Remote sensing technology has been widely used in agriculture, forestry, geology, ocean, meteorology, hydrology, military affairs, environmental protection and other fields. In the next decade, remote sensing technology is expected to enter a new stage, which can provide various earth observation data quickly and timely. The spatial resolution, spectral resolution and temporal resolution of remote sensing images will be greatly improved. With the development of space technology, especially the development and mutual penetration of geographic information system and global positioning system technology, its application field will be more and more extensive.
GPS is the abbreviation of English Global Positioning System. GPS was started as a project of the US military in 1958 and put into use in 1964. In 1970s, the United States army, navy and air force jointly developed a new generation of satellite positioning system GPS. The main purpose is to provide real-time, all-weather and global navigation services for land, sea and air, and to be used for some military purposes such as intelligence gathering, nuclear explosion monitoring and emergency communication. After more than 20 years of research and experiments, it cost 30 billion dollars. By 1994, 24 GPS satellite constellations with global coverage of 98% have been deployed.
In fact, GPS can:
The application of GPS is based on two basic services.
1. spatial location service
GPS application scope
GPS application scope
① Positioning: such as car anti-theft, ground vehicle tracking, emergency rescue, etc.
(2) Navigation: For example, marine navigation and water diversion of ships, aircraft route guidance and approach landing, intelligent transportation, autonomous navigation of automobiles and missile guidance.
③ Measurement: It is mainly used for measuring time, speed and geodesy, such as underwater topographic survey, crustal deformation survey, deformation monitoring of dams and large buildings, and data of floating vehicles. GPS is used to record the position and speed information of vehicles regularly. So as to calculate the road congestion.
2. Time service
① System synchronization: such as CDMA communication system and power system.
② Timing: accurate time and frequency.
Geographic Information System (GIS) is sometimes called "Geographic Information System". It is a specific and very important spatial information system. With the support of computer hardware and software system, it is a technical system that collects, stores, manages, calculates, analyzes, displays and describes the relevant geographical distribution data of the whole or part of the earth's surface space (including the atmosphere).
Many disciplines benefit from geographic information system technology. The active geographic information system market leads to the low cost of GIS components and the continuous improvement of software and hardware. These developments in turn lead to the wider application of this technology in science, government, enterprises and industries, including real estate, public health, crime map, national defense, sustainable development, natural resources, landscape architecture, archaeology, community planning, transportation and logistics.
It can be seen that GPS can only solve the problem of "where" and RS can only solve the problem of "what". Only by putting these information into GIS can they become comprehensive and meaningful.
For example, cruise missiles, it is useless for you to only have the GPS coordinates of the target. In the past, you had to send a remote sensing satellite to find out the geographical conditions along the flight route, and input these altitude data into the missile, so that it would know how to bypass the mountains and automatically adjust the altitude along the terrain to achieve the whole ultra-low altitude penetration. This combination of pure GPS and RS is laborious. If you have a GIS database, you can know the situation along the way as soon as you check it, so you don't have to send satellites to reconnaissance every time.
1. Geographic information system is a comprehensive subject combining geography with cartography, remote sensing and computer science. It has been widely used in different fields. It is a computer system for inputting, storing, querying, analyzing and displaying geographic data. GIS is a computer-based tool, which can analyze and process spatial information (in short, it is a phenomenon on the earth). GIS technology integrates the unique visualization effect and geographical analysis function of maps with general database operations (such as query and statistical analysis).
Source: Baidu Encyclopedia-Geographic Information System
2. Remote sensing refers to non-contact and long-distance detection technology. Generally, it refers to the detection of electromagnetic radiation and reflection characteristics of objects by sensors/remote sensors. Remote sensing is to detect the target object by remote sensors and other instruments sensitive to electromagnetic waves under the condition of being far away from the target and not touching the target object.
Source: Baidu Encyclopedia-Remote Sensing
3. The system that uses GPS to locate satellites and conduct real-time positioning and navigation on a global scale is called Global Positioning System, or GPS for short. GPS is an omni-directional, all-weather, all-day and high-precision satellite navigation system developed by the US Department of Defense. It can provide users around the world with low-cost and high-precision three-dimensional navigation information such as position, speed and accurate timing. It is a typical application of satellite communication technology in navigation field, which greatly improves the information level of the earth society and effectively promotes the development of digital economy.
Source: Baidu Encyclopedia -GPS