| 摘要 |
The two way trip taken by an HF radar signal between a radar transmitter (4) and target (5) by reflection from ionospheric layers (2, 3) can be made by a number of different combinations of paths (6, 7, 8), each combination constituting a mode. The different delays associated with different modes produce a number of returns from a single target. For each return, a first image is calculated comprising the positions in which the target would have had to have been to produce that return by each mode, and using these positions, a double image is calculated comprising the returns which would be produced by targets in those positions by the different modes. A "cost" for each double image is calculated taking into account distance from a radar track, range, azimuth and doppler. The track having the lowest cost is assumed to be correct. |
