Navigation device and method using data pre-integrated asynchronously in a remote imu

A navigation device comprising an inertial measurement unit and an electronic navigation calculation unit that are connected to each other by a data link, the inertial measurement unit comprising inertial sensors which supply first signals containing first data representative of a variation in velocity and second data representative of a variation in angle, and the electronic navigation calculation unit being arranged to calculate a navigation from signals supplied by the inertial measurement unit, wherein the inertial measurement unit comprises an electronic processing circuit that is connected to the inertial sensors and arranged to perform at least a first integration, as a function of time, of the first data and of the second data over an integration period, which begins at a single integration start time and is measured, in order to produce first processed data and second processed data contained in second signals together with time information representative of the integration period, and in that the electronic navigation calculation unit is arranged to extract the processed data and the time information from the second signals and to process them in order to calculate the navigation while taking the integration period between two successive extractions into account.