1. Beacon/Telemetry
12/8/2018

2. Overview
Beacon
Used to send satellite state information periodically to the ground station
Packets follow APRS standard
In addition to the ground station packets also logged at findu.com – can be accessed by other HAM users and can be used to plot graphs
Consists of a total of 4 packets/messages
Parameter Name Message: specifies the parameters each of the beacon value fields corresponds to
Unit/Label Message: specifies units for the analog and labels for the digital data fields.
Equation Coefficient Message: contains a set of 3 coefficients for each of the analog channels in the beacon packet
Beacon: contains the raw analog (5 channels) and digital (8 channels) values in ASCII format
Format and values for first 3 packets fixed and sent by the ground station
Beacon packet sent by the satellite at predefined (adjustable) intervals
12/8/2018

3. Overview (contd.) Telemetry
Used to send additional satellite status information
Packets are sent based on user requests rather than periodically
KYSat custom format (not APRS standard)
Can be used to send state information covered/not covered by the beacon
Currently implemented by 2 packets (sizes variable from 0-45 bytes)
12/8/2018

4. Packet Framing Diagrams
Beacon
12/8/2018

5. Packet Framing Diagrams (contd.)
Telemetry 1 (42 bytes)
12/8/2018

6. Packet Framing Diagrams (contd.)
Telemetry 2 (40 bytes)
12/8/2018

7. Tasks and Libraries Beacon Task (beacon.c):
Forms the APRS compliant beacon packet
Sends it to Packet_Tx at a predefined period (adjustable)
Uses following:
Functions/Macros
TRY_BCN_PERIOD(unsigned char* period /* Minutes */, unsigned char bcn_interval /* OSTicks */); (waits for a beacon period)
send_tx_bcn(unsigned char *data, unsigned char num_bytes); (send packet to Packet_Tx)
Libraries
“__cross_studio_io.h”
“salvo.h”
"kysat_com_lib.h"
"beacon.h"
"debug.h“
Telemetry Task (telemetry.c)
Forms the custom telemetry packet on receiving command from Command_Parse
Sends it to Packet_Tx for MIME/KS64 encoding
Will also be used to implement other (future) commands
GET_TLM_CMD(unsigned char* cmd, unsigned char* data, unsigned char* num_bytes); (gets command from Command_Parse)
send_tx_raw( unsigned char cmd, unsigned char* data, unsigned char num_bytes ); (send raw unencoded packet to Packet_Tx)
Same as beacon
12/8/2018