Telemetries North and DJI Smart Controller North are not same.
Completed
On M30 and M300 we are using POS_VO and Gimble Angle telemetry in our application. We are facing problem in which after start of the flight, north that above telemetries shows are not align with north that is shown in the DJI smart controller. What could be reason and fix for it?
-
For the M300, you have the option to subscribe to the gimbal angle from DJI_FC_SUBSCRIPTION_TOPIC_THREE_GIMBAL_DATA. The angle value you receive will be consistent with the remote control. However, for the M30, it only supports DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES. Currently, there is a slight inconsistency in the coordinate system between this topic and the remote control. the subsequent version of PSDK will correct the obtained value to keep it consistent with the coordinate system of the value on the remote control. -
Thank you for explaining. For M300 we can use DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES as well? Would this topic will have inconsistency in the coordinate system w.r.t. remote controler?
Apart from the we noticed similar inconsistency in POS_VO data, is that problem specific to M30 as well?
-
On a separate note, we need to get an opinion regarding what would be best telemetry to use for accurate drone positioning (relative position to flying point). We need data at atleast 30Hz. As GPS and RTK has limited update frequency we are planning to go with POS_VO.
Whats your opinion on that?
-
1、DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES also supports M300, this TOPIC subscription value will be different from RC gimbal attitude. 2、POS_VO is based on the visual odometry inside the flight control. Unfortunately, this TOPIC has stopped maintenance, and this data may be unreliable, so it is not recommended to use it. -
1. Can you please elaborate DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES value will be different from RC Gimbal Altitude?
2. So which telemetry we should use for accuracy? Basically, we want position and gimbal angle data from m30 and m300 at 30Hz. Can you please help to suggest the best telemetry for both drones?1. M300
- Position @ 30Hz: ???
- Gimble Angle @ 30Hz: DJI_FC_SUBSCRIPTION_TOPIC_THREE_GIMBAL_DATA (and DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES ?????)
3. M30
- Position @ 30Hz: ???
- Gimble Angle @ 30Hz: ???
-
1、The attitude angle values displayed by DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES and RC shows value are divided into different coordinate systems inside the flight controller. With M300, you will see the difference by subscribing DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES and DJI_FC_SUBSCRIPTION_TOPIC_THREE_GIMBAL_DATA. 2、The maximum subscription frequency of GPS position only supports 5HZ. Gimble Angle can support up to 50HZ. -
Thank you for the quick response.
1. What coordinate systems both of these telemetries follow: DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES and DJI_FC_SUBSCRIPTION_TOPIC_THREE_GIMBAL_DATA
2. I see for only option would likely be GPS + IMU data fusion. Also, how to we get an accurate gimbal angle for M30? considering DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES doesn't give correct data.1. M300
- Position @ 30Hz: GPS/RTK + IMU data fusion?
- Gimble Angle @ 30Hz: DJI_FC_SUBSCRIPTION_TOPIC_THREE_GIMBAL_DATA
2. M30
- Position @ 30Hz: GPS/RTK + IMU data fusion?
- Gimble Angle @ 30Hz: ???
-
1、Both DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES and DJI_FC_SUBSCRIPTION_TOPIC_THREE_GIMBAL_DATA are NEU coordinate systems, because the flight controller internally processes the coordinate system differences, resulting in differences in the data values obtained by the two TOPICs. 2、M30 only supports DJI_FC_SUBSCRIPTION_TOPIC_GIMBAL_ANGLES , the current obtained value is different from the RC APP display, and the subsequent PSDK version will correct this value.
Please sign in to leave a comment.
Comments
8 comments