Centerline and depth locating method for non-metallic buried utility lines

• US 20050156776A1
• Filed: 11/23/2004
• Published: 07/21/2005
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: MetroTech Corporation Inc.
• Original Assignee: MetroTech Corporation Inc.
• Inventors: Waite, James W.
• Granted Patent: US 7,113,124 B2
• Time in Patent Office: Days
• US Class Current: 342/22
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: Y02A 90/30 Assessment of water resources

Abstract

A locator capable of tracking buried, non-metallic utility lines (fiber optic, gas, water, waste, conduits) using ground penetrating radar (GPR) and an inertial position sensor is described. In some embodiments, a tracking filter is applied to a hyperbolic trajectory model based on the radar range data to determine a predicted track of the target utility line. After comparison of the predicted track to the measured inertial position, the centerline variance of the tracked line can be deduced. In some embodiments, an electromagnetic pipe and cable locator may also be included. Some embodiments of the invention can include accurate depth calibration and line depth tracking. Further, a display may provide results to a user in a simplified fashion.

Claims

1. A buried utility line locator, comprising:

an electromagnetic locator function capable of sensing the location and depth of metallic utility lines;

a ground penetrating radar capable of sensing the location and depth of non-metallic and metallic utility lines;

an inertial position sensor capable of sensing the location of the locator relative to the centerline position of the utility line; and

a microprocessor capable of executing a signal processing algorithm that predicts track of the target utility line based on inputs from the ground penetrating radar and the inertial sensor data, using depth calibration data derived from independent operation of the line locator function.

2. The buried utility line locator of claim 1, further comprising a display shared between the line locator and the ground penetrating radar, the display including:

a proportional, distance sensitive left/right indication of divergence of the line locator from the target centerline;

a guidance compass display that alerts the user to large scale curvature and direction changes in the tracked line; and

a depth readout that displays the real-time depth of the tracked utility line