Software time synchronization method for position and orientation system

Abstract

The invention provides a software time synchronization method for a position and orientation system (POS). The POS comprises an inertial measurement unit, a POS navigation computer, a GPS (Global Positioning System) receiver and the like. The time synchronization method comprises the following steps of: firstly synchronizing system time of the POS navigation computer to world coordinated time by using a GPS second pulse sent by the GPS receiver and a time counter; and synchronizing the data acquisition time of the inertial measurement unit with the world coordinated time through a method of correcting a frequency division period of a data acquisition pulse clock of the inertial measurement unit so as to complete the time synchronization of the POS. In the invention, the problem of reducing of synchronization accuracy of the POS in a short time due to the clock drift is solved through the method of changing the frequency division period of the data acquisition pulse clock, and the software time synchronization method has the characteristics of high accuracy and high anti-interference capacity.

Description

technical field [0001] The invention relates to a software time synchronization method of a position and orientation measurement system (Position and Orientation System, POS), which belongs to the field of remote sensing information acquisition and is used for time synchronization of position and orientation measurement system data and external events. Background technique [0002] The position and attitude measurement system consists of a POS navigation computer (POS Computer System, PCS), an inertial measurement unit (Inertial Measurement Unit, IMU) and a GPS receiver. The PCS first obtains the angular velocity and acceleration output by the IMU, the velocity and position output by the GPS receiver, and auxiliary information output by other auxiliary sensors, such as temperature, attitude and other data, and then the PCS performs data fusion processing to obtain high-precision motion information of the carrier, providing Used for application payloads. [0003] It is meani...

AI Technical Summary

Problems solved by technology

[0005] The existing position and attitude measurement system time synchronization method (public number 1: CN101105401, public number 2: CN101067656) realizes the time of the system by using the GPS second pulse to reset the system clock or generating a time synchronization pulse based on the GPS second pulse Synchronization does not solve the problem that the short-term time synchronization accuracy decreases due to system clock drift within two GPS second pulse intervals, which leads to insufficient overall accuracy of system time synchronization, and its time synchronization error always accumulates in the same direction in a short period of time, making the system time Synchronization error appears jagged jump phenomenon

Aiming at the problem that the measurement characteristics of the position and attitude measurement system require high time synchronization accuracy, while overcoming the long-term accumulation of system clock drift over time, it is also necessary to consider the decrease in time synchronization accuracy due to system clock drift errors within two GPS second pulse intervals Since there is no time reference in the time interval of two GPS second pulses, it is necessary to propose a time synchronization method that can simultaneously improve the time synchronization accuracy in the two GPS second pulse intervals and the time synchronization error changes uniformly around the true value. Improve overall system time synchronization accuracy

Images