Processing device and method

Abstract

The present invention discloses a processing device for processing a radio signal, comprising a plurality of receivers designed to receive the radio signal in a predetermined frequency range and to output each signal as a received signal, comprising a detection apparatus designed to detect, for each received signal, a number of sources in the corresponding radio signal, comprising a selection apparatus designed, if there is more than one source in at least one of the received signals, to select one of the receivers on the basis of the information on the number of sources in the individual received signals and to forward the received signal of said selected receiver. The present invention also discloses a corresponding method.

Claims

1. A processing device for processing a radio signal, the processing device comprising: a plurality of receivers designed to receive the radio signal in a predetermined frequency range and to output each signal as a received signal; a detection apparatus designed to detect, for each received signal, a number of sources in the corresponding radio signal; a selection apparatus designed, if there is more than one source in at least one of the received signals, to select one of the receivers on the basis of the information on the number of sources in the individual received signals, and to forward the received signal of said selected receiver, wherein, if there is more than one source in a received signal, at least one of the detection apparatus and the selection apparatus is designed to determine a level of each signal component corresponding to the individual sources, and the selection apparatus is designed to select the receiver according to the determined levels.

2. The processing device of claim 1, further comprising a transmission apparatus designed, if more than one source is detected in a radio signal, to transmit an alert signal to the corresponding sources.

3. The processing device of claim 1, wherein, if there is more than one source in a received signal, the selection apparatus is designed to select the receiver in whose received signal the difference in the levels for the individual sources is the smallest.

4. The processing device of claim 1, wherein, if there is more than one source in a received signal, the selection apparatus is designed to select the receiver in whose received signal the difference in the levels for the individual sources is the greatest.

5. The processing device of claim 1, further comprising a signal generation apparatus designed, if there is more than one source in a received signal, to generate an alert signal that is output by the selection apparatus together with the selected received signal.

6. The processing device of claim 1, wherein the selection apparatus is designed, if there is more than one source in at least two of the received signals, to determine whether the level of a different source is the strongest level in different received signals.

7. The processing device of claim 6, wherein the selection apparatus is designed to output, one after the other, the received signals in which the level of a different source is the strongest level.

8. The processing device of claim 6, wherein the selection apparatus is designed to subtract from one another the received signals in which the level of a different source is the strongest level, and to output the resultant signal.

9. A method for processing a radio signal, the method comprising: receiving the received signal by means of a plurality of receivers in a predetermined frequency range; outputting a received signal for each of the receivers; detecting a number of sources in the corresponding radio signal for each of the received signals; if there is more than one source in at least one of the received signals, selecting one of the receivers on the basis of the information on the number of sources in the individual received signals, wherein, during the detecting, if there is more than one source in a received signal, a level of each signal component corresponding to the individual sources is determined, and the receiver is selected according to the determined levels; and forwarding the received signal of the selected receiver.

10. The method of claim 9, wherein, if more than one source is detected in a radio signal, an alert signal is transmitted to the corresponding sources.

11. The method of claim 9, wherein, during the selection, if there is more than one source in one of the received signals, the received signal of the receiver in whose received signal the difference in the levels for the individual sources is the greatest is selected.

12. The method of claim 9, wherein, during the selecting, if there is more than one source in one of the received signals, the received signal of the receiver in whose received signal the difference in the levels for the individual sources is the smallest is selected.

13. The method of claim 9, wherein, if there is more than one source in a received signal, an alert signal is generated and output together with the selected received signal.

14. The method of claim 9, wherein, during the selecting, if there is more than one source in at least two of the received signals, it is determined whether the level of a different source is the strongest level in different received signals.

15. The method of claim 14, wherein the received signals in which the level of a different source is the strongest level are output one after the other.

16. The method of claim 14, wherein the received signals in which the level of a different source is the strongest level are subtracted from one another and the resultant signal is output.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention is described in greater detail below on the basis of the embodiments set out in the schematic drawings, in which:

(2) FIG. 1 is a block diagram of an embodiment of a processing device according to the invention;

(3) FIG. 2 is a flow chart of an embodiment of a method according to the invention;

(4) FIG. 3 is a block diagram of another embodiment of a processing device according to the invention;

(5) FIG. 4 is a graph showing two superposed signals in the frequency domain.

(6) In all the drawings, like elements and devices or those with the same function have been provided with the same reference signs, unless indicated otherwise.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(7) FIG. 1 is a block diagram of an embodiment of a processing device 1 according to the invention. The processing device 1 can for example be integrated in an air traffic control system at an airfield.

