I love these engineering "hacks". Similarly, a friend of mine wrote a paper on how to use the GPS signal as radar source (so you only need a receiver) [0].
[0] https://udrc.eng.ed.ac.uk/sites/udrc.eng.ed.ac.uk/files/atta...
replies(1):
[0] https://udrc.eng.ed.ac.uk/sites/udrc.eng.ed.ac.uk/files/atta...