liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
High Resolution Frequency Estimation in an FMCW Radar Application
Linköping University, Department of Electrical Engineering, Automatic Control.
2018 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

FMCW radars are widely used in the process industry for range estimation, usu- ally for estimating the liquid level in a tank. Since the tank system, often is an automatically controlled system, reliable estimates of the surface level are re- quired, e.g. to avoid the tank from pouring over or become empty.

The goal of this thesis is to investigate methods which can distinguish fre- quencies closer to each other than the FFT resolution limit. Two properties are of interest, the accuracy and the resolution performance. Three such methods have been evaluated: one that tries to compensate for the leakage and interference of close frequencies, one subspace-based method and one deconvolution method. The deconvolution is performed with the iterative Lucy Richardson algorithm. The methods are evaluated against each other and against a typical FFT based algorithm.

The methods sensitivity to amplitude differences is examined together with the robustness against noise and disturbances which appear due to imperfections in the radar unit. The deconvolution algorithm is the one that performs the best. The subspace-based method SURE requires prior knowledge of the number of ingoing frequencies which is difficult to know for real data from an FMCW radar. The leakage compensation method main weakness is the influence of the phase difference between close frequencies.

The deconvolution algorithm is evaluated on some real data, and it is proven that it has better resolution performance than the FFT. However, the accuracy of the estimates are dependent on the number of iterations used. With a large num- ber of iterations, the algorithm finds peaks with small amplitude nearby the large peaks and they will thus interact and hence contribute to a worse accuracy even in the undisturbed case. If too few iterations are used in the deconvolution algo- rithm the resolution performance is about the same as the FFT algorithm. With a suitable choice of iterations about 40–50 mm, extra of continuous measurements are achieved. However, the estimation error of the gained resolution can in the worst case be about 40–50 mm.

Place, publisher, year, edition, pages
2018. , p. 70
Keywords [en]
FMCW
National Category
Signal Processing
Identifiers
URN: urn:nbn:se:liu:diva-148526ISRN: LiTH-ISY-EX--18/5141--SEOAI: oai:DiVA.org:liu-148526DiVA, id: diva2:1217060
External cooperation
Rosemount Tank Radar AB
Subject / course
Automatic Control
Supervisors
Examiners
Available from: 2018-06-13 Created: 2018-06-12 Last updated: 2018-06-13Bibliographically approved

Open Access in DiVA

fulltext(4083 kB)1367 downloads
File information
File name FULLTEXT01.pdfFile size 4083 kBChecksum SHA-512
26fbde170acf96016ffa4beb7dcf0d1f4e7f412436ea010f69d661925836773f05f7c7fb329f39c3c879324e1cb965f6e5e8d95a0ff304c4303759af080e982a
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Svensson, Johan
By organisation
Automatic Control
Signal Processing

Search outside of DiVA

GoogleGoogle Scholar
Total: 1367 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

urn-nbn

Altmetric score

urn-nbn
Total: 281 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf