Global Positioning System (GPS) refers to a satellite system that orbits around the earth to give location data to GPS receivers. This data is useful in finding our way in new towns to monitoring vessels at sea. Indeed, GPS technology has revolutionized the way we relate with our surroundings. However, there are many principles underlying the working of this technology. The following article explores GPS technology and tries to explain how it works.
GPS Technology Explained The GPS technology uses a constellation of 24 satellites to transmit precise location data to GPS receivers. Apart from these 24 operational satellites, there are three others maintained as spares just in case of failures. The GPS satellites transmit radio signals carrying information about the satellite position and the exact time at which the messages are transmitted. Subsequently, GPS receivers receive this information and compute their location by using the GPS signal transmitted by the satellites.
GPS technology is basically made up of two major parts; GPS receivers and GPS satellites. As mentioned earlier, GPS receivers are devices that collect and analyze the information from the satellites. These devices are installed in mobile phones, automobiles and aircrafts among other vehicles in order to determine the location of these vehicles. On the other hand, the GPS satellites are used to transmit their location information to GPS receivers through radio waves.
How GPS Receivers Work GPS receivers are made up of a GPS antenna, amplifiers, filters, decoders, and microprocessors. The incoming radio signals are amplified and filtered by the GPS receivers and then decoded and analyzed by the microprocessors to find out the GPS receivers’ location.
There are various technologies used in GPS receivers to improve their performance. These include assisted global positioning system (A-GPS), wide area augmentation system (WAAS) and differential GPS (DGPS). A-GPS technology refers to the process of improving the performance of GPS receivers by combining the GPS signal with the wireless and cell towers’ signals.
As stated earlier, WAAS is a GPS technology enhancement that helps in determining the position of GPS receivers. The technology utilizes the network of ground reference stations to collect information on errors in the GPS receiver signal and transmit the results to the master station which creates the correction factor and then forwards it to the GPS receivers.
DGPS technology is another technology advancement that utilizes differences between the GPS receiver signal readings in order to reduce signal interference. In this regard, one GPS receiver serves as a base station that does not move but the other moves. The difference between the two is transmitted to the mobile station to assist it to determine its location.
The Mathematics Behind GPS Technology Like any other technology, GPS technology depends greatly on mathematics to perform its operations. GPS technology consists of GPS receivers and satellites. Different mathematical concepts are applied to help GPS receivers find their locations using GPS satellite information.
Trilateration is the mathematics concept used in GPS technology to determine a point in three-dimensional space. In this regard, the trilateration process requires drawing three non-coplanar spheres whose centers coincide with GPS satellites’ positions. The radius of these spheres represents the distance between the satellites and the receiver.
Another mathematics principle used in GPS technology is known as triangulation. Triangulation is used to find the intersecting point of two lines that emanate from different points. The intersecting point provides the location, altitude and the distance to the satellites of the GPS receivers.
Another mathematics concept used in GPS technology includes spherical geometry. In this case, spherical coordinates are used to represent the GPS receivers’ and satellites’ positions. All the operations on these coordinates are performed through spherical geometry.
Signal Propagation and Interference GPS radio signals are transferred from the satellites to GPS receivers via the atmosphere, where they encounter several impairments such as ionospheric delay, tropospheric delay, multipath and signal interference from other sources.
Ionospheric delay is encountered when GPS radio waves pass through the ionosphere. This delay is directly proportional to the frequency of the GPS signals but inversely proportional to their wavelengths. Tropospheric delay arises due to variations in temperature, air pressure, and water vapor content in the troposphere. Multipath delay is caused when GPS radio waves reflect from other objects before reaching the GPS receivers.
Real-World Applications of GPS The applications of GPS technology are limitless today. Some of the common applications of GPS include navigation, agriculture, surveying among many others.
Navigation
One way of applying GPS technology is in navigating roads and highways. GPS technology is used in modern cars to provide turn-by-turn directions and in tracking vehicles in real-time. Also, navigation systems can be installed on mobile phones to enable navigation for individuals without a car.
Agriculture
GPS technology is also applied in precision agriculture. GPS technology is used to map and analyze agricultural fields and guide farmers on planting crops.
Surveying
Another important application of GPS technology is surveying. GPS technology is applied in surveying to determine precise location and elevation points in the earth’s surface. Surveyors require precise location points for purposes of mining, construction and geological studies among other applications.
Conclusion GPS technology is a remarkable technology making our lives much simpler than before. The technology uses satellite technology to provide location data to GPS receivers on the earth. GPS receivers use mathematical principles like trilateration, triangulation and spherical geometry to determine their positions based on the GPS satellite data.
