Payload Development Criterion

2022-08-09
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To ensure the safety of drones when carrying payload devices to perform flight tasks, please follow DJI's payload criterion when using PSDK to develop payload devices.

Hardware Interface Standard

Notice

  • NOT shorting the pins of the drone or hardware platform.
  • NOT Connecting the drone to a power output system or inputting current to the aircraft.
  • The load capacitance needs to be ≤500uF. If it exceeds this threshold, the aircraft will trigger short-circuit protection at the moment of power-on, and the SDK power supply will turn off the output.
M30/M30T

Note: DJI M30/M30T only provides a PSDK Type-C port to expand development and connect PSDK payload. Accessories that can be used are SDK round ribbon cable and PSDK mounting bracket.

Interface pinsDevelopment accessoriesIndicator requirements
power outputSDK round ribbon cable19.2~26.1V/4A(6S battery voltage)
PPS pin voltageSDK round ribbon cable≤3.3V
UARTSDK round ribbon cableMust follow 3.3V TTL protocol
USBSDK round ribbon cableMust follow USB 2.0 protocol
M300 RTK

Note:

  • DJI M300 RTK provides PSDK interfaces and OSDK Interface to expand development and connect PSDK payload. Accessories that can be used with PSDK interfaces are SkyPort V2 and X-Port. Accessories that can be used wit(h OSDK Interface are SDK round ribbon cable and OSDK expansion module.
  • PSDK Interfaces includes one top-mounted gimbal port and two bottom-mounted gimbal ports. For details, please refer to Device Connectionopen in new window.
Interface pinsDevelopment accessoriesIndicator requirements
power outputX-Port13.6V / 2A
SDK round ribbon cable24V / 4A
SkyPort V213.6V / 4A
SkyPort13.6V / 4A
high power outputX-Port17V / 2.5A
SDK round ribbon cable-
SkyPort V217V / 4A
high power applicationX-Port
SkyPort V2
0~3.3V
PPS pin voltage SDK round ribbon cable
X-Port
SkyPort V2
SkyPort
≤3.3V
UARTMust follow 3.3V TTL protocol
LANMust follow the LAN IEEE802.3 protocol

Interference Compatibility Requirements

ItemM30 and M30TM300 RTK
Light Source Flashing If the payload is built-in a light source, the light source flashing frequency of the payload cannot be between 0.2 and 50 Hz.
Light Wave Emission The payload cannot emit light with wavelengths between 600 and 700 nm.
Magnetic FieldThe payload should minimize magnetic interference, including but not limited to interference created by ferromagnetic substances producing high-intensity alternating magnetic fields.
Electromagnetic Noise • The payload should not transmit electromagnetic waves in the 1 - 1.7 GHz, 2.3 - 2.6 GHz, and 5.7 - 5.9 GHz bands.
• The equivalent isotropic radiated power (EIRP) of the payload should be less than 1W.
• The payload should not transmit electromagnetic waves in the 1 - 1.7 GHz, 2.4 - 2.5 GHz, and 5.8 - 5.9 GHz bands.
• The equivalent isotropic radiated power (EIRP) of the payload should be less than 1W.
-
Acoustic NoiseThe payload cannot transmit or generate 35~45KHz band sound waves.-

Structural Design Standards

Notice:

  • To prevent the load equipment mounted on the drone from being affected by the flight inertia of the drone, hitting the battery compartment and blades, and damaging the drone or the load equipment, please design the size of the load equipment reasonably.
  • To prevent the load equipment from affecting the moment of inertia of the drone, please minimize the size of the load equipment.

