Claims
- 1. A reference station for distance-measuring systems of the type that includes an antenna for receiving an interrogation signal from an aircraft, a receiver for said signal and a transmitter for providing a reply signal through said antenna so that the distance between aircrafts and said reference station can be measured, comprising:
- a plurality of spatially distributed nondirectional elements on said antenna, each of said elements being adapted for connection to one of said receiver and transmitter.
- 2. A reference station according to claim 1 further comprising:
- a power distributor; and
- a plurality of controllable phase shifters each coupled to one of said spatially distributed elements, said elements being adapted for simultaneous connection to one of said receiver and transmitter.
- 3. A reference station according to claim 2 wherein said plurality of controllable phase shifters comprise n phase shifters and further including a control unit for controlling the phase shift in each of said phase shifters such that the i.sup.th phase shifter causes i times the phase shift of the first phase shifter, and wherein the phase shift of the n.sup.th phase shifter is N times 360.degree. where N is an integer.
- 4. A reference station according to claim 3 further including a random generator for controlling said control unit.
- 5. A reference station according to claim 4 wherein said phase shifters are switched synchronously with the transmission of a transmitter signal.
- 6. A reference station according to claim 1 wherein said plurality of said spatially distributed elements are arranged in a circle.
- 7. A reference station according to claim 1 further including
- a switch; and
- a control unit for controlling said switch such that only one element is coupled to said receiver and transmitter at a time.
- 8. A reference station according to claim 7 wherein said plurality of spatially distributed elements are arranged on a circle.
- 9. A reference station according to claim 1 wherein each of said plurality of said spatially distributed elements is connected to a receiver and one of said elements is connected to a transmitter further including an evaluating device for determining from measured amplitudes (n.sub.i, m.sub.28, m.sub.i+(n/2)) of the received signal and from the time differences (.DELTA.t.sub.i -.DELTA.t; .DELTA.t.sub.i+(n/2) -.DELTA.t) between the times of arrival of the signal at the spatially distributed elements taking into account the geometric arrangement of the elements, whether thee is a time error (t.sub.s) determined by the difference between the measured time of arrival of the received signal and the calculated time of arrival of the direct path signal, and that the time error (t.sub.s) is considered twice when fixing the time of transmission of the reply signal.
- 10. A reference station according to claim 9 wherein at least three elements are arranged along a straight line.
- 11. A reference station according to claim 10 wherein said elements are equally spaced.
- 12. A reference station according to claim 11 wherein a plurality of three element groups are arranged in a rotationally symmetrical configuration.
- 13. A reference station according to claim 9 further comprising at least two pairs of elements, with the connecting lines between the elements of one pair being parallel to that between elements of the other pair.
- 14. A reference station according to claim 1, wherein said antenna comprises at least three spatially distributed non-directional elements.
Parent Case Info
This is a continuation of application Ser. No. 813,923, filed July 8, 1977, now abandoned.
US Referenced Citations (4)
Non-Patent Literature Citations (2)
Entry |
Annex 10 to the Convention on International Civil Aviation, vol. 1, 3rd edition, Jul. 1972, pp. 28-37. |
Kayton et al., Avionics Navigation Systems, J. Wiley & Sons, 1969, p. 186. |
Continuations (1)
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Number |
Date |
Country |
Parent |
813923 |
Jul 1977 |
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