Log files of field sensor system of Olympus Tough TG series camera

I have an Olympus Tough TG-5 camera only and following information is extracted from my camera. These information may be valid on other Tough TG series camera and Tough TG-Tracker action camera. I don't have these so I cannot verify that.

![log.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/232557/8f4c259a-0deb-8411-f1c0-e95ef15f7b0a.jpeg)
(Extract from https://asia.olympus-imaging.com/product/compact/tg5/feature2.html)

When level is in "LOG" positon, sensor data will be logged in file every 30 seconds. Log interval will be increased to 2 seconds if camera taking a video.

#.SNS file
filename format: YYMMDDSS.SNS
YY is last two digit of year, year 2019 is 19
MM is month
DD is day
SS is sequence of that day

##[OLTIM]
```
$OLTIM,20200504,123322
````
First value is date, YYYYMMDD
Second value is UTC time of **CAMERA**, HHMMSS

##[OLCMP]
```
$OLCMP,252.0
````
First value is compass reading. Camera's lens toward east is 90.0, south is 180.0, west is 270.0. Not sure toward north is 0.0 or 360.0. Reading is valid only if camera is position parallel to ground likes below image.

![compass.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/232557/bc4e6b90-7f70-fad1-5b45-a32d898480de.jpeg)
(Extract from https://asia.olympus-imaging.com/product/compact/tg5/feature2.html)

##[OLPRE]
```
$OLPRE,1007,46.7,150.0
```
First value is atmospheric pressure, unit is hPa
Second value is altitude, unit is meter
Third value is altitude also, unit is feet

##[OLTMP]
```
$OLTMP,28.2,0,0
```
First value is temperature
Second value is the unit of first value, 0 is degree Celsius, 1 is degree Fahrenheit
Don't know the meaning of third value

##[OLACC]
Reading of accelerometer, unit is meter per second squared (m/s^2) divided by 100. Describe 3D direction by text is little bit difficult, so please refer following three examples. The camera of all three example is still and only gravity is act on it.

###Example 1
![01.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/232557/17d85083-d23c-3032-3f6b-47eeba164607.jpeg)

```
$OLACC,-10.0,1012.0,5.0
```

###Example 2
![02.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/232557/09bd2a69-8217-ce31-b9a5-4e6f31fb47a8.jpeg)

```
$OLACC,-1.0,26.0,-1038.0
```

###Example 3
![03.jpg](https://qiita-image-store.s3.ap-northeast-1.amazonaws.com/0/232557/bbf2ddcc-e33a-87ca-4aeb-a1b31fb29940.jpeg)

```
$OLACC,-995.0,58.0,27.0
```

##[OLSNSGPSTIM]
Log the different between time from camera clock and GPS clock. This line exists only if camera is getting data from GPS.

```
$OLSNSGPSTIM,20200107,014303,20200107,014304
```
First and second value is date and time of camera clock
Third and fourth value is date and time of GPS clock
Format is the same as "OLTIM" tag

#.LOG file
filename format: YYMMDDSS.LOG
YY is last two digit of year, year 2019 is 19
MM is month
DD is day
SS is sequence of that day

This log exists only if camera is getting data from GPS. Log is in NMEA-0183 format. There is plenty of resource on the web so I don't repeat it anymore. I found that altitude is not greater than 255, which may be a bug in firmware.