Common Structural Standards

Structural parametersM300 RTK M30 and M30T
Structural InterferenceProhibit the payload equipment from colliding with various components on the drone when the drone is performing a flight mission.
VibrationAfter the drone is powered on, in a stationary state, the payload device cannot generate vibrations that affect the IMU (you can view the IMU status on the DJI Pilot or Mobile App).
Case Temperature≤70℃
Weight The maximum load weight of the drone cannot exceed 2.7Kg;
When using the gimbal bracket, the weight of the load device that can be mounted on a single gimbal must not exceed 930g.
Do not exceed the maximum load weight of the drone: 230g.
Height - If used with DJI Dock, it should be less than 10cm.
Movement TrackThe motion trajectory of the load equipment should not cover sensors and ventilation holes.
1. The field of view of the front and rear vision sensors is 70° × 56° (horizontal*vertical);
2. The field of view of the up-looking vision sensor is 64° × 79° (horizontal × vertical);
3. The field of view of the downward-looking vision sensor is 56° × 70° (horizontal × vertical);
4. The field of view of the left and right vision sensors is 79° × 64° (horizontal × vertical);
5. The field of view of the six-direction infrared sensor is 30°;
6. The range of 5cm from the bottom and top of the drone body is the air inlet and air outlet.
The motion trajectory of the load equipment should not cover sensors and ventilation holes.
1. The front and rear vision sensors are tilted upwards by 8 degrees, and their field of view is 70°*55°;
2. The left and right visual sensors are tilted upward by 11 degrees, and their field of view is 70°*55°;
3. The top visual sensor has no inclination, and its field of view is 55°*70°;
4. The downward visual sensor has no inclination, and its field of view is 70°*55°;
5. The field of view of the six-direction infrared sensor is 30°;
6. The air inlet of the M30 series is behind the gimbal, and the air outlet is behind the fuselage/above the battery.
Center of GravityUse the gimbal bracket to mount the load device, and the center of gravity of the load device must be on the vertical line of the center of the gimbal interface.Use the PSDK quick release bracket to mount the load device, and the center of gravity of the load device must be within the orthographic projection area of the quick release bracket.

Construction Standard for X-Port

X-Port‘s structural

Figure 1 display the dimension of X-Port.

Figure 1 The dimension of X-Port(unit:mm)

Payload‘s Structural

Before designing the structure of the payload, please choose a tripod, if the size of the payload is limited by the tripod.

Gimbal Type Pitch axis rotation limit (Idle speed) Landing Gear Type X-Port payload structure limitation
Single gimble platform Restricted Original The distance between the lower surface of the payload and the pitch axis is not more than 54mm.
Long The distance between the lower surface of the payload and the pitch axis is not more than 72mm.
None Original The payload must in the mass center, which the diameter of the ball is 118mm.
Long The payload must in the mass center, which the diameter of the ball is 154mm.
Double Gimbal Restricted Original The distance between the lower surface of the payload and the pitch axis is not more than 45mm.
Long The distance between the lower surface of the payload and the pitch axis is not more than 63mm.
None Original The payload must in the mass center, which the diameter of the ball is 100mm.
Long The payload must in the mass center, which the diameter of the ball is 136mm.

The requirements of the payload which is mounted on the X-Port are as follows:

  • The width of the pitch on the X-Port is 80mm. The width of the payload couldn't exceed the wheelbase.
  • The weight of the payload must be lighter than 450g otherwise the payload may damage the gimbal or the pressure-reducing ball.
  • The centroid of the normal payload must be on the axis line of X-Port, and the payload couldn't strike the X-Port when the payload raised to 45°. The centroid of the payload must on the axis line when the payload’s zoom is in the maximum factor.
  • If the payload touches the ground, please use the Long Landing Gear.
  • Be sure that the port of the payload is completely flat, ensure that the waterproof could be sealed completely.
  • The shell of the payload could be aluminum alloy. A plastic or carbon case is not recommended.

Custom Data Transmission Standard

Use M30/M30T or M300 RTK
TypeDirectionLimitation
Command Channel Mobile App ➟ Payload≤4096B/s
Payload ➟ Mobile App
User Load Equipment ➟ Payload
Payload ➟ User Load Equipment
High-speed data transmission channel Payload ➟ Mobile AppSingle Gimbal:≤ 8192Kbps
Double Gimbals:other ≤ 4096Kbps

Video Stream Transmission Standard

Use PSDK to develop the Payload must select one of the two H.264 standard.

Custom-H264 standard

Characteristic

  1. Standard H264 standard stream is more common and easier to obtain.
  2. When using this video stream format to send the code stream, it will be transparently transmitted to the App terminal through the aircraft for decoding, and the real-time code rate must not exceed the feedback value.
  3. Use this format to transmit the video stream, and the SEI content can be transmitted to the App.

