Editing Global Positioning System (section)

==== Inscribed sphere ====
[[File:Descartes Circles.svg|thumb|A smaller circle ({{color|red|'''red'''}}) inscribed and tangent to other circles ({{color|black|'''black'''}}), that need not necessarily be mutually tangent]]

The receiver position can be interpreted as the center of an [[inscribed sphere]] (insphere) of radius ''bc'', given by the receiver clock bias ''b'' (scaled by the speed of light ''c''). The insphere location is such that it touches other spheres. The [[Circumscribed sphere|circumscribing spheres]] are centered at the GPS satellites, whose radii equal the measured pseudoranges ''p''<sub>i</sub>. This configuration is distinct from the one described above, in which the spheres' radii were the unbiased or geometric ranges ''d''<sub>i</sub>.<ref name=HWLW />{{rp|36–37}}<ref name="Hoshen 1996">{{cite journal |author=Hoshen |first=J. |year=1996 |title=The GPS Equations and the Problem of Apollonius |journal=IEEE Transactions on Aerospace and Electronic Systems |volume=32 |issue=3 |pages=1116–1124 |bibcode=1996ITAES..32.1116H |doi=10.1109/7.532270 |s2cid=30190437}}</ref>