Frequently asked questions
Laser Range Finding
No, shock or vibration does not affect accuracy in any way. Whenever the receiver receives a signal, it calculates the distance, always with the specified accuracy. In addition, we perform intensive shock and vibration testing on all of our laser rangefinders to ensure that all stated technical specifications are maintained over time.
In some applications, e.g., measurement through vegetation or targets of a convoy, there are reflections from more than one object in the beam path. If they have a distance difference of at least 30 m (target differentiation), the LRF identifies them as separate objects and displays separate distances. Depending on the module, up to 5 multiple targets are possible.
Targets are sorted by signal strength, not distance. Our embedded software algorithms calculate them using a relationship based on signal strength versus noise. Typically, the strongest signal comes from the target at which most of the beam is directed, and therefore appears first.
The divergence indicates the field of view of the laser beam. For example, a divergence of 0.5 mrad means that the laser beam is circular and has a diameter of 0.5 m at 1000 m distance. A narrow beam divergence is important to be able to accurately hit a selected target and to achieve a long-range performance. It must be ensured that most of the beam is reflected by the selected object and is not lost in the environment.
The rangefinder algorithm is a closed loop controlled circuit. This means that the LRF dynamically adapts its behaviour based on the environment, the target distance, target albedo etc. A lower range performance when integrated into a host system typically occurs when the range finder experiences optical crosstalk within a system. This happens if energy from the transmitter channel is directly coupled to the receiver. This causes the LRF to reduce the emitted energy in order to protect the receiver from being destroyed; and the result is a reduced range performance.
Yes, we provide a so-called interface kit, so that you can put the LRF module into operation within 10 minutes of receiving the goods. This way you get a better feeling of how the module works and what you can achieve with it.
Yes, it is possible to use pointer (830 nm) and measuring laser (1550 nm) simultaneously. The module will keep its original eye-safety level, as the two wavelengths are independent for the laser classification.
The housing of our LRFs is not sealed and the module itself is not gas or water-tight. In case, the host system is flushed with a gas (e.g. nitrogen), our modules provide ventilation openings to deal with this.
When the laser rangefinder is activated, a series of extremely short laser pulses from the transmitter are sent through the smaller objective lens to the target (multi-pulses). At the target, laser pulses are reflected back. Most of the pulses are absorbed or diffusely reflected by the target and only a very small percentage are reflected back to the LRF module. These remaining pulses are received by the larger objective lens and are focused onto the proprietary receiver diode. The receiver diode starts sampling the echo at a very high frequency and together with our sophisticated measuring algorithms it allows the laser rangefinder module to calculate a reliable distance – even if only a few pulses were reflected.
Vectronix is one of the few truly integrated fiber laser manufacturing companies on the world. We have two different versions of fiber lasers (LRF 6019 & LRF 7047) and they are all fully developed and produced here in Heerbrugg, Switzerland. We developed our own transmitter electronics as well as the matching receiver electronics to get the optimal performance out of our laser rangefinder module.
When integrating or handling a module, be careful with ESD as the LRF module is sensitive to electrostatic discharge. Do not touch any electronics or components unless protective measures are in place. Measures such as wearing a grounded wrist strap, use of anti-static bags and trays, and a workplace with grounded mats.
Yes, it is possible to mount and operate our fiber laser modules (LRF 6019, LRF 7047) with the Laserbox detached, to minimize the front area. To do this, a special mounting set is required. This set contains a flexcable, a flexcable securing clip and mounting screws with washers.
The laser rangefinder modules LRF 6019, LRF 6042 and LRF 7047 are equipped with a 1550 nm laser for distance measurement and with an optional 830 nm laser pointer. The pointer is built directly into the laser measuring system and uses the same fiber and optics as the 1550 nm laser. If this option is chosen, the boresighting of the complete LRF module can be done easily by just aligning the 830 nm pointer, as this aligns automatically also the 1550 nm laser, which is responsible for the distance measuring.
