[DJI-log-discuss] Getting start time of a DAT file?

[John Burns]

I wonder if I'm misunderstanding something basic? I should add I know little about drones as we normally subcontract drone surveys so I don't own one.

I have a drone file FLYxxx.DAT and I've been decoding it, the GPS record I'm using looks like https://github.com/unhcfreg/DROP/blob/master/modules/GPSPayload.py which seems to have a different format to the GPS(gps#) record on https://datfile.net/DatCon/fieldsV3.html.

Sorry if this is a stupid question :-)

--
John G.Burns


________________________________________
From: DJI-log-discuss <dji-log-discuss-bounces at us.live555.com> on behalf of David Kovar <dkovar at ursasecure.com>
Sent: 24 January 2022 14:31
To: Discussion of DJI's log file formats
Subject: Re: [DJI-log-discuss] Getting start time of a DAT file?

Greetings,

DATCon has a good list of all the records and their fields: https://datfile.net/DatCon/fieldsV3.html (Look for the GPS record.)

Regards,

-David

David Kovar
CEO, Founder URSA Inc.
Cell: 650-278-1774


[cid:8993EDD1-F627-4A82-871D-951B696571BD]

On Jan 24, 2022, at 9:09 AM, John Burns <john at unixnerd.co.uk<mailto:john at unixnerd.co.uk>> wrote:

Thanks for the reply! If you have more details that would be very helpful. I'm reading a GPS record to get lat/long/height, according to the DROP source code it has many other fields but not time.

--
John G.Burns


________________________________________
From: DJI-log-discuss <dji-log-discuss-bounces at us.live555.com<mailto:dji-log-discuss-bounces at us.live555.com>> on behalf of David Kovar <dkovar at ursasecure.com<mailto:dkovar at ursasecure.com>>
Sent: 24 January 2022 14:06
To: Discussion of DJI's log file formats
Subject: Re: [DJI-log-discuss] Getting start time of a DAT file?

Greetings,

There is a GPS record with the real world timestamp (in UTC, I think.) You can work backwards from that to get the start time of the logging.

If you need more detail, let me know.

Regards,

-David

David Kovar
CEO, Founder URSA Inc.
Cell: 650-278-1774


[cid:8993EDD1-F627-4A82-871D-951B696571BD]

On Jan 24, 2022, at 8:39 AM, John Burns <john at unixnerd.co.uk<mailto:john at unixnerd.co.uk><mailto:john at unixnerd.co.uk>> wrote:

Hello. I've managed to write some Java code to import DAT files into my specialist GIS package. I'm struggling with time though.

I can see that time increments in milliseconds come from the "tick"/600, but I can't find any way of getting the start time of logging. I've been using the DROP (https://www.google.com/url?q=https://www.google.com/url?q%3Dhttps://github.com/unhcfreg/DROP%26source%3Dgmail-imap%26ust%3D1643636411000000%26usg%3DAOvVaw2XT1gUceOqvTjo3pKDC-NM&source=gmail-imap&ust=1643638221000000&usg=AOvVaw2HZifjtTYycqVrMleSEzgF) python software as my guide in this. It seems to use the file's OS time stamp with the obvious problems that entails.

Any help is appreciated :-)

--
John G.Burns


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