DE3202432A1 - High-energy laser fine tracker - Google Patents

Abstract

High-energy laser fine tracker, the HEL laser of which is associated with a directional laser and a HEL beam divider, the beam of which, having the wavelength lambda 2, is coupled in with the HEL beam having the wavelength lambda 1, and both beams are directed onto the target point via telescope optics and the reflected light, having the wavelength lambda 2, is focused onto a quadrant detector, the output signals of which are input to the detector of electronics for controlling the tilting mirror for this centre focusing, and thus the advantages of hot-spot tracking and of glint-tracking are retained but their disadvantages are avoided.

Description

High energy laser fine tracker

The invention relates to a high-energy laser fine tracker, consisting of a HEL laser with telescope optics.

The previously known methods and arrangements according to the prior art Technology are based either on so-called "glint-tracking" (the "outgoing-wave-glint-tracking") the wavelength Ik7 of the HEL beam or laser or aut.

so-called "hot spot tracking". In the former case, they do stray light problems occurring in the process, a separation of the transmitting and receiving optics necessary because the scattered light of the powerful HEL radiation would hit the detector saturate in a "return-wave system" and thus render it unusable, which inevitably leads to a considerable effort.

But there is now the one returning from the target to the separate receiving optics Light does not travel the same optical path as the emitted HEL light, the atmospheric influences are different on both light paths, i. H. there can be no '2return-wave control', as is the case with a quadrant detector, for example Represents difference logic can be used.

The control method used is based on active wobbling of the emitted HEL-ray at small angles .. The resulting changes in intensity at the destination are recognized by the receiving system and used for readjustment.

But this leads to further disadvantages, because once the necessary one leads Wobbelung to a reduction of the mean laser intensity at the target point and for the second time the sweeping must take place at a higher frequency than the control frequency of the system, namely about a factor of 10 higher. However, this leads to considerable difficulties when designing the required tilting mirrors, as these necessarily have a must have a very high mechanical frequency response.

Another disadvantage of the method described above the Arrangements of the prior art is the fact that the change of the target point are not compensated for on the target surface when moving relative to the beam axis can. Furthermore, the reflection properties of the target point change here when heated through the HEL beam, which leads to reductions in the received light intensities and thus causes incorrect regulations.

The procedures based on sole hot spot tracking has the disadvantage that in the initial phase before the target point is heated, no Fine tracking takes place. The effect of the HEL radiation on the target point therefore takes place only after a longer period of time and the target point becomes larger and therefore less defined. When rotating the target, as is the rule with missiles or projectiles, the target point disappears from the field of view of the HEL optics and the Regulation indefinite.

The present invention is based on the object of a high-energy laser fine tracker to create the type mentioned, in which the advantages of the above Process can be obtained and exploited, but the disadvantages are simpler and more reliable Way are eliminated.

This task is achieved by the measures laid down in the main claim solved in a surprising way. Advantageous design measures are given in the subclaims laid down and in the description is an embodiment dealt with.

In the single figure of the drawing is a schematic representation the embodiment described shown in a block diagram.

The proposed combination of "glint tracking" and "hot-spot-tracklng" it is possible to take advantage of the situation-related advantages of each individual system benefit and to eliminate the given disadvantages. However, "glint tracking" takes place in contrast to the prior art in the "return wave glint tracking method" what the above-described disadvantages of the "out-going-wave-glinttracking method" largely avoids, since no filter of the HEL beam is necessary.

To a high-energy laser beam (HEL beam) 11 of a HEL laser 10 of wavelength 1 (e.g. 10.6 ») becomes collinear via a HEL beam splitter 15, the beam 14 of a directional laser 13 with the wavelength A2 (z. B. 9.1) is coupled. The collinearity of the two laser beams is, if necessary, through active stabilization measures guaranteed. About two tilting mirrors 17, 18, the two standing perpendicular to each other Axes can be swiveled at high frequency (swivel range typically about + 10 mrad), and a telescope will point the two beams to a target point ZP des Goal 20 focused.

From the reflected at the target point ZP and through the transmission optics 19 Light that has returned through the beam splitters 15, 16 becomes light of the wavelength A2 (i.e. that of the directional laser) with a lens 21 through an interference filter 22 focused on the quadrant detector 23 with passband at A 2. About this detector 23 and a subsequent control electronics 24 are the tilting mirrors 17, 18 with the help mechanical drives 25a, 25b controlled by electronics 24 so tracked, that the light of wavelength 12 reflected back from the target point ZP is centered on the Detector 23 remains in focus.

