Note: Detection jitter of pulsed time-of-flight lidar with dual pulse triggering.

To enable very large dynamic range of optical input amplitude for pulsed time-of-flight laser rangefinders required in industrial applications, multi-triggering receivers have been previously proposed. In this Note, the detection jitter of such a receiver using the average of leading and trailing edge crossing times as a pulse timing estimate is experimentally evaluated, with especial attention on the jitter due to signal shot noise. It is shown that the average of leading and trailing edge threshold crossing times gives smaller detection jitter than either edge solely, and that this effect is emphasized at higher signal shot noise levels.

Radiometric analysis and simulation of signal power function in a short-range laser radar.

A key issue in designing laser radar devices for short-range applications is the ability to estimate accurately the power seen by the receiver as a function of the measurement distance. To obtain a reasonable approximation of this power, the irradiance distribution over the sensor as well as the target surface, which is highly dependent on the type of the detector used, must be analyzed in detail. The calculation of signal power function by means of radiometry is discussed. A software package developed for simulating power transfer as a function of various optical parameters is presented. It can be applied to various types of laser sources, including high-power laser diodes (wide-stripe or stacked) and pigtailed laser diodes.

Profiling of hot surfaces by pulsed time-of-flight laser range finder techniques.

The possibilities for using the pulsed time-of-flight (TOF) laser radar technique for hot refractory lining measurements are examined, and formulas are presented for calculating the background radiation collected, the achievable signal-to-noise ratio (SNR), and the measurement resolution. An experimental laser radar device is presented based on the use of a laser diode as a transmitter. Results obtained under real industrial conditions show that a SNR of 10 can be achieved at measurement distances of up to 15-20 m if the temperature of the converter is 1400 °C and the peak power of the laser diode used is 10 W. The single-shot resolution is about 60 mm (sigma value), but it can be improved to millimeter range by averaging techniques over a measurement time of 0.5 s. A commercial laser radar profiler based on the experimental laser radar device is also presented, and results obtained with it in real measurement situations are shown. These measurements indicate that it is possible to use the pulsed TOF laser radar technique in demanding measurement applications of this kind to obtain reliable data on the lining wear rate of a hot converter in a steel works.