S-BAND GROUND STATION VERIFICATION AND OPERATION FOR
LEAN SATELLITE, HORYU-IV
Department of Applied Science for Integrated System Engineering
Graduate School of Engineering
Kyushu Institute of Technology, Kitakyushu, 804-8550 Fukuoka, Japan
Name: BONSU Benjamin, Student No: 14350943
1. INTRODUCTION: Lean-satellites is equivalent to small/micro/nano/pico satellites that utilizes
untraditional risk-accepting development methodology to achieve low-cost and fast-delivery. Leansatellites mostly developed by universities are launched into Low Earth Orbit (LEO) with analtitude range from 400km to 900km. Communication between satellites and ground stations mostly
utilizes Amateur VHF and UHF bands, with respective data throughput of 1200bps and 9600bps.
The challenge in LEO satellites is limited time window of communication. Therefore, larger size
data downlink requires several passes during communication. As lean satellite missions become
sophisticated, demand for high-speed communication is arising.
2. ABOUT HORYU-IV LEAN SATELLITE: The Arc Event Generator and Investigation Satellite(AEGIS) also known as HORYU-IV was developed by Kyushu Institute of Technology (Kyutech).
HORYU-IV was released into LEO on the 17th of February 2016 (18:17:34 JST) at an altitude of
575km to acquire images of the discharge occurrence phenomenon on the experimental solar panels
onboard. To demonstrate this advanced scientific technology, S-band communication subsystem
was implemented onboard with transmitter data throughput of 100kbps, BPSK modulation scheme,
bandwidth of 120kHz and transmitter output power of 0.4W (26.4dbBm) to downlink packets ofdata to its dedicated S-band ground station.
3. S-BAND GROUND STATION: A 2.4m parabolic dish antenna system (parabolic reflector, horn
feed antenna, antenna drive system, and termination box) was installed at the Kyutech General
Research building-1 rooftop. The control interface system (tracking and receiver computers) andcustomized S-band radio receiver were installed at the control room in the 8th floor of the samebuilding. The development and installation of the S-band ground station was done by both Microlab
and ELM Companies.
4. RESEARCH PURPOSE: My research purpose is to perform verification test on the S-band
ground station installed and configured by Mircrolab and ELM and be able to operate the S-bandground station to receive downlink data during HORYU-IV operation.
5. VERIFICATION TEST AND RESULTS:
Before HORYU-IV was launch, interference test performed on S-band ground station was free from
WiFi signals and Mobile signal. End to End communication test results at a distance of 2600km(path loss of 168.3dB) between transmitter station and S-band ground station could able to satisfy
the design requirement with a link margin of 20.2dB and data rate reception of 46kbps
6.OPERATION : During HORYU-IV initial operations, the received data rate and link margin
resuts could not satisfy the mission requirement. The two main anomalies detected that affected
data rate reception and received signal strenth was doppler shift and attitude control. To mitigate
these anomalies, doppler correction software was developed to interface with a commercial off theshelf radio receiver, (ICOM R9-500) and its hardware interface to control the frequency shiftduring HORYU-IV operation. After modification of S-band ground station and satellite
stabilization, the downlink data rate reception could able to satisfy the requirements. Also afterattitude control was able to stabilize

1S-band ground station configuration before
modification

Good Packets

S-band ground station configuration aftermodification

Good Packets

Error Packets

Error Packets

600500500

Packets

Packets

400300

400
300

200

200

100

10001015202530354009845100 102 104 106 108 110 112 114

Day from Launch

Day from Launch

Downlink packet data analysis results before S-band
ground station modification

Downlink packet data analysis results after S-band
ground station modification

7. CONCLUSION AND FUTURE WORKS: S-band ground station was successfully installed atKyushu Institute of technology General Research Building 1. Before launch, verification test could
satisfy the mission requirements. After HORYU-IV launch, it was realized that satellite attitudecontrol and Doppler shift can greatly influence data reception. After modification of the S-band
ground station configuration, the data rate reception could satisfy data mission requirement. Fromthe lesson learned in this research, Doppler shift should be included in end to end communication
test by performing real satellite operation with the ground station under test. Enough link margin
should be set so that in case of attitude control delay, to stabilize the satellite, the S-band groundstation can able to still decode the weak downlink signal. One general advise, is youngcommunication engineers, should not rely on manufacturers documents regarding system
specification but verification test should be performed to verify system performance.

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