GPS Chip MT2503 Disaster in 2025
Recently, some GPS Tracing devices at GPSPOS server starts to behave abnormally. The status is GPS tracker is online while there is no trace playback since August 17th, 2025, and the SMS reply time or GPRS location time are both set back to January 1st, 2006.
What is MT2503?
MediaTek MT2503 is an ARMv7-based chip that contains dual mode Bluetooth and integrated 2G modem for simple mobility, security or industrial applications. MT2503D is wide used in 2G GPS tracker for its competitive cost and stable performance. MT2503D platform is the GSM platform MT6261 and GNS platform MT3333 combination. Model UM552 and LK720 uses MT6261 chipset so they are working fine.
Why does MT2503 stop GPS updates?
It is because of GPS week number rollover.
What is GPS week number rollover?
To provide the current date, the Global Positioning System (GPS) keeps an internal count of the number of weeks since January 5, 1980. The main civil GPS signal (C/A code) broadcasts the GPS week number using a 10-bit code with a maximum value of 1,023 weeks. This means every 19.7 years, the GPS week number in the C/A code rolls over to zero. The GPS week number rollover is a phenomenon that happens every 1,024 weeks, which is about 19.6 years.
1999 occurrence
The first rollover took place midnight (UTC) August 21 to 22, 1999.
2019 occurrence
The second rollover occurred on the night of April 6 to 7, 2019, when GPS Week 2,047, represented as 1,023 in the counter, advanced and rolled over to 0 within the counter.
2038 occurrence
The third rollover will occur between November 20 and 21, 2038. This is unrelated to the Year 2038 problem, which will occur in January of that year.
2137 occurrence
The above rollovers are due to a ten-bit week number; the more recent CNAV protocol, successor to the original NAV protocol, uses thirteen-bit week numbers, which amounts to a 157-year cycle; therefore, using the same epoch of 1980, the first rollover will not be until 2137.
Why does it happen now on August 18 2025?
MT2503 chipset internal count of the number of weeks starts at January 1, 2006. From January 1, 2006 to August 17, 2025, it is just 1024 weeks. That is why all 2G GPS Tracker with MT2503 chipset all report time at January 1, 2006.
What are the damages for GPS tracker with MT2503 chipset?
Most of them shall go offline or fix at one location without updating new GPS data. The purpose of tracking the asset will become impossible, so is the history playback and other GPS data connected reports.
What is the solution?
1 GPSPOS software shall use server time when such GPS trackers report wrong date, to make them display right time and right place. This is a temporary solution faking the MT2503 GPS tracker right. This solution does not work if the GPS Tracker does not send valid GPS data.
2 GPS Tracker companies have started to discuss with MediaTek to see if they can solve the GPS Week number rollover from chip side, which is the best solution.
What is the consequence of software solution?
Since all GPS data time are based on server time. Normal GPS data and GSM-blind area data are combined, which makes history playback or reports disorder. GSM-blind area data are the data stored in GPS tracker when there is no GSM network coverage, so their time are normally earlier than the latest right GPS data time.
What actions should you do?
If your GPS tracker shows right location after software operation, that will be great. But please explaine to your clients about History Playback disorder issue. Otherwise, you will have to replace them for your clients. Most of the devices are sold 4 years ago. It is time to replace them with the new GPS tracking devices and give best service to your clients.