Frequently Asked Questions
Why are my SeaTag logs empty?
You must NOT alter the American date format and/or notation or your tag will not be capable of being programmed correctly. If you have a Desert Star provided laptop, it is already currently configured in this way. Do NOT change the date-time formatting or you will risk compromising your mission's success.
When processing your data, you must have your computer set in the American date format and/or notation or your data will be corrupt.
Contact Desert Star if you have any questions regarding this topic: firstname.lastname@example.org
Should I reboot my SeaTag?
Almost never. There's a small chance the SeaTag-MOD may need a reboot, but you will almost NEVER reboot any other tag. You risk damaging your tag and needing a replacement if you attempt to reboot your tag. Only ever put in black powder and arm your tag after configuration. Do not mess with your tag after arming it.
Where's my data?
There's two data logs that you will automatically download after correctly configuring the SeaWatch software: The ARGOS Log and the SeaTag log. SeaWatch downloads the raw ARGOS file and places it in the ARGOS folder located near the SeaTag log folder. Click “open logs folder” button in SeaWatch config to access those folders and logs.
We had the tags out all day today and did not get an ARGOS detection, what gives?
There are a few different things that could have caused the tags to not show up for Argos transmissions. If the weather is sub-optimal or the satellite passing over isn't high enough in the sky this could lead to the tags not showing up.
How can I tell if the tag is at the surface?
ENG packets are not archived and are only transmitted once every 10 transmission at the surface only.
Why do my SeaTag sometimes return negative depth readings such as -2.43m?
SeaTag depth sensors can sense pressures anywhere from the vacuum of outer space (eg. 0 PSI) to the depth sensor pressure limit, such as 3000 PSI corresponding to ~2000 m ocean depth. The typical surface atmospheric pressure of 14.7 PSI is thus merely a point on the pressure curve. While some tags 'clamp' any negative readings to zero meters depth because negative depths are not possible for an ocean tag, this practice results in a loss of valuable information. Expect to see depth readings at the surface of a few tens of cm to a few meters while at the surface, typically well less than +/- 1% of the full scale value of the sensor (such as < +/- 20m for a 2000m depth rated tag). For example, an engineering packet indicating a depth of -2.43m indicates the depth sensor has a bias of -2.43m because an engineering packet reflects the tags current status, and can only be received by Argos if the tag is in fact at the surface. An archived packet such as a daily summary of the same tag indicating that the minimum depth for a given day was -1m then really implies that the fish was at a depth of -1m - -2.43m = 1.43m. In summary, make it a habit to check the engineering depth reports to verify the validity of the depth readings in the archived packets. If the tag is reporting 0 +/- a few meters while at the surface, .you can trust the archival data to be accurate to the same amount (and you might even subtract out that reported bias). If however a tag at the surface reports 420m or -164m or the like, then the depth sensor is not reading correctly now and you should be sceptical of the depth reports in the archived packets.
How do I change the SeaTag's mode to SAFESHIPPING mode?
Use the same transition method once to get the tag from OnFish Mode to ARMED Mode. Then do the same transition method again to transition the tag from ARMED Mode to Safe Shipping Mode.
Also see: Changing Modes for a SeaTag Tutorial
I noticed on CLS some dataless “pings”. Any idea why this may have been the case?
Notice in your file that there is data there, but that the Argos position fixes are missing. Look further in column J identifying the satellite that received each message, that these five first messages were just one per satellite pass each. You then get the first position when in a single pass satellite MA receives five messages. Thereafter, you see cases where even a single message received in a satellite pass DOES give you a position, such as NK, NP and NN receptions also on the same day.
This is how the Argos doppler-shift location system works!
Initially Argos has no idea where a tag might be. Doppler shift localization is like listening to an ambulance pass. At first the pitch of the siren is high as it approaches you, and then it rapidly shifts to a lower pitch as it passes you by and now drives away from you. Close your eyes and just listen to any random ambulance passing by, and you will be able to judge pretty closely the point of closest approach. Now let's say you heard this same ambulance pass several times, memorize its characteristics like siren pitch and now you get to hear only a quarter of a second of its siren as it passes. You could still tell if that moment it was approaching you, passing by or departing, right? The pitch would tell you. But now, lets say a new ambulance passes and you don't know its natural pitch (which is the equivalent of the natural transmit frequency of one of your tags). You get to hear only a quarter of a second worth of the siren. Was it approaching, passing by or departing? You couldn't tell - because you don't know yet how that pitch of the siren you hear relates to the pitch of the siren of that ambulance standing still.
So, you'd have to listen once for a full pass, and then you know and just a brief reception will do to judge the next time. CLS calls that 'priming the pump', and it will take four receptions in a single satellite pass before you get the first position fix. Thereafter,it can be less. The fact that now just a single reception in a subsequent pass still gives you a fix is actually a recent improvement of their algorithm. It didn't used to be that way.
Note that after some time of few or no receptions, the algorithm will actually reset and the pump has to be primed again. CLS does that because eventually the data they have just gets too uncertain.
Note also that my explanation here is simplified over the reality of it, but it captures the essence of what you are seeing.
