Method and apparatus for providing an integrated communications, navigation and surveillance satellite system

Abstract

A system provides integrated communications, navigation and surveillance capabilities. The system includes a space segment having a plurality of satellites broadcasting multiple navigation signals and a communication signal. A user segment includes a user device that is operable to broadcast communication signals to the satellites and of using the navigation signals broadcast by the satellites to determine a position of the user device. The satellites are operable to receive the communication signals from the user device and determine a position of the user device based upon the received communication signals. The satellites broadcast one of the navigation signals and the communication signal at a same frequency. The navigation signal acts as a pilot tone for the system to acquire and synchronize the user device with the system.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 09 / 972,355 filed on Oct. 5, 2001, and now issued as U.S. Pat. No. _____, the disclosure of which is incorporated herein by reference.FIELD OF THE INVENTION [0002] The present invention relates to a global integrated communications, navigation and surveillance satellite system. BACKGROUND OF THE INVENTION [0003] Current satellite systems provide positioning and time information by broadcasting navigation signals to properly equipped users. For example, a the US Global Positioning System (GPS) consists of 24 satellites orbiting the earth twice a day at an altitude of approximately twelve thousand miles, as well as a network of ground stations to monitor and manage the satellite constellation. The GPS satellites transmit continuous Navigation Data and Ranging (NDR) information 24 hours a day toward the earth. A GPS receiver which properly decodes, tracks and interprets ...

AI Technical Summary

Benefits of technology

The GCNS system provides enhanced accuracy and robustness for navigation and surveillance, reducing costs by eliminating the need for extensive ground-based networks and enabling self-monitoring and correction of errors, while supporting precise positioning and interference detection.

Problems solved by technology

The current GPS receivers and the GPS satellites are not capable of two-way commuication with each other.

Consequently much of the capability of the GPS (i.e. the Precise Positioning Service or PPS) is not available to Civil users.

Furthermore, even the GPS SPS service which is available to the civil community was not designed with adequate integrity, reliability or availability necessary to support safety of life civil applications.

Furthermore, the SPS includes a relatively low power signal on only a single frequency and is consequently vulnerable to intentional or unintentional interference.

These problems with the integrity and robustness of the civil GPS services are well known in the art.

The ionospheric induced delay in the reception of the SPS signals limits the accuracy of the determination of the position of the GPS receiver and is the largest location dependent error source in the calculation of the position of the GPS receiver.

Therefore, the use of the GPS SPS signals to compute a position of the GPS receiver has limited accuracy and cannot be used for applications requiring a high degree of precision in the determination of the position of the GPS receiver.

Hence SBAS does little or nothing to address the robustness concerns of GPS.

However, the complexity and cost of such a system makes it impractical for most States or regions to consider employing such a system.

Particularly, the cost of the ground based telecommunications network can be very significant.

Also, in order to get good sampling of the ionosphere and a more accurate grid of the errors introduced by the ionosphere, a large number of reference stations are required, which in turn increases the cost of connecting all the reference stations with the ground based telecommunication networks.

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