US 11,041,954 B2 · Lidar system to detect doppler effects

Abstract

Doppler correction of broadband LIDAR includes mixing, during a first time interval, a returned optical signal with an in-phase version of the transmitted signal to produce a first mixed optical signal that is detected during the first time interval to produce a first electrical signal. During a non-overlapping second time interval the returned optical signal is mixed with a quadrature version of the transmitted signal to produce a second mixed optical signal that is detected during the second time interval to produce a second electrical signal. A complex digital signal uses one of the digitized electrical signals as a real part and a different one as the imaginary part. A signed Doppler frequency shift of the returned optical signal is determined based, at least in part, on a Fourier transform of the complex digital signal. A device is operated based on the Doppler frequency shift.

Claims24

Dependent claims

A method comprising:

transmitting an optical signal that is output from a laser and modulated based on a modulating signal;
receiving a returned optical signal in response to transmitting the optical signal;
mixing, during a first time interval, the returned optical signal with a first reference optical signal that is modulated based on a first version of the modulating signal, to produce a first mixed optical signal;
mixing, during a second time interval, the returned optical signal with a second reference optical signal that is modulated based a second version of the modulating signal, to produce a second mixed optical signal;
generating a digital signal based on the first mixed optical signal and the second mixed optical signal;
determining a Doppler frequency shift of the returned optical signal based, at least in part, on the digital signal;
and
operating a vehicle based on the Doppler frequency shift.

5 more elements

A light detection and ranging (LIDAR) system comprising a transmitter, a receiver, an optical mixer and a processor, wherein:

the transmitter is configured to transmit an optical signal that is output from a laser and modulated based on a modulating signal;
the receiver is configured to receive a returned optical signal in response to transmitting the optical signal;
the optical mixer is configured to:
mix, during a first time interval, the returned optical signal with a first reference optical signal that is modulated based on a first version of the modulating signal, to produce a first mixed optical signal;
and
mix, during a second time interval, the returned optical signal with a second reference optical signal that is modulated based a second version of the modulating signal, to produce a second mixed optical signal;
and the processor is configured to:
generate a digital signal based on the first mixed optical signal and the second mixed optical signal;
determine a Doppler frequency shift of the returned optical signal based, at least in part, on the digital signal;
and
operate a vehicle based on the Doppler frequency shift.

8 more elements

Dependencies are inferred from the claim text.

Lidar system to detect doppler effects

Life of this patent

Lidar system to detect doppler effects

Life of this patent

Abstract

Claims24