SLANT RANGE MEASUREMENT BY IMPULSE LASER RANGE FINDER

Abstract

We consider the problem of slant range distance measurement from aircrafts in conditions of complex spatial structure. The range determination in active laser range finders, including slant range, is based on measuring the time difference of two time points, the time point when the pulse exits the laser range finders, and the time point when the pulse comes back, after being reflected from a target. The signal emission reflected from a target is a variable of random process, because of the irradiated surface length, even under narrow field radiation. When determining the slant range distance from aircraft to a target, it is necessary to identify the signal emission reflected from a target, from background signal reflected by underlying surface. We propose two methods of slant range measurements, provided identification of target that is located on the underlying surface with complex structure. The first method is based on the measurement of slant range distance when the lower edge of the radiation field is aligned with the pointing direction. The second method is based on the measurement of slant range distance when the upper edge of the radiation field is aligned with the pointing direction. We propose structural schemes based on these methods and describe their operation principles. Evaluation of the advantages and disadvantages for each method is given.

Keywords

• slant range measurement
• reflective impulse characteristics
• pulsed laser range finder
• underlying surface
• beam divergence angle