PROCESS AND SYSTEM TO DETERMINE TEMPORAL CHANGES IN RETRANSMISSION AND PROPAGATION OF SIGNALS USED TO MEASURE DISTANCES, SYNCRONIZE ACTUATORS AND GEOREFERENCE APPLICATIONS

• US 20140225779A1
• Filed: 04/17/2012
• Published: 08/14/2014
• Est. Priority Date: 04/18/2011
• Status: Active Grant

• Current Assignee: Instituto Presbiteriano Mackenzie
• Original Assignee: Instituto Presbiteriano Mackenzie
• Inventors: Kaufmann, Pierre, Levit Kaufmann, Pedro
• Granted Patent: US 9,726,759 B2
• Time in Patent Office: Days
• US Class Current: 342/458
• CPC Class Codes: G01S 1/04 Details
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 19/31 Acquisition or tracking of other signals for positioning
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0263 by combining or switching between positions derived from two or more separate positioning systems
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence

Abstract

The proposed solution includes the use of four reference bases on the ground at known positions, with a coded time signal transmitted by one of them which is retransmitted by the repeater station and received by each of the reference bases. Using two distinct sets of three reference bases it is possible to calculate the differences between two positions for the repeater station, assigning to the later changes in time, phase or frequency as well as temporal changes due to the signal propagation in the medium, for the respective elevation angles found for the repeater. It can be then identified which values attributed to the temporal changes produces a minimum difference between the two respective positions of the repeater station. The identified temporal change can be used for the correct determination of the repeater station and its use on pertinent applications.

Claims

1. Process to determine temporal changes in retransmission and propagation of signals, to measure distances, synchronize actuators, and georeferencing, characterized by the fact of comprehending the steps of:

a—

installing four reference bases on the ground, every three of them not collinear, at known geographic positions and visible from the repeater station;

b—

emitting, at a reference instant and from a transmitter device provided a tone of the above mentioned reference bases, one time coded signal containing the identification of the emitting reference base and of the instant of emission;

c—

receiving, in a receiver device installed at each one of the four reference bases the coded signal, received and retransmitted by the repeater station;

d—

attributing, systematically, different arbitrary values to the change in time, phase or frequency, to the repeater and calculate, for each one of the attributed temporal change, one respective position difference for the repeater station obtained with the use of two distinct sets of three reference bases;

e—

identifying which one of the attributed values for the temporal changes at the repeater results in a minimum difference between the two positions of the repeater station, obtained using two distinct sets of three reference bases; and

f—

utilizing the temporal change found in “

e”

to determine the position of the repeater.

2. Process, according to claim 1, characterized by the fact that the difference positions for the repeater station are calculated algebraically attributing certain values to the so said temporal change, in sufficiently high number of values enough to identify the so called minimum value of the comparative differences.

3. Process, in agreement with claim 2, characterized by the fact that the realization of the iterative calculations of the differences between positions of the repeater station include and correct effect caused by temporal changes due to the signal propagation characteristic of the medium in which the system operates, adopting known propagation models, and using elevation angles for the repeater station as seen from the different bases to determine the accurate and definitive position of the repeater station.

4. Process, in agreement with claim 3, characterized by also including another step:

the determination of the repeater station coordinates with corrections for changes in time, frequency or phase, for a given instant of reference.

5. Process, in agreement with claim 3, characterized by also including another step to disseminate time signals to other points on the ground, with know geographic positions, for synchronization of the respective clocks.

6. Process, in agreement with the claim 3, characterized by also including the following steps:

emit, from the said reference base and at successive instants, coded signals and to obtain successive coordinates for the repeater station, corrected taking into account the time, frequency or phase changes in retransmission and propagation of Said coded time signals in order to determine the navigation of the repeater station;

retransmit, by the repeater station, the coded time signals to other targets with unknown geographic positions, each one with their own clocks synchronized to clocks installed at the four reference bases;

obtain distances from the repeater station to the other targets, corrected for the time changes on retransmission and on the propagation in the medium; and

determine targets'"'"' coordinates by measuring time differences at least three successive instants, with the adoption of changes in time, phase or frequency.

