Techniques for angle resolution in radar

1. An apparatus comprising:

a receive antenna unit, the receive antenna unit comprising:

a linear array of antennas; and

and

a signal processing unit, the signal processing unit configured to:

estimate an azimuth frequency associated with an obstacle from a signal received from the obstacle at the linear array of antennas;

estimate a complex amplitude associated with the obstacle from the estimated azimuth frequency associated with the obstacle and from the signal received from the obstacle at the linear array of antennas;

estimate a complex phasor associated with the obstacle from the estimated complex amplitude associated with the obstacle and from a signal received from the obstacle at the linear array of antennas; and

estimate an azimuth angle and an elevation angle associated with the obstacle from the estimated complex phasor associated with the obstacle and from the estimated azimuth frequency associated with the obstacle.

2. The apparatus of claim 1 , wherein the obstacle have a fixed distance and a fixed relative velocity with respect to the radar apparatus.

3. The apparatus of claim 1 , wherein the estimate of complex amplitude associated with the obstacle is one of a least squares estimate and a weighted least squares estimate.

4. The apparatus of claim 1 , wherein the estimate of the complex phasor associated with the obstacle is one of a least squares estimate and a weighted least squares estimate.

5. A method comprising:

estimating, at a radar apparatus, an azimuth frequency associated with an obstacle from a signal received from the obstacle;

estimating, at a radar apparatus, a complex amplitude associated with the obstacle from the estimated azimuth frequency associated with the obstacle and from the signal received from the obstacle;

estimating, at a radar apparatus, a complex phasor associated with the obstacle from the estimated complex amplitude associated with the obstacle and from the signal received from the obstacle; and

estimating, at a radar apparatus, an azimuth angle and an elevation angle associated with the obstacle from the estimated complex phasor associated with the obstacle and from the estimated azimuth frequency associated with the obstacle.

6. The method of claim 5 , wherein the radar apparatus comprises a receive antenna unit, the receive antenna unit further comprising:

a linear array of antennas.

7. The method of claim 5 , wherein estimating the azimuth frequency further comprises estimating the azimuth frequency associated with the obstacle from a signal received from the obstacle.

8. The method of claim 5 , wherein estimating the complex amplitude further comprises estimating the complex amplitude associated with the obstacle from the estimated azimuth frequency associated with the obstacle and from the signal received from the obstacle.

9. The method of claim 5 , wherein estimating the complex phasor further comprises estimating the complex phasor associated with the obstacle from the estimated complex amplitude associated with the obstacle and from a signal received from the obstacle.

10. The method of claim 5 , wherein:

the estimate of complex amplitude associated with the obstacle is one of a least squares estimate and a weighted least squares estimate; and

the estimate of the complex phasor associated with the obstacle is one of a least squares estimate and a weighted least squares estimate.

11. An apparatus comprising:

a transmitter configured to generate an outbound RF (radio frequency) signal;

a receiver configured to receive an inbound RF signal, wherein the outbound RF signal is scattered by the obstacle to generate the inbound RF signal;

a mixer coupled to the receiver and to the transmitter and configured to demodulate the inbound RF signal to generate a demodulated signal;

an analog to digital converter (ADC) coupled to the mixer and configured to generate a digital signal in response to the demodulated signal received from the mixer;

an FFT (fast fourier transform) module coupled to the ADC and configured to transform the digital signal from a time domain to a frequency domain; and

a signal processing unit coupled to the FFT module and configured to process the digital signal, the signal processing unit further configured to:

estimate an azimuth frequency associated with an obstacle from the digital signal;

estimate a complex amplitude associated with the obstacle from the estimated azimuth frequency associated with the obstacle and from the digital signal;

estimate a complex phasor associated with the obstacle from the estimated complex amplitude associated with the obstacle; and

estimate an azimuth angle and an elevation angle associated with the obstacle from the estimated complex phasor associated with the obstacle and from the estimated azimuth frequency associated with the obstacle.

12. The apparatus of claim 11 , the receive antenna unit further comprising:

a linear array of antennas; and

an additional antenna at a predefined offset from at least one antenna in the linear array of antennas.

13. The apparatus of claim 12 , wherein the complex phasor associated with the obstacle is estimated from a signal received from the obstacle at the additional antenna and from the estimated complex amplitude associated with the obstacle.

14. The apparatus of claim 11 , wherein the outbound RF signal comprises a plurality of frames of the RF signal generated by the transmitter and the inbound RF signal comprises a plurality of frames of the signal received from the obstacle.