How gps technology monitors earthquakes

Nowadays, the rapid advancement of high-tech technology has made people understand earthquakes further. Here are some of the relationships between gps and earthquakes.

For earthquake monitoring and forecasting, this urgency is particularly significant, because China's seismic network, especially the earthquake precursor network, there are three serious major defects:

First, from 1988 to 1999, a total of 53 or more earthquakes of magnitude 6 or above occurred in the Chinese mainland, including 9 earthquakes with magnitudes of 7 or higher. If the eastern longitude is 105°, the western region has 8 occurrences, and the eastern region has 1 occurrence. 1:1. However, due to the sparsely populated area west of 105° E, traffic is inconvenient.

The network layout is extremely rare. In an area where more than 90% of the seismic energy is released, the Taiwan network is too thin, which undoubtedly wasted precious natural resources of seismic information, greatly delaying human practice, and thus delaying the process of improving the level of earthquake prediction. ?

Second, the National Earthquake Precursor Network is conducting daily observations of relative changes in the form of “spot measurement”. The observation data of each station is relatively independent, and there is no correlation between the stations. In the event of an abnormality, due to the observation of point structure, there is no contact on the surface.

It is difficult to judge its authenticity.

Third, seismic activity is regional and global. While precursory observations are independent and irrelevant, it is difficult to study their relationship with global seismic activity. ?

For high-precision observation systems that can encrypt western observations, have a global framework meaning, and have “face structure” links, only use spatial measurement techniques (very long baseline interferometry—VLBI, human-surveillance distance—SLR, global positioning System - GPS, Satellite Remote Sensing - RS

Synthetic Aperture Radar Interferometry (INSAR). In particular, GPS technology has developed rapidly in the past 10 years and the observation accuracy has increased by almost three orders of magnitude, providing an effective method for monitoring the movement of the earth's crust. ?

First, cps satellite positioning ?

The Global Positioning System (GPS) was established by the U.S. Department of Defense to meet the requirements of the military sector for high-precision navigation and positioning of maritime, land, and air facilities. The first experimental satellite (Block I) was launched in 1978.

The first working satellite (Block II) was launched in February 1989. By the end of 1994, all 24 satellites had been launched. Since the satellites have a life span of about five years, there are currently 27 satellites in operation, most of which were launched later.

1. GPS positioning basic principles ?

• Absolute positioning method: Absolute positioning, also called single-point positioning, refers to the direct determination of the coordinates of an observing station in a coordinate system that is the origin of coordinates relative to the Earth's center of mass. The principle is based on the observation of the distance between the GPS satellite and the user's receiver antenna, and based on the known satellite instantaneous

Coordinates to determine the coordinates of the point corresponding to the user's receiver antenna. ?

Due to the distance between the actual observation point and the satellites, it is difficult to maintain strict synchronization between the instantaneous satellite clock and the receiver clock. This kind of distance that contains the influence of the clock difference is called “pseudorange”. The satellite clock difference can be corrected using the clock difference parameter given in the navigation message, and the receiver

The clock difference can not be known in advance, so it needs to be solved as an unknown number and the three-dimensional coordinates of the observation point in the data processing. Therefore, four unknowns must be solved in real time at one observation point, that is, at least 4 satellites must be observed at the same time. ?

• The relative positioning method uses two GPS receivers to be placed at both ends of the baseline, and simultaneously observe the same GPS satellites to determine the relative position or baseline vector of the baseline in Earth coordinates. Because the same satellite can be observed synchronously at two or more observation points, it can effectively eliminate

Or reduce the impact of satellite orbit errors, satellite clock skew, receiver clock skew, and so on. At present, China's crustal movement monitoring is a static relative positioning method with an accuracy of 10-8 to 10-9?. ?

