Communication & Message Formats

Owned by Anthony Luo
Last updated: 2023-03-10 by R D
2 min read

This is a follow up to the 2022-2023 sys architecture. Page has been moved for clarity. All units are SI unless otherwise specified.

https://en.m.wikipedia.org/wiki/High-Level_Data_Link_Control

Usage for ZP-Jetson communication:

Usage for ZP-IMACS communciation: TODO

Frame Structure

  • flag [ uint8_t ]

    • starting byte, to show that a new message has started

  • length [ uint16_t ]

    • length in bytes of the message

    • Includes length of all of the below fields

  • Type [ uint8_t ]

    • type of the message. This relates to one of the below Datatype Structs.

    • Indicates where the data came from and who its meant to go to

  • Info [ bytes ]

    • One of the packets below

  • CRC [uint32_t ]

    • 4 byte CRC32 value

Datatype Structs.

[0] [SF → TM → Jetson] Odometry Data

latitude

[double]

decimal degrees

longitude

[double]

decimal degrees

altitude

[float]

metres AGL

climb rate

[float]

metres per second

track

[float]

bearing (degrees)

heading

[float]

bearing (degrees)

airspeed

[float]

metres per second

groundspeed

[float]

metres per second

roll

[float]

degrees

pitch

[float]

degrees

yaw

[float]

degrees

roll rate

[float]

degrees per second

pitch rate

[float]

degrees per second

yaw rate

[float]

degrees per second

[1] [PM → SM → TM → Jetson] Movement Request

request_id

[uint8_t]

integer {0,1,2}

[2] [Jetson → TM → SM → PM] Relative Movement Command

request_id

[uint8_t]

integer {0,1,2}

x

[float]

metres

y

[float]

metres

z

[float]

metres

heading

[float]

bearing (degrees)

[3] [Jetson → TM → SM → PM] Landing Initiation Command

request_id

[uint8_t]

integer {0,1,2}

[4] [GSPC → TM → SM → PM] Waypoints

waypoints

[Waypoint]

number of waypoints

[4.5] Waypoint

latitude

[double]

decimal degrees

longitude

[double]

decimal degrees

altitude

[double]

metres AGL

waypoint_id

[uint8_t]

integer

[5] [GSPC → TM → SM] Software Arm/Disarm

arm

[bool]

boolean

[6] [GSPC → TM → SM → AM] PID Values

controller

[uint8_t]

integer index

axis

[uint8_t]

integer index

P

[double]

Proportional value

I

[double]

Integer value

D

[double]

Derivative value

[7] [AM → SM → TM → GSPC] Ground Station Data

Motor Outputs

[12][uint8_t]

12 integers

latitude

[double]

decimal degrees

longitude

[double]

decimal degrees

altitude

[float]

metres AGL

climb rate

[float]

metres per second

track

[float]

bearing (degrees)

heading

[float]

bearing (degrees)

airspeed

[float]

metres per second

groundspeed

[float]

metres per second

roll

[float]

degrees

pitch

[float]

degrees

yaw

[float]

degrees

roll rate

[float]

degrees per second

pitch rate

[float]

degrees per second

yaw rate

[float]

degrees per second

battery voltages

[13][uint8_t]

1st val overall voltage

12 cells voltage

voltage 0-200 where 0 is 3v and 200 is 5v

controller values

[16][uint8_t]

16 channels 0-100

[8][AM → SM → TM → GSPC] PID Set Response

Controller Number

[uint8_t]

integer index

P, I, D values

[6][3][uint8_t]

6 channels, 3 values of PID’s

[ 0 ] [ Sf → TM → Jetson ] Odometry Data

  • Latitude [double]

  • Longitude [double]

  • Altitude [float]

  • climb rate [float]

  • track [float]

  • heading [heading]

  • air speed [float]

  • ground speed [float]

  • roll [float]

  • pitch [float]

  • yaw [float]

  • roll rate [float]

  • pitch rate [float]

  • yaw rate [float]

[ 1 ] [ PM → SM → TM → Jetson ] MovementRequest

  • request [bool]

[ 2 ] [ Jetson → TM → SM → PM ] RelativeMovementCommand

  • x [float]

  • y [float]

  • z [float]

  • heading [float]

[ 3 ] [ Jetson → TM → SM → PM ] Landing initiation Command

  • empty

[ 4 ] [ GSPC → TM → SM → PM ] Waypoints

  • Num of valid waypoints

    • A max will have to be decided

  • Waypoint

    • latitude [double]

    • longitude [double]

    • altitude [double]

    • waypoint id [uint8_t]

[ 5 ] [ GSPC → TM → SM ] Software ARM/DISARM

  • arm [bool]

[ 6 ] [ GSPC → TM → SM → AM ] PID Values

  • controller [uint8_t]

  • axis [uint8_t]

  • P [double]

  • I [double]

  • D [double]

[ 7 ] [ AM → SM → TM → GSPC ] Ground Station Data

  • Motor Outputs [ uint8_t ] x 12

  • Latitude [double]

  • Longitude [double]

  • Altitude [float]

  • climb rate [float]

  • track [float]

  • heading [heading]

  • air speed [float]

  • ground speed [float]

  • roll [float]

  • pitch [float]

  • yaw [float]

  • roll rate [float]

  • pitch rate [float]

  • yaw rate [float]

  • Battery Voltages [uint8_t] x 13

    • Note: the first value is the overall voltage

    • The value is a value between 0 and 200 where 0 is 3V and 200 is 5V

  • Controller Values [uint8_t] x 16

[ 8 ] [ AM → SM → TM → GSPC ] PID Set Response

  • controller number [uint8_t]

  • for each of the 6 axis

    • P, I and D values