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DIGISONDE-4D
SYSTEM MANUAL
VERSION 1.2.11
SECTION 3 - OPERATING INSTRUCTIONS 3-15
Programming Vertical Incidence Ionogram Measurement
3:25. The following data processing options shall be considered when programming the ionogram measure-
ment:
a. OUTPUT FILES: RSF versus SBF output format.
• Default setting is RSF (Routine Scientific Format), ionogram with echo directions
• SBF (Single Byte Format), for ionograms without echo directions, used for sustaining operations
during periods of hardware faults in one or more receiver channels
b. TWO-FREQUENCY PRECISION RANGING / PRECISION GROUP HEIGHT (PGH)
• Precision ranging is disabled by default.
• Precision ranging is enabled by (a) setting number of fine steps to 2 and (b) selecting fine frequen-
cy step of 5 kHz. Then data from the second frequency are used to calculated precise range of ech-
oes with 1 km resolution and then discarded.
NOTE
Ionograms with enabled two-frequency precision ranging take double time to complete.
• Precision ranging mode requires RSF format for the output ionograms
c. DATA REDUCTION: enabled/disabled
• Data reduction is disabled by default.
• For locations with a limited Internet bandwidth available for data delivery to the external data re-
positories, it may help to threshold data below the noise level (as determined by most probable am-
plitude, MPA) for a better file compression.
d. RFIM:
• RF Interference Mitigation removes powerful narrowband interferers in the receiver bandwidth
RSF Ionogram with Echo Directions
3:26. Typical example of the RSF ionogram measurement program and corresponding ionogram display is
shown in Figure 3-8. The concept for assigning colors to echo directions is explained in Section 1, Chapter 1.
The insert in Figure 3-8 summarizes the mapping and provides direction codes used in the color legend. “No
Value” color is used for signals whose direction of arrival could not be determined reliably.
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