Method and apparatus for determining the relative height of two targets

• US 6,414,745 B1
• Filed: 03/07/2000
• Issued: 07/02/2002
• Est. Priority Date: 06/30/1998
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Netmor Ltd.
• Inventors: Moriya, Netzer
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US09/462,700
• Time in Patent Office: 847 Days
• Field of Search: 342/126, 342/123, 367/118, 367/99, 356/3.11, 356/141.1
• US Class Current: 356/3.11
• CPC Class Codes: G01C 5/00 Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels G01C3/20, G01C3/30 take precedence
• CPC Class Codes: G01S 13/46 Indirect determination of position data
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar

Abstract

An apparatus for determining the relative height between two targets is disclosed. The present invention also discloses a method for determining the relative height between two targets; the method is substantially similar to the operational aspects of the device of the present invention. The method requires no angular measurements in order to determine the different height between the two targets, but rather only distance measurements that can be performed simply and accurately.

The apparatus for determining the relative height between two targets a disclosed. The apparatus includes: two signal-responsive target-objects; a casing housing first and second measurement ports displaced a known distance from each other; at least one signaling module within the casing at each of the measurement ports, for signaling each of the two targets from both of the measurement ports; a distance measuring module coupled to each of the signaling modules for measuring the distance from each port to each target according to the respective signalings of the corresponding signaling modules; and a calculation module coupled to the signaling modules and to the distance measuring module and being responsive to the measured distances for determining: a first triangle formed by the first and second measurement ports and a first one of the two targets, a second triangle formed by the first and second measurement ports and a second one of the two targets, and the relative height between the two targets as the height of a virtual tetrahedron formed the first and second triangles.

Claims

1. A method for determining the relative height between two targets, the method comprising the steps of:

(a) placing a first signal-responsive target and placing a second signal-responsive target;

(b) signaling each of the targets from a first reference which is remote from both targets and measuring a respective first and second distance from the first reference to the two targets;

(c) signaling each of the targets from a second reference which is displaced a known distance from the first reference, which is substantially vertically aligned with the first reference, and which is remote from both targets and measuring a respective third and fourth distance from the second reference to the two targets;

(d) determining a first triangle formed by the first and second reference points and a first one of the two targets;

(e) determining a second triangle formed by the first and second reference points and a second one of the two targets; and

(f) forming a virtual tetrahedron from the first and second triangles and calculating the relative height between the two targets.

2. The method according to claim 1, wherein steps (b) and (c) are performed substantially simultaneously.

3. The method according to claim 1, wherein steps (b) and (c) are performed using radio frequency techniques in respect of at least one of the measurements.

4. The method according to claim 1, wherein the first and second reference points are mounted in a common casing and there is further included the step of compensating for variations in said known distance due to fluctuations in temperature.

5. An apparatus for determining the relative height between two targets, the apparatus comprising:

two signal-responsive target-objects;

a casing housing first and second measurement ports displaced a known distance from each other, and substantially vertically aligned;

at least one signaling module within the casing at each of the measurement ports, for signaling each of the two targets from both of the measurement ports;

a distance measuring module coupled to each of the signaling modules for measuring the distance from each port to each target according to the respective signalings of the corresponding signaling modules; and

a calculation module coupled to the signaling modules and to the distance measuring module and being responsive to the measured distances for determining;

(a) a first triangle formed by the first and second measurement ports and a first one of the two targets;

(b) a second triangle formed by the first and second measurement ports and a second one of the two targets, and

(c) the relative height between the two targets as the height of a virtual tetrahedron formed from the first and second triangles.

6. The apparatus according to claim 5, wherein the distance measuring modules measures the distance from the corresponding measurement port to the target acoustically.

7. The apparatus according to claim 5, wherein the distance measuring modules measures the distance from the corresponding measurement port to the target using a radio frequency.

8. The apparatus according to claim 7, wherein the distance measuring modules measures the distance from the corresponding measurement port to the target using a heterodyne of radio frequencies.

9. The apparatus according to claim 7, wherein said radio frequency is in the microwave frequency range.

10. The apparatus according to claim 5, wherein the distance measuring module uses interference techniques to improve the measurement accuracy.

11. The apparatus according to claim 5, wherein at least one of the signaling modules includes coding for activating the response of a predetermined target object.

12. The apparatus according to claim 5, wherein the calculation module includes means for statistically aggregating a plurality of measurement data taken from at least one location of the apparatus so as to improve the accuracy of the computed relative height of the two points.

13. The apparatus according to claim 5, wherein the calculation module includes means for computing the relative height of the apparatus with respect to the two targets.

14. The apparatus according to claim 5, wherein the calculation module is responsive to respective (x, y) coordinates of the two targets in accordance with a predetermined Cartesian (x, y) frame for computing the corresponding (x, y) coordinates of the apparatus.