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Position_data4 & Velocity_data4 "mintime"
4 years 4 weeks ago #1068
by liu1322
Position_data4 & Velocity_data4 "mintime" was created by liu1322
Hi!!!! 
I obtained ADS-B raw messages for aircraft icao24='ae0943' on 9/9/2019 between hour>=1568037600 AND hour<=1568066400. After convert epoch to GMT, I sorted Position_data4 & Velocity_data4 together with respect to "mintime". For time period from 6:11:41pm to 6:11:44pm, receivers only received position message and from 6:11:45pm to 6:11:48pm they only received velocity message. How come ADS-B be transmitting only position or only velocity message for such a long period of time? My understanding is that ADS-B should transmit airborne position and velocity messages every 0.4 – 0.6 sec.
To further understand what's going on, may I know how OpenSky keeps track of mintime? and how could I figure out which receiver is receiving that raw message? Thank you in advance for helping me out!
I obtained ADS-B raw messages for aircraft icao24='ae0943' on 9/9/2019 between hour>=1568037600 AND hour<=1568066400. After convert epoch to GMT, I sorted Position_data4 & Velocity_data4 together with respect to "mintime". For time period from 6:11:41pm to 6:11:44pm, receivers only received position message and from 6:11:45pm to 6:11:48pm they only received velocity message. How come ADS-B be transmitting only position or only velocity message for such a long period of time? My understanding is that ADS-B should transmit airborne position and velocity messages every 0.4 – 0.6 sec.
To further understand what's going on, may I know how OpenSky keeps track of mintime? and how could I figure out which receiver is receiving that raw message? Thank you in advance for helping me out!
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4 years 3 weeks ago #1070
by liu1322
Replied by liu1322 on topic Position_data4 & Velocity_data4 "mintime"
Thanks a lot!!! One more quick question, I tried to query information from "sensor_visibility_data3" to find the sensors/time information. However it seems to me that there's no information available after 04/27/2016. How may I find information for data during September/2019?
I'm hoping to figure out, for each raw message from position_data4, which OpenSky sensor is receiving and uploading that message.
One more quick question, I tried to query information from "sensor_visibility_data3" to find the sensors/time information. However it seems to me that there's no information available after 04/27/2016. How may I find information for data during September/2019?I'm hoping to figure out, for each raw message from position_data4, which OpenSky sensor is receiving and uploading that message.
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