Type classification and application analysis of pulsed laser range finder
As a military equipment, the pulsed laser rangefinder was developed in the early 1960s. After more than 30 years of development, development and equipment, foreign countries have completed "handheld, tripod, periscope, tank, armor, surface carrier, submarine periscope, antiaircraft gun, airborne, airport cloud, missile There are more than 400 varieties and models in thirteen categories, including rocket launch, artificial satellite, and spacecraft, among which the solid-state pulse laser rangefinder with Nd:YAG as the device is the most equipped, followed by Raman frequency shift Nd:YAG and Er:glass and CO2 pulsed laser rangefinders.
1. Lightweight portable pulsed laser rangefinder
Lightweight portable pulsed laser rangefinders include handhelds for infantry and artillery reconnaissance and dual-purpose forward reconnaissance and forward air control (FAC) laser rangefinders-target designators. For the above-mentioned system, it is required to be flexible, light in repetition, small in size, use a battery pack as a power source, high in reliability and maintainability, and low in cost of a single product.
Main technical performance: the maximum measurement range is 4~10km, the distance measurement accuracy is ±10m, the repetition frequency is single, and the beam divergence angle is 1~2mrad. It is worth noting that since the above-mentioned laser range finder and its system often cooperate closely with other friendly forces and do not carry out large-scale training of armored forces, there are no cooperative targets, and the operator does not wear protective goggles, etc., human eye safety is extremely important. Therefore, this type of pulsed laser range finder has gradually changed from Nd: YAG laser range finder to Raman frequency shifted Nd: YAG and Er: glass 1.54μm eye-safe laser range finder.
In modern warfare, the independent operations of infantry and artillery have developed into joint operations of special forces consisting of infantry, artillery and marines. The weapon system has also gradually adopted multi-functional comprehensive high-tech from a single ground artillery and antiaircraft artillery. Therefore, the laser rangefinder has also developed from a portable and hand-held one with a single ranging function to a laser rangefinder, a day and night sight for infrared aiming, and a laser infrared target indicator for laser rangefinder, target indication, and infrared aiming.
For example, the small laser infrared observer (MELIOS) of the American Optoelectronics Company using Er: glass lasers is a representative of the more advanced laser rangefinders in the contemporary era.
2. Ground Vehicle Pulse Laser Rangefinder
Ground-vehicle pulse laser rangefinders include tanks, infantry fighting vehicles (IFV), fire control, air defense, artillery or missile-guided fire control, and the currently developed ground-vehicle laser rangefinder-target designator, etc.
Its main technical performance: the maximum measuring range is 4~10km, the ranging accuracy is ±5~10m, the target resolution is about 20m, the repetition frequency is 0.1~1Hz, and the beam divergence angle is 0.4~1mrad.
The application of the laser range finder in the tank fire control system is to provide the super-elevation correction information of the ballistic trajectory, the azimuth correction information and distance information caused by headwind or target movement. The infantry fighting vehicle mainly uses the laser range finder to measure whether the target is within the distance of the anti-tank missile, and secondly it is used for gun fire control and target sorting. In order for the laser range finder to be fully effective in ranging any target that can be detected and to passively detect, identify and sort through the fire control system around the clock, these systems should also include: aiming optics, television cameras and infrared thermal imagers (FLIR), etc. This is a system that is very urgently needed but cannot be fully satisfied by any single-function and single-wavelength laser range finder. According to foreign reports, Hughes Corporation of the United States uses Raman frequency-shifted Nd:YAG laser rangefinder, TV camera and infrared imaging to form the tank and armored vehicle laser rangefinder system, which is the latest equipment at present.
However, if this kind of system uses 1.06μm Nd:YAG laser rangefinder, even if an attenuation filter is installed on the rangefinder, it can basically meet the safety requirements of human eyes during the rangefinder training for cooperative targets. After demonstration, the tank and Operators, commanders, and combatants of infantry operations should take human eye safety measures, or use human eye safe 1.54μm laser wavelength ranging, to fundamentally meet the requirements for human eye safety.
3. Anti-aircraft artillery and missile defense pulsed laser rangefinder
The pulse laser range finder for air defense and the air defense pulse laser range finder for infantry fighting vehicles with self-protection measures should work according to the requirements of the fire control system and combat system, and maneuver at high speed in the air within the distance and distance speed The target provides stable tracking information and distance information to counter the threats of armed helicopters, stealth aircraft, cruise missiles, and anti-radiation missiles.