7. Process, in agreement with claim 6, characterized by also comprehending the step of:

calculate the distance from the repeater station to the reference bases and to the targets with geographic positions to be determined, with corrections for the time changes at the repeater station and those caused by the signal propagation in the medium, for repeater station (PO positions at four different instants, which positions are not along a single straight line, defining univocally, at a given arbitrarily selected coordinate system in space, through four successive measurements, the spatial positioning of the targets, which location are searched.

8. System to determine temporal changes in retransmission and propagation of signals, addressed for measurement of distances, synchronize actuators and georeferencing, from a remote and inaccessible repeater station, containing a transponder, being such system characterized by the fact of comprehending:

a—

four reference bases on the ground, every three of them not collinear, at known geograghic positions and visible from the repeater station;

b—

one transmitting device provided a tone of the bases capable to emit, at a reference instant, a time coded signal containing the identification of the reference transmitting base and of the instant of emission;

c—

one receiving device installed at each one of the four reference bases capable to receive the time coded signal, emitted by the transmitting device and received and retransmitted by the repeater station;

d—

precision clocks each one installed at every one of the four reference bases;

e—

one central processing station that receives the coded time signal, retransmitted by the by the repeater station, comparing it to the coded time signal generated at the emitting reference base and assigning different arbitrary values for the changes in time, phase or frequency, to the repeater station calculating, for each of the assigned temporal changes, a respective difference between positions for the repeater station, obtained with use of two distinct sets of three reference, identifying which value assigned to the temporal change at the repeater results in a minimum difference between the two positions found for the repeater station, and processing the corresponding temporal change to determine the position of the repeater station; and

f—

one transmission mean or device provided at each of three reference bases, distinct from that transmitter that generates the coded time signal, with each transmission mean or device forwarding to the central processing station the time difference between the coded time signal received from the transponder at the repeater station and the respective coded time signal generated at each one of the referred three reference bases.

9. System, according to claim 8, characterized by the fact that the central processing station is defined at the emitting reference base, provided with a transmitter.

10. System, according to claim 8, characterized by the fact that the central processing station is able to calculate algebraically the differences between positions of the repeater station, assigning certain values for the temporal changes, in sufficient number of assignments to allow the identification of the minimum value for the comparative differences.

11. System, according to claim 10, characterized by the fact that the repetition of the iterative calculations of differences between positions of the repeater station, processed by the central processing station, include the signal propagation velocities characteristics to the medium where they propagate, obtained from known models, and the elevation angles of the repeater station as seen from the different reference bases.

12. System, according to claim 11, characterized by the fact that the central processing base determine the coordinates of the repeater station with correction of changes in time, frequency or phase, for the given instant of reference.

13. System, according to claim 11, characterized by the fact of also include other points on the ground, with known geographic positions, for which the time signals are disseminated, for synchronization of the respective clock systems.

14. System, according to claim 11, characterized by the fact of also include other targets with unknown geographic positions and having their own clocks synchronized to the clocks installed at the four reference bases, with reference base emits, at successive instants, coded time signals, with the central processing base providing successive coordinates for the repeater station, corrected for the changes in time, phase or frequency occurred in retransmission and due to propagation of the said time coded signals, determining the navigation of the repeating station;

with the said other targets receiving the coded time signals retransmitted by the repeater station with the said central processing station obtaining the distances from the repeater station to the other targets corrected for the temporal changes in retransmission and in propagation in the medium, and determining the target coordinates by measuring the differences in time at least three successive instants, adopting the corrections for temporal changes in time, phase or frequency and for propagation in the medium.

15. System, according to claim 14, characterized by the fact that the central processing station calculate the distance of the repeater station to the reference bases and to the targets with geographic positions to be determined, with corrections for temporal changes at the repeater station and those caused by propagation in the medium, at positions of the repeater station in four different instants, which positions are not in a same straight line, defining univocally, in any coordinate system in space, the searched spatial position of the target, through four successive measurements.