Device for exchanging radio signals provided with time markers for synchronizing clocks

• US 6,870,819 B1
• Filed: 10/22/1999
• Issued: 03/22/2005
• Est. Priority Date: 10/27/1998
• Status: Expired due to Fees

• Current Assignee: Thomson Csf Detexis
• Original Assignee: Thomson Csf Detexis
• Inventors: Potier, Thierry
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): Hyun, Soon D.
• Application Number:
  US09/422,944
• Time in Patent Office: 1,978 Days
• Field of Search: 370/507, 370/316, 370/324, 370/514, 370/509, 370/510, 370/512, 370/520, 370/515, 370/503, 370/350, 370/280, 375/367, 375/358
• US Class Current: 370/324
• CPC Class Codes: H04B 7/2125 Synchronisation

Abstract

Radio transmission of chronometric information. A device comprising an antenna (A1, A2) to which there are coupled on one hand a generator (G1, G2) generating a signal to be sent (e1, e2) and a reception processing circuit (C1, C2), capable of processing a received signal (r1, e2) where the signals exchanged have the same carrier frequency. Separate time segments are generated with successive random positions. Transmission is enabled only during these time segments, whilst reception is enabled only outside these segments, making it possible to use the time markers of the signals without any effect of recurrent masking of the reception signal by the transmission signal.

Claims

1. Apparatus for exchanging radio signals provided with time markers comprising radio transmission means having a generator to generate a transmission signal, comprising a carrier and a repetitive time marker, reception means having a reception processing circuit for processing a received signal, said received signal comprising a carrier and a repetitive time marker, the radio transmission and reception means transmitting and receiving, respectively, the same carrier frequency signal, and sequencing means to define separate time segments with substantially random successive positions to control the transmission and reception means enabling transmission only during said time segments, and enabling reception outside the segments, whereby the time markers may be processed without any recurrent effect of the transmission signal masking the reception of the received signal.

2. Apparatus according to claim 1, wherein the time segments have a random rate, centered around a mean rate.

3. Apparatus according to claim 1, wherein the sequencing means produce time segments, for controlling transmission and reception, to have substantially equivalent respective mean durations.

4. Apparatus according to claim 1, wherein the sequencing means are arranged to repetitively define each time segment and its random position in an interval of time.

5. Apparatus according to claim 4, wherein the time interval durations are predetermined whilst the time segments durations are random and less than the time interval durations.

6. Apparatus according to claim 5, wherein the duration of each said time segment is on average equal to approximately one half of that of the time interval.

7. Apparatus according to claim 1, wherein the time marker of received signal is linked to a pattern which can be discriminated by correlation.

8. Apparatus according to claim 7, wherein the time marker of the transmission signal is linked to another pattern which can be discriminated by correlation.

9. Apparatus according to claim 7, wherein said reception processing circuit is arranged to selectively distinguish by correlation and tracking the pattern linked to the time marker of said received signal and the pattern linked to the time marker of a second received signal.

10. Apparatus according to claim 9, wherein said second received signal corresponds to said transmission signal sent by the device and returned by the source of said received signal, whereby the time difference between the two time markers is obtained compensating for the instantaneous propagation time differences.

11. Apparatus according to claim 7, wherein the time marker of each signal is linked in frequency and phase to the carrier of this signal, and in that the reception processing circuit has a pattern tracking by correlation and a phase tracking on the carrier with a prior spectral analysis.

12. Apparatus according to claim 1, wherein said received signal is returned to a source producing said signal.

13. Apparatus according to claim 12, wherein the pattern of the returned signal is substantially equal to the pattern of said received signal.

14. Apparatus according to claim 13, wherein the signal generator is able to cooperate with the reception processing circuit in order to generate said signal to be returned which is equivalent to the signal received.

15. Apparatus according to claim 14, wherein the time markers of the return signal and of the signal to be sent are linked to distinct patterns, which can be discriminated by correlation.

16. Apparatus according to claim 7, wherein the carrier of each signal generated is modulated according to a chosen pulse shape, whose repletion is defined according to a pattern which can be discriminated by correlation of this signal.

17. Apparatus according to claim 16, wherein the carrier is modulated according to a substantially Gaussian pulse shape.

18. Apparatus according to claim 16, Wherein the pulses are substantially of the same chose duration and with substantially random respective time positions.

19. Apparatus according to claim 18, wherein the positions in time of two successive pulses are separated by a period less than a threshold value, and on average are separated by a period substantially equivalent to one half of said threshold value.

20. Apparatus according to claim 1, wherein the said carrier frequency is within the gigahertz band.

21. Apparatus for the radio transfer of chronometric information comprising:

(a) a plurality of separated radio stations;

(b) each station having means for transmitting radio signals and means for receiving return signals from another of said radio stations, of the same frequency as said radio signals and having at least one antenna for transmitting the signals from the transmitting means and for conveying return signals from said another radio station to the receiving means;

(c) wherein said transmitting and receiving means of each radio station exchange signals having a common carrier frequency between said stations; and

(d) said transmitting and receiving means having sequencing means enabled to define separate time segments with successive random positions, and to enable transmission of said transmission signals during said segments and reception of said return signals outside said segments.