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Top Cute Digipeater Service

2006/3/1 updated

*Outline of Service* *Function* *Operation mode* *How to Use* *Operaiton Schedule*

Cute Digipeater service

Cute-1.7 + APD has a digital repeater(Cute Digipeater) service mission using amateur 1200MHz band for uplink, 430MHz downlink mode. Although this mission is simple and experimentaly developed, it will be the first challenge for nano/pico satellites manufactured in a university in Japan. We sincerely welcome your advice to make it wonderful.

Cute Digipeater service uses amateur 1268.5MHz, GMSK, Ax.25 protocol to register your message to the satellite. When you succeed message registration, Cute-1.7 + APD will reply acknolegde imediately. This message will be sent at moderate interval when Cute-1.7 + APD is in an amateur service mission mode. Sine anyone can listern this message, international communication can be realized not only in the same sight of the satellite but also in another sight.

Cute Digipeater service has 2 functions. One is "Multicast mode" and the other is "Uplink mode".

• Multicast mode

In this mode all stored messages will be sent sequentially. Anyone who has Cute-1.7 + APD telemetry decodable radio transceiver can listen these messages. Message format is shown in follwing.





Multicast message format example： #01 00 200602181200 JQ1YCZ CQ Hello, world! #77 28 200702180600 JQ1YCZ JQ1YCC Happy Birthday to Cute-1.7! ### ## ############ ###### ###### ################################# * value * H0(3words): Message ID (from #01 to #99) H1(2words): Downloaded count of this message． (This message is automatically deleted when 50 downloaded) H2(12words): Date and Time message accepted A(6words): Call sign Source (no more than 6 byte) B(6words): Call sign Destination (no more than 6 byte) C(Max50words): Massage (no more than 50 byte)

Messages are downloaded sequencially from #01. When all registered messages are downloaded, the following message will be shown and message #01will be downloaded again.




Now 7 saved messages


When this mode is restarted after resumed, message which was suspended to be sent before will be downloaded. Massage which was downloaded 50 times will be removed automatically. This service is at any time suspended by operation center at Tokyo Institute of Technology. Please understand that in this case all messages might be deleted without informaion. When no massages are registered, messages which were pre-registered before lauch by developers are downloaded. These message starts from the word [BLANK].


• Uplink mode

In this mode, 1200MHz receiver for Cute Digipeater mission is ready for accept your message to store. Message must be in the format determined in the following and transmitted in 1268.5MHz GMSK 9600bps Ax.25 protocol or SRLL protocol. When Cute-1.7 + APD accept your message, satellite will reply acknowledge signal imediately in 437.505MHz telemetry link. Anyone can listern this reply signal. More detailed information, please see communication subsystem section.


Uplink message format example： JQ1YCZ CQ Hello, world! JO1ZUT JQ1YCC How are you? ###### ###### ################################# A(6words): Call sign Source (exactly 6 byte) B(6words): Call sign Destination (exactly 6 byte) C(Max50words): Massage (no more than 50 byte) ** Call sign must be 6 byte. When less than 6 words, use 'space'.

When message over 50 byte or less than 14 byte including call sign, satellite reply error as shown below.




Illegal data

When message is successfully registered, the word [via cute] is added after the message frame when it is downloaded. Check this message to confirm registration. Anyone can listern this message.




reply from Cute-1.7 + APD JQ1YCZ CQ Hello, world! -> JQ1YCZ CQ Hello, world! [via cute] JO1ZUT JQ1YCY How are you? -> JO1ZUT JQ1YCY How are you? [via cute] ###### ###### ####################### -> ###### ###### ####################### [via cute]

After message successfully registered, it will be downloaded with the latest ID and header in Multi-cast mode. Cute-1.7 + APD replies number of registered message against the following command . Anyone can know how many messages registered now.




Command: countmsg Reply: Now 17 saved messages Now ## saved messages


Cute-1.7 + APD change its mode from uplink mode to multi-cast mode, when satellite accept the follwing command. Only the latest message will be downloaded.




Command: multicast Reply: #17 17 200602181500 JQ1YCZ CQ Hello, world2! ### ## ############ ###### ###### ###################

Next time when satellite operates in multi-cast mode, message download will start from next ID number.

Cute-1.7 + APD will reply time, to the command.