The light scattered back from the target point ZP with the wavelength A2 is generated by two different mechanisms; 1. By reflection of the directional laser light 14 at the target surface. The control fixes the HEL beam in this case the target point with the highest reflection in the backward direction (so-called glint).

2. Due to the heating of the target point by the HEL beam is of this thermal radiation with a spectral component at the wavelength k2 generated (so-called hot-spot).

The tracking process takes place in several steps: After recording of target 20 by a rough tracker (e.g.

Radar or passive infrared tracker) the HEL beam is tracked by "glint tracking" at wavelength A2 to the point of highest reflection of the target at 2 within the viewing angle of the transmission optics 19 fixed. Glint tracking at wavelength 2 has the advantage over the wavelength 1 of the HEL beam 11 that the Light reflected back from the target point is much easier than the emitted light the same wavelength can be separated, which is caused by scattering on the components arises in the transmission optics.

After the HEL beam has been fixed on the target point the aforementioned "glint tracking" with wavelength 2 is the target point ZP through heats the HEL beam. the thermal radiation at wavelength 2 leads to an increase in the received signal at the detector 23. This received signal is proportional the intensity I of the light of wavelength 2 reflected back from the target point ZP. The intensity is the sum of the intensity of the light reflected on the "glint" of the directional laser 13 and the intensity of the light thermally generated there with the Wavelength t2. In the second phase there is a combined "glint" and "hot spot tracking".

After the increase in the intensity at the detector 23 a predetermined Exceeds the value (due to the effect of the HEL beam at the target point ZP) the directional laser 13 is switched off.

The detector then only sees the thermally generated radiation of wavelength 2 at the target point. The HEL beam is controlled by this "hot" point fixed (so-called hot spot tracking). This "hot spot tracking" possesses compared to "glint-tracking" the following advantage: When aiming with curved surfaces, what z. B. is the rule with missiles, migrates with relative movement the target surface to the beam axis of the HEL beam (e.g.

with rotational movement of the target) the point of highest reflexivity of the Target (glint) to always new areas of the target surface. In the case of a "glint tracking procedure" In such a case, there will be a constantly changing portion of the target surface provided with the HEL radiation, which leads to less than optimal target exposure.

In the case of “hot spot tracking”, on the other hand, the regulation guides the HEL beam with the mentioned relative movements of the target surface always to the point of the target surface, where already the greatest impact (i.e. heating) is from the HEL beam is.

Disappears z. B. by rotating the target of the "hot-spot" from the Reception area of the HEL optics, this is indicated by the disappearance of the intensity at Detector 23 is detected and the directional laser 13 is automatically switched on again. Thereupon the glint tracking takes place again ". When the previously heated one reappears The target point ZP in the field of view of the HEL optics 19 is due to its thermal Radiation at wavelength 1L2 detected and possibly by the previously described "hot-spot-tracking method" detected again from the HEL beam.

It should also be mentioned that when the detection system is operated in heterodyne mode the laser 13 can be used as a local oscillator and also as a lidar laser for measuring the distance and speed of the target 20.

Claims (3)

High-energy laser fine tracker Patent claims 19 High-energy laser fine tracker, Consists of a HEL laser with telescopic optics, which means that it is not shown e t that the HEL laser (10) is assigned a directional laser (13) and a HEL beam splitter (15) which is collinear with the beam (11) of the HEL laser (10) with the wavelength 21 the beam (14) with the wavelength # 2 of the directional laser (13) couples and two tilting mirrors (17, 18) that can be swiveled at high frequency and a telescope (19) for Focussing the two beams on the target point (ZP) of the target (20) arranged are, whose reflected and returning light beam via the transmission optics (19) two beam splitters (15, 16) are assigned, the light of wavelength # 2 via a Lens (21) and an interference filter (22) with passband at h 2 on a quadrant detector (23) fohçsieren, whose output signals an electronics (24) for controlling the tilting mirror (17, 18) for the center focusing of the reflected light component of the wavelength P 2 are fed to the detector (23). 2. Laser tracker according to claim 1, characterized in that g e k e n n -z- e; L c h n e t that the swivel range of the tilting mirror is about + 10 mrad. 3. Laser tracker according to claims 1 and 2, thereby g e -k e n n z e i c h n e t that the electronics (14) when a predetermined value is exceeded Intensity value on the detector (23) switches off the directional laser (13) and if it is not reached switch this value back on.