<p>Perhaps you could share a screen grab of one of the waveforms of a click that get's a poor bearing. That will show if there is multipath, or some other 'good' reason as to why the cross correlation of the two waveforms is giving a poor result</p>

CC BY-SA 4.0
2024-11-14T15:33:17.130Z
I am not exactly sure of what you mean by multipath, but there is certainly reflections of a same click arriving at different times in my recordings as I was using PAMGuard precisely to detect them to use multipath ranging. As the reflections are not as knit as the first arrival on the spectrogram it's possible that the software "misestimated" the real start of a reflection. I can get back to this material and edit the original post to include more information if you want, but if multipath is likely to cause such behaviour I would consider this as the explanation of this behaviour.
Patou
CC BY-SA 4.0
2024-11-13T13:56:31.087Z
2024-11-13T13:56:31.087Z
Doug Gillespie
<blockquote>
<p>parameters related to bearing calculation before running PAMGuard, is there some and if yes where can I access them? If there is none where can I find information on how PAMGuard calculates its bearings?</p>
</blockquote>
<p>A good place to start regarding information on how PAMGuard calculates it's bearings would be the in the friendly manual (AKA the online help system). You can access this within PAMGuard under the Help menu, then the option labelled Help. There you can find information on the click detector, as well as additional information under the Localisation topic for &quot;Time Difference of Arrival&quot; as well as &quot;Bearing Calculator&quot;.</p>
<p>Otherwise, there's not really enough information provided in the question to understand what is going on in your recording. Perhaps if you showed your work more clearly more suggestions might be forthcoming.</p>
<p>As it stands, you've stated that &quot;multipath and motion of the array&quot; are not likely to be responsible for the results, but are asking us to take your word for it without any evidence as to why you've reached that conclusion. Even if the reasoning seems obvious to you, there are benefits to the community, as well as a higher likelihood of a useful response if you can spell out your problem and show all your work in lucid detail. Indeed, isn't that what Stack Exchange is all about?</p>

CC BY-SA 4.0
2023-10-06T07:37:44.850Z
I have dived into the bearing calculator help page and I am now a bit confused. I was not using the bearing calculator module previously (it was not even installed) and the bearings I plotted were those I found in the exported database. 
Were these bearing calculated from the click detector module?
If yes, does it mean they were calculated using Target module analysis? 
If yes, and as my array is not moving, does it means the bearing are false/inaccurate/unreliable?
Concerning the bearing calculator module, how does FFT length and Hop will affect accuracy of the calculated bearings?
Patou
CC BY-SA 4.0
2023-10-06T07:55:02.253Z
Continuing from my previous answer, from what I understood the grouping in the bearing calculator is used to select a group of hydrophone that will be used to calculate one bearing, as I have only two hydrophones, if I want to calculate bearings I need to group them.
Finally, when clicking on the settings button for the algorithm PAMGuard output these lines _No available settings pane for array shape Line Array
No available settings pane for bearing algorithm TDOA Localiser and no tab open. I don't think I need it but just to be sure why I someone would restrict the primary angle range?
Patou
CC BY-SA 4.0
2023-10-06T08:05:23.113Z
It's a bit difficult for me to identify what informations/data would be useful to help the understanding of my problem, and precise request would help me in this task. I could provide a recording or an output dataset from PAMGuard but they are quite large files. If you are interested I can create a temporary link to a sample of the data though.
Patou
CC BY-SA 4.0
2023-10-09T01:58:32.183Z
Hi Patou, I'm afraid I'm not available to analyse and debug your data for you. I think perhaps I should have first directed you to the Help topic for the Click Detector, as I understand that this is the module you are using, so its documentation might be a bit more relevant than the others. As with most software, there are no guarantees that the Help files contain all the answers to your questions -- but for PAMGuard, it is usually a good place to start. You may also find additional support on the PAMGuard mailing list or by writing to: support@pamguard.org.
Brian Miller
CC BY-SA 4.0
2023-10-05T01:14:35.227Z
2023-10-05T01:14:35.227Z
Brian Miller
<p>I am running PAMGuard click detector on a two hydrophone array's recording to detect sperm whales clicks and calculate their bearing. The array is at a roughly 2300m depth, 40m above ocean's floor, recording 5 min every 10 min and the two hydrophones are 69 cm from one anothers.
The click detector is roughly working, there is some over-detection but I'm fine with it as I am manually checking and annotating detections to separate false detections from first, second and third arrival of a click to the hydrophone (multipath), as well as separating between animals when there is more than one. The bearings calculated are sometimes lacking consistency however, with bearing jumping between two sets of values tens of degrees apart from one another.
The graph below illustrated my problem. It shows the variations of bearing (in radians) calculated from the first arrival by PAMGuard over the time of an 'encounter' (a series of recordings with consistent click parameter leading to confidently think its the same animal over all the recordings). All recordings are problematic for this encounter but those between 4:10 and 4:15 or between 5:10 and 5:15 are the most striking.</p>
<p><a href="https://i.sstatic.net/8TBpM.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/8TBpM.png" alt="" /></a></p>
<p>The heading of the array is measured only every 30 seconds but it is rarely rotating tens of degrees in one direction or another.</p>
<p>I haven't modified any parameters related to bearing calculation before running PAMGuard, is there some and if yes where can I access them?
If there is none where can I find information on how PAMGuard calculates its bearings?</p>

