| 摘要 |
Apparatus for receiving ranging signals (e.g. signals from Global Positioning System satellites) has a receiver coupled to a plurality of spaced antennas. The receiver includes a signal combiner which receives, from a processing circuit, signal components individually representative of a characteristic of the received ranging signals (e.g. signal-to-noise ratio) at a respective antenna and weights the said components to produce a range estimate of improved accuracy in difficult reception conditions. In one embodiment receiver includes a common i.f. channel which filters a combination signal representative of all the incoming signals in order substantially to maintain phase coherence between the incoming signals, yielding improvements in carrier phase measurement and discrimination.
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