Command: timeplease Reply: Cute Onboard Time is 2007/01/11 06:30:00 Cute Onboard Time is ####/##/## ##:##:##

On nominal operation phase of Cute-1.7 + APD, FM telemetry including nominal mission data(APD sensor data, Thermal data, Gyro data, etc) are periodically downlinked according to the operation schedule. When you want to know the status of Cute Digipeater service, you should check satellite status "serviceMode" within frame 0 of CW telemetry.
Cute-1.7 + APD has only one telemetry downlink line except for CW beacon downlink line. Therefore, 430MHz FM telemetry downlink line are shared between Cute-Digipeater message downlink and another mission data downlink. Because of the above case, Cute-Digipeater service has two following operation modes.

1. User uplink is enable under downlinking nominal mission data
2. User uplink is enable under downlinking stored messages(Multicast mode)

The details are shown in the following table. Each number of the operation mode(I and II) corresponds to the value of "serviceMode" within CW telemetry.

When you want to uplink the message to Cute-1.7, you should transmit your message by UI frame packet following the above uplink message format.
Below is a example of communication with Cute-1.7.

On nominal operation, Cute-1.7 + APD periodically transmits the following FM packets in the same format as CUTE-I
  JQ1YCC>JQ1YCZ: *************Nominal TLM*********
We will take an example of the case that user uplink is enable under downlinking nominal mission data, as follows.

I. < User uplink is enable under downlinking nominal mission data >

[Check of Frame 0 of CW telemetry: serviceMode = 1]

JQ1YCC>JQ1YCZ: *************Nominal TLM*********

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: *************Nominal TLM*********

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: *************Nominal TLM*********

(time interval(ex. 2sec))

-User transmit countmsg command (to acquire the number of stored messages)-

 JQ1YCZ>countmsg

JQ1YCC>JQ1YCZ: Now 0 saved messages

(time interval(ex. 2sec))

-User transmit message data-

 JQ1YCZ>JQ1YCZ ALL    ****message data****

JQ1YCC>JQ1YCZ:JQ1YCZ ALL    ****message data**** [via cute]

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: *************Nominal TLM*********

(time interval(ex. 2sec))

-User transmit multicast command (to conduct multicast on purpose)-

 JQ1YCZ>multicast

JQ1YCC>JQ1YCZ: #01 00 200602181500 JQ1YCZ ALL    ****message data****

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: *************Nominal TLM*********

(time interval(ex. 2sec))

-User transmit timeplease command (to acquire onboard time)-

 JQ1YCZ>timeplease

JQ1YCC>JQ1YCZ: Cute Onboard Time is 2007/01/11 06:30:00

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: *************Nominal TLM*********

．．．

Next, we will take an example of the case that user uplink is enable under downlinking stored messages(Multicast mode), as follows.

II. < User uplink is enable under downlinking stored messages(Multicast mode) >

[Check of Frame 0 of CW telemetry: serviceMode = 2]

JQ1YCC>JQ1YCZ: #01 17 200602181500 JQ1YCZ ALL    Hello, world!

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: #02 17 200602181500 JQ1YCZ ALL    Hello, world2!

(time interval(ex. 2sec))

-User transmit countmsg command (to acquire the number of stored messages)-

 JQ1YCZ>countmsg

JQ1YCC>JQ1YCZ: Now 5 saved messages

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: #03 17 200602181500 JQ1YCZ ALL    Hello, world3!

(time interval(ex. 2sec))

-User transmit message data-

 JQ1YCZ>JQ1YCZ ALL    ****message data****

JQ1YCC>JQ1YCZ:JQ1YCZ ALL    ****message data**** [via cute]

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: #04 17 200602181500 JQ1YCZ ALL    Hello, world4!

(time interval(ex. 2sec))

-User transmit timeplease command (to acquire onboard time)-

 JQ1YCZ>timeplease

JQ1YCC>JQ1YCZ: Cute Onboard Time is 2007/01/11 06:30:00

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: #05 17 200602181500 JQ1YCZ ALL    Hello, world5!

(time interval(ex. 2sec))

JQ1YCC>JQ1YCZ: #06 00 200701110630 JQ1YCZ ALL    ****message data****

．．．

We are currently conducting initial checkout of the satellite. Please wait for a while.

Other Information

Because Cute-1.7 + APD has only one downlink frequency, Cute digipeater mission can not be opetated at any time. While in other missions mode, we suspend Cute digipeater service. Please check CW telemetry whether or not this Cute Digipeater accessable. CW telemetry can be listened at any time all over the world. Detailed information about CW telemetry, please see page about CW telemetry format. We also inform on operation schedule page.

Point of Contact

If you have any questions and comments about Cute-Digipeater service, please contact the following address.
POC: cute1.7_question[at]lss.mes.titech.ac.jp

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