[DJI-log-discuss] RC_GPS record format

[Brett Spell]

I meant to attach a different file but the one I'm sending this email
definitely has examples of what I described.

 

As far as why the file formats are so different, I can only speculate that
the different records were designed at different times by different people
and / or that the  level of programming experience and sophistication
increased over time. I have noticed, for example, that while the older
(lower-numbered) records often contained fixed-length fields in the payload
that would be difficult to expand without affecting parsing logic, the newer
/ higher-numbered records are more likely to have a field length prefix
included in the payload that provides greater flexibility ("future
proofing", you might say). So it seems to me that either the people
designing these records have gotten smarter over time, or DJI has hired
programmers with more experience and sophistication who chose to use more
efficient and industry-standard ways of storing data.

 

From: DJI-log-discuss [mailto:dji-log-discuss-bounces at us.live555.com] On
Behalf Of Chris
Sent: Monday, January 27, 2020 12:48 AM
To: Discussion of DJI's log file formats
Subject: Re: [DJI-log-discuss] RC_GPS record format

 

For the Flight records i have that seems not to match.

I would also wonder why all formats in this are completely different to the
seens time and lat/lon formats.

Am 27.01.20 um 03:49 schrieb Brett Spell:

Ross,

 

Here's what I believe to be the format of the RC_GPS (type 11) record found
on older models, and I've also attached a TXT that includes instances of the
record. Note that the first six fields represent a "Startup timestamp" field
that's a bit funky in that it doesn't use epoch milliseconds (or seconds) to
represent a date / time value and is local to GMT.

 

Brett

 

P.S. I've also seen the record present but with all zeroes for the field
values.

 


Offset

Length

Type

Units

Description


0

1

Unsigned integer

Hours

Hour of day (0-23)


1

1

Unsigned integer

Minutes

Minute (0-59)


2

1

Unsigned integer

Seconds

Second (0-59)


3

2

Unsigned integer

Year

e.g., 2020


5

1

Unsigned integer

Month

Month (1-12)


6

1

Unsigned integer

Date

Date (1-31)


7

4

Signed integer

Degrees * 10000000

Latitude


11

4

Signed integer

Degrees * 10000000

Longitude


15

4

Signed integer

Millimeters per second

East / west velocity


19

4

Signed integer

Millimeters per second

North / south velocity


23

1

Unsigned integer

Integer

Satellite count


24

4

Float

?

"Accuracy"?


28

1

Unsigned integer

Enumeration (?)

"Status"?

 





-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://ns.live555.com/pipermail/dji-log-discuss/attachments/20200127/4564ff34/attachment-0001.htm>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: DJIFlightRecord_2016-03-25_[12-30-19].txt
URL: <http://ns.live555.com/pipermail/dji-log-discuss/attachments/20200127/4564ff34/attachment-0001.txt>