IEEE Geoscience and Remote Sensing Magazine - June 2021 - 123

◗ broadband technologies, e.g., focal planes and refractive/diffractive
optical solutions designed to extend the
operational bands of optical instruments
◗ digital integration, e.g., fast detector sampling and digital
processing
◗ hardware- and software-based computational imaging
(including super resolution)
◗ lensless imaging methods.
GNSS AND SIGNALS OF OPPORTUNITY
WORKING GROUP
The purpose of the GNSS and Signals of Opportunity
Working Group is to cover all nonnavigational uses of
GNSS signals (Figure 3). These can be broadly divided
into two distinct groups: the use of GNSS signals received
after passing through the limb of Earth's atmosphere
(i.e., occultation) and the use of GNSS signals reflected
off Earth's surface, from which properties of that surface
may be determined (e.g., for mesoscale ocean altimetry),
also known as GNSS-R. Current technological trends covered
by the working group are
◗ multistatic and multifrequency GNSS instruments
◗ agile and stable antenna beam-forming techniques
◗ software-defined radio instruments
◗ onboard, real-time data processing.
REMOTE SENSING INSTRUMENTS FOR
SMALL SATELLITES WORKING GROUP
The Remote Sensing Instruments for Small Satellites Working
Group focuses specifically on remote sensing instruments
for small satellites. Nowadays, there is a very significant
increase in the deployment of CubeSat and small
satellite constellations by both governments and commercial
entities. In this new space environment, there are more
opportunities for cheaper and better ways to perform science
measurements that were out of reach with larger satellites.
Hence, this group addresses advances in
◗ miniaturization and low-mass,
low-power technologies
◗ deployable and origami designs
◗ space-qualification of low-cost instruments
◗
constellation-based measurements.
REMOTE
SENSING INSTRUMENTS
FOR UAVS WORKING GROUP
The Remote Sensing Instruments for
UAVs Working Group was recently
created in response to feedback from
members. Today, UAVs play an increasingly
important role as platforms
for remote sensing sensors in environmental
and industrial research. In
particular, lightweight optical sensors
already fill an important gap for
cost-effective observational studies in a huge variety of environments.
Radar sensors are still less common as weight,
energy, and processing requirements are often more demanding.
With this working group, we aim to foster experience
exchange, development, and application of microwave
remote sensing instrumentation specifically applicable for
UAVs (Figure 4). Applications range from active and passive
sensors in the centimeter-to-millimeter-wave frequency
spectrum, possibly in combination with optical and thermal
sensors.
(a)
(b)
(c)
FIGURE 3. A next-generation GNSS bistatic radar receiver. (a) An
NGRx digital motherboard and radio-frequency daughterboards.
(b) A low-noise amplifier/Cal module. (c) A GNSS-R dual-polarized
antenna. (Photos courtesy of Prof. Christopher Ruf, University of
Michigan, USA.)
(a)
(b)
FIGURE 4. The UAV instrumentation deployment. (a) The SAR instrument onboard a JX-1. (b)
Remote sensing instrumentation on a drone. (Photos courtesy of Prof. Josaphat Tetuko Sri Sumantyo,
Chiba University, Japan, and Prof. Wolfgang Rack, University of Canterbury, New Zealand.)
JUNE 2021 IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE
123

IEEE Geoscience and Remote Sensing Magazine - June 2021

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