Novatel OEM6 Integration Manual

Also see for OEM7 SPAN: User manual Installation and operation user guide Installation and operation manual Installation and Operation User Manual

Contents

Novatel OEM6 Integration Manual Manual pdf 155 page image

Chapter 2 New for OEM7 – FirmwareOEM6 to OEM7 Integration Guide v1 1552.4.9 INS Seed / Fast INS InitializationThe INS Seed functionality is an alignment method whereby INS alignment information from aprevious powerup can be injected into the system at startup to achieve an INS alignment veryquickly. This is especially useful for systems that previously required a kinematic alignment.This works by automatically saving the current INS position and attitude information to NVMwhen the system is stationary. During subsequent power ups, the saved solution is compared tothe current position of the system, and if it is determined not to have moved since the seed datawas stored, this information is used to rapidly initialize the INS filter, meaning the system willbe ready for navigation.This feature is enabled via the INSSEED command. This command setting must be saved toNVM via the SAVECONFIG command to be used upon next system boot-up.CriteriaFor the INS seed functionality to be enabled, the INSEED ENABLE command must be sent.SavingThe following criteria must be met for a valid seed to be saved into receiver NVM.l The INS solution status must be INS_SOLUTION_GOOD.l The velocity drops below 0.2 m/s.When these conditions are met, the requirement information is automatically saved to NVM. Ifthese conditions cease to be met, the saved information is automatically discarded.Use at Boot-upUpon boot, several checks are done to verify that any seed data existing in NVM is appropriatefor use. These checks require a GNSS position to be computed, so an NVM seed will never beinjected prior to achieving a GNSS position. The following criteria must be met in order to use aseed:l Seed data from NVM must be validl The system must be stationaryl The system must not have moved significantly from the seed position: <10 metres positionand 5 degrees in roll and pitchINJECT Option (Advanced Users Only)There is an advanced option available to skip the second and third validationsteps described in the boot-up section above. This can be used if GNSS is notavailable on power-up or if speed to achieve an alignment is imperative.This option is for advanced users only. Forcing an injection of an NVM seedwithout the validation checks can cause an unstable INS solution if the vehiclehas moved.Apart from injecting the seed at startup without validation, this will alsoremove some requirements typically asserted to allow the filter to converge.This will allow the system to run without GNSS adequately at startup.