GNSS Applications

Applications
Title	GNSS Applications
Author(s)	Rui Barradas Pereira, GMV.
Level	Basic
Year of Publication	2011

GNSS applications are applications that use GNSS systems for its functionality. GNSS applications use GNSS Receivers to collect position, velocity and time information to be used by the application. In some specific cases other measurements output by the receiver might be used. The receivers might be generic all purpose receivers or can be built specifically having the application in mind.

The initial objective of the first GNSS systems was military. But with the free availability of GNSS signal and the availability of cheap GNSS receivers, the GNSS technology is having a pervasive use in civil, industrial, scientific and military areas.

The European Satellite Navigation Competition recognises the best ideas in the field of downstream applications based on satellite navigation.

Criticality of GNSS Applications

The GNSS Applications range from non-critical to highly critical applications. The different criticallity of GNSS applications lead to different performance requirements from the GNSS systems. Usually GNSS applications are grouped in terms of criticality as:

• Safety critical applications
• Liability-critical applications
• Non-critical applications

Location Based Services

Location Based Services (LBS) include applications that depend on the user location to provide a service/information that is relevant to the user at that location.

LBS normally use mobile devices with positioning ability to provide the service or information to the user. LBS can be used for personal or professional purposes although most of the services covered here are for personal use since professional services will be covered in other sections.

Different types of Location Based Services are:

• Location based Information Streams
• Tourist Information
• Games
• Carpooling and Transport on Demand

Civil Applications

The initial purpose of the first GNSS systems (GPS and GLONASS) was military but very early in the experimental phase of GPS the incident with the Korean Air Lines Flight 007 lead the US Government to issue a directive making GPS freely available for civilian purposes.

Currently the use of GNSS systems in Civil Applications is generalized and every GNSS system in operation or in construction takes civil applications as one of the most important uses of GNSS systems.

Different types of civil applications are:

• Personal Applications
• Road Applications
• Aviation Applications
• Rail Applications
• Maritime Applications
• Industry Applications

Surveying, Mapping and GIS

One of the most obvious uses for GNSS systems is the realization of surveys and production of maps. Although a simple standalone GNSS Receiver might not have the required precision for some survey requirements, most of these requirements can be fulfilled using high-end dual frequency multi-constellation receivers built specifically for surveying and by using GNSS Augmentation techniques.

The use of GNSS techniques in geodesy have revolutionized the way geodetic measurements are made. An increasing number of national governments and regional organizations are using GNSS measurements as the basis for their geodetic networks.

Different types of Surveying, Mapping and GIS Applications are:

• Land Surveying
• Mapping & GIS
• Aerial Survey

GNSS-based Products

With the decrease of the price and miniaturization of GNSS chipsets the number of products that include GNSS receivers increases every day. This trend has caused the improvement of existing products with the addition of GNSS capabilities and the outburst of new GNSS-based products.

The global shipments of GNSS-enabled LBS devices have grown from 150 million to 800 million between 2008 and 2013 corresponding to 40% CAGR. This phenomenal growth is also due to rapid economic growth in some very populated regions of the globe. In addition the application stores are also playing an important role since 40% of the available applications use location information, according to the estimates provided by GNSS Market Report, Issue 3.

Different types of GNSS-based products are:

• Personal Products
• Road Products
• Aviation Products
• Maritime Products

Space Applications

GNSS systems were originally designed for earth-based positioning and navigation. Despite this, real-time spacecraft navigation based on spaceborne GNSS receivers is becoming a common technique for low-Earth orbits and geostationary orbits, allowing satellites to self-determine their position using GNSS, reducing dependence on ground-based stations.

The space community started experimenting with spaceborne receivers very early in the deployment of the GPS network.The first spaceborne GNSS receiver was deployed in Landsat 4 in July 16^th 1982. The GPSPAC receiver deployed with Landsat 4 was also deployed with Landsat 5 and 2 other US Department of Defense missions and despite the few number of GPS satellites deployed (at that time only 6 Block I satellites were deployed), the GPSPAC was able to demonstrate the feasibility of using GNSS for space navigation.

Different types of Space Applications are:

• Precise Orbit Determination
• Satellite Realtime Navigation
• Satellite Formation Flying

Scientific Applications

GNSS systems offer important contributions in a variety of scientific research domains. As a matter of fact, a good part of the progress achieved in recent years is due to new or improved data analysis techniques, jointly with a growing variety of available measurements. In addition the already implemented GNSS systems are evolving and new systems are being developed, such as Galileo and BeiDou, which will contribute to further improvements in the current available applications as well to promote new applications.

Different types of Scientific Applications are:

• Earth Sciences
• Space-time Metrology
• Fundamental Physics

Military Applications

The first GNSS systems (GPS and GLONASS) were developed for military purposes and only later in the development of these systems it was decided to open then to civilian use. Still today the military applications are one of the drivers for these systems.

For instance GPS makes available 2 services: the Precise Positioning Service and the Standard Positioning Service. The Precise Positioning Service is encrypted and is only available to the US military and its allies.

Different types of Military Applications are:

• Military Navigation
• Target Acquisition

Autonomous Applications

Driverless cars are ubiquitous in imagined future scenarios. Autonomous vehicles technology is a multi-disciplinary technology where different engineering areas, such as Navigation, are required. GNSS systems where revolutionary in the area of Navigation by providing positioning and navigation capabilities to the autonomous vehicles. With precise positioning, GNSS can be used for lane or track determination (for road and rail vehicles) and attitude determination by using multiple antennas.

Autonomous vehicle technology is still at its infancy but currently the first laboratory prototypes are being tested and demonstrated. GNSS has been one of the key drivers for the recent developments in this area.

Different types of Autonomous Applications are:

• Autonomous Driving
• Autonomous Flying

Other Applications

The main objective of GNSS systems is to provide positioning but by design other information is available or can be derived from the measurements gathered by GNSS receivers. This led to less conventional uses of the technology in application areas that were not initially envisioned.

By design GNSS systems deliver precise time along with the position and velocity of the user. This capability has been used to provide a precise time reference in different areas such as financial transactions and stock markets. One other example of a less conventional use of GNSS technology is the use of the measured interference of the atmosphere on the GNSS signals to do atmospheric sensing.

Other Applications types are:

• Precise Time Reference
• Atmospheric Sensing