To make the laser spot of the 830 nm laser pointer visible, a standard NIR camera or a night vision device can be used. These devices are significantly cheaper than a 1550 nm camera. By using a boresight chart at a defined distance, the LRF can be aligned by bringing the main optical axis of the host system and the LRF to the predefined positions on the boresight chart.
Magnetic North Finding
The DMC-SX had to be discontinued as many of the components are no longer manufactured. The DMC-pico was developed as the ideal replacement. The specifications such as accuracy, shock, vibration are identical. Furthermore, the DMC-pico offers additional benefits, such as:
- Software commands are similar to DMC-SX
- Line-of-sight orientation is now user programmable, allowing for integration design changes without having to return the DMC to the factory for reprogramming
- Impressive improvements in size and weight
- UART and SPI interfaces
- CE certified
- Additional features such as Magnetic Disturbance Detection that can warn users if their azimuth readings are being affected by magnetic disturbances
- System State Compensation that allows a method to negate the effect of hard magnetic sources on the DMC-pico in numerous states of operation
To achieve the azimuth accuracy stated in the data sheet, the elevation and bank angles must be kept within a range of –45 to +45 °.
- there has been a significant temperature change (e.g. +/- 20°C) as the magnetization of materials is temperature dependent
- there has been mechanical shocks in case the position of materials have changed
- substituting or adding magnetic materials, for example, changing a battery
The Figure of Merit (FOM) is a magnetic compensation value and is the output from a compensation procedure.
The FOM or compensation accuracy does not predict the final azimuth accuracy. In other words, the FOM is an indicator of the compensation quality rather than of the azimuth accuracy.
The FOM is expressed in degrees x10. For example, an FOM of 03 represents 0.3 degrees. If the FOM is greater than 0.5 degrees, we recommend repeating the compensation procedure.
The Magnetic Disturber Detection (MDD) gives feedback on whether the compass is influenced by external magnetic disturbers. If activated, the DMC displays a “Probability Value” in percent, which is calculated based on history data, precisely from last 12-point compensation procedure. The value indicates the whether a measurement is disturbed more than a given value.
The System State Compensation (SSC) is a feature unique to the DMC-pico only. This is a software which allows the removal of influences due to magnetism for different states in host system. This can save the integrator from expensive last-minute design changes. And the good thing is that no additional hardware is required.
Example: The host system has different operational states. Instead of performing / saving / restoring a 4- / 12-point for each state, just do one compensation and measure once the “deltas”, then restore the deviations based on the host system state (= added / removed disturbers).
Example states are: camera on/off, battery powered/remote powered
Yes, here we recommend using the DMC-pico as it measures within a range of 360°. This means that the line of sight is fully under the control of the user.
This may be caused by a strong magnetic influence. Reposition the DMC away from any disturbers. If the problem remains, there could be an A/D fault. Please contact Safran Vectronix customer support for further advice.
Inside a vehicle is a ‘noisy’ environment for a compass, however the DMC can be user compensated to cope with static or fixed disturbances. The problems come when there are unstable fields such as from electric motors and equipment. Each installation is different however and the DMC has been successfully fitted to vehicles with accuracies in the region of 1 degree.
As the maximum range value in hex is 7FFF (32767 decimal), the best resolution can be 6400/32767 which is 0.2 mil or 0.011 degrees.
The DMC is designed to be mounted within a host system and so only subject to internal pressure levels.
There is no noticeable difference in power consumption between the two.
There is no restriction but as you move towards the magnetic poles, the DMC becomes less accurate as the earth’s magnetic field lines gradually become less horizontal and more vertical.
There is no set distance after which we recommend to recompensate. It is good housekeeping to do a compensation before going out on a mission/task or where the unit has travelled and has been subject to shock and vibration during transit. The compensation procedure compensates for magnetic influences that ’move’ with the compass. That is, the magnetic influences within your device or are fixed to the device. Therefore, compensation becomes necessary when you change something within the device. For handheld devices, this usually means battery changes. Because the magnetic effect of materials changes with temperature, we also recommend a compensation where there has been a change of more than 20° C between current and last compensation temperature.