Since in recent years，with the development of science and technology,more and more demand for optoelectronic tracking equipment,the traditional discrete detection and ranging system, the detection and ranging system layout independently,the uncertainty of the problems in the system, at the same time on the photoelectric system structure is compact, have a big impact in term of volume, indirect influence the performance of the whole system.
However, the non-collinearity of the optical axes, which is caused by independently internal integration of detection system and ranging system, will results in the problem of ineffective measure of the distance frequently, and limits the system performance. In this paper, on the basis of traditionally discrete detection and ranging system, attempts on establishing the integrated detection and ranging system is made to make their optical paths collinear and their apertures identical, to eliminate parallax and to improve the system integration. Taking the traditional discrete detection and ranging system as the research object, this paper is aimed at promoting the miniaturization of the photoelectric measurement system, and improving the adaptability of the orientation system.
Visible imagery and laser ranging are the important components of traditional orientation systems. The imaging system is used to image the target to acquire the target imaging features and to track the target azimuth information through real-time tracking. The ranging system is mainly for acquisition the distance information of the target. The target can be measured only when the target azimuth and distance information have been gained.
In this paper, the basic principles of detection and ranging are discussed first, where a detector is utilised to convert the optical signal into the electrical signal, while the detection system converts the optical signal into an image. The ranging signal is the electrical signal converted from the laser echo signal, of which the waveform has been processed. The measured distance can be calculated by the measurement of the flight time. Finally, the actual measuring points are simulated by the digital simulation of laser ranging. Furthermore, the waveforms of each step are obtained. The simulation results correspond with the theory and practice.
For the non-collinearity of the optical axes caused by the discrete layout of the detection and ranging system, attempts are made on designing the integrated system of detection and ranging, where the design of the receiving end is the key point. There are three solutions proposed regarding to the design of the receiving end. The advantages and disadvantages of the three structures are analysed and discussed. The zoom lens is determined as the main receive lens of the receiving end, which ensures the clear imaging of the target at different distances, makes the structure relatively simple and compact, reduces the whole size and eliminates parallax.
Considering the requirements of actual project and conditions, the detailed design of integrated detection and ranging system has been conducted. At the receiving end, the zoom lens with large calibre and long focal length is applied to image the targets at different distances. The continuously adjustable zoom lens is implemented, where the range of the focal length is from 100 mm to 600 mm, the calibre is 135.56 mm and the total length is 564 mm. The F-number is nearly unchangeable and the imaging surface is stable and uniform. The great significance will be reflected in applications of integrated photoelectric equipment..
Finally, the integrated system is established. The error of ranging is analysed. Then, the structural design of the three-dimensional model for the whole system is carried out, and the finite element thermal analysis of the key parts is carried out to ensure that it can work normally under the change of the external field temperature.
Attempt of establishing the integrated detection and ranging system aimed at close and small targarts is made in this paper. Validation by the field experiment shows that the integrated design of detection system and measuring system can replace the traditionally discrete design, without changing the overall indices of the ATP system. This method provides a reference for further developing an orientation system for miniaturized multi-scene applications.
Key words: Detection system, Laser ranging, Zoom lens, Detection and ranging integration;Optical design