IEEE Geoscience and Remote Sensing Magazine - December 2023 - 168

a nonzero intermediate frequency of 70 MHz, at which it
is filtered using a fifth-order Chebyshev bandpass filter.
Then, its instantaneous power is computed using a received
signal strength indicator (RSSI) in 4-MHz frequency bins,
acquiring 1,000 samples in each one. Finally, a simple suite
of detection algorithms are performed onboard, including
both pulse and frequency detection/blanking as well as
temporal and spectral kurtosis and skewness analysis [15].
K-BAND RADIO-FREQUENCY INTERFERENCE
MONITORING PAYLOAD
The frequency range of 23.6-24 GHz plays a crucial role in
monitoring water vapor in Earth's atmosphere, benefiting
weather forecasting and improving radar altimeter measurements
[16]. However, the licensing of nearby frequency
bands for the new 26 GHz 5G communication network,
particularly from 24.25 to 25.25 GHz, has raised concerns
in the microwave radiometry community regarding potential
interference. Such interference poses a risk to passive
Earth observation measurements, potentially impairing
their accuracy and having adverse effects on meteorological
forecasting.
The K-band RFI monitoring payload, available in Figure 10,
consists of a 2 × 2 patch antenna array connected to a doubleconversion
superheterodyne receiver and an RSSI to measure
the power in 10-MHz frequency bins between 24 and 25 GHz.
The same RFI detection algorithms as for the L-band payload
will be implemented [15] and tested in a drone field experiment,
sponsored by the GRSS Frequency Allocations in Remote
Sensing (FARS) Technical Committee, that is planned
for the coming months.
GROUND SUPPORT EQUIPMENT
With a plethora of interconnected devices and functionalities,
the mission's strict testing requirements naturally
render subsystem-limited verification insufficient, thus
leading to the design of ground support equipment (GSE),
which can be seen in Figure 11, in order to better identify
and correct possible errors in both design and integration.
FIGURE 9. The L-band RFI monitoring payload antenna (PL2).
FIGURE 10. The K-band RFI monitoring payload (PL3).
ELECTRICAL GROUND SUPPORT EQUIPMENT
To test the system without the need for full assembly, which
would both obscure the proper testing of some features and
reduce the integrity of the subsystems by repeated manipulation
and fastening, a FlatSat approach was adopted. Consequently,
a PCB test bed of 32 × 27 cm2 was designed with
the highest grade of flexibility in mind. The board features
both vertical connectors for mounting the inner PCBs on
either side and cable headers for the outer boards, allowing
full access for inspection and testing. Additionally, an identical
version of the satellite's EPS is embedded in the board,
(a)
(b)
FIGURE 11. The GSE: (a) electrical GSE and (b) mechanical GSE.
168
IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE DECEMBER 2023
IEEE Geoscience and Remote Sensing Magazine - December 2023

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