Procedures

This page outlines the procedures for the following :

Ground plane bonding to the satellite structure
Assembly of the coaxial cable
Assembly of the transceiver to the communication board
Assembly of the test jig for the antenna and ground plane combination
GUI & SDR test procedure

Coaxial Cable Assembly

This section outlines the procedure to properly build the coaxial cable as per NASA-STD 8739.4A

Transceiver Assembly

This section outlines the procedure to assemble the transceiver to the communication board.

Setting up the Gomspace transceiver

This section outlines the procedure to set/configure the Gomspace AX-100 transceiver. To ensure you are using the AX100 safely, read the Quickstart guide in the manual and wear gloves and an ESD wristband when handling the device. An antenna should be connected to the AX100 whenever there is anything connected to the board/AX100.

Warning: Please ensure that any PC/Laptop connected to the USB cable has a properly grounded AC-plug.

The external power supply ground and PC/Laptop ground must be the same. Failure to do so will result in

Common Mode noise on the GND lines of up to 100+ Volts.

Warning: Do not power the system using FTDI power and external power supply simultaneously.

Important: Please make sure that the default-file has been stored correctly before launching. Otherwise the

system will startup using the internal backup configuration in the MCU Flash. The internal backup configuration

in the MCU Flash will have the tx_inhibit parameter set, so the radio will effectively stop transmitting.

0 Flight Parameter Setup

These are the instructions on how to set the AX100 Gomspace Transceiver for flight. Steps 9 and 13 verify that the AX100 parameters are saved correctly, will withstand a power interruption or watchdog timer expiry, and are ready for flight.

Supplies: Comms board, FTDI cable, computer with Putty installed, gloves, and ESD wristband.

Disconnect any external power to the board.
Ensure that the antenna is connected to the AX100.
Connect the FTDI cable from the computer to the AX100.
Open Putty, and set the baud rate to 500 000.
Use this process to check and save parameter tables 0, 1, and 5.
1. Type
  param mem {Table Number}
  then enter into Putty to load the table into memory.
2. Type
  param list {Table Number}
  to view the parameter list.
3. Ensure that all of the parameters match the table values in the table below under the "IRIS Flight value" or the "Default Value" if not specified.
  - For all the values that do not match, type
    param set {Name} {Value}
    to change it.
4. After all values for the table have been set properly, type
  param list {Table Number}
  to make sure the values are all correct.
5. Type
  param save {Table Number} {Table Number}
  to save the table to file number {Table Number}.
Type

config update_default all
to save the default configuration for all tables. You should see the following messages:
Table CRC 9508
Data CRC 1900
Updated settings in FRAM for table 0, saving to file 0: OK

Table CRC 9508

Data CRC 1900

Updated default factory settings in FRAM for table 0, saving to file 24: OK

Table CRC 57481

Data CRC 53000

Updated settings in FRAM for table 1, saving to file 1: OK

Table CRC 57481

Data CRC 53000

Updated default factory settings in FRAM for table 1, saving to file 25: OK

Table CRC 56172

Data CRC 13489

Updated settings in FRAM for table 5, saving to file 5: OK

Table CRC 56172

Data CRC 13489

Updated default factory settings in FRAM for table 5, saving to file 29: OK

Unplug the FTDI cable to power off the AX100.
Plug the FTDI cable back in.
Verify that tables 0, 1, and 5 have not changed using:
param mem {Table Number}
param list {Table Number}
Type
config gnd_wdt 10
to set the watchdog timer to 10 seconds.
Wait 10 seconds.
Type
config gnd_wdt
to check the watchdog timer value. It should have been reset to 171155 seconds after timeout and counting down.
Verify that tables 0, 1, and 5 have not changed using:
param mem {Table Number}
param list {Table Number}

Flight parameters:

AX100 Tables

1 Setup Parameters

The AX100 needs to have its parameters set up to operate properly. Use the manual to see descriptions for the parameter tables and parameter values. The AX100 should already have the correct parameters set, but you should check the parameter values using section 1.2. After setting up the parameters, the system configuration (table 0) should look something like this:

1.1 Physical setup

Connect the FTDI cable to the AX100.
Open Putty, and set the baud rate to 500 000

1.2 View parameters

To see what the parameters

param mem {parameter table number}

param list {parameter table number}

1.3 Set parameter

param mem {parameter table number}

param set {parameter label name} {value}

param save {parameter table number} {file number}

Use the same file number as the parameter table number.

Note: some parameters will require you to restart the device before they will be applied.

1.4 Configure the AX100 for CAN CSP

On parameter table 0 (System configuration):

Enable CAN (can_en)
Set the CAN baud rate to 250 kHz (can_khz)
Set the CSP node to 3 (csp_node)
Set up the routing table (in this format [csp_node]/[bits of mask] [destination]). AX100 is the radio destination, and LOOP destination means that the message will be routed to the CSP Server itself. 0/0 sets the default location to send packets. The current working routing table is:

"4/5 CAN, 9/5 CAN, 3/5 LOOP, 0/0 AX100"

This will send 4 and 9 to CAN (for the CDH and IrisTerminal), loop messages for 3 (Comms), and send all other messages to the radio.

2 Sending messages over CAN to the AX100

This section outlines how to send CAN messages from CDH to the AX100.

2.1 Physical setup

Connect the CAN-H and CAN-L of the AX100 to the CAN lines for CDH. Connect the FTDI cable from your computer to the AX100.

If the FTDI cable is unplugged, you can power the board with 6.4 V instead.

2.2 Sending messages with the IrisTerminal

2.2.1 Sending a ping

After opening the IrisTerminal, type "ping 3" into the terminal. You should see that the ping succeeded (positive response time) if the AX100 routing table is setup properly.

2.2.2 Sending data

Run the sendCommsMessage command in the IrisTerminal. Currently it is set to send 0xAAAA using CSP to Comms (csp node 3). You can change the message in commsCommands.c in the terminal project. This code has only been tested by seeing that the current consumption rises when the command is entered.

2.3 Sending messages with the CDH code

Add this line to the vCSP_Server method in csp_server.c in the CDH code ping Comms with one byte with a 100 ms timeout:

int return_val = csp_ping(COMMS_CSP_ADDRESS, 100, 1, CSP_O_NONE);

When testing, the ping returned 2, indicating a successful response in 2 ms.

2.4 AX100 Transmitter settings

2.5 Sending a ping from the Putty terminal

You can ping from the AX100 to CDH (by entering ping 5), the IrisTerminal (ping 9), or the radio by sending a ping to another location (i.e. ping 2) (with the current working routing table in 1.4). When entering ping 2, there is no response because the ground station is not set up with CSP. However, it was confirmed that the messages was sent, as described in the HackRF and GNURadio. You can verify that the ping was sent over the radio by checking the total transmitted packets telemetry (parameter list 4 on the AX100).0

2.6 Sending CSP packets using GOSH (Debugging)

If the routing table is set wrong, the transceiver will not respond, but the packet should still be received. To see how CSP detects and routes the packet by enabling csp debug information over the GOSH connector. To check CSP packets are received over can, the following command can be used:

debug csp i

After that command over GOSH is ran, the CAN message can be sent. If it’s received properly you, a line describing an incoming packet and where the response is routed.