Evaluating The Performance Of A Laser Rangefinder

A laser rangefinder, laser range finder, eye safe laser rangefinder performance is mainly see working distance, measuring rate and reliability life.

  •  Measuring range is mainly see target effect area, target reflectivity, measuring rate and air visibility.

1, If effect area is differnt, then measuring distance is different too, For example, tank have many types, also tank have front, side, behind etc, their effect area is different. 

For example:

one LRF measure 10 square meter vehicle 12km, then normal measure 5 square meter vehicle is about 10km.

Also, when the angle of the LRF to the target changes, then, measuring range will change too, even rapidly changing.

 2, If target is different type, then reflectivity is very different. For example, tank reflectivity is different with 2.3m x 2.3m target, 2.3m x 2.3m target can be similar mirror and even reflectivity can be 60% or more.

For example:

one LRF measure high reflectivity 2.3m x 2.3m target 12km, then said their LRF that measure NATO 2.3m x 2.3m 30% reflectivity target 12km.

This is why many 30% reflection NATO 2.3m x 2.3m target 12km laser rangefinder can not measure 10 square meter vehicle 10km in standard 23.5km visibility.

In fact, when one LRF measure big target 20km in standard 23.5km visibility, then, normal measure 30% reflection 2.3m x 2.3m target can ensure only 9km and at most 12km.

Then, when you see one LRF for 2.3m x 2.3m target 10% reflection 10km in 10km visibility or 2.3m x2.3m target 18km in 23km visibility, you can ask for why the LRF can only measure big target about 20km in 23.5km visibility.

Or, when you see one LRF for max range 12km, then you can ask for how to measure 2.3m x 2.3m vehicle 8km.


 3, When LRF increases the measurement frequency, then, LRF distance performance will decay, even decay rapidly. normal high rate mid-long range LRF laser energy need 5mJ and at least 2mJ.

For example, 

when one LRF measure tank 10km with 1Hz, then, if use for 10Hz measuring rate, then maybe the LRF measure tank is only 7km.

When this LRF laser energy is very low, then attenuation speed will accelerate, even attenuation speed can be more than 60%, or only balance 40% / less than 40% for 1Hz to 10Hz.


4, Air visibility will affect distance performance, when air visibility is very bad, then distance performance will decay rapidly.

For example,

500m visibility is very different with 20km visibility. this is why many LRF is only said 2.3m x 2.3m vehicle 8km without any air visibility contidtion.


 5,  Continuous measurement and single measurement mean is very different, especially low energy Erbium-glass laser and fiber optic laser.

For example:

1Hz 2minutes 10km and 1Hz single measurement 10km is very different. 

some low energy LRF can be 1Hz continuous 2minutes, but, the starting measuring distance is different from the final measuring distance for max distance. This is very evident under the relevant standard conditions, especially strict and extreme measurement conditions.


6, Temperature condition will affect some LRF distance performance.

For example:

some LRF can measure max 18km in -20ºC, when temperature is -40ºC, then max disance is only 12km and even do not work.


  • Each one LRF have own typical measuring rate, some LRF have also max measuring rate mode and burst mode, burst mode measuring rate is very different with typcial measuring rate.

For example,

one LRF burst mode measuring rate is 6Hz continuous 30 seconds, then maybe typical measuring rate is only 1Hz continuous, when use for 3Hz measuring rate, then normal 3Hz can be continuous about 1 minute;

one LRF burst mode measuring rate is 1Hz contnuous 20 seconds, then maybe typical measuring rate is only 10ppm continuous to 0.2Hz continuous;

One LRF burst mode measuring rate is 3Hz, then, typical measuring rate is only 0.5Hz continuous, when use for 1Hz measuring rate, then 1Hz is only continuous about 1 minute(some model can be 90 seconds to 2 minutes). 

One LRF single measurement is 1.5 seconds, in fact, the measuring rate is burst mode,  real typical measuring rate is only 5ppm to 8ppm, especially low energy LRF.


Also, LRF must note meausring rate details, then can show the LRF real performance.

For example, typical 1Hz continuous 10minutes is very different with typical 1Hz continuous 30 seconds.  this is why many LRF meausring rate is only show 5Hz, 1Hz, 0.5Hz without any details.

This is why 6Hz burst mode and 3Hz burst mode typical measuring rate performance is lower than typical 1Hz continuous 10minutes.

  • Each one LRF have own typical reliability life, typical reliability life is LRF overall life performance, including all LRF part life and technological level . when use for cheap cost part or only assembled, then LRF cost can reduce, even reduce much, this is why some LRF do not show their reliability life and only said price is cheap.

For example,

one LRF reliability life is 20000 range measurement is lower than 100000 range measurement, many cheap LRF reliability life is only 5000 to 20000 range measurement, even lower than 5000 range measurement.

Shot lifetime is only set laser life or one part module life, such as Xenon lamp, diode pump etc, that is only one part for LRF.

Also, if working temperature condition is different, then shot lifetime is different too, even very different.

This is why normal best LRF reliability life can ensure at least 1000000 range measurement.

Then, when one LRF is used for bad cable, messy interface, messy wiring etc, then you can ask for how to warranty reliability life.