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:
TK100B- Accurate Pro version GT06/TK100
6 GPS/GPRS/CDMA antenna installation instructions.gps vehicle tracker Production
Last article:GPS positioning function
Next article:What is the Galileo Plan?
Related Information
4G GPS Tracker for vehicles
2023-04-11personal gps tracker distributors
2023-03-16apple airtags
2023-03-16simple gps tracking Solution
2023-04-234G GPS Tracker company
2023-04-23Dog gps tracker Production
2023-04-23pet gps tracker cat
2023-04-11pet gps tracker cat price
2023-03-16gps tracker for kids supplier
2023-04-23Dog gps tracker wholesaler
2023-04-23P60L Personal gps tracker
2025-07-1110000mAh Magnetic Asset GPS Tracker
2025-04-08G06L
2022-06-21G07L 4G GPS Tracker
2022-09-06G02M Pet Tracker
2022-06-19This section describes GPS working modes
2022-11-01What are the main parts of the receiver of the car GPS
2023-06-15Factors related to GPS satellites
2022-10-10The role of GPS satellite.GPS Tracker for vehicles manufacture
2023-04-21The concept of static drift of the car GPS positioner and cause.plug & play Obd gps tracker manu
2023-03-25GPS drift
2022-12-05The running track of the gps tracker is an important auxiliary evidence
2022-09-16GPS death phenomenon
2022-09-14Why does the GPS module take a long time to obtain positioning data after being turned on?mini gps t
2023-07-11GPS Application field
2022-10-20GPS classification and usage.gps vehicle tracker company
2023-07-14Why does China Beidou dare to compete with the first tier GPS team?
2022-11-17How to help the GPS positioner help take care of the elderly and children?Car gps Solution
2023-02-18Gps speed limiter.C/S version client vehicle management and scheduling system
2023-11-11Car GPS has two main uses.Car gps tracking wholesaler
2023-07-20