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DIGISONDE-4D
SYSTEM MANUAL
VERSION 1.2.11
3-54 SECTION 3 - OPERATING INSTRUCTIONS
OFFLINE DATA VISUALIZATION
3:93. DCART provides additional display capabilities for offline visualization of data previously saved. The
offline display selections can be found in Action menu of DCART. All viewing actions of DCART open a sepa-
rate window with similar displays as in the real-time sounding mode visualization of data, with additional con-
trols for opening files and browsing its contents.
AUTONOMOUS OPERATIONS OF DIGISONDE-4D
3:94. In order to configure Digisonde 4D for autonomous operations, it is necessary to complete the follow-
ing tasks:
1) Prepare measurement program specifications
2) Assemble programs in schedules
3) Design planning rules for schedule switching within one day
4) Add campaign requests if needed
5) Switch the sounder into autonomous mode
3:95. It is recommended to have different schedules for routine daytime and nighttime operations, and for
campaign periods:
• DAYTIME ionogram measurements typically have wider frequency coverage, coarser frequency reso-
lution, and higher receiver gain.
• NIGHTTIME ionogram measurements typically have smaller frequency coverage, finer frequency res-
olution, and lower receiver gain to accommodate stronger returns from ionosphere when no D region
absorption occurs.
• CAMPAIGN periods usually require higher cadence of measurements.
Basic Schedule Editing with DCART
3:96. Once a schedule is started, it repeats the measurement programs defined within it in an unending loop
until the schedule is stopped. In order to arrange 15 minute cadence of Digisonde-4D measurements (4 times an
hour), it is sufficient to define a 15 minute schedule. If a schedule has to combine operations of different ca-
dences, its duration shall match the least frequent cadence. For example, if 15 minute ionogram measurements
have to be combined with an hourly passive sensing observation, the usual solution is to create a 1 hour sched-
ule with 4 copies of ionogram measurement and one passive operation. Refer to Chapter 1 of this Section, Para
3:2 and onward, for review of programs and schedules.
3:97. The DCART Schedule Editor panel is used to assemble programs in schedules. Figure 3-43 shows a
sample schedule #17 that makes ionograms every 15 minutes. The left column of the DCART screen displays
the list of available schedules. The central panel made up by two Schedule editor components, the Program List
(upper section), and Schedule Image (lower section). Schedule #17 has fixed length of 15 minutes and, in addi-
tion to the daytime ionogram measurement program #8 at the schedule start, it also contains three additional
support programs: Built-In Test program #11 to evaluate system health status, Cross-Channel Equalizing pro-
gram #25 to calculate compensations for inequalities in 4 receiver channels, and CreateGainTable program #27
to refresh the autogain table (see discussion in Para 3:23 and Figure 3-7). The ionogram measurement is placed
at the schedule start so that ionograms are made at minutes 0, 15, 30, and 45 of each hour; historically a com-
mon Ionosonde cadence. The autogain program is placed at the end of the schedule to evaluate current noise
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