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US4334775A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for dynamically determining the horizontal motion and twist of a microwave tower

Assignee: AT&T Inc
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Filing: 1980-04-03
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Granted: 1982-06-15
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Expires: 2000-04-03
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Abstract

Abstract A plurality of retroreflector devices (22-23) are fixedly mounted in spaced relation on a microwave tower (10) are raster scanned with a laser beam (46). The direction of the beam (46) is monitored as it impinges on each device to determine the position of each device. The twist and sway of the tower is then determined using the positional information of the devices.

Inventors

  • 👤 Jerry D. Breecher
  • 👤 Bruce E. Truax

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 14:04
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/16

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 249 words
A method for dynamically determining the twist and sway of a microwave radio tower, comprising the steps of: (a) directing a laser beam at a first galvanometer controlled rotatable mirror positioned proximate the base of the tower; (b) reflecting the beam from the first mirror to a second galvanometer controlled rotatable mirror having an axis of rotation orthogonal to that of the first mirror to scan an area in a plane which is substantially perpendicular to the axis of the tower, which plane contains a first and second retroreflector fixedly mounted, in spaced relation, on the tower; (c) searching the area by scanning said plane with the laser beam in a predetermined pattern; (d) reflecting the beam over the same path from whence it came from the beam impinges on the first retroreflector; (e) detecting the beam reflected from the first retroreflector to initiate interrogation of the galvanometer control apparatus to obtain the positions of the mirrors at the time the beam was reflected by the first retroreflector; (f) processing the positional information of the mirrors to determine the direction of the beam impinging on the first retroreflector; (g) repeating steps (c), (d), (e) and (f) to determine the direction of the beam impinging on the second retroreflector; (h) calculating the position of the first and second retroreflectors based upon the laser beam directions determined in steps (f) and (g); and (i) determining the twist and sway of the tower using the position of the first and second retroreflectors.
Claim 2
Independent Claim 249 words
A method for dynamically determining the twist and sway of a microwave radio tower, comprising the steps of: (a) directing a laser beam at a first galvanometer controlled rotatable mirror positioned proximate the base of the tower; (b) reflecting the beam from the first mirror to a second galvanometer controlled rotatable mirror having an axis of rotation orthogonal to that of the first mirror to scan an area in a plane which is substantially perpendicular to the axis of the tower, which plane contains a first and second retroreflector fixedly mounted, in spaced relation, on the tower; (c) searching the area by scanning said plane with the laser beam in a predetermined pattern; (d) reflecting the beam over the same path from whence it came from the beam impinges on the first retroreflector; (e) detecting the beam reflected from the first retroreflector to initiate interrogation of the galvanometer control apparatus to obtain the positions of the mirrors at the time the beam was reflected by the first retroreflector; (f) processing the positional information of the mirrors to determine the direction of the beam impinging on the first retroreflector; (g) repeating steps (c), (d), (e) and (f) to determine the direction of the beam impinging on the second retroreflector; (h) calculating the position of the first and second retroreflectors based upon the laser beam directions determined in steps (f) and (g); and (i) determining the twist and sway of the tower using the position of the first and second retroreflectors.
Claim 3
Dependent Claim 45 words
The method set forth in claim 1 wherein the scanning step (c) is characterized by: scanning said area until the laser beam impinges on the first retroreflector; and moving the beam a predetermined distance to scan a second area which contains only the second retroreflector.

References Cited (Backward Citations)

US3021749A Cited
US3504979A Cited
US3809477A Cited
US4025193A Cited
US4003626A Cited
GB1528691A Cited
US4172661A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1985-06-14 1985-12-14 1986-06-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1989-06-14 1989-12-14 1990-06-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1993-06-14 1993-12-14 1994-06-15 $7700.00 Window Closed / Lapsed

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