Payload SDK Features - Data Transmission

2019-06-17

Direct Data Transmission (UART/CAN)

The direct data transmission feature allows you to send custom data streams between your payload and the Mobile SDK.

  • This channel accepts data on UART/CAN from the payload
  • The channel does not enforce any protocols on the data; it will transparently transmit bytes between the PSDK and the MSDK.
  • It allows the developer to develop protocols for interpreting this data on the MSDK.
  • This feature is analogous to the Data Transparent Transmission feature of the Onboard SDK.

Data Bandwidth Considerations

Transmit data directly between Mobile SDK and SKYPORT via UART/CAN port within the following bandwidth:

Link Indicators
Uplink (form Mobile SDK to Payload) Approx. 500B/s
Downlink (from Payload to Mobile SDK) Approx. 4KB/s

Network Stream Data Transmission (UDP)

The network stream transmission feature allows the payload to publish high speed bulk data to a network port through UDP. This data is then sent transparently to the Mobile SDK.

Video Data Transmission

  • The network stream channel greatly simplifies video transmission by providing native video decoding and display in the Mobile SDK, without requiring any coded development on the MSDK.
  • To take advantage of this feature, your payload must encode your video data into a specific format and send it to a specific port (the details are given below).
  • If your video data is correctly formatted, all of DJI's iOS and Android applications that use the MSDK will be able to display this video with no code changes.
  • This also allows backward compatibility with existing mobile applications, as well as greatly enhancing interoperability with DJI cameras and gimbals.

Non-Video Data Transmission

  • If you are interested in transmitting high speed bulk data that isn't video, the PSDK also gives you that option.
  • Your payload can send any data over UDP to a different network port than the video network port, and you need to implement decoding on the Mobile SDK app to parse this data.

Network Port Bandwidth Considerations

The bandwidth information of network port data transmission is provided as follows:

Usage condition Total bandwidth (downlink data + code stream)
M200 series aircraft with the third-party payload only. The maximum theoretical bandwidth is 8Mbps.
M210 or M210 RTK, with both DJI camera and the third-party payload. The maximum theoretical bandwidth is 4Mbps.

Comparison : Direct Data Transmission v/s Network Stream Data Transmission

  • Usually, for small amount of data, use the direct data transmission link.
  • The network link offers higher bandwidth, but this comes at the cost of additional overhead since you need to pack your data into UDP packets.
  • For video transmission, the network stream is the better choice
  • If you require reliable data transmission, prefer the direct data link over the best-effort UDP channel.