2. Features of GPS

Due to the large number of GPS satellites and their reasonable distribution, at least 4 satellites can be continuously observed at any location on the earth. In China, up to 13 satellites can be observed simultaneously (according to the current 27 satellites). This ensures global, all-weather continuous three-dimensional positioning. ?
The real-time determination of the three-dimensional position and velocity of the moving object can both ensure the movement of the motion carrier along the predetermined route, as well as monitor and correct the navigation route, and select the optimal route. ?
High positioning accuracy. At present, on a baseline of more than 1000 km, relative positioning accuracy can reach 10-9; 100 km can reach 10-8. ?
Observations are not required between observing stations, and observation time can be shortened. ?
The real-time positioning of this navigation technology is an important symbol of modernization, which has broadened the field of application of GPS and has become one of the greatest technological achievements of the 20th century.

Second, GPS technology in the monitoring of earthquake and crust movement in the application ?

The application of GPS technology is extremely extensive. In recent years, GPS has become an inestimable role in determining Earth's rotation parameters from improving observation accuracy to improving time resolution, compared to VLBI or SLR. The establishment of GPS in the earth reference system has the effect of space-time encryption and resolution enhancement

The accuracy of the 3D geocentric coordinates relative to the Earth reference frame on the global scale obtained by GPS global data has reached centimeters. The accuracy of the geodetic height determined by studying the sea level changes using GPS positioning can also reach centimeter-level accuracy.

The GPS receiver is placed on the aircraft (aircraft, spacecraft, satellite, etc.) to determine the three-dimensional position and flight attitude. In particular, it is a GPS automatic navigation system and management dispatch system for various land, sea and air transportation vehicles, launch of low-orbit communication satellites, satellite global navigation established, and positioning

The three-in-one system of communications has reduced the entire world to a new electronic global village. In addition to traditional measurement and military applications, GPS meteorology and GPS are used in the development of marine resources, tropical forests, fishing, grazing, tourism, adventure, and various disaster prevention and reduction projects.

High-precision GPS technology has become an important means for monitoring volcanic earthquakes, tectonic earthquakes, and global plate movements in major countries and regions in the world, especially in the plate boundary areas. ?

There are 200 GPS reference stations around the world, and it is planned to encrypt GPS monitoring networks in about 25 areas of the plate boundary and global known tectonic activity areas to achieve automatic monitoring of global crust movement. In addition, together with the regional networks of various countries, the main research content is:

· To study the relative motion between the global plates; to monitor the structural deformations at the edge and inside of the plate; to determine the scale and movement rate of the blocks at different scales.

• Determine the area displacement field, velocity field, and strain field. ?

Geodynamics is based on the overall movement of the Earth. The dynamic processes of the interior and surface of the earth are used to explore its dynamic evolution process, and its driving mechanism is sought. The basic problem is to study the deformation and deformation mechanism of the earth. ?

The eastern part of the Chinese mainland was affected by the subduction and reduction of the Western Pacific Ocean-type plate, resulting in a series of continental marginal sea extension and fault depression basins related to the post-arc expansion; and the western and southwestern structures subjected to the collision between the Indian plate and the Qinghai-Tibet block. Effects, forming epochs of different geological periods

Structural belt. Modern crustal movements are characterized by the rapid uplift of the Qinghai-Tibet Plateau and the strong changes in strike-slip or reverse-sliding along the giant activity belt. According to limited observations, its horizontal movement rate is as high as 1-4 cm per year and the vertical movement rate is 1 cm per year. This shows that there is a contemporary section

The two most representative boundaries of the structural doctrine, namely land-continent crust collisions and oceanic continental crust subduction boundaries, have both major global tectonic significance and unique evolutionary characteristics. The types of modern crust movements here are diverse, complex in nature, clear in appearance, and globally dynamic.

The research field has an important special status. ?

The concept of plate tectonics has led to a major revolution in geosciences. Whether or not the inter-panel structure and plate movement theory can be established or accepted is supported by the latest direct measurement results of the global plate movement. In addition, the dynamics of plate motion, the complexity of plate and plate edge movements

The fine description and other aspects need to be further measured to improve. ?

Therefore, regardless of the geodynamics, plate movement or uplift of the Tibetan Plateau, the use of high-precision, high-temporal-spatial-resolution, dynamic real-time quantitative observation techniques to establish a unified national observing network that conforms to the actual geodynamic foundation is imperative. . ?