Cobham Satcom quality system has detected an issue with legacy terminals EXPLORER 500 and EXPLORER 700 where registration on the Inmarsat network is inaccessible. They have analyzed the inputs and concluded this is a consequence of GPS roll over in the GPS module. This results in an erroneous timestamp in the software, and this prevents the terminal from registering. A user will see the terminal turn on, but never register to the network. At the moment, terminals from the 2004 to 2007 timeframe are affected, but all remaining EXPLORER 500/700 terminals will be impacted in the next few years and cease to operate.
The EXPLORER 500 and 700 products were discontinued in 2014/2015 with last service date in 2018/2019. While the reliability and long life has been a great benefit, age does have its consequences, and unfortunately the terminals are no longer able to continue operation. The issue is related to the GPS chipset which was not envisioned to last beyond 1024 weeks (19 years) from the chip manufacture. The root course is not possible to fix within the limits of the products’ status.
We have seen that ‘GPS Rollover’ has started to occur in some early production series of E700/500/300 terminals. This means that the terminals have an internal GPS chipset version which no longer will be able to calculate correct timestamps and therefore not be able to register to the Inmarsat BGAN network.
The issue does not apply to all terminals - but to some which have a certain Ublox4 GPS chipset revision TIM-LC. The GPS chipset is located in the antenna, so the issue relates to production of the antenna. We have found that antennas manufactured until end of 2007 can have this particular chipset mounted for EXPLORER 700.
Identifying affected terminals
As stated, terminals from 2004 to 2007 can be affected. The attached list includes serial numbers of all affected EXPLORER 500 terminals. Unfortunately, it is not possible to provide a similar list for EXPLORER 700. Therefore, the chipset must be checked in the diagnostic report or by the production time at the terminal label.
In the diagnostic report, the following procedure must be carried out.
- Go to the webpage of the terminal via the IP address http://192.168.0.1/ or if another is configured on the terminal
- Go to “HELPDESK”
- Click the button “Generate report” and save the file
- Open the file with notepad or similar program
The version of GPS chipset can be found in the top part diagnostic report. HW/SW information is listed in the beginning of the report where the Ublox4 revision which will show the GPS rollover can be identified as:
GPS Software: 3.0 Nov 07 2003 19:54:59
GPS Hardware: 00000040, Ublox 4
Example report with error:
Other revisions like the below is manufactured after end of 2007 and does NOT show the GPS Rollover before July 2025 or Dec. 2028.
GPS Software: 5.00 Jan 09 2006 12:00:00
GPS Hardware: 00040001, Ublox 4
For EXPLORER 500, some software versions do not show the GPS information. Therefore, we recommend updating to the latest software which is general benefit for the performance of the terminal.