(8) The processing device 1 comprises a plurality of receivers, of which only the receivers 2 and 3 are shown. Other possible receivers are indicated by three dots. The individual receivers 2, 3 receive a radio signal 9 (formed here merely by way of example from the signal components 12, 13). In this case, the signal components 12, 13 are transmitted from respective aircraft 10, 11 and are superposed at the receivers 2, 3 to form the radio signal 9. It goes without saying that superposition of this type only occurs when two signal sources 10, 11 actually transmit a signal 12, 13 at the same time.

(9) Since the distances between the aircraft 10, 11 and the individual receivers 2, 3 are not the same, the signal strengths of the individual signal components 12, 13 picked up by the receivers 2, 3 are different. In this case, the signal strengths are not only affected by the distance of the aircraft 10, 11 to the particular receiver 2, 3. Other factors may include for example reflections or damping owing to different objects between the aircraft 10, 11 and the receivers 2, 3.

(10) The receivers 2, 3 thus each output different received signals 4, 5, in which the individual signal components 12, 13 are present at different strengths.

(11) The individual received signals 4, 5 are now picked up and analysed by the detection apparatus 6. To do so, the detection apparatus 6 analyses the individual received signals 4, 5 and checks them for the presence of two signal components 12, 13. For this purpose, the detection apparatus 6 can transform the received signals 4, 5 for example into the frequency domain, where it can identify the carrier 20 (see FIG. 4) of the stronger signal component 12, 13. Next, one of the sidebands 21, 22 corresponding to this carrier 20 can be mirrored and subtracted from the other sideband 22, 21. A conclusion can then be drawn from the remaining signal on whether there is another carrier 23 or signal component 24, 25.

(12) The detection apparatus 6 provides the information on the number 7 of possible sources, i.e. aircraft 10, 11, or signal components 12, 13 to the selection apparatus 8 together with the received signals 4, 5.

(13) On the basis of the information on the number 7 of signal components 12, 13, the selection apparatus 8 can now select which received signal(s) 4, 5 are output. These output received signals 4, 5 are then played to an air traffic controller, for example.

(14) To select the received signals 4, 5 to be output, the selection apparatus 8 can determine, within the received signals 4, 5, the level of the signal components 12, 13 corresponding to the individual sources 10, 11. On the basis of these levels, the selection apparatus 8 can, for example, select the received signal 4, 5 in which the difference in levels for the individual sources, i.e. aircraft 10, 11 in this case, is the smallest. This increases the likelihood that an air traffic controller can hear the double transmission solely because of the distortions between the signal components 12, 13.

(15) Alternatively, the selection apparatus 8 can select the received signal 4, 5 in which the difference in levels for the individual sources, i.e. aircraft 10, 11 in this case, is the greatest. This allows the air traffic controller to understand at least one of the signal components 12, 13 as well as possible.

(16) The selection apparatus 8 can also ascertain whether the level of a different source 10, 11 is the strongest level in different received signals 4, 5. This can be done, for example, by searching for the maximum level in the frequency domain and comparing the frequencies of each maximum found in the received signals 4, 5. If each of these maximums has a different frequency, a different signal component 12, 13 is dominant in the individual received signals 4, 5.

(17) If the selection apparatus 8 recognises a different attribute of this kind in the individual signal components 12, 13 in the received signals 4, 5, it can output, one after the other, the received signals 4, 5 in which the level of a different aircraft 10, 11 is the strongest level.

(18) The selection apparatus 8 can also subtract from one another the received signals 4, 5 in which the level of a different source 10, 11 is the strongest level, and output the resultant signal. This can minimise the mutual distortions of the signal components 12, 13.

(19) For example, a first signal component may be dominant in a first received signal and a second signal component may be dominant in a second received signal. However, the less dominant signal components can still cause distortion.

(20) The selection apparatus 8 can now comprise appropriate signal processing that can scale the dominant signal to the level at which this signal is contained in the other received signal and deduct it therefrom. As described above, the levels can for example be determined in the frequency domain. The resultant signals then comprise just one of the signal components 12, 13, and are thus very easily understood.

(21) FIG. 2 is a flow chart of an embodiment of a method according to the invention for processing a radio signal 9.

