TI mmWave radar sensors Tutorial 笔记 | Module 3: Velocity Estimation

本系列为TI(Texas Instruments) mmWave radar sensors 系列视频公开课 的学习笔记。

---

内容在CSDN和微信公众号同步更新

FMCW Radars – Module 1 : Range Estimation
FMCW Radars – Module 2 : The Phase of the IF Signal
FMCW Radars – Module 3 : Velocity Estimation
FMCW Radars – Module 4 : Some System Design Topics
FMCW Radars – Module 5 : Angle Estimation

Module 3 Velocity Estimation

This module : to answer the following questions

FFT’s on a complex sequence

Note: 下图中的 ω 1 = ω omega_1 = omega ω1​=ω

Question: How far apart the two frequencies ω 1 omega_1 ω1​ and ω 2 omega_2 ω2​ have to be for them to show up as separate peaks in the FT?

结论: Longer the sequence length ⇒ Rightarrow ⇒ better resolution

---

总结: 离散信号 VS 连续信号 频率分辨率

Discrete signals:

---

How to measure the velocity (v) of an object using 2 chirps

速度计算：

结论: The phase difference measured across two consecutive chirps can be used to estimate the velocity of the object

Maximum measurable velocity

结论 : The maximum relative speed ( v m a x v_{max} vmax​) that can be measured by 2 chirps spaced T c T_c Tc​ apart is:

Measuring velocity with multiple objects at the same range

目前，已经知道了如何测量 the velocity of a single object

结论 : ω 1 omega_1 ω1​ and ω 2 omega_2 ω2​ correspond to the phase difference between consecutive chirps for the respectively objects

Velocity resolution

推导：

注意: 这里的 N: number of chirps in one frame !

Question: 比较下述两个雷达的maximum measurable velocity ( v m a x v_{max} vmax​) 和 velocity resolution ( v r e s v_{res} vres​)

Next module: