System and method for local oscillator drift estimation and compensation in cascaded sensors

A method for compensating for local oscillator (LO) phase shifts in cascaded integrated circuit (IC) devices of a frequency modulated continuous wave (FMCW) radar system, the method comprising:

• providing an antenna array of the FMCW radar system, the antenna array including C antennas, where (C=A+B−1), and where A, B, and C are integers greater than one;
• coupling A first sensor inputs of a first IC device to a first A of the antennas;
• receiving, on each first sensor input an associated first reflected signal;
• mixing, in the first IC device, the first reflected signals to associated first baseband signals based upon a first local oscillator (LO) signal, wherein the first LO signal has a first phase shift, and wherein a common first baseband signal is associated with the common first sensor input;
• outputting, from the first IC device, the first baseband signals;
• coupling B second sensor inputs of a second IC device to a last B of the antennas such that a common one of the first sensor inputs and a common one of the second sensor inputs are both coupled to a common antenna;
• receiving, on each second sensor input an associated second reflected signal;
• mixing, in the second IC device, the second reflected signals to associated second baseband signals based upon a second local oscillator (LO) signal, wherein the second LO signal has a second phase shift, wherein the first and second LO signals are based upon a common LO signal, and wherein a common second baseband signal is associated with the common second sensor input;
• and
• outputting, from the second IC device, the second baseband signals.

A frequency modulated continuous wave (FMCW) radar system, comprising:

• a transmitter configured to provide a plurality of FMCW chirps;
• and
• a receiver, comprising:
• an antenna array including C antennas, where (C=A+B−1), and where A, B, and c are integers greater than one;
• a first integrated circuit (IC) device including A first sensor inputs, each first sensor input coupled to a first A of the antennas, the first IC device configured to receive on each first sensor input an associated first reflected signal associated with the FMCW chirps, to mix the first reflected signals to associated first baseband signals based upon a first local oscillator (LO) signal, and to output the first baseband signals, wherein the first LO signal has a first phase shift;
• and
• a second IC device including B second sensor inputs, each second sensor input coupled to a last B of the antennas such that a common one of the first sensor inputs and a common one of the second sensor inputs are both coupled to a common antenna, the second IC device configured to receive on each second sensor input an associated second reflected signal associated with the FMCW chirps, to mix the second reflected signals to associated second baseband signals based upon a second local oscillator (LO) signal, and to output the second baseband signals, wherein the second LO signal has a second phase shift, wherein the first and second LO signals are based upon a common LO signal, and wherein a common first baseband signal is associated with the common first sensor input and a common second baseband signal is associated with the common second sensor input.