Sunstrobe recording
The Sunstrobe recording is from the English acquired technical term for a statistical measurement method, with which the vertical antenna diagram of a switched on receiving radar antenna is determined.
description
The sun not only emits visible light and neighboring frequencies, but a very broad spectrum of electromagnetic waves . This radiation could already be received with extremely sensitive receivers from old analog radar devices. On the radar screen this radiation appeared as a narrow Störsektor with noise interference (Engl. Strobe ), which came exactly from the direction of the sun and therefore Sunstrobe was called.
This sunstrobe is suppressed in modern digital radar devices, as the radar signal processor can precisely calculate the current position of the sun based on the date, time and the geographical position of your own location .
With sunstrobe recording, the level of solar noise is continuously recorded and it is assumed that solar radiation is constant during a measurement cycle . Since the sun passes through all elevation angles of the radar antenna during sunrise or sunset, the change in the amplitude of the sun noise can be used as a measure of the change in antenna gain as a function of the elevation angle .
During the measurement campaign, each measured value receives a time stamp with which the elevation angle of the sun associated with this measured value is later calculated.
Since the exact level of solar radiation at the receiving frequency of the radar device is unknown during the measurements, only a relative level is used as a reference in the method described so far. Usually the largest measured value is defined as ± 0 and all other measured values are shown as damping. Thus, a sufficiently precise statement can be made about the diagram form , but not about the expected range of the radar device.
Only when a measurement aircraft at a known altitude approaches the radar device can an absolute reference be made from the image with the relative measured values. If the size of the diagram is adapted to the range determined with the measurement flight, i.e. absolute ranges and heights are plotted on the abscissa and ordinate of the diagram, then all other ranges at the various flight altitudes can be read from the diagram without further measurement flights.
For radar devices that are not yet able to carry out this measurement process independently, there are measurement device sets that can record the antenna diagram. These sets of measurement devices are called RASS-S ( Radar Analysis Support System for Sites ) or SASS-S ( Surveillance Analysis Support System for Sites ).
From a Sunstrobe alignment (dt. Sunstrobe orientation) is used when the radar uses the measurement results of the Sunstrobes automatically to check, for example, the classification and corrected if necessary.
Individual evidence
- ↑ Measurement of vertical antenna diagram , radar tutorial
- ^ Sun strobe recording , radar tutorial, description of the measurement process