ADS-B and radar display terminal-multi-source monitoring data simulation platform 5.5

Modify logs

1 This version modifies the software coordinate conversion algorithm.

The position information of the secondary radar monitoring data is expressed in polar coordinates, which is determined by the distance from the target to the radar, the azimuth, and the air pressure height measured by the aircraft. In the display, You need to convert the polar coordinate data to the WGS-84 coordinate system, then from the coordinate system to the station center Cartesian coordinate system, and then to the screen coordinate system. Three coordinate transformations are required to display the target on the computer screen.

The ADS-B measures the location information through the airborne GPS device, and the location information is represented by the WGS-84 coordinate system, including longitude, latitude and geometric height three-dimensional information. It also requires two coordinate transformations to display the target on the computer screen.

When a radar data and ADS-B monitoring data are connected at the same time, there is a certain deviation between the positions displayed by the terminal. After analysis, it is found that the possible problem is that the methods of coordinate transformation adopted by different coordinate systems are different and uniform, resulting in a large deviation between the two. After the corrected coordinate conversion algorithm, the deviation is reduced.

After the modification, the final result is displayed:

Local graph:

In the figure, the style size is set to 1 km. After the data of the two types of sensors are connected to the display terminal, the target location deviation is reduced.

However, the deviation still exists and cannot be eliminated. There are two main reasons:

1. Influence of ground curvature. As we all know, the shape of a map is not a positive sphere or positive elliptical body, but an irregular shape. The ground curvature varies in different places. The existing coordinate conversion algorithm is used, during processing, an elliptical shape closest to the Earth is usually selected for approximate analysis. WGS-84 is one of them. Therefore, such algorithms have unavoidable errors in actual use. The farther away from the coordinate conversion center, the larger the error will be.

2. Measurement Error effects of different types of sensors. The parameters of secondary radar and ADS-B measurement are not the same, and the measurement accuracy is also different. Therefore, there will be deviations between the two types of data.

3. Radar calibration problems. During a long period of operation, the horizontal state of the radar will change, so the data measured by the radar will also be deviated.

The software is still under development. You are welcome to give more comments to promote the maturity of the software. qq387969934.

ADS-B and radar display terminal-multi-source monitoring data simulation platform 5.5