- #1
Ray_Xu
- 8
- 0
Hey all,
I'm a newbie here with a question regarding doppler shift. Before I ask, I only have a very basic understanding of the doppler effect.
So, my big question is: can a doppler shift measurement be converted to the distance between the source and target, without using the time of flight method?
What I'm trying to do here is using this product http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/SortField/0/Level/a/ProductID/606/Default.aspx I want it to determine the distance to a target, based on the output of that radar module. Its intended to be used as a proximity sensor, but the datasheet says it can also be used to measure speed via the doppler effect. It may sound crazy, but I'm planning to mount this onto my bike for my own useful and safety purposes; as well as to gain more experience working with radars and doppler shift. Since this is going to be mounted onto my bike, I will know the speed I'm/the radar is traveling at. Not all targets in the radar's view will be stationary (ex: cars, pedestrians, etc); FYI.
But forget about my application here; I just want to know how to derive the distance based on doppler effect. I won't be able to modify any part of the radar as well. I also cannot use the time of flight method either.
So far, I *think* this can be done, however I'm not sure how to do it. My theory to this right now is assuming that my bike is moving and doppler shift is present, the frequency difference must cross 0Hz when I pass the target. There for, that means the distance must be a (slight?) function of the frequency di8fference; assuming I know the speed my bike is traveling at. Can anyone else help me extend on this?
Thanks,
Ray Xu
I'm a newbie here with a question regarding doppler shift. Before I ask, I only have a very basic understanding of the doppler effect.
So, my big question is: can a doppler shift measurement be converted to the distance between the source and target, without using the time of flight method?
What I'm trying to do here is using this product http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/SortField/0/Level/a/ProductID/606/Default.aspx I want it to determine the distance to a target, based on the output of that radar module. Its intended to be used as a proximity sensor, but the datasheet says it can also be used to measure speed via the doppler effect. It may sound crazy, but I'm planning to mount this onto my bike for my own useful and safety purposes; as well as to gain more experience working with radars and doppler shift. Since this is going to be mounted onto my bike, I will know the speed I'm/the radar is traveling at. Not all targets in the radar's view will be stationary (ex: cars, pedestrians, etc); FYI.
But forget about my application here; I just want to know how to derive the distance based on doppler effect. I won't be able to modify any part of the radar as well. I also cannot use the time of flight method either.
So far, I *think* this can be done, however I'm not sure how to do it. My theory to this right now is assuming that my bike is moving and doppler shift is present, the frequency difference must cross 0Hz when I pass the target. There for, that means the distance must be a (slight?) function of the frequency di8fference; assuming I know the speed my bike is traveling at. Can anyone else help me extend on this?
Thanks,
Ray Xu