Traditional users, such as geodesy and mapping applications, were among the earliest to adopt GNSS technology and have achieved great success by creating a wide variety of application models and data processing methods in use, still up to now A fairly large market segment. Measurement requirements are high precision, centimeter level positioning is already very mature, for manufacturers, power consumption and physical size requirements is the most important. And users of cartography applications demand more than just location, but also the course and other parameters of cameras or sensors that work with the receiver.
Once accuracy issues have eased, the issue of ubiquitous availability is clearly highlighted. Because GNSS devices do not always stay open and many applications require precise positioning under many challenging environmental conditions, GNSS is a backup swap technology with GNSS-like navigation technologies. These new users may be downtown, rural areas, mines, and may also be on the ground, in the air, location accuracy is only part of their needs. From this we can see that more needs, such as the integrity monitoring of real-time quality control and positioning solutions, become more and more important as the accuracy is met.
The new user needs are not a single positioning, but rather the space-time dynamic environment experienced by the navigation application, often in an automatic or semi-automatic situation. Must keep track of all the visible GNSS signals, each code includes tracking each satellite signal generation subsystem (pseudorange), carrier phase and Doppler measurements, a plurality of global and regional systems with a plurality of system frequency signals, generated The amount of data is quite large, and these measurements eventually achieve positioning solutions, ranging from code positioning to real-time dynamics (RTK) up to Precise Point Positioning (PPP), which need to be implemented with different positioning algorithms. The results of tracking all signals, then use the positioning engine from a large number of inputs, the receiver needs to promote the needs of batch processing and storage capabilities, which all contribute to increasing the physical size of the receiver size, price and power, and just expect users The opposite.