芯讯通无线科技(上海)有限公司-芯讯通无线科技(上海)有限公司

官网通知

2019/04/03

Declaration of GPS week rollover issue

Dear customer,

Thank you very much for choosing SIMCom modules

We：

Shanghai SIMCom Wireless Solutions Ltd.

Declare that there is no GPS week rollover issue (refer to Appendix) on the modules listed below until the date marked.

Module No	FW	When the week rollover issue would occur
SIM5320 Series	All FW versions	2019/11/3
SIM5360 Series	All FW versions
SIM7100 Series	All FW versions
SIM68R	B03V00SIM68R11,B03V10SIM68R11	2022/10/29
SIM68R	B03V11SIM68R_11/96 ~ B03V23SIM68R_11/96
SIM68RB	B03V60SIM68RB 11/96,B03V61SIM68RB96
SIM68V	B03V00SIM68V_11, B03V10SIM68V_11,B03V21SIM68V_38
SIM68V	B03V11SIM68V_11/96 ~ B03V23SIM68V_11/96
SIM68VB	B03V60SIM68VB11/96,B03V61SIM68VB11
SIM968	B03V11SIM968_11,B03V20SIM968_11
SIM33ELA	B03V20SIM33ELA1/9 ~ B05V83SIM33ELA1/9	2025/8/16
SIM33EAU	B05V82SIM33EAU1/9
SIM68E	B03V60SIM68E_96 ~ B05V84SIM68E_96
	B04V62SIM68E_11 ~ B05V84SIM68E_11
	B04V64SIM68E3D9 ~ B05V81SIM68E3D9
SIM68M	B03V20SIM68M_11/96 ~ B05V81SIM68M_11/96
SIM68MB	B03V62SIM68MB11/96 ~ B05V80SIM68MB11/96
SIM68R	B03V24SIM68R_11/96 ~ B05V80SIM68R_11/96
SIM68RB	B03V62SIM68RB1A/9A
SIM68RB	B03V62SIM68RB11/96 ~ B04V61SIM68RB11/96
SIM68V	B04V64SIM68V48P
SIM68V	B04V62SIM68V_11/96 ~ B05V85SIM68V_11/96
SIM68VB	B03V62SIM68VB_11/96 ~ B04V60SIM68VB_11/96
	B04V61SIM68VBD9 ~ B05V81SIM68VBD9
	B05V82SIM68VB9B
SIM968	B03V21SIM968_96,B04V60SIM968_11/96, B05V20SIM968_J1,B05V81SIM968_11
SIM968	B04V60SIM968B11/96 ~ B04V61SIM968B11/96
SIM808	All FW versions	2030/8/10
SIM28ML	All FW versions
SIM28ML-H	All FW versions
SIM28M	All FW versions
SIM28	All FW versions
SIM928A	All FW versions
SIM39EAR	All FW versions
SIM39EAU	All FW versions
SIM39EA	B02V32SIM39EA48,B02V60SIM39EA11/96/19
	B02V50SIM39EA19 ~ B02V51SIM39EA19
	B02V31SIM39EA11 ~ B02V32SIM39EA11
	B02V10SIM39EA96 ~ B02V51SIM39EA96
SIM7500 Series	All FW versions	2032/12/12
SIM7600 Series	All FW versions
SIM7800 Series	All FW versions
SIM7000 Series	All FW versions
SIM868	All FW versions	2034/8/12
SIM868E	All FW versions
SIM68E	B06V11SIM68E_11/96 ~ B06V14SIM68E_11/96
SIM68M	B05V83SIM68M_11
SIM68M	B06V11SIM68M_11/96 ~ B06V14SIM68M_11/96
SIM68MB	B06V10SIM68MB11/96 ~ B06V11SIM68MB11/96
SIM68R	B06V10SIM68R_11/96 ~ B06V11SIM68R_11/96
SIM68RB	B05V10SIM68RB11/96 ~ B06V11SIM68RB11/96
SIM68V	B06V10SIM68V_11/96 ~ B06V11SIM68V_11/96
SIM68VB	B06V10SIM68VB11/96 ~ B06V11SIM68VB11/96
SIM33ELA	B06V10SIM33ELA1/9 ~ B06V11SIM33ELA1/9
SIM33EAU	B06V10SIM33EAU1/9 ~ B06V11SIM33EAU1/9
SIM39EA	B02V60SIM39EA11/96/19	2035/9/8

Appendix

What is GPS week rollover issue?

The Week Rollover Problem is a known issue caused by the way that GPS used to handle the week element of the data that forms an essential part of the navigation signal. GPS used a 10 bit field to encode the week number in each GPS time message, which means that a maximum of 1,024 weeks (19.7 years), could be handled. Each of these periods is known in GPS terms as an “epoch”.

At the end of each epoch of 1,024 weeks, the receiver resets the week number to zero and starts counting again.