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About ChubuSat-3 Satellite

Latest Information (on November 6, 2017)

We have received signals via amateur radio band from the ChubuSat-3 satellite on October 2017 since February 2017.
The status report is shown here.

Status report and favor to ask (on April 13, 2016)
Thank you very much for your support on the ChubuSat-3 mission.
We have taken a look at all the information that you kindly gave to us, and have used it as extremely valuable information.
The ChubuSat-3 satellite has a trouble now. We will try to recover the satellite, so it is very helpful for us if you can provide information about satellite modes: telemetry, slow beacon (50 word/min) and fast beacon (100 word/min). Especially, the fast beacon mode means the satellite is in a special state.
Thank you for your cooperation.

The ChubuSat-3 is now in the initial operation phase (on March 5, 2016).
  • The satellite communication via Amateur radio band was established
    • CW Beacon: The central frequency is 2 kHz lower than the expected value.
    • FM telemetry: The central frequency does not change, but a peak structure at +/-5 5 KHz is seen in the spectrum.
  • We have successfully received signals from ChubuSat-3.
Thank you for your reports on receiving signals from our satellite. We still need further information. We appreciate for your kind help.



E-mail address: chubusat3 [at] frontier.phys.nagoya-u.ac.jp

ChubuSat-3 Satellite


ChubuSat-3 is the 50kg-class microsatellite. In 2014, ChubuSat-3 was selected as one of the piggy-back payload of H-IIA launch vehicle.

Mission Purpose

The primary mission of ChubuSat-3 is to observe the situation of the global warming such as reduction of the glacier or retreat of the shoreline. For this mission, ChubuSat-3 has a high resolution camera. Furthermore, we will try to observe space debris with the camera as the extra mission.

System Overview

Attitude Control System

3-axis control with sun sensor, magnetic sensor, gyro, reaction wheel and magnetic torquer.

Power System

Solar cell with light weight and high efficiency, and NiMH battery.

Communication System

S-band for uplink/downlink, amateur VHF for uplink, and amateur UHF for downlink.

Amateur Radio Information

Orbit information

The TLE is shown below as of 10 AM on March 5, 2016. (Satellite ID 41339).
1 41339U 16012C   16063.72954763  .00000957  00000-0  69337-4 0  9992
2 41339  31.0095 219.1239 0013747  89.2458 270.9756 14.99457215  2280
The TLE is being updated.
The latest TLE is available at NORAD web site.

CW Beacon Information

ChubuSat-3 normally transmits CW beacon (437.425MHz ASK) including the Morse code (about 100/min.) as follows.
「S1 ** ** ** **」
「S2 ** ** ** **」
(interval and repeat from the top)

** following 'S1' indicates receive level, voltage of the battery ch1, ch2, and ch3 respectively. ** following 'S2' indicates voltage of the battery ch4, temperature of the battery A, B, and solar cell current respectively. Each value is converted from original analog value to digital value (0-255 HEX format) with ASCII characters. The conversion table from HEX value to original value is avaiable here.
If you receive the Morse message from ChubuSat-3, please report to chubusat3 [at] frontier.phys.nagoya-u.ac.jp .

HK Telemery Information

  • Rate: 9600 bps
  • Frequency: 437.425 MHz
  • Modulation: GMSK
  • Protocol: KISS
  • Decode Sequence
    1. Receive KISS protocol packet data (2 packets/second)
    2. Detect and remove packet header(0xC0 0x10) and footer(0xC0)
    3. Inverse FEND transformation (0xDB+0xDC->0xC0,0xDB+0xDD->0xDB) into 492 bytes packet
    4. Divide the 492 bytes packet into four 123 bytes sub-packets
    5. Remove 16 bytes header and 3 bytes footer from each 123 bytes sub-packet into 104 bytes data
    6. Decode error-correcting code (source code) from each 104 bytes data into 71 bytes telemetry data (HK telemetry data)
  • Contents of 71 bytes telemetry data
  • Telemetry List
  • Notes : The telemetry list refers thermal sensor temperature conversion table.
If you receive the HK telemetry data, it would be appreciated for providing us the data in KISS format (.kss).

Message Exchange Service Information

ChubuSat-3 provides the message exchange service. After the on-orbit checkout of the satellite (about one month after the launch), you can use the service, sending your message with amateur VHF (145.84MHz FSK 1200bps) then your message is written to the on-board memory. Anyone can read your message with amateur UHF (437.425MHz GMSK 9600bps) by sending inquiry message. The uplink/downlink format is available here.

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