Data structure and display
The image below shows radar beam propagation in a complete sweep. The principle is the same for a WindCube Scan Lidar.
The image shows several azimuthal scans (PPI) at several elevation angles from 0° to 5°. Each azimuthal scan is full (the scanning head or antenna does a full 360° azimuthal rotation).
The data structure is two-dimensional, indexed by rays (or beams) and bins (or range gates). Each ray is oriented as a result of the antenna (or scanning head) in the atmosphere and is characterized in polar coordinates by an azimuth angle and an elevation angle.
- Azimuth angle
Angle between the projection of the line of sight on the local horizontal plane and the geographic north. It is defined clockwise from the geographic north, which corresponds to a 0° azimuthal angle.
- Elevation angle
Angle between the line of sight and the local horizontal plane, defined by the local reference framework associated to the device. 0° is the elevation within the local plane and 90° the zenithal direction.
- Angular resolution
Angular sector covering one ray (or beam). Minimum angle step that the line of sight can move.
- Bin (range gate)
A single sample of weather data measured at a known direction and distance from the device site.
- Bin size (range gate length)
The size of the bin (or range gate) along the ray (or beam).
- Display resolution
Constant spatial interval between the centres of two successive radar bins or lidar range gates. The displayed resolution is also the size of a bin or range gate on the display. It is determined by the bin size or range gate length and the overlap between successive bins or range gates.
| Weather Radar WRM200 | Weather Radar WRS400 | WindCube Scan Lidar | |
|---|---|---|---|
|
Azimuth angle |
Min. 0° Max. 360° |
Min. 0° Max. 360° |
Min. 0° Max. 360° |
|
Elevation angle |
Min. −2° Max. 108° |
Min. −2° Max. 92° |
Min. −16° Max. 196° |
|
Position accuracy |
0.05° |
0.05° |
0.005° |