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Precise absolute time transfer from satellite systems

An absolute time, satellite technology, applied in the field of satellite-based time transfer and navigation technology, which can solve problems such as expensive, inertial navigation system drift, and failure to meet user expectations.

Active Publication Date: 2018-02-23
THE BOEING CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, inertial navigation systems drift and are expensive
Beacons require dedicated, fixed resources that are expensive and not standardized, and thus have only proprietary uses, and high-sensitivity GPS systems often fail to meet user expectations due to weak GPS signals in indoor environments

Method used

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  • Precise absolute time transfer from satellite systems
  • Precise absolute time transfer from satellite systems
  • Precise absolute time transfer from satellite systems

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Embodiment Construction

[0026] According to various embodiments discussed herein, the system includes satellites, such as Low Earth Orbit (LEO) satellites, which can be used to augment receiver units (also referred to as receivers), such as cellular phones or other compact devices, such that they Operates even in heavily attenuated, shadowed or interfering environments. According to one or more embodiments herein, a navigation system can address current problems with receiving units due to fundamentally weak signals received from existing sources, such as Global Positioning System (GPS) satellites.

[0027] Signals from certain satellites, such as communication satellites, are generally stronger than signals from other existing positioning systems such as GPS. One such satellite is the Iridium constellation of low-Earth orbiting satellites. For example, a receiver unit configured to operate with signals received from a LEO satellite, such as Iridium, may operate at a signal level at the antenna of t...

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Abstract

Various techniques are provided for obtaining precise absolute time using satellite systems. In one example, a method for communicating precise absolute time from a satellite to a device includes receiving data from a message channel, wherein the data has a frame structure. The method also includes using the data to identify the satellite and the location of the satellite, using the satellite identification and the location to calibrate a time of transmission of a signal, and using the data as a time reference to calibrate a receiver clock to The frame structure. The method also includes receiving a precise time signal from the satellite using the receiver clock calibrated to the frame structure, wherein the precise time signal includes a periodically repeating codeword. The method also includes determining a timing phase of the codeword, and using the timing phase to determine a precise absolute time.

Description

technical field [0001] The present invention relates generally to time transfer and, more particularly, to satellite-based time transfer and navigation techniques. Background technique [0002] Existing navigation and timing signals provided by various existing satellite navigation systems often fail to provide satisfactory system performance. In particular, the signal power, bandwidth, and geometric leverage of these navigation and timing signals are insufficient to meet the needs of many demanding application scenarios. [0003] In many cases, existing navigation and timing solutions, such as those based on Global Positioning System (GPS) signals, may not be available to navigation users. Typically, a GPS receiver must receive at least four simultaneous ranging sources to allow three-dimensional positioning and precise time transfer. Nonetheless, GPS signals often provide insufficient low signal power or geometry to easily penetrate urban canyons or the walls of building...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S19/27G01S19/13
CPCG01S19/256G04R20/04G04R20/06
Inventor G·M·格特D·A·威兰
Owner THE BOEING CO