source:truck tracking webfleet solutions release time:2022-12-10 Hits: Popular:realtime gps tracker online
In order to obtain the receiver's position, when the receiver clock is strictly synchronized with the GPS standard, the position to be solved is three unknown variables and requires three independent equations to solve. However, in practice, it is difficult to strictly synchronize the receiver clock with the GPS standard time. In this way, we regard the receiver time and the GPS standard time deviation as an unknown variable. In this way, four independent equations are required to solve, that is, four observation satellites are required. Figure 1 Schematic diagram of GPS positioning (time deviation is not considered) assumes that the receiver position is (xu, yu, zu) and the receiver time deviation is tu, then the distance deviation caused by time deviation is the pseudo range observation value obtained. We can get simultaneous equation (5) to linearize the above equation, that is, Taylor series expansion is performed at the real location (xu, yu, zu), ignoring the higher order terms, and we can get (6), where equation (6) is the actually calculated iteration formula, and the iteration termination condition is that the change of the real location (xu, yu, zu) is less than a certain threshold, which can be used as the basis for adjusting the receiver time deviation, The matrix method is generally used for calculation. To solve this equation, we also need to know the positions of the four satellites (xj, yj, zj) in advance, and the satellite positions can be obtained from the ephemeris of the satellite. The GPS satellite ephemeris gives the ephemeris of the star, according to which the real-time position of the satellite can be calculated. In addition, the ephemeris gives the parameters to eliminate satellite clock error, relativity error, earth rotation error, ionosphere and troposphere error. The satellite position calculated according to these parameters can basically eliminate the above errors. The basic steps to solve the satellite position are: calculate the average angular velocity of satellite operation ① calculate the domestication time; ② Calculate the angle of the horizontal approach point at the observation time; ③ Calculate the near point angle; ④ Calculate the vector diameter of the satellite; ⑤ Calculate the true perigee angle of the satellite; ⑥ Calculate the angular distance of ascending intersection point; ⑦ Calculate the perturbation correction term; ⑧ Calculate the elevation angle, satellite vector diameter and orbit inclination angle corrected by perturbation; ⑨ Calculate the longitude of the ascending intersection point at the observation time; ⑩ Calculate the position of the satellite in the geocentric coordinate system. It is particularly worth pointing out that formula (7) should be used to calculate the satellite true perigee angle Vk, where e is the eccentricity and Ek is the satellite perigee angle. Some reference books have incorrect formulas for calculating the true perigee angle of the satellite, which will lead to the quadrant ambiguity of the true perigee angle of the satellite, and thus the correct position of the satellite cannot be obtained. After the above calculation, the errors are further eliminated according to the error parameters broadcast in the ephemeris. In this way, we can get a complete navigation and positioning solution process using GPS ephemeris
Read recommendations:
3 Years Disposable Asset GPS Tracker
Buses equipped with GPS for private use should be held accountable
Last article:GPS positioning function
Next article:What is the Galileo Plan?
Related Information
fleet gps trackers price
2023-04-23simple gps tracking custom
2023-04-234G GPS Tracker Factory
2023-04-23Portable car gps systems
2023-03-16GPS Trackers sales
2023-04-11fleet gps tracking wholesale
2023-04-23real-time gps tracking wholesaler
2023-04-23real-time gps tracking Factory
2023-04-23Pet GPS Tracker manufacturer
2023-03-16fleet management software webfleet solutions
2023-03-16G200NY -Cow/Camel GPS Tracker
2022-06-213 Years Disposable Asset GPS Tracker
2024-10-17G200(L) -Magnet GPS Tracker
2022-06-20G183 serials -JOBD GPS Tracker
2022-09-06G08L - 4inch Smart Tail Light Tracker
2022-06-20GPS knowledge base: what is RTK technology
2022-12-02Micro Tracking Locator
2022-09-21Portable Wireless GPS Tracker
2022-09-20What are the GPS satellites?gps tracker for trailer manufacturer
2023-04-21The core chip is one of the key parts of a GPS system
2022-10-15Actual demand and development trend of GPS market
2022-12-22Compared with the difference between vehicle GPS positioning system and mobile phone navigation.real
2023-04-25Where is the car GPS positioner?
2023-02-22This product focuses on humanized design to minimize the false alarm rate.
2022-12-15Are the mortgage loan cars installed in the car GPS terminal?mileage tracking webfleet solutions
2023-03-14GPS/GPRS power-off terminal
2022-12-20Some usage suggestions from the manufacturer of the driving recorder for everyone.gps vehicle tracke
2023-06-26Vehicle positioning system.gps tracker app manufacturer
2023-07-04The concept and composition of the car positioning terminal.gps tracker no monthly fee wholesaler
2023-04-04Considerations for choosing a gps tracker
2022-09-13