Criterion

The camera payload device developed based on PSDK, when using the Custom-H264 standard, need to pay attention to the following key configuration information:

ItemH.264 Itemvalue
The maximum video resolution - <1920 × 1080
The maximum frame rate - <30fps
The maximum bit rate - <8Mbps
The recommended video aspect ratio - 4: 3
The GOP encoding structure must use Period I - -
Level Level Number <5.1
profile_idc7.3.2.1.1 Baseline=66,Main=77,High=100
YUV420 Format 7.3.2.1.1chroma_format_idc=1
8Bit video 7.3.2.1.1bit_depth_luma_minus8=0
bit_depth_chroma_minus8=0
Not allowed customization,Scaling Matrix 7.3.2.1.1
7.3.2.2
seq_scaling_matrix_present_flag=0
pic_scaling_matrix_present_flag=0
Only supports frame format encoding, not field encoding 7.3.2.1.1 frames_mbs_only_flag=1
Only P-frames and I-frames are allowed, and P-frames have a single reference frame 7.3.3
7.3.2.2
7.3.3
slice_type = 0 or 2
num_ref_idx_l0_default_active_minus1=0
num_ref_idx_active_override_flag=0
Not support Muti-Slice Group 7.3.2.2 num_slice_groups_minus1=0

NOTE: When using the H.264 encoding standard, the GOP encoding structure must use Period I (intra-frame encoded frames, one IDR frame will be inserted every 1 second to ensure that image data can be recovered if lost).

DJI-H264 standard

Characteristic

  1. The more stringent DJI H264 standard stream standard.
  2. When using this video stream format to send the code stream, it will be transcoded by the aircraft. Within the maximum code rate limit, the code rate can be dynamically adjusted according to the real-time image transmission link to achieve the best image transmission display effect.
  3. When using this format to transmit the video stream, the SEI content will be discarded by the aircraft and cannot be transmitted to the App.

Criterion

When using the camera payload device developed based on PSDK, when using the DJI-H264 standard, you need to pay attention to the following key configuration information:

ItemH.264 Itemvalue
The maximum video resolution - <1920 × 1080
The maximum frame rate - <30fps
The maximum bit rate - <8Mbps
AUD information must be added at the end of each frame - fixed 6 bytes: 0x00 0x00 0x00 0x01 0x09 0x10
The recommended video aspect ratio - 4: 3 or 16:9
The maximum byte size of a stream - <256KBytes
Level Level Number <5.1
profile_idc7.3.2.1.1 Baseline=66,Main=77,High=100
YUV420 Format 7.3.2.1.1chroma_format_idc=1
8Bit video 7.3.2.1.1bit_depth_luma_minus8=0
bit_depth_chroma_minus8=0
Not allowed customization,Scaling Matrix 7.3.2.1.1
7.3.2.2
seq_scaling_matrix_present_flag=0
pic_scaling_matrix_present_flag=0
Only supports frame format encoding, not field encoding 7.3.2.1.1 frames_mbs_only_flag=1
Only P-frames and I-frames are allowed, and P-frames have a single reference frame 7.3.3
7.3.2.2
7.3.3
slice_type = 0 or 2
num_ref_idx_l0_default_active_minus1=0
num_ref_idx_active_override_flag=0
Not support Muti-Slice Group 7.3.2.2 num_slice_groups_minus1=0
Long-term reference frames are not supported 7.3.3.3 long_term_reference_flag=0
The decoding order is required to be consistent with the playback order E.1.1 max_num_reorder_frames=0
Limit the number of decoded reference frames to 5 E.1.1 max_dec_frame_buffering=5
The maximum number of reference certificates supported is 1 frame, and the maximum reference interval is 1 7.3.2.1.1 max_num_ref_frames=1

NOTE

  • When using H.264 encoding standard, Gop structure is optional, which is Period I or GDR.
  • If it is Period I, each I frame is required to be an IDR frame. If it does not meet the requirements, there is no guarantee that the image transmission can be recovered from the packet loss error; Send After finishing SPS/PPS, immediately transmit the stream of frame I, and then transmit AUD. There is no AUD information between SPS/PPS and slice. In the Period Ⅰ structure, it is recommended to have an IDR per second.
  • If it is GDR, sps/pps need to be transmitted in each GDR refresh frame.

Compatibility Note: If the video stream format is set to DJI H264 format, data transmission functionopen in new window will not be available, it is recommended to switch to SDK interconnection functionopen in new window use.

Reference: H.264 Protocolopen in new window

Video stream check tool: Stream check toolopen in new window