System for Determining a Relative Position and/or a Relative Distance of a Transmitter with Respect to a Receiver, and Inductive Vehicle Charging System Having Such a System

A method of determining a relative position POSS1-E2 and/or a relative distance DS1-E2 of a transmitter S1 with respect to a receiver E2, the method comprising:

• wirelessly emitting a sign SigS1(ti) at the time ti from the transmitter S1, with time transit index i=1, 2, . . . , wherein the transmitter S1 adjusts a signal level P(SigS1(ti)) and/or a carrier frequency F(SigS1(ti)) of the signal SigS1(ti);
• receiving the sign SigS1(ti) at the receiver E2 at the time ti+Δt as signal SigE2(ti+Δt), where Δt is a signal transit time, where:
• 2Δt<|ti+1−ti|, in particular 2Δt<<|ti+1−ti|, and where the receiver E2 carries out the following:
• determining a signal level P(SigE2(ti+Δt)) of the received signal SigE2 and/or a signal-to-noise ratio SNR(SigE2(ti+Δt)) of the received signal SigE2(ti+Δt),
• determining a direction of incidence {right arrow over (E)}2 of the received signal SigE2(ti+Δt), and
• based on P(SigE2(ti+Δt)) and {right arrow over (E)}2, determining the relative position POSS1-E2 of the transmitter S1 with respect to the receiver E2 and/or the relative distance DS1-E2 between the transmitter S1 and the receiver E2;
• and
• wirelessly transmitting the determined signal level P(SigE2(ti+Δt)) and/or the determined signal-to-noise ratio SNR(SigE2(ti+Δt)) and/or the direction of incidence {right arrow over (E)}2 and/or the relative position POSS1-E2 and/or the distance DS1-E2 to a receiver E1 which is connected to the transmitter S1 by means of a transmitter S2 connected to the receiver E2,
• wherein the transmitter S1 adjusts the signal level P(SigS1(ti+1)) and/or the carrier frequency F(SigS1(ti+1)) of the signal SigS1(ti+1) emitted in the next time step ti+1 depending on the signal level P(SigE2(ti+Δt)) and/or the signal-to-noise ratio SNR(SigE2(ti+Δt)) and/or the relative position POSS1-E2 and/or the distance DS1-E2, and/or adding information to the signal SigS1(ti+1) to be emitted by the transmitter S1 in the next time step ti+1, which information is dependent on one of the signal level P(SigE2(ti+Δt)) and/or the signal-to-noise ratio SNR(SigE2(ti+Δt)) and/or the relative position POSS1 and/or the distance DS1-E2, which information is indicative of at least one damping parameter DP for adjusting the damping of a signal SigE2(ti+1+Δt) received by the receiver E2.