The Laser Rangefinder System in Quadrature Modem and Ambiguity Resolution

Area of Science:

• Optical Engineering
• Metrology
• Signal Processing

Background:

• Traditional laser rangefinder systems often face challenges with measurement accuracy and hardware complexity.
• Secondary mixing methods can introduce inaccuracies and design complications in phase measurement.
• Range ambiguity is a common issue in distance measurement processes.

Purpose of the Study:

• To develop an advanced laser rangefinder system utilizing quadrature modem amplitude modulation.
• To enhance phase measurement accuracy and simplify hardware design.
• To introduce a novel algorithm for resolving range ambiguity without optimal solution searching.

Main Methods:

• Implementation of a quadrature modem for amplitude modulation in the laser rangefinder.
• Development of a ranging ambiguity resolving algorithm based on over-determined equations.
• Experimental validation using three proposed rangefinders and two K60 laser rangefinders on a national standard baseline.

Main Results:

• Achieved a precision of 0.18 mm in experiments on a national standard baseline.
• Demonstrated a measuring time of less than 1.8 seconds.
• Exhibited an average measuring error of less than 2 mm and a standard deviation of less than 1 mm within a 0-60 m range.

Conclusions:

• The proposed laser rangefinder system offers superior measurement accuracy and speed compared to traditional methods.
• The novel ambiguity resolving algorithm effectively eliminates the need for optimal solution searching.
• The system demonstrates high reliability and practical applicability for precise distance measurements.