(22) In a first step S1, the radio signal 9 is received in a predetermined frequency range by a plurality of receivers 2, 3. The radio signal 9 may for example be an amplitude-modulated signal having a carrier 20, 23, a lower sideband 21, 24 and an upper sideband 22, 25 (see FIG. 4). For each of the receivers 2, 3, a received signal 4, 5 is then outputS2.

(23) In step S3, a number 7 of sources 10, 11 is determined for each of the received signals 4, 5. If there is more than one source 10, 11 in at least one of the received signals 4, 5, one of the receivers 2, 3 is selected in step S4 and the received signal 4, 5 of the selected receiver 2, 3 is forwardedS5.

(24) When detecting the number 7 of sources 10, 11, a level for each signal component 12, 13 corresponding to the individual sources 10, 11 can be determined. In this case, the level of a carrier signal 20, 23 of each signal component 12, 13 can be determined, for example.

(25) This information can then be used in the selection S4. For example, the received signal 4, 5 of the receiver 2, 3 in whose received signal 4, 5 the difference in the levels for the individual sources 10, 11 is the smallest can be selected. Alternatively, for example, in the selection S4 the received signal 4, 5 of the receiver 2, 3 in whose received signal 4, 5 the difference in the levels for the individual sources 10, 11 is the greatest can be selected.

(26) Comparing the individual received signals 4, 5 with one another can also provide information for selecting the individual received signals 4, 5. For example, it can be determined whether the level of a different source 10, 11 is the strongest level in different received signals 4, 5. If this is the case, it means that another signal can be heard more clearly in the particular received signal 4, 5.

(27) In these cases, the received signals 4, 5 in which the level of a different source 10, 11 is the strongest level can be output one after the other. In addition, the received signals 4, 5 in which the level of a different source 10, 11 is the strongest level can also be subtracted from one another and the resultant signal output.

(28) Furthermore, if there is more than one source 10, 11 in a received signal 4, 5, the method can provide for the generation of an alert signal 15 that is output together with the selected received signal 4, 5. The alert signal 15 can also be output to the sources 10, 11, i.e. to the aircraft 10, 11 or their pilots, for example.

(29) FIG. 3 is a block diagram of another embodiment of the processing device 1. By comparison with the processing device 1 in FIG. 1, a signal generation apparatus 14 and a transmission apparatus 16 have been added to the processing device 1 in FIG. 3.

(30) If a double transmission is identified, the signal processing apparatus 14 can generate an alert signal 15 that can be played to an air traffic controller before or after the actual received signal 4, 5, for example. At the same time, the transmission apparatus 16 can also transmit the alert signal 15 to the aircraft 10, 11 such that the pilots thereof are also informed of the double transmission.

(31) In particular if the selection apparatus 8 only selects the received signal 4, 5 in which the difference in levels for the individual aircraft 10, 11 is the greatest, the alert signal 15 can notify the air traffic controllers and pilots that there is a double transmission.

(32) FIG. 4 is a graph showing two superposed signals in the frequency domain.

(33) The first signal comprises a carrier 20 having a first level that is higher than the level of the carrier 23 of the second signal. Each signal also has a lower sideband 21, 24 and an upper sideband 22, 25.

(34) It can also be seen that the frequencies of the carriers 20, 23 are shifted relative to one another. The lower and upper sidebands 21, 24 and 22, 25 are thus also shifted relative to one another.

(35) When there is a difference in the levels of the carriers 20, 23 of as little as 10 dB, the signal having the lower level can be completely covered by the other signal. It can therefore not be picked up by air traffic controller.

(36) As described above, a transformation into the frequency domain can be carried out to detect the second signal. In the frequency domain, a sideband of the stronger carrier 20, e.g. sideband 21, can then be mirrored and subtracted from the other sideband 22. It can be seen that the remaining signal does not contain a second signal.

(37) Although the present invention has been described above on the basis of preferred embodiments, it is not limited thereto and instead can be modified in many ways. In particular, the invention can be altered or modified in many ways without departing from the basic concept of the invention.

(38) The individual elements of the processing device can comprise discrete components and/or some can be implemented as a program executed on a computer, for example.

LIST OF REFERENCE SIGNS

(39) 1 Processing device 2, 3 Receiver 4, 5 Received signal 6 Detection apparatus 7 Number 8 Selection apparatus 9 Radio signal 10, 11 Source 12, 13 Signal component 14 Signal generation apparatus 15 Alert signal 16 Transmission apparatus 20, 23 Carrier 21, 24 Lower sideband 22, 25 Upper sideband S1-S5 Method steps