source:truck tracking webfleet solutions release time:2022-08-18 Hits: Popular:realtime gps tracker online
At present, the GPS receiver circuit in practical application is generally composed of four parts: antenna unit, radio frequency unit, communication unit and calculation unit. Based on the analysis of the composition of GPS satellite signals, this paper gives the principle and application of the radio frequency front-end GP2010.
1. Composition of GPS satellite signals
The GPS satellite signal is synthesized by typical code division multiple access (CDMA) modulation technology, and its complete signal mainly includes three components: carrier, pseudo-random code and data code. The signal carrier is in the L-band, and the center frequencies of the two carriers are denoted as L1 and L2, respectively. The satellite signal reference clock frequency f0 is 10.23MHz, and the center frequency of the signal carrier L1 is 154 times the frequency of f0, namely:
fL1=154×f0=1575.42MHz (1)
Its wavelength λ1=19.03cm; the center frequency of the signal carrier L2 is 120 times the frequency of f0, namely:
fL2=120×f0=1227.60MHz (2)
2. Analysis of GPS Antenna Principle
Its wavelength λ2=24.42cm. The frequency difference between the two carriers is 347.82MHz, which is about 28.3% of L2. The carrier frequency is selected in this way to measure or eliminate the propagation delay error caused by the ionospheric effect when the navigation signal propagates from the GPS satellite to the receiver. Pseudo-random noise code (PRN), that is, ranging code, mainly includes two kinds of fine ranging code (P code) and coarse ranging code (C/A code). The code rate of the P code is 10.23MHz, and the code rate of the C/A code is 1.023MHz. The data code is the navigation and positioning data sent by the GPS satellite to the user receiver in binary form. It is also called the navigation message or D code. It mainly includes satellite calendar, satellite clock correction, ionospheric delay correction, working status information, and C/A code conversion. To capture the information of the P code and the general ephemeris of all satellites; the total message consists of 1500 bits, divided into 5 subframes, each subframe transmits 10 words within 6s, each word 30 bits, a total of 300 bits, so the data The baud rate of the code is 50bps.
Read recommendations:
Main Errors and Elimination Algorithms in GPS Positioning
Main Errors in GPS Positioning and Their Elimination Algorithm
Last article:Handheld GPS Device
Next article:GPS helps you avoid electronic eyes
Related Information
car gps tracker custom
2023-04-11Dog gps tracker
2023-04-23cat gps tracker wholesaler
2023-04-234G LTE gps tracker
2023-04-11Magnetic gps tracker wholesaler
2023-03-16real-time gps tracking Vendor
2023-04-23fleet gps tracking Solution
2023-04-23simple gps tracking Factory
2023-04-23fleet gps tracking
2023-04-11Dog gps tracker Processing
2023-04-23G07L 4G GPS Tracker
2022-09-06TK103B
2022-06-20GF30 Magnet GPS tracker with Voice listen
2022-06-21G02M Pet Tracker
2022-06-19VSL100 GPS Speed Limiter, Speed Governor
2022-06-19When the car stops mobilizing, will the car GPS positioner consume power?
2023-02-14GPS forward direction (heading).gps tracker for bike wholesale
2023-06-10GPS Processor (GPSPU)
2022-09-05GPS wireless communication transmission
2023-02-01GPS cannot search for satellite signal problems.plug & play Obd gps tracker distributors
2023-04-12Car GPS.obd-II port gps tracker Processing
2023-05-13System Composition of GPS PPS Clock Synchronization Technology
2022-11-11GPS position difference principle
2022-10-11What are the precautions for installing the car GPS positioner
2023-02-25GPS power consumption and noise
2022-09-01GPS monitoring system develops rapidly.Hidden GPS Trackers Manufacturing
2023-04-18Preparation before using GPS
2022-12-28A-GPS scheme is favored.gps tracker with magnet Processing
2023-05-23The core of third-generation chips.vehicle gps tracker Solution
2023-07-06GPS positioning car driving recorder driver ID IC card.Gps speed limiter
2023-09-05