Shaanxi Engineering Laboratory for Microsatellites (SELM) of Northwestern Polytechnical University
Aoxiang Zhixing (AX-1)

Satellite	Status	NORAD	Uplink	Downlink	Beacon	Mode	Callsign	Reports	Info	IARU freq coord	Telemetry Decoder
Star of AoXiang	DECAYED	41625	.	.	437.600	9k6 BPSK		latest report	details	YES	.

Star of Aoxiang is used for sun light polarization pattern detection. The satellite can determine the direction of sunlight with its polarization pattern under different angle. And then the sunlight direction can be used for navigation in space.

Most of the CubeSats have a volume range from 1U to 3U, which limits their applications due to the difficulty of miniaturizing payloads. To facilitate the needs on a larger but low-cost satellite platform, the AOXiang (AOX) project has been developed by Northwestern Polytechnical University (NPU). The primary objectives of AOX project are four-folds: 1) To demonstrate the world first 12U CubeSat Star of AOXiang and 12U orbit deployer which uses an innovative electromagnetic unlocking technology. 2) To investigate the feasibility of using polarized sunlight for spacecraft attitude determination and navigation, and perform microgravity research using a miniaturized gravimeter. 3) To test a fault tolerant on-board computer using the System On the Programmable Chip (SOPC) technology, and 4) To gain the experience from developing the CubeSat and the subsystems. The CubeSat was launched in June 2016.

SAOX has more than six months‘ lifetime in Low Earth Orbit (LEO). It carries two science payloads and will carry some innovative components. One payload is a Polarization Light Sensor (PLS) which is used to collect the polarized sunlight data in space. Polarization is a property of waves that can oscillate with more than one orientation. Polarized sunlight has useful information for spacecraft attitude determination and navigation. The PLS developed by SELM is based on the bionic research. It can get the maximum polarization angle which is vertical to the solar meridian plane, and then the attitude and navigation information of the CubeSat could be collected from the polarization angle information. As the main payload of SAOX, the PLS can effectively detect the Earth’s atmosphere polarization mode with the data collected in orbit, and provide an early-stage research for the application of polarization in satellite navigation[4]. The other payload is a gravimeter which comes from an open call. In 2014, the SAOX team called for a second science mission payload. Finally, the proposal of micro gravimeter was selected from many candidates. It is used for orbit gravity field measurement and could contribute to e.g. seismic survey and forecast, oil and gas exploration, etc.

Telemetry

Communication system SAOX use the amateur band for Telemetry, Tracking, and Command(TT&C). Ultra High Frequency (UHF) is for downlink and Very High Frequency (VHF) is for uplink. The communication system consists of a transceiver board and a monopole antenna system from Innovative Solution In Space B.V. The I2C bus is used to communicate with OBC. The maximum data rate of the transmission is 9600 bps.

Links

https://www.researchgate.net/publication/311279434_Star_of_Aoxiang_An_innovative_12U_CubeSat_to_demonstrate_polarized_light_navigation_and_microgravity_measurement
http://mstl.atl.calpoly.edu/~bklofas/Presentations/DevelopersWorkshop2017/Research%20of%20CubeSats%20in%20Northwestern%20Polytechnical%20University%20and%20other%20Chinese%20Universities.pdf

Launch

June 25, 2016 – 12:00 UTC with an Long March 7 rocket from Wenchang Satellite Launch Center, Hainan, China

The Chinese AX-1 satellite re-entered the atmosphere on September 29, concluding a three-month mission to test out innovative navigation technology.

DECAY_EPOCH          WINDOW   REV    DIRECTION   LAT    LON    INCL   NEXT_REPORT
2016-09-29 21:30:00  120      1536   descending  34.7   307    40.8   0      
2016-09-29 21:29:00  120      1536   descending  36.3   302.2  40.8   2      
2016-09-29 21:29:00  120      1536   descending  36.3   302.2  40.8   0      
2016-09-29 21:29:00  120      1536   descending  36.3   302.2  40.8   2      
2016-09-29 21:27:00  120      1536   descending  38.9   292.3  40.8   6      
2016-09-29 22:37:00  540      1537   ascending   23.1   192.3  40.8   24     
2016-09-29 23:39:00  780      1537   ascending   -38.4  81     40.8   72