Haicom HI-203E User Manual

Also see for HI-203E: User manual Use manual

Contents

Haicom HI-203E User Manual Manual pdf 5 page image

SECTION 2RECEIVER OPERATIONUpon power up, after initial self-test has completed, the HI-203E will begin satelliteacquisition and tracking process. Under normal open-sky condition, position-fix can beachieved within approximately 45 seconds (within 15 seconds if valid ephemeris data isalready collected from recent use). After receiver position has been calculated, valid position,velocity and time information are transmitted through the on board serial interface.The receiver uses the latest stored position, satellite data, and current RTC time to achieverapid GPS signal acquisition and fast TTFF. If the receiver is transported over a large distanceacross the globe, cold-start automatic-locate sequence is invoked. The first position fix maytake up to five minutes searching the sky for the GPS signal. The acquisition performance canbe improved significantly if the host initializes the receiver with a rough estimate of time anduser position.As soon as GPS signal is acquired and tracked, the HI-203E will transmit valid navigationinformation through its serial interface. The navigation data contains following information:l Receiver position in latitude, longitude, and altitudel Receiver velocityl Timel DOP error-magnification factorl GPS signal tracking statusThe HI-203E will perform 3D navigation when four or more satellites are tracked. When threeor fewer satellites are tracked, altitude-hold is enabled using the last computed altitude and 2Dnavigation mode is entered.With signal blockage or rising and setting of the satellites, where a change in satelliteconstellation used for position fix occurred, large position error may result. The HI-203Eincorporates a proprietary algorithm to compensate the effect of satellite constellation change,and maintains an accurate smooth estimate of the receiver position, velocity, and heading.5