Methods of Precise Distance Measurements for Laser Rangefinders with Digital Acquisition of Signals

Abstract

The article presents methods of long range distance measurements using pulsed lasers and the Time of Flight principle. Various algorithms of laser distance measurements with digital acquisition of echo pulses (acquisition of a signal’s full waveform) are presented. The main focus of work is concentrated on the method of distance measurements developed by the authors. With this method, during laboratory trials, a total measurement error of one centimeter was achieved using a 905 nm pulsed laser diode and pulse width of 39 ns. The maximum range of measurements with such high precision is limited only by a signal to noise ratio, duration of measurements and atmospheric conditions. All algorithms were implemented in a laser rangefinder module developed by the authors. Simulations and laboratory experiments were conducted and algorithm’s accuracy and precision were tested for various SNR conditions and changing distances.

Experimental Validation of LiDAR Sensors Used in Vehicular Applications by Using a Mobile Platform for Distance and Speed Measurements

“…The authors of [3,4] propose various systems using neural networks or multiple LiDAR units to detect the presence of pedestrians. The authors of [5] present a method for very precise distance measurement using LASER rangefinders that has an uncertainty at the level of of 1 cm. The authors of [6,7] propose different methods for detecting obstacles using LiDAR sensors with applications in 3D measurements and autonomous guidance systems.…”

“…Sensors 2021, 21, x FOR PEER REVIEW where c is the speed of light, and T is the total time of flight of the radiation [5 The LiDAR has a high-precision real-time counter (RTC) that measures takes for a pulse of light to travel from the emitter, a laser or LED, to the target back to the LiDAR receiver. To ensure proper measurement, both the emitter a are synchronized by this RTC.…”

Visualized NIR Obstacle Ranging Based on Upconversion Nanoparticles

“…Therefore, laser ranging is preferred over other methods, as it provides higher accuracy, robustness, and versatility in distance measurements. 11,12 For instance, Jung et al proposed an algorithm that detects transparent obstacles by analyzing the mode of reflection noise generated when a laser encounters such obstacle. 13 developed an algorithm primarily focused on locating obstacles.…”

“…Compared to the aforementioned methods, the laser ranging measurement can accurately determine distances by emitting short pulses of laser light and measuring the time taken for the light to return to the sensor, allowing for the calculation of the distance based on the speed of light. Therefore, laser ranging is preferred over other methods, as it provides higher accuracy, robustness, and versatility in distance measurements. , For instance, Jung et al proposed an algorithm that detects transparent obstacles by analyzing the mode of reflection noise generated when a laser encounters such obstacle . Dekan et al conducted further research on moving obstacles and developed an algorithm primarily focused on locating obstacles .…”

Self-Mixing Laser Distance-Sensor Enhanced by Multiple Modulation Waveforms

“…This is mainly because of triangular geometry which implies the minimum width of the sensor to provide the distance between its transmitter and receiver. For long distances, instruments based on the Time-of-Flight technique show reliable performance with resolution between 1 mm and 1 cm [ 3 , 4 ] and are extensively employed for commercial and consumer applications. Distance measurement systems based on interferometric techniques have been studied extensively, due to demanding higher resolution in industrial and scientific environments.…”