnik launch! The Transit system’s precision level was about 200 meters, quite amazing for the mid-60s.
Navigation technology continued to make headway, phasing in new tools along the way like atomic clocks, crucial for today’s navigation systems. From 1978 to 1985 the first satellites of the NAVSTAR system were designed, developed and launched, a military system that would then continue evolving up to the current GPS. In 1993 GPS was declared to have “initial operational capacity” and, in 1995, “full operational capacity”. GPS satellites emit signals that, processed on earth, enable the so-called set of ephemerides to be established (orbit and clock data). These ephemerides are sent to the satellites, which then send them back to earth where they can be picked up by any user with a suitable receiver. By means of trilateration satnav users can determine their position from the known positions of the satellites in view. In general the problem boils down to solving any user’s position coordinates plus a timing parameter; this means that at least 4 satellites have to be in sight at once.
Since then GPS has continued to evolve. Several generations of satellites have now been launched; many improvements have been phased in, such as satellite signal definition, the processing of these signals and, above all, revolutionary breakthroughs in receiver design. The first commercial GPS receivers cropped up in the early 80s. They were like a knapsack with a thick antenna several decimeters long, and largely unaffordable at the time. Today, by contrast, cell phones have inbuilt multi-constellation chips (capable of picking up signals from several navigation systems at the same time) that cost less than one dollar and can pick up signals with inbuilt antenna tucked away inside the cell-phone’s case.
Alongside GPS development, other navigation systems have been designed and developed by other countries, taking their cue from GPS but incorporating their own developments and technology while also taking into account the interoperability factor, i.e., making sure they are compatible for end users to tap into several systems at once. The Soviet Union began to develop GLONASS in the early 80s, the first satellites being launched in 1982. Now the GPS-analogue system is run and developed by the Russian Federation. The equivalent European-developed system is Galileo. The initial Galileo program definition phase began in 2000. The first satellite was launched in 2005; in 2016 the system was declared to be initially operational. The system is scheduled to be complete and fully operational by 2020. China, for its part, is developing its own system. In 2000 the system’s first generation was declared to be operational, offering regional coverage of China and bordering areas. The second generation, giving global coverage, is now under development and is also scheduled to be fully operational by next year.
Galileo’s greatest input is to ensure the availability of navigation services in complicated environments, on the strength of system redundancy, and to improve positioning precision. Galileo is now well-and-truly with us and looks set to offer a slightly better performance than the current GPS.
Satnav systems have a notable impact on the global economy. Some of this impact is direct and is measureable in terms of such indicators as the sale of satnav receivers; another part is indirect insofar as navigation systems are an essential element in many of today’s most groundbreaking technological developments, such as Internet of Things, Big Data, augmented reality, smart cities, multi-modal logistics. Take the case, for example, of the current estimates of satnav receiver sales, reckoned to be 8 billion units by 2020; another good example is innovating applications such as self-driving vehicles or automatic drone piloting.
GMV has taken an active part in the Galileo program since its initial phases. GMV’s store of knowledge and expertise has won us pole position in Europe’s satnav market. It is nowadays one of Galileo’s most important contractors, leading important items, especially in the ground segment area. GMV is likewise a leader in high-precision applications and receivers for public regulated service applications.
Author: María Dolores Laínez
Las opiniones vertidas por el autor son enteramente suyas y no siempre representan la opinión de GMV
The author’s views are entirely his own and may not reflect the views of GMV