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Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613875165200384 |
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| access_status_str | Open Access |
| author | Geldenhuys, Christiaan |
| author2 | Niesler, Thomas |
| author_browse | Geldenhuys, Christiaan Niesler, Thomas |
| author_facet | Niesler, Thomas Geldenhuys, Christiaan |
| author_sort | Geldenhuys, Christiaan |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/128931 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:43:05.531Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/128931 Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder Geldenhuys, Christiaan Niesler, Thomas Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Acoustic localization Animal sounds -- Recording and reproducing Infrasonic waves Tracking (Engineering) Acoustic models Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: We present the hardware design of a temporally synchronised high-fidelity low-cost infrasonic-capable (6Hz) passive acoustic monitoring (PAM) device. This research instrument allows recordings made by independent spatially distributed nodes to be synchronised in time for the purpose of acoustic monitoring and localisation of the African elephant, using for example time difference of arrival (TDoA). Each recorder is capable of sampling with a 24-bit resolution at a sampling frequency that is adjustable between 8 kHz and 192 kHz. Audio samples are stored locally on a microSD card, along with global navigation satellite system (GNSS) derived timestamp metadata that is shown to be accurate to within 500 ns (6σ). Four prototype recorders were built and evaluated. Estimates of the acoustic frequency response were obtained using Welch spectral averaging and confirmed that the recorders have a flat (±3 dB) pass-band over the frequency range 30Hz to 450 Hz. An analysis of the sampling clock confirmed an oscillator bias within specification (±2.5 ppm) and an oscillator stability, estimated using Allan variance, that was substantially improved using a simple regular resynchronisation method based on the GNSS timestamp metadata. Finally, without additional post-processing, the temporal alignment error is to within half a sampling period. However, if additional signal processing techniques are used, this alignment error can be reduced to approach the GNSS timestamp accuracy of 500 ns, which is well below half the highest sample frequency. We conclude that the recorders are well suited for sparsely distributed PAM experimental data collection, especially over the frequency range of African elephant vocalisations, for which it is intended. AFRIKAANSE OPSOMMING: Ons beskryf die hardeware-ontwerp van ’n tyd-gesinchroniseerde hoe-akuraatheid laekoste infrasonies-bekwame (6 Hz) passiewe akoestiese moniterings-toestel (PAM). Hierdie instrument maak dit moontlike om opnames, wat gemaak is deur onafhanklike ruimtelike-verspreide nodusse, in tyd te sinchroniseer vir die doel van akoestiese monitering en lokalisering van die Afrika olifant, deur byvoorbeeld gebruik te maak van die tydsverskil van aankoms (TDoA) algoritme. Elke nodus is in staat om met ’n 24-bis resolusie te monster, teen ’n verstelbare monsterfrekwensie, tussen 8 kHz en 192 kHz. Oudiomonsters word plaaslik op ’n microSD-kaart gestoor, saam met globale navigasiesatellietstelsel-verkree (GNSS) tydstempel-metadata, wat tot in met 500 ns (6σ) akkuraat is. Vier prototipe-opnemers is gebou en geevalueer. Beramings van die opnemers se akoestiese frekwensierespons is verkry deur Welch-spektrale gemiddeldes te gebruik, en het bevestig dat die opnemers ’n gelyke (±3 dB) deurlaatband oor die frekwensieinterval 30 Hz tot 450 Hz het. ’n Analise van die monsterklok-ossillator het ’n ossillatorafwyking binne spesifikasie (±2.5 ppm) bevestig, asook ’n ossillatorstabiliteit, beraam met behulp van Allan-variansie, wat aansienlik verbeter is deur gebruik te maak van ’n eenvoudige gereelde hersinkronisasiemetode gebaseer op die GNSS tydstempel metadata. Ten slotte, sonder bykomende naverwerking, is die tyd-belyningsfout binne ’n halwe monsterperiode. As addisionele seinverwerkingstegnieke egter gebruik word, kan hierdie tyd-belyningsfout verminder word om die GNSS tydstempel akkuraatheid te benader (van 500 ns), wat aansienlik better is as die tyd-belyningsfout teen die hoogste monstertempo. Ons kom tot die gevolgtrekking dat die opnemers goed geskik is vir yl verspreide PAM data-insameling, veral oor die frekwensie-interval beset deur die volkalisering van die Afrikaanse olifant, waarvoor die toestel ontwerp is. Masters 2023-11-20T08:54:34Z 2024-01-08T16:15:15Z 2023-11-20T08:54:34Z 2024-01-08T16:15:15Z 2023-12 Thesis https://scholar.sun.ac.za/handle/10019.1/128931 en_ZA en_ZA Stellenbosch University xv, 159 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Acoustic localization Animal sounds -- Recording and reproducing Infrasonic waves Tracking (Engineering) Acoustic models Geldenhuys, Christiaan Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder |
| title | Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder |
| title_full | Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder |
| title_fullStr | Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder |
| title_full_unstemmed | Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder |
| title_short | Kleinvoet: a spatially-distributed temporally-synchronised infrasonic recorder |
| title_sort | kleinvoet a spatially distributed temporally synchronised infrasonic recorder |
| topic | Acoustic localization Animal sounds -- Recording and reproducing Infrasonic waves Tracking (Engineering) Acoustic models |
| url | https://scholar.sun.ac.za/handle/10019.1/128931 |
| work_keys_str_mv | AT geldenhuyschristiaan kleinvoetaspatiallydistributedtemporallysynchronisedinfrasonicrecorder |