source:truck tracking webfleet solutions release time:2024-03-04 Hits: Popular:realtime gps tracker online
Roughly speaking, the ground coordinates and their conventional geographic features (i.e. spatial resection) are obtained by measuring the distance from an in orbit satellite (which determines it to be a known data) to a ground point. Because the position variables in the equation include XYZ and clock deviation T, the number of accepted satellites must be greater than or equal to 4.
In the positioning process, there are two methods to obtain the pseudorange (i.e. the distance with errors) from the satellite to the ground: 1. ranging code; 2. Carrier phase.
1. The ranging code belongs to pseudo-random noise code, which is a binary code sequence. The key is to measure the time difference between the transmitted signal and the received signal, which is obtained through atomic clock synchronization. Due to the refraction of the carrier wave carrying the ranging code when passing through the current layer, ionospheric errors are generated. Solar activity has an impact on the total electron density of the ionosphere, so it can also have an impact on GPS positioning. According to our teacher, there was a period of time when GPS could not be used due to solar flares.
2. If a satellite S emits a carrier model (which is used as a ranging signal here), the signal propagates to various places. At a certain moment, the phase of the signal at receiver R is ψ R. At satellite S ψ S. Note that what is mentioned here is ψ R, ψ S is the complete carrier phase, including the entire number of cycles, calculated from the same starting point. The distance between the satellite and the ground ρ=λ ( ψ S- ψ R) .
As can be seen from the above, if the corresponding phase number is inaccurate or cannot be directly obtained, then GPS will not work. In addition, during the measurement process, if the altitude angle of the satellite (the angle between the satellite and the ground level) is too small, it is also impossible to perform measurement and positioning. In summary, during the measurement period, there were no four or more satellites, the altitude angle was too small, there were obstructions such as high-rise buildings, intense solar activity, the position and operation of satellites in orbit, and the condition of the receiver may all cause GPS to be unable to locate or inaccurate.
Read recommendations:
A brief introduction to several different recorders by the supplier of the driving recorder.gps trac
How to solve the problem of inaccurate car GPS positioner?plug & play Obd gps tracker Production
Last article:Gps speed limiter.Working principle of GPS Bluetooth positioning technology
Next article:GPS Tracker.Application of GPS module
Related Information
4G GPS Tracker Solution
2023-04-23gps tracker no monthly fee
2023-03-16car gps tracker sales
2023-04-23fleet gps trackers
2023-03-16cantrack g05
2023-04-23vehicle gps tracker webfleet solutions
2023-03-16Magnetic gps tracker Vendor
2023-04-23trailer gps tracker
2023-04-114G GPS Tracker Production
2023-04-23pet gps tracker cat manufacture
2023-03-16C32 (9~90V E-bikes/Motorcycle/Car gps tracker)
2022-06-21GF20-Mini Magnet GPS Tracker
2022-06-21GF70L-Solar Magnetic Asset GPS Tracker
2023-10-07P60L Personal gps tracker
2022-06-21TK08AL- RFID Car GPS Tracker
2023-10-07What can GPS do besides navigation?
2022-08-25GPS Tracker Features and Benefits
2022-07-09Everyone knows about gps trackers, but what is LBS?
2022-09-15GPS Modules and Products
2022-08-19satellite-satellite tracking technology
2022-07-28SMS command for car GPS Beidou recorder
2023-09-04GPS drift
2022-12-05GPS addressing locator
2023-07-27mini gps tracker.Installation and usage methods for automotive GPS locators
2023-11-08How to choose the installation location of the wireless GPS positioner?4G GPS Tracker for vehicles
2023-03-22International requirements aircraft must be equipped with GPS
2022-09-06GPS signal in the air
2022-11-08GPS Earth Coordinate Series Brief description
2023-02-10Key Points for GPS Purchase.gps tracker no monthly fee wholesale
2023-08-10What are the GPS positioning methods
2022-09-22