But it’s a good time to make sure all of them including our handheld GPS receivers for hiking, etc., as well as any high precision surveying or construction GPS devices are updated to the current software version through the manufacturer. Most of our consumer devices, phones, tablets, computers, cars, etc. To prepare for the week number rollover, it is recommended to install the latest GPS receiver firmware version. The newer message types (CNAV and MNAV) use 13-bit binary numbers to represent the GPS week number, so the issue should not occur in the future when more receivers are using the newer GPS signals.By Dave Bunting, Shopper Editor GPS Week Number Rollover Boeing’s 737Max Super Commuters Earn More ENJOY Your Exercise GPS Week Number RolloverĪ GPS week number rollover will occur at the end of the GPS day on Saturday, 6 April 2019, at which time the GPS week will transition instantly from week 2047 to 2048.īecause the GPS message structure broadcast by the satellites defines the week as a 10-bit binary value, in which 2047 is the largest possible number, the GPS messages will indicate that the week has changed from 2047 to week 0. GPS is currently undergoing a modernization program to upgrade the signals with new modulation and data message structures. This verifies the receiver’s capability to obtain the correct date and time in the next GPS epoch without having any previous information from GPS.Verify that the receiver can obtain the correct date and time.Verify the receiver still outputs the correct date and time.Observe the rollover from April 6 to April 7, 2019.Allow the receiver to get a fix, and report the correct date and time.Set GSG transmit power to a suitable level for your receiver (typically -115 to -125dBm).These settings can also be configured on the front panel of the unit by modifying a present scenario, such as GPSStatic. The scenario file starts the simulation at on Ap23:25 and runs for two hours. If you are using any Spectracom GSG-5 or GSG-6 simulator, you can download a scenario to test for the rollover event: Scenario File Possibility to program custom date and time.The requirements for the simulator are straightforward: To be sure that your system will not experience any failures related to this issue, it is possible to test for this event using a GPS/GNSS simulator. Many manufacturers have already issued compliance statements, and we expect them to continue to do so over the next year, up until the event occurs. At a minimum, we recommend consulting your receiver manufacturer to confirm that the issue has been fully tested and will not occur. In these cases, we want to verify that an issue will not occur. Receiver is a core component of a critical timing system – ask yourself – what is the impact to my system if the GPS receiver stopped operating or put out wrong GPS or UTC information.Receiver has been fielded for more than 10-15 years without firmware updates.You should be concerned, though, if either of the following applies: Using this method, the problem could occur, but at a different date and year than the actual GPS rollover date.īecause this it is the second time the GPS week rollover will occur, many receiver manufacturers have prepared for it, and newer receivers will continue to operate without issue. It is also possible for the user to modify this reference date in some receivers.Īnother way is to shift that 1023 window with reference to some firmware or manufacture date within the receiver. This works well if the receiver is new or is receiving firmware updates. One common method is to use the firmware date as a reference. To do this, receivers use various methods to ensure that they are providing the correct date. Receivers must properly interpret that week number as the correct date, not 19.7 years into the past or future. The next time the counter will reach week 1023 and rollover to zero is on April 6, 2019. The week counter then reset to zero, and it has been recounting ever since. The 1024 weeks counter ran out and rolled over on August 21, 1999. This limits the range of the week number to 0 – 1023, or 1024 total weeks. However, the field that contains the week number is a 10-bit binary number. This allows the receiver to translate the date and time into a more typical format – day, month, year, and time of day. It also includes the ability to transmit the proper date and time to a receiver by supplying the receiver with the current week and the current number of seconds into the week. The Global Positioning System provides accurate timing information to many of our critical systems – power grid, communications, financial markets, emergency services, and industrial control to name a few.
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