FMCW lidar is a type of laser radar that uses frequency-modulated continuous wave (FMCW) light. It is used for remote sensing, with surveillance, traffic monitoring, and mapping applications. FMCW lidar systems use laser diodes or solid-state lasers to generate the modulated waveforms. Lidar systems can also be used for non-laser-based sensors such as radar and radio wave detectors.
FMCW lidar has become an increasingly important component of many modern surveillance systems due to its ability to provide high-resolution 3D mapping and time-series data collection at a long range. Lidar is used in many applications, including security, transportation, utility management, land management, and real estate development.
The Components of the FMCW Lidar System
The FMCW lidar system consists of three major components:
1. Laser source: A laser is a light source that produces a beam of light at a specific wavelength; this beam is either continuous or pulsed. The laser can be focused through lenses to generate an image with high resolution.
2. Scanner: The scanner receives the laser’s beam and projects it onto the target area for processing by the computer system.
3. Receiver: The receiving unit collects reflected signals back from the target area by using spatial filters that filter out unwanted noise caused by clouds or other objects in its path while retaining the desired return signals from targets located within its field of view (FOV).
FMCW Lidar Benefits
Better range resolution
In laser radar, the range data is usually acquired in an angular format, the same as that used for lidar ranging. The range resolution increases with increasing frequency, i.e., higher frequency gives better range resolution. However, at a certain point in time, when the wavelength becomes too small such as when the laser wavelength becomes very small, this technique cannot be used because it will not provide sufficient information to determine spatial coordinates. This is because higher frequencies require shorter wavelengths and, therefore, smaller fields of view.
No need for calibration
The main advantage of FMCW lidar is that it does not need any calibration since it works on reflected light. Hence, no moving parts are involved in causing errors in its measurement process. As a result, there is no need for calibrating or adjusting parameters such as power levels, etc.
More accurate
FMCW lidar sensors are more accurate than traditional lidars, which is why they are so popular for autonomous vehicles. In addition to their precision, FMCW sensors also have a wide field of view, allowing them to see in all directions simultaneously. This makes them ideal for detecting road hazards and hazards such as pedestrians or cyclists.
Ideal for different weather conditions
They can be used in sunny and cloudy conditions since they use light from reflected light from the sun or other sources. This means that they do not need to use any image processing techniques like cameras or filters, making them very easy to use even in bad weather conditions.
Longer range
FMCW lidar sensors can be used to generate 3D maps with a longer range than traditional lidars, especially if you place the sensor on a high point such as a building or pole where there is more space for the laser beam to travel through before hitting something. The long-range means that you can create 3D maps that accurately show the environment around your vehicle without having to drive back and forth repeatedly over the same area multiple times over several days or weeks like traditional lidars do when trying to collect data from different angles and distances at once while collecting data from multiple points.
Flexible
FMCW lidar can be used as a stationary or mobile device, depending on your needs and requirements. It can also be used in harsh weather conditions without any problems, making it one of the best solutions available when it comes to measuring distances accurately without any issues at all.
Reliability of traditional LIDAR systems
A LIDAR system relies on a laser beam to measure distances, and it is prone to errors when the laser beam is obstructed by clouds or fog or when the temperature changes rapidly.
However, FMCW lidars use radio waves with much smaller bandwidth and can be used in adverse weather conditions. The results from an FMCW lidar system are more reliable than those from a traditional LIDAR system.
Key Takeaway
FMCW lidar is the most reliable type of lidar system. It uses two rotating polarization beams and can detect moving objects with a rotational velocity of more than 10 meters per second.