CC BY-SA 4.0
2023-10-02T23:10:41.133Z
To help us answer, it would be helpful if you could provide more information and context. For example, under what scenario were you recording the sperm whales? How certain are you that all of the detected clicks in the recording have come from a single source? Are you sure that the variability in bearings is due to inaccuracy, or could this be due to multiple sources, multipath, motion of hydrophones? The figure that you've included doesn't look like it was created by PAMGuard, so what is actually plotted in the figure? What are the units of Y-axis; how were the x & y data obtained?
Brian Miller
CC BY-SA 4.0
2023-10-03T08:22:00.240Z
I have edited my question to include as much information I could think of to answer your questions. Overall multiple sources, multipath and motion of the array are not very likely to cause what I think is inaccuracies. The clicks are not very loud though and as there is often more than one detection for a single click I am wondering if it could be possible that PAMGuard struggles to accurately match the clicks arrivals from the two channel.
Patou
CC BY-SA 4.0
2023-10-04T13:05:29.320Z
Adding to Brian'comment, how exactly are you using PAMGuard? You are saying click detector is roughly working and you were checking and annotation detections. Are you feeding the anotated detections to PAMGuard (not a PAMGuard user myself)? Could you provide a inter-hydrophone delay plot in addition to the PAMGuard bearing estimations? The figure you show is not really helpful for assessing the issue.
WMXZ
<pamguard><bearing>
How to parametrize PAMGuard to avoid great bearing inaccuracies all along a recording
# How to parametrize PAMGuard to avoid great bearing inaccuracies all along a recording

(Asked by: username_0 on 2023-10-02)

I am running PAMGuard click detector on a two hydrophone array's recording to detect sperm whales clicks and calculate their bearing. The array is at a roughly 2300m depth, 40m above ocean's floor, recording 5 min every 10 min and the two hydrophones are 69 cm from one anothers.
The click detector is roughly working, there is some over-detection but I'm fine with it as I am manually checking and annotating detections to separate false detections from first, second and third arrival of a click to the hydrophone (multipath), as well as separating between animals when there is more than one. The bearings calculated are sometimes lacking consistency however, with bearing jumping between two sets of values tens of degrees apart from one another.
The graph below illustrated my problem. It shows the variations of bearing (in radians) calculated from the first arrival by PAMGuard over the time of an 'encounter' (a series of recordings with consistent click parameter leading to confidently think its the same animal over all the recordings). All recordings are problematic for this encounter but those between 4:10 and 4:15 or between 5:10 and 5:15 are the most striking.

[![](https://i.sstatic.net/8TBpM.png)](https://i.sstatic.net/8TBpM.png)

The heading of the array is measured only every 30 seconds but it is rarely rotating tens of degrees in one direction or another.

I haven't modified any parameters related to bearing calculation before running PAMGuard, is there some and if yes where can I access them?
If there is none where can I find information on how PAMGuard calculates its bearings?

**Tags:** pamguard, bearing

> **Comments:**
> **username_1**: To help us answer, it would be helpful if you could provide more information and context. For example, under what scenario were you recording the sperm whales? How certain are you that all of the detected clicks in the recording have come from a single source? Are you sure that the variability in bearings is due to inaccuracy, or could this be due to multiple sources, multipath, motion of hydrophones? The figure that you've included doesn't look like it was created by PAMGuard, so what is actually plotted in the figure? What are the units of Y-axis; how were the x & y data obtained?  
> **username_0**: I have edited my question to include as much information I could think of to answer your questions. Overall multiple sources, multipath and motion of the array are not very likely to cause what I think is inaccuracies. The clicks are not very loud though and as there is often more than one detection for a single click I am wondering if it could be possible that PAMGuard struggles to accurately match the clicks arrivals from the two channel.  
> **username_2**: Adding to username_1'comment, how exactly are you using PAMGuard? You are saying click detector is roughly working and you were checking and annotation detections. Are you feeding the anotated detections to PAMGuard (not a PAMGuard user myself)? Could you provide a inter-hydrophone delay plot in addition to the PAMGuard bearing estimations? The figure you show is not really helpful for assessing the issue.  

---

## 2 answers

### Answer by username_3 on 2024-11-13. Score: 1

Perhaps you could share a screen grab of one of the waveforms of a click that get's a poor bearing. That will show if there is multipath, or some other 'good' reason as to why the cross correlation of the two waveforms is giving a poor result

> **Comments:**
> **username_0**: I am not exactly sure of what you mean by multipath, but there is certainly reflections of a same click arriving at different times in my recordings as I was using PAMGuard precisely to detect them to use multipath ranging. As the reflections are not as knit as the first arrival on the spectrogram it's possible that the software "misestimated" the real start of a reflection. I can get back to this material and edit the original post to include more information if you want, but if multipath is likely to cause such behaviour I would consider this as the explanation of this behaviour.  

---

### Answer by username_1 on 2023-10-05. Score: 0

> parameters related to bearing calculation before running PAMGuard, is there some and if yes where can I access them? If there is none where can I find information on how PAMGuard calculates its bearings?

A good place to start regarding information on how PAMGuard calculates it's bearings would be the in the friendly manual (AKA the online help system). You can access this within PAMGuard under the Help menu, then the option labelled Help. There you can find information on the click detector, as well as additional information under the Localisation topic for "Time Difference of Arrival" as well as "Bearing Calculator".

Otherwise, there's not really enough information provided in the question to understand what is going on in your recording. Perhaps if you showed your work more clearly more suggestions might be forthcoming.

As it stands, you've stated that "multipath and motion of the array" are not likely to be responsible for the results, but are asking us to take your word for it without any evidence as to why you've reached that conclusion. Even if the reasoning seems obvious to you, there are benefits to the community, as well as a higher likelihood of a useful response if you can spell out your problem and show all your work in lucid detail. Indeed, isn't that what Stack Exchange is all about?

> **Comments:**
> **username_0**: I have dived into the bearing calculator help page and I am now a bit confused. I was not using the bearing calculator module previously (it was not even installed) and the bearings I plotted were those I found in the exported database.  Were these bearing calculated from the click detector module? If yes, does it mean they were calculated using Target module analysis?  If yes, and as my array is not moving, does it means the bearing are false/inaccurate/unreliable? Concerning the bearing calculator module, how does FFT length and Hop will affect accuracy of the calculated bearings?  
> **username_0**: Continuing from my previous answer, from what I understood the grouping in the bearing calculator is used to select a group of hydrophone that will be used to calculate one bearing, as I have only two hydrophones, if I want to calculate bearings I need to group them. Finally, when clicking on the settings button for the algorithm PAMGuard output these lines _No available settings pane for array shape Line Array No available settings pane for bearing algorithm TDOA Localiser and no tab open. I don't think I need it but just to be sure why I someone would restrict the primary angle range?  
> **username_0**: It's a bit difficult for me to identify what informations/data would be useful to help the understanding of my problem, and precise request would help me in this task. I could provide a recording or an output dataset from PAMGuard but they are quite large files. If you are interested I can create a temporary link to a sample of the data though.  
> **username_1**: Hi username_0, I'm afraid I'm not available to analyse and debug your data for you. I think perhaps I should have first directed you to the Help topic for the Click Detector, as I understand that this is the module you are using, so its documentation might be a bit more relevant than the others. As with most software, there are no guarantees that the Help files contain all the answers to your questions -- but for PAMGuard, it is usually a good place to start. You may also find additional support on the PAMGuard mailing list or by writing to: support@pamguard.org.  

---