To confirm tag functionality, is it okay if I program a 2-day mission (without gun powder), leave outside and then let the tag “pop-off” and start sending archived data? Will this still ensure full tag functionality after the mission is complete? I want to make sure nothing needs to be replaced after program pop-off if not using gunpowder?
If you want to run a test in which the tag runs its missions and then transmits you will have take a few precautionary steps. Prior to performing your test you will have to remove the ignitor chip that is located in the blast section. If you leave the chip in the base of the tag and let the tag “pop off” then it will ignite the resistor on the chip and the chip will be useless. Please see the link that I have supplied to a short youtube video on how to remove the chip and how to properly handle the chip once removed. When the chip is removed you can place it in the dummy tag to ensure that the hydrophilic element of the chip does not absorb any moisture.
Is my SeaTag still on the fish?
Look at the Bit Status code - tells you if it released (requires decoding) SeaTag-MOD Engineering Status Reporting
CDR range in engineering packet - tells you difference between shallowest 6hr period and the deepest 6hr period the tag experienced in the last 24hr period (tells me the fish is moving up and down in depth)
Verify depth sensor is working by looking at engineering packets - engineering packets are only sent at the surface and take a snapshot of what is happening at that very moment, so if the depth sensor readings are close to zero meters then it working correctly. (Zero is not an indication of a broken depth sensor due to design of depth sensor, negative values are okay, as long as they are close to zero).
Look at raw sensor packet - plot z axis column from multiple packets over time (this tells you the vertical orientation of the tag over time)
Common Bit Status Codes: 131: clock loss 145: CDR met and release requested
Which pins are used for data transfer in the MOD?
The TXD, RXD and ground pin are used for transferring data. Please refer to the SeaTag-MOD Manual.
In the SDPT_HST_DEPTH I have in the “% of time” for several histogram bins values that are greater than 100%. How do I interpret this data? Shouldn't values in each bin be between 0 and 100% of the time?
Yes, each bin should have a value of less than zero,with the sum of all bins being close to but not necessarily exactly 100%. Due to the particular presentation of the data in the satellite transmitted packets, there can be a slight rounding or quantization error in the total. This can be compensated for by dividing the percentage of time in an individual bin by the percentage of time in the sum of all bins.
I can explain a sum of all bins being more than 100%, which can happen due to a satellite data transmission error that is not caught by the space efficient but also not fully secure single-byte checksum. You will see such occasional outliers in all packet types, and they must be manually rejected.
However since the bin presentation in the data packet is parts of 255, and the highest possible value for a bin is 255, it should never be possible to have a bin value of more than 100% in a bin.
So, if you in fact see that, please send the data file for inspection.
How is the day length interpreted in several of the output (e.g., SDPT_MODDAILY and SDPT_MODSN2)? What units is it in?
The observed day length is the time from the morning to the evening light threshold crossing. If a tag is at the surface, the threshold crossings happen roughly at civil sunrise and sunset, i.e. when the sun is 6 degrees below the horizon and approximately 30 minutes before true sunrise and after true sunset. The further the tag is underwater, or the more turbid the water, the later the morning threshold crossing will occur and the earlier the evening threshold crossing. Observed days that are shorter than the true sunrise to sunset period also generally will exhibit a larger noon time measurement error, and thus a reduced confidence in the computed longitude. For this reason, SeaTrack has a 'longitude confidence' filter that can be used to reject daily summaries that show a short (i.e.low confidence) day length.
The day length is stated in hh:mm:ss. Note that Excel or other programs may convert that into a fraction of a day depending on formatting settings. In that case, just highlight the column and select the hh:mm:ss time format.
In the SDPT_MODSN2 packet, is the reference date and time listed the same as the date and time the location was taken?
The time stamp of a MODSN2 packet reflects the time that time that the various sensor readings in the packet were taken. So, it's the moment that this particular 'sensor snapshot' was taken. It does not relate to the reference time of the location for a daily summary packet, which is stated in the time stamp of the MODDAILY packet.
Why isn't my tag transmitting after it was scheduled to release?
This could be from a multitude of things. For example, if the tag is for some reason caught in vegetation it could prevent the tag from properly transmitting to the ARGOS satellite. While another reason could be that during the times of good satellite passes there was sub-optimal weather conditions that hindered the ability of the tags to properly transmit. We have seen tags that have been programmed to pop off a particular month not transmit for over a month and then begin to transmit, and due to our inability to see what condition the tag is in at the time of release it makes it hard for us to judge why the tag is not transmitting correctly.
Can the tag be transmitting signals but the satellite not receive the signals?
Yes. Even if the satellite is directly in line of sight of the tag, the signal may not get to the satellite for a variety of reasons including weather, waves, and a variety of other factors that may affect transmission.
If the solar panel is exposed to light, will the tag try to transmit?
Yes, this is the tag's default behavior.
If the solar panel is NOT exposed to light, will the battery charge the tag to transmit?
The battery's purpose is to keep the tag “on” in a data gathering state and to ensure that the release mechanism fires. Beyond that, it is assumed that the tag will eventually be exposed to light post-release, and thