truck tracking webfleet solutions

Home > NEWS > Other information > truck tracking webfleet solutions

Company News

Industry News

GPS Global Positioning System

source:truck tracking webfleet solutions release time:2022-08-12 Hits:     Popular:realtime gps tracker online

  

  Due to the limitations of the Meridian satellite system, in 1973 the United States began to plan to develop a new navigation and positioning system, the GPS positioning system. After 20 years of hard work, the system was initially built and put into use in 1993. At this time, the system has a total of It consists of 24 satellites, including Block I experimental satellites and Block II, Block IIA working satellites. After the completion of the GPS navigation constellation, the use of C/A codes for navigation and positioning can also achieve high positioning accuracy. Therefore, considering the huge use of GPS in the military field, in order to prevent the enemy from using GPS to endanger the national security of the United States, the United States defense The Ministry stipulates that the SA technology should be implemented on all working satellites, that is, it is considered to reduce the accuracy of the navigation system. There are two specific technical means:

  1. A technology that artificially adds errors to the broadcast ephemeris of the satellite to reduce the accuracy of the satellite ephemeris.

  2. Technology, consciously adding a pseudo-random process rapid change to the satellite clock frequency.

  On the other hand, in order to prevent the enemy from electronically spoofing and electronically jamming GPS satellite signals, the US Department of Defense has implemented the AS policy. The specific method is to add a strictly confidential W code to the GPS P code. After modulo two addition, a completely secret Y code is generated. Although the AS policy is a defensive measure, it also limits the possibility of unlicensed users to use the Y code, so it is impossible to obtain high-precision ranging codes, which greatly reduces the navigation accuracy.

  Later, the GLONASS satellite navigation system managed by Russia announced that it would not implement the SA policy, so the positioning accuracy of its navigation system was much higher than that of the GPS system using the SA policy. Announced in 2009 to suspend the implementation of SA.

  As satellite navigation systems play an increasingly important role in various fields of military and civilian use. However, the original GPS system has many shortcomings, such as: 1. It is difficult to receive satellite signals in hidden areas; 2. The energy of C/A code and P code is concentrated near the center frequency and is prone to human interference; 3. L2 carrier Ranging code is not modulated on the device, which makes it impossible for ordinary users to perform dual-frequency ionospheric delay correction, which affects positioning accuracy. Therefore, the C/A code was modulated on the L2 carrier of the navigation satellites of the subsequent Block IIR-M and Block IIF models, and later changed to the L2C code, so that civilian users can also use dual-frequency observation to improve positioning accuracy. Later, the L5 signal was added to the GPS navigation satellite after Block IIF, so that tri-frequency positioning can be used for non-military users.


Read recommendations:

fleet solution webfleet solutions

gps vehicle tracker manufacture

3000mAh Magnet Asset GPS Tracker

GPS mobile engineering mode.gps tracker device wholesale

When the car stops mobilizing, will the car GPS positioner consume power?

Last article:GPS positioning technology

Next article:Composition of GPS system

Related Information

Dog gps tracker supplier

2023-04-23

Magnetic gps tracker

2023-04-11

Pet GPS Tracker custom

2023-04-11

fleet gps tracking supplier

2023-04-23

simple gps tracking manufacture

2023-04-23

Gps speed limiter wholesaler

2023-04-23

Pet GPS Tracker wholesale

2023-03-16

simple gps tracking

2023-04-11

vehicle gps tracker wholesale

2023-04-23

Cantrack TK100

2023-04-11

Mini Sized GPS Tracker PCBA

2022-06-17

G02M Pet Tracker

2022-06-19

G05N Vehicle Tracker

2022-06-21

G900LM J16-4G Car GPS Tracker

2025-03-25

GF30 Magnet GPS tracker with Voice listen

2022-06-21

Differences between GPS cold start and hot start

2022-12-01

Two major trends of GPS navigators

2022-08-10

The following aspects mainly affect the performance of GPS antenna

2022-11-12

This section describes GPS working modes

2022-11-01

GPS and National Security

2022-09-26

6 GPS/GPRS/CDMA antenna installation instructions.gps vehicle tracker Production

2023-08-02

Bring a GPS tracker and never be afraid of losing it again!

2022-09-15

Brief introduction to GPS principle

2022-12-13

GPS positioning monitoring system

2022-12-06

Beidou 4G wiring GPS positioner installation precautions.realtime gps tracker online Processing

2023-03-28

How to judge the quality of a car GPS locator?vehicle gps tracker webfleet solutions

2023-03-21

Application place for GPS technology

2022-10-10

What is the Beidou GPS positioner?gps tracker no monthly fee distributors

2023-03-28

The application process of GPS positioner in car loans is as follows.vehicle gps tracker Manufacturi

2023-03-17

The difference between manufacturers compare the Beidou satellite navigation system and GPS navigati

2023-06-15