120km Laser Range Finder Module

(1)There are three modes-operating mode, standby mode and error mode. With standby mode, pumping power and thermal-control power can be switch off. Operating mode is set as a default, if you want to switch to standby mode and set it as a default, it can be realized by laser communication instructions. In addition, it can also achieve power fail safeguard function.
(2)When power switch on, it can monitor and give feedback immediately. If it’s in error, it will self-check and report (every 1s on self-check).
(3)It is able to collect times of transmitting laser pulse.
(4)With external trigger operating mode(No more than 25Hz).
(5)With overvoltage safeguard function.
(6)With overcurrent safeguard function: when current in laser LD excesses the maximum value, it will switch to standby mode and send error report.
(7)With overheat safeguard function: when radiator temperature excesses the maximum value in standby mode, it will switch to standby mode and send error report.

With bold and clear marks, special design of socket and connectors is tend to protect it from reverse and false connection. For external interface, it adopts military J30J micro-connectors(names vary according to different manufacturers) Socket: XS1
Table 1 and table 2 show the socket and plug of external interface, table 3 shows definition of Pin NO.

Table 1 Socket of external interface of laser rangefinder

Table 2 Plug of external interface of laser rangefinder

Table 3 Definition of Pin NO.

Targets and condition requirements
Ranging ability: 120km(ranging from sky to ground, reflectivity:≥0.1, Altitude of aircraft:≥6km)
Ranging ability:≥16km(ranging from ground to sky, target area:0.1㎡, reflectivity:≥0.3, visibility≥16km)
(2)Analysis and verification
The main parameters that affect ranging ability are peak power of lasers, divergence angle, transmitting and receiving transmittance, wavelength of laser, etc.
For this laser rangefinder, it takes≥10MW peak power of lasers, 0.6mrad divergence angle, 1570nm wavelength, transmitting transmittance≥90%, receiving transmittance≥80% and 140mm receiving aperture.
It is a laser rangefinder for small targets, ranging ability can be calculated by the following formula. Ranging formula for small targets：



: Detectable optical power
: Transmitting power of laser rangefinder(10MW)
: Transmitting transmittance(0.9)
: Receiving transmittance(0.8)
: Optical receiving area(140mm receiving aperture)
: Target reflectivity(0.3)
: Atmosphere attenuation coefficient(0.01)
: Distance to targets
As long as detectable optical power that reflected by targets is larger than minimum detectable power, a laser rangefinder is able to range distance to a target. For a laser rangefinder with 1570nm wavelength, generally, the minimum detectable power(M.D.S) of APD is 5×10-9W.
Under 40km visibility with 32km distance to targets, the minimum detectable power is lower than M.D.S of APD(5×10-9W), therefore, under a condition with 40km visibility, a laser rangefinder can range distance for (2.3m×2.3m) targets up to 31~32km(might be close or less than 32km).