Space based or aeronautical augmentation system with simplified management of its navigation messages

Patent metadata

Field	Value
Publication number	US-10613230-B2
Application number	US-201615183637-A
Country	US
Kind code	B2
Filing date	Jun 15, 2016
Priority date	Jun 17, 2015
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A space based or aeronautical augmentation system comprises space based or aeronautical broadcasting means adapted for retransmitting streams of messages NOF m.j transmitted by broadcasting ground stations, one or more observation and reception ground stations for signals transmitted by the satellites of the GNSS global navigation system and by the N space based or aeronautical broadcasting means. The space based or aeronautical augmentation system further comprises K computation centres, located on geographically remote sites, and each configured to formulate i-th streams of messages NOF i.j, j varying from 1 to j, such that all the data streams NOF i.j, independently of the computation centre CPF#i which formulate them, comprises one and the same sequence of types MTs of messages, which is independent of the space based or aeronautical broadcasting means.

First claim

The invention claimed is:

1. A space based or aeronautical augmentation system, configured for improving a precision and reliability of data delivered by a global satellite navigation system comprising:
a space based or aeronautical segment having a first integer number N, greater than or equal to two, of space based or aeronautical broadcasting means, furnished respectively with transmit/receive means configured for transmitting data received respectively from associated broadcasting ground stations, destined for one and a same predetermined geographical zone;
a ground infrastructure segment comprising:
N transmission ground stations, associated respectively with the N space based or aeronautical broadcasting means so as to transmit navigation data to the N space based or aeronautical broadcasting means and numbered respectively by a first integer index j varying from 1 to N, and
at least one observation and reception ground station for signals transmitted by at least one satellite of the global satellite navigation system and by the N space based or aeronautical broadcasting means,

a second number K, greater than or equal to 2, of computation centres, made mutually redundant, numbered respectively by a second index i varying from 1 to K, and configured to compute, on a basis of the signals transmitted by the observation and reception ground station or stations, streams or sequences of navigation messages NOF i.j, i varying from 1 to K and j varying from 1 to N, that are ready to be transmitted respectively according to the index j to N broadcasting ground stations;
at least two of the K computation centres being located respectively on geographically mutually remote sites linked by a first communications network,
the at least one reception and observation ground station, the N broadcasting ground stations being connected to the K computation centres respectively by a second communications network and a third communications network,
the space based augmentation system (SBAS) being wherein:
the K computation centres are each configured to formulate a string of N i-th parallel streams of messages NOF i.j, j varying from 1 to N, such that the string of all the streams of messages NOF i.j, independently of the computation centre which formulate them, comprises one and the same temporal sequence of types of messages MTs (Message Types) and which is independent of the space based or aeronautical broadcasting means, and
the types of messages MTs of the sequence lying in a predetermined set {Tm} of types of navigation message contents Tm.

2. The space based or aeronautical augmentation system according to claim 1 , wherein the K computation centres are configured so that at each current computation cycle of the messages, a single computation centre, taken from among the K computation centres, is selected and authorized to transmit to the broadcasting ground stations the current messages NOF m.j, m denoting the index of the computation centre selected at the current computation cycle and the selected computation centre being considered to be a master computation centre of the augmentation system during the said current computation cycle.

3. The space based or aeronautical augmentation system according to claim 1 , wherein each computation centre CPF#i is configured so that contents of N data streams NOF i.j that the said computation centre CPF#i generates differ only by the content of messages,
wherein the content of messages relates to predicted or recently measured trajectories of the N space based or aeronautical broadcasting means.

4. The space based augmentation system according to claim 1 , wherein
each computation centre CPF#i is configured so that the contents of two data streams NOF i.j 1 , NOF i.j 2 , that the said computation centre CPF#i formulates in parallel and which are intended for two different space based or aeronautical broadcasting means (j 1 ≠j 2 ), which differ only by a content of the messages of a first type having content relating to ephemerides data of one or more space based or aeronautical broadcasting means, and/or by a content of the messages of a second type having content relating to navigation data of a space based or aeronautical broadcasting means that are more precise than the ephemerides data provided by the messages of the first type.

5. The space based or aeronautical augmentation system according to claim 4 , wherein the messages are defined by an international standards document: RTCA MOPS DO-229-D, entitled “Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation Equipment”,
wherein the first type of message is denoted as “MT17”; and
wherein the second type of message is denoted as “MT9”.

6. The space based or aeronautical augmentation system according to claim 1 , wherein each computation centre is configured so that all the data streams that it generates share one and the same algorithm, implemented for processing of GNSS and SBAS data received by the at least one observation station and for the formulation of all the streams of the data entailing one and the same scheduling of types of messages MTs and the same contents of a majority of the messages from which majority are excluded messages of a first type of message MT relating to ephemerides data of one or more space based or aeronautical broadcasting means, and/or messages of a second type of message MT relating to navigation data of a space based or aeronautical broadcasting means that are more precise than the ephemerides data provided by the messages of the first type of message.

7. The space based or aeronautical augmentation system according claim 1 , wherein the space based or aeronautical broadcasting means lie in the set composed of GEO geostationary satellites, HEO satellites, MEO satellites, LEO satellites, drones, balloons and aircraft.

8. The space based or aeronautical augmentation system according to claim 1 , wherein the second number K of computation centres is equal to 2; and for i varying from 1 to 2, each i-th computation centre CPF# i comprises:
an i-th radioelectric receiver, located on the i-th site associated with the i-th computation centre, and
an i-th unit for authorizing the i-th computation centre to transmit N data streams NOF i.j according to the index j to the N broadcasting ground stations; and
each i-th authorization unit from among the two authorization units being configured to
at each computation cycle,
determine a mode of activity of the i-th computation centre in the SBAS system from among a master mode and a backup mode,
the master mode authorizing the single computation centre placed in this mode from among the two computation centres to transmit the data streams NOF m.j generated to the N broadcasting ground stations NLES#j, j varying from 1 to N,
the backup mode prohibiting the computation centre placed in this mode from transmitting its data streams to the broadcasting ground stations but authorizing the said computation centre to toggle to master mode when a persistent fault in the computation centre currently in master mode has been detected;
the mode of activity of the i-th computation centre being determined as a function
of the knowledge of the computation centre currently in master mode and in the process of transmitting towards the broadcasting stations;
of the regular knowledge of the operating states in terms of absence or existence of faults with the computation centres of the remote sites and of their mode of activity; and
of the quality of reception of the messages transmitted to the broadcasting stations; and
of the quality of the messages actually transmitted by the space based or aeronautical broadcasting means and received by the radioelectric recei

Assignees

• Thales Sa

Inventors

• Chambre Eric
• Benassy Foch Céline
• Charlot Bernard

Classifications

• G01S19/08

  providing integrity information, e.g. health of satellites or quality of ephemeris data · CPC title

• G01S19/45

  by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement · CPC title

• G01S19/07 Primary

  providing data for correcting measured positioning data, e.g. DGPS [differential GPS] or ionosphere corrections · CPC title

• G01S19/03

  Cooperating elements; Interaction or communication between different cooperating elements or between cooperating elements and receivers · CPC title

• G01S19/02 Primary

  Details of the space or ground control segments · CPC title