Frequency estimator for aeronautical communication

Patent metadata

Field	Value
Publication number	US-9859958-B2
Application number	US-201514699353-A
Country	US
Kind code	B2
Filing date	Apr 29, 2015
Priority date	Apr 30, 2014
Publication date	Jan 2, 2018
Grant date	Jan 2, 2018

Abstract

A method and device are provided suited to estimating a frequency value for aeronautical communication between a first station and an airborne system moving in relation to the first station, the data being transmitted in the form of a succession of frames, a frame comprising at least one first header field of known data followed by one or more fields of unknown data, and having at least the following steps: Step 1: performance of a supervised correlation on the known data ( 300 ) of the header, and estimation of a first frequency range centered on a frequency ; Step 2: production of a blind correlation on at least all of the unknown data of a field of data, by looking for a correlation peak over the frequency range +/− , as determined in step 1, and by retaining of the frequency corresponding to the correlation peak.

First claim

The invention claimed is:

1. A method for estimating a frequency value for aeronautical communication between a first station and an airborne system moving in relation to the first station, data being transmitted in a form of a succession of frames, a frame comprising at least one first header field of known data followed by one or more fields of unknown data, at least one of the first station and the airborne system comprising a radiocommunication receiver, the method comprising at least the following steps being executed by the radiocommunication receiver:
Step 1: performance of a supervised correlation on the known data of the header by the radiocommunication receiver, and estimation of a first frequency range centered on an estimated frequency having a precision of +/− by the radiocommunication receiver, and
Step 2: production of a blind correlation on at least all of the unknown data of a field of data by the radiocommunication receiver, by looking for a correlation peak over the range centered on the frequency +/− , as determined in step 1, and by retaining the frequency corresponding to the correlation peak, said retained frequency being used for transmitting data between the first station and the airborne system,
wherein the frame is modulated with a modulation by change of phase comprising a field of pilots ( 302 1 ) that is arranged before a field of data and in that it has at least the following steps:
Step 1: performance of a supervised correlation by Fourier transform on the field of pilots ( 302 1 ), in order to obtain a range centered on an estimated frequency having a precision of +/− , and
Step 2: use of the symbols of the modulated frame and use of the Fourier transform from the modulated symbols of the short frame, corresponding to the range centered on the frequency +/− defined in step 1, determination of the frequency corresponding to the maximum of the norm of the Fourier transform and deduction of the value of the Doppler effect therefrom.

2. The method according to claim 1 , wherein the frame is a frame of DVB-S2 type using a DVB-S2 QPSK type modulation t.

3. The method according to claim 2 , wherein it comprises at least the following steps:
Step 1: estimation of the frequency ,

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Assignees

• Thales Sa

Inventors

• Hirsch Antonin
• Arnaud Mathieu
• Rosset Pierre-Alexandre
• Zouitane Khaled

Classifications

• H04W56/0035 Primary

  detecting errors in frequency or phase · CPC title

• H04B7/18513

  Transmission in a satellite or space-based system · CPC title

• H04L25/0238

  using blind estimation · CPC title

• H04B7/01 Primary

  Reducing phase shift · CPC title

• H04B7/18506

  Communications with or from aircraft, i.e. aeronautical mobile service · CPC title