Investigation of Digitalization in Laser Rangefinder Receiver - How to Use Digital Signal Processing and Pulse Detection to Improve Performance in the Laser Rangefinder Receiver
Typ
Examensarbete för masterexamen
Program
Communication Engineering (MPCOM), MSc
Publicerad
2022
Författare
Åberg, Josefine
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Digitization provides many opportunities for a wide range of applications since it
can generate more flexible and stable solutions compared to analog solutions. It also
allows using other tools than the ones available for analog solutions. The purpose of
this master’s thesis was therefore to investigate how the performance of an analog
laser rangefinder receiver can be improved by digitalizing the receiver and using
digital techniques on the laser rangefinder’s received echo signal. This included
investigating the detection sensitivity, as well as, the possibility to separate false
alarms and true optical echo pulses in the received signal. Separating the two would
provide a possibility for increased bias voltage in the Avalanche Photodiode (APD),
used for detection in the laser rangefinder. An increase in bias voltage would also
improve the sensitivity of the laser rangefinder.
The investigation was done by simulations in MATLAB. The simulations consisted
of constructing a laser rangefinder’s received echo signal, applying digital signal
processing to it and using digital pulse detection. It was also investigated if some
other analog solutions in the laser rangefinder can be replaced by digital techniques
in a digital solution. The Central Processing Unit (CPU) time for the investigated
digital methods was also measured.
The result demonstrated that a digital laser rangefinder receiver would be superior
to an analog receiver under the circumstances of the thesis. The detection statistics
were much improved and the detection sensitivity of the optical pulse amplitude was
increased by 10.57 dB. The digital solution also managed to separate false alarms
and true optical pulses to a certain extent. Thereby making it possible to increase
the bias voltage in the APD.
Beskrivning
Ämne/nyckelord
Laser Rangefinder, Digital Signal Processing, Digital Pulse Detection, Filtering, Avalanche Photo Diode, Denoising, Denoise Received Echo Signal, Digitalization