GT06 protocol - Wrong Date and Time noticed in the log

I found an abnormal device and when I check the log I seen this.

2024-08-08 03:54:58  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 7878312418080803363800019d0104f81b00644d68f81b00808b4ff81b004a5454f81b00644c4900000000000000000000f6a4540d0a
2024-08-08 03:54:58  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 03:54:58  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878052400f6606a0d0a
2024-08-08 03:55:08  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1304f0047d0200f7e1f80d0a
2024-08-08 03:55:08  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 03:55:08  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878051300f77b480d0a
2024-08-08 03:58:08  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1304f0047e0200f83cc20d0a
2024-08-08 03:58:08  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 03:58:08  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878051300f883bf0d0a
2024-08-08 03:59:09  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 79790020940a086711106220220241301668887704008994010216688877041600f9e23b0d0a
2024-08-08 03:59:09  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:01:09  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1304f0047e0200fa1fd00d0a
2024-08-08 04:01:09  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:01:09  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878051300faa0ad0d0a
2024-08-08 04:04:09  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1304f0047e0200fb0e590d0a
2024-08-08 04:04:09  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:04:09  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878051300fbb1240d0a
2024-08-08 04:04:10  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 79790020940a086711106220220241301668887704008994010216688877041600fcb5960d0a
2024-08-08 04:04:10  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:07:10  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1304f0047e0200fd6b6f0d0a
2024-08-08 04:07:10  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:07:10  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878051300fdd4120d0a
2024-08-08 04:09:10  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 79790020940a086711106220220241301668887704008994010216688877041600fe96840d0a
2024-08-08 04:09:10  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:10:10  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1304f0047e0200ff487d0d0a
2024-08-08 04:10:10  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:10:10  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878051300fff7000d0a
2024-08-08 04:10:30  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78783124180808040a1d00019d0104f81b00644c68f81b00808b51f81b00644d44f81b00644e4f0000000000000000000100729e0d0a
2024-08-08 04:10:30  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:10:30  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 787805240100eb0b0d0a
2024-08-08 04:11:46  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78783124180808040b2c00019d0104f81b00644d68f81b00808b50f81b004a4f5df81b004a53550000000000000000000101ef660d0a
2024-08-08 04:11:46  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:11:46  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 787805240101fa820d0a
2024-08-08 04:12:14  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1306f0037e0201027aa80d0a
2024-08-08 04:12:14  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:12:14  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 787805130102c2b20d0a
2024-08-08 04:13:16  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78783124180808040d0f00019d0104f81b00644e68f81b004a4f61f81b00644d44f81b00808b52000000000000000000010392d60d0a
2024-08-08 04:13:16  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0
2024-08-08 04:13:16  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 787805240103d9900d0a
2024-08-08 04:13:32  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78782222180808040d1ec800cd6b54089f5db90014ae019d01f81b00644d010000010447bd0d0a
2024-08-08 04:13:32  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-08 04:13:30, lat: 7.47909, lon: 80.36775, course: 174.0
2024-08-08 04:13:32  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 7878052201047bf60d0a
2024-08-08 04:14:11  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 79790020940a08671110622022024130166888770400899401021668887704160105c6000d0a
2024-08-08 04:14:11  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-08 04:13:30, lat: 7.47909, lon: 80.36775, course: 174.0
2024-08-08 04:14:57  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1344f00477020106058e0d0a
2024-08-08 04:14:57  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-08 04:13:30, lat: 7.47909, lon: 80.36775, course: 174.0
2024-08-08 04:14:57  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 78780513010684960d0a
2024-08-08 04:17:58  INFO: [Tf8bbc4aa: gt06 < XXX.245.171.109] 78780a1344f00383020107211c0d0a
2024-08-08 04:17:58  INFO: [Tf8bbc4aa] id: 867111062202202, time: 2024-08-08 04:13:30, lat: 7.47909, lon: 80.36775, course: 174.0
2024-08-08 04:17:58  INFO: [Tf8bbc4aa: gt06 > XXX.245.171.109] 787805130107951f0d0a

I tried to decode the packet manually and I noticed the data is wrong.

see example below

78783124180808040d0f00019d0104f81b00644e68f81b004a4f61f81b00644d44f81b00808b52000000000000000000010392d60d0a

Its timestamp is 180808040d0f which mean 2024-08-08 04:13:14 but the decoded data from the log is different.

id: 867111062202202, time: 2024-08-07 12:01:36, lat: 7.47732, lon: 80.36757, speed: 7.6, course: 133.0

I seen many data came from the device but the decoded log keep saying time: 2024-08-07 12:01:36

Looks like it's not supported. In our current implementation message type 0x24 is for a LBS message type.

According to the document, 24 means LBS packet but still the flag has datetime and some other details.

Here is the protocol document.

could you have a look.

I suspect you're mixing up device time and fix time.

I dont think so. my device time and the server time both have GMT 0 time zone. so the fix time must be device time right?

also I see below packet decoded correctly

78782222180808040d1ec800cd6b54089f5db90014ae019d01f81b00644d010000010447bd0d0a

it says time: 2024-08-08 04:13:30 in log.

I recommend searching forum to understand the different between different timestamps and how we use it. Your current assumption is wrong.

Thank you so much for the advice. I will search and read.

Fix time: came from the device. this time is the time obtained with last position packet.

Device time: this one also came from the device with any packet.

Server time: the server time when the position data saved

here what I understood from the old posts. Please correct me if I’m wrong.

Kind of. Fix time is the time of last GPS fix. In your case it's not a GPS message, so it will use the last known fix time.

Thanks for the clarification ❤️