Patent ID: 8717234
Filing Date: 2014-05-06
Classification: G01S

Abstract:
1. A monitoring system for monitoring positioning signals emitted by a satellite constellation belonging to a positioning system, said monitoring system comprising: at least one monitoring satellite comprising the following: at least one receiver being able to directly receive positioning signals emitted by satellites of said satellite constellation; and at least one emitter being able to emit to the Earth, integrity data indicating, which satellites of the satellite constellation are emitting an erroneous positioning signal; at least one control center being arranged on the Earth, controlling the position of said at least one monitoring satellite and configured to receive integrity data emitted by such a monitoring satellite; and at least one integrity message distributing center being arranged on the Earth and comprising: a receiver for receiving the integrity data from said at least one control center; a processor for determining, from such integrity data, integrity messages relating to satellites of said satellite constellation of the positioning system; and a transmitter for emitting such integrity messages to users, wherein said at least one monitoring satellite is placed on orbit at an altitude lower than that of the satellites of said satellite constellation and higher than that of the dense layers of the ionosphere, and said monitoring satellite further comprises at least one processing unit configured to check the integrity of the received positioning signals, using positioning information independent from said positioning signals, to determine, which, if any, satellites of the satellite constellation are emitting erroneous positioning signals.