Techniques to use power spectrum density in coherent lidar systems
A number of measurements of an input spectrum is determined based on a scan mirror speed of the LiDAR system and a predetermined accuracy threshold in the number of measurements of the input spectrum. A set of signals are sampled at the LiDAR system and the set of signals are converted to a frequency domain to generate a set of sampled signals in the frequency domain. The set of signals are received consecutively over time. A set of first functions are created based on the set of sampled signals. The set of first functions are averaged to generate a second function. The second function represents a power spectrum density estimate of the set of signals. A peak value of the second function is detected to determine range and velocity information related to a target based on a corresponding frequency of the peak value of the second function.
1. A method of determining range and velocity information of a target in a light detection and ranging (LiDAR) system, comprising:
determining a number of measurements of an input spectrum based on a scan mirror speed of the LiDAR system and a predetermined accuracy threshold in the number of measurements of the input spectrum;
sampling a set of signals at the LiDAR system and converting the set of signals to a frequency domain to generate a set of sampled signals in the frequency domain, wherein the set of signals are received consecutively over time, wherein each signal of the set of signals corresponds to a measurement of the input spectrum to produce the number of measurements of the input spectrum;
creating a set of first functions based on the set of sampled signals;
averaging the set of first functions to generate a second function, wherein the second function represents a power spectrum density estimate of the set of signals; and
detecting a peak value of the second function to determine range and velocity information related to a target based on a corresponding frequency of the peak value of the second function.
2. The method of claim 1 , wherein averaging the set of first functions further comprises calculating a magnitude squared of the set of signals.
3. The method of claim 1 , wherein the number of measurements of the input spectrum is increased in response to an increase of a predetermined level of accuracy in frequency measurement of the input spectrum of the LiDAR system.
4. The method of claim 1 , wherein the number of measurements of the input spectrum is increased in response to an increase of a predetermined level of accuracy in energy measurement of the input spectrum of the LiDAR system.
5. The method of claim 1 , wherein the number of measurements corresponds to an increase or a decrease of a scan mirror speed of the LiDAR system.
6. A light detection and ranging (LiDAR) system, comprising:
a processor; and
a memory to store instructions that, when executed by the processor, cause the LiDAR system to:
determine a number of measurements of an input spectrum based on a scan mirror speed of the LiDAR system and a predetermined accuracy threshold in the number of measurements of the input spectrum;
sample a set of signals at the LiDAR system and converting the set of signals to a frequency domain to generate a set of sampled signals in the frequency domain, wherein the set of signals are received consecutively over time, wherein each signal of the set of signals corresponds to a measurement of the input spectrum to produce the number of measurements of the input spectrum;
create a set of first functions based on the set of sampled signals;
average the set of first functions to generate a second function, wherein the second function represents a power spectrum density estimate of the set of signals; and
detect a peak value of the second function to determine range and velocity information related to a target based on a corresponding frequency of the peak value of the second function.
7. The LiDAR system of claim 6 , wherein the LiDAR system is further to calculate a magnitude squared of the set of signals.
8. The LiDAR system of claim 6 , wherein each signal of the set of signals corresponds to a measurement of an input spectrum to produce a number of measurements of the input spectrum.
9. The LiDAR system of claim 6 , wherein the number of measurements of the input spectrum is increased in response to an increase of a predetermined level of accuracy in frequency measurement of the input spectrum of the LiDAR system.
10. The LiDAR system of claim 6 , wherein the number of measurements corresponds to an increase or a decrease of a scan mirror speed of the LiDAR system.
11. A frequency-modulated continuous-wave (FMCW) light detection and ranging (LiDAR) system, comprising:
a first optical source to transmit a portion of a first light signal towards a target;
a second optical source to transmit a portion of a second light signal towards a target;
an optical receiver to receive a first return signal from the target based on the first light signal and a second return signal from the target based on the second light signal,
a circuitry; and
a memory to store instructions that, when executed by the circuitry, cause the LiDAR system to:
determine a number of measurements of an input spectrum based on a scan mirror speed of the LiDAR system and a predetermined accuracy threshold in the number of measurements of the input spectrum;
sample a set of signals at the LiDAR system and converting the set of signals to a frequency domain to generate a set of sampled signals in the frequency domain, wherein the set of signals are received consecutively over time, wherein each signal of the set of signals corresponds to a measurement of the input spectrum to produce the number of measurements of the input spectrum;
create a set of first functions based on the set of sampled signals;
average the set of first functions to generate a second function, wherein the second function represents a power spectrum density estimate of the set of signals; and
detect a peak value of the second function to determine range and velocity information related to a target based on a corresponding frequency of the peak value of the second function.
12. The LiDAR system of claim 11 , wherein the LiDAR system is further to calculate a magnitude squared of the set of signals.
13. The LiDAR system of claim 11 , wherein the number of measurements of the input spectrum is increased in response to an increase of a predetermined level of accuracy in frequency measurement of the input spectrum of the LiDAR system.
14. The LiDAR system of claim 11 , wherein the number of measurements of the input spectrum is increased in response to an increase of a predetermined level of accuracy in energy measurement of the input spectrum of the LiDAR system.
15. The LiDAR system of claim 11 , wherein the number of measurements corresponds to an increase or a decrease of a scan mirror speed of the LiDAR system.