This requires the laser rangefinder to provide a relatively high data rate (high laser pulse rate) and a relatively high distance accuracy, such as a maximum range of 4~20km, a ranging accuracy of ±2.5~5m, and a repetition rate of 6~ 20Hz, the beam divergence angle is 0.5~2.5mrad, etc. However, if the combat distance is quite far (about 20km or more), the actual confrontation at such a long distance occurs under unambiguous atmospheric conditions, and the sensitivity of the laser range finder is only slightly higher than that of the tank range finder; In some high-humidity seasons or some high-temperature meteorological regions, due to the strong absorption of H2O molecules, the maximum ranging capability of the long-wavelength (such as 10.6μm CO2) pulse laser rangefinder is limited. At this time, 1.06 should be used. μm Nd:YAG pulsed laser rangefinder, or Raman frequency shifted Nd:YAG and Er:glass (1.54μm) pulsed laser rangefinder.
For example, the US Hughes company uses Raman frequency shift Nd: YAG and Er: glass photoelectric tracking detection laser rangefinder is a typical example of the current advanced system.
4. Airborne pulsed laser range finder
The airborne pulsed laser rangefinder can be used to equip armed helicopters with missile command guidance and equipped with fixed-wing aircraft to block targets such as supporting photoelectric aircraft and intercept aircraft and missile attacks. These typical applications generally use a 1.06μm Nd:YAG laser rangefinder with laser ranging and target pointing capabilities, or an eye-safe Raman frequency shifted Nd:YAG pulsed laser rangefinder_target pointing at a wavelength of 1.54μm devices, etc., to protect airborne systems to complete combat missions or actively attack photoelectric targets in the air.
The main technical performance of the airborne pulse laser rangefinder: long range (4~10km for armed helicopters, 10~20km for fixed-wing aircraft), high ranging accuracy (±5~10m for armed helicopters) , for fixed-wing aircraft is ±1~10m), repetition rate (for armed helicopters is 4Hz, for fixed-wing aircraft is 5~20Hz), beam spread angle is small (for armed helicopters is 0.4~1mrad, for 0.1~0.5mrad for fixed-wing aircraft), and the airborne equipment should be small in size, light in weight and shared with aviation indicators.
Therefore, the laser must use a high-efficiency circulating liquid as a cooler to meet the high operating speed requirements, otherwise it must use gas or mixed gas booster cooling. At present, the "Liden" laser system (LANTIRN) developed by the United States uses the Raman frequency shifted Nd:YAG laser target designator rangefinder, which is a typical example of the multi-function and expanded airborne application of modern laser rangefinders.
5. Shipboard pulsed laser range finder
The development of the shipboard pulse laser rangefinder is after the light portable, vehicle-mounted and air defense laser rangefinder, and it includes two categories: surface shipboard and submarine periscope.
The surface carrier-borne pulse laser rangefinder is the same as the vehicle-mounted fire control and air defense laser rangefinder in terms of technical performance indicators. The requirements on volume, weight, electrical efficiency, maintenance capability and cost are not strict. Therefore, at present, a large number of naval ships are used to equip conventional fire control and air defense, such as cover (silent radar) carrier-based aircraft recovery and tracking systems composed of infrared thermal imaging, television, etc., all-weather monitoring and tracking of air targets and other unique ships. Online applications are emerging, and its application prospects are quite broad.
The submarine periscope pulse laser rangefinder currently adopts two combinations. The first one is to install the laser rangefinder, image intensifier and thermal imager in its periscope, while the distance display and trigger button are respectively installed above the operator’s hand. or nearby. Its advantage is that the laser loss in the transmission optical path is small, but the beam drifts and it is difficult to capture the target; the second method installs the upper three parts at the bottom of the periscope, and the installation, debugging, and disassembly of the entire system are very convenient, but the laser using this method The beam has to pass through a 12m long periscope tube and 15~20 lenses, and the energy loss is relatively large.
The main technical performances are: ranging range 300~6000m, ranging accuracy ±5~10m, repetition frequency 1~5Hz, beam divergence angle 1~1.5mrad.
