| 摘要 |
PURPOSE:To execute rational arithmetic processing even when the number of satellites is less than four, by converting user coordinates to a cartesian coordinate system, and thereafter, determining a virtual satellite MSR, calculating repeatedly four equations based on this MSR, and executing a convergent decision. CONSTITUTION:First of all, cartesian coordinates of catching satellites S1-S3 and a measured value MSR of a pseudo range of each satellite are inputted by a P0, and an estimation PIG, height KHT, and a time offset estimated value PB are inputted as a user in P1. User coordinates are converted to Cartesian coordinates in P2, and in P3, a pseudo range MSR4 of a virdual satellite S4 placed in the center of the earth is derived, and base thereon, four simultaneous equations are made. Subsequently, by solving said simultaneous equations in P5, four variables are derived. Next, a curve coordinate position is calculated in P6. In P7-P9, a convergent decision condition of a repeated arithmetic operation is determined, and in case of convergence, said variables are converted to latitude, longitude, height, and a time offset. IN case of non-convergence, the arithmetic operation is suspended and bailing-out is executed.
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