Answers.Body: <p>I see that you would have at least 5 options</p>
  <ul>
  <li>synchronize ADC (not practical over 10s of km)</li>
  <li>get caesium clocks for ADC (possible but not widely used)</li>
  <li>synchronize ADC clock phase locked with GPS (needs surface expression and could generate phase jitter noise)</li>
  <li>record GPS PPS (pulse per second) with data and correct during analysis (needs surface expression)</li>
  <li>emit time calibration pulses at beginning and end of deployment (works under assumption of constant time drift)</li>
  </ul>
  <p>Not sure which commercial recorder implements one of the first four options, but last option can be used for all types of recorders. It requires only careful planned deployment and recovery.</p>
  
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Answers.CreationDate: 2022-07-14T15:46:22.703Z
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Answers.Body: <p>You might want to check out a more recent product by Desert Star Systems, the <a href="https://www.desertstar.com/sonarpoint" rel="nofollow noreferrer">SonarPoint</a> which is lower cost recorders intended to be used for localization and are time synchronized (in an after recovery step of time alignment)!</p>
  
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Answers.CreationDate: 2022-07-14T22:27:30.623Z
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Body: <p>Are there any underwater acoustic recorders that have low clock drift?  We'd like to deploy a widely-spaced (10s of km) array of single-sensor recorders for localization of low frequency (&lt;1000 Hz) sounds but these distances make in-water time synchronization methods more challenging.</p>
  
Tags: <localization>
Title: Underwater acoustic recorders with low clock drift?
ThreadText: # Underwater acoustic recorders with low clock drift?
  
  (Asked by: username_0 on 2022-07-14)
  
  Are there any underwater acoustic recorders that have low clock drift? We'd like to deploy a widely-spaced (10s of km) array of single-sensor recorders for localization of low frequency (<1000 Hz) sounds but these distances make in-water time synchronization methods more challenging.
  
  **Tags:** localization
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_1 on 2022-07-14. Score: 7
  
  I see that you would have at least 5 options
  
  * synchronize ADC (not practical over 10s of km)
  * get caesium clocks for ADC (possible but not widely used)
  * synchronize ADC clock phase locked with GPS (needs surface expression and could generate phase jitter noise)
  * record GPS PPS (pulse per second) with data and correct during analysis (needs surface expression)
  * emit time calibration pulses at beginning and end of deployment (works under assumption of constant time drift)
  
  Not sure which commercial recorder implements one of the first four options, but last option can be used for all types of recorders. It requires only careful planned deployment and recovery.
  
  
  ---
  
  ### Answer by username_2 on 2022-07-14. Score: 3
  
  You might want to check out a more recent product by Desert Star Systems, the [SonarPoint](https://www.desertstar.com/sonarpoint) which is lower cost recorders intended to be used for localization and are time synchronized (in an after recovery step of time alignment)!
  
  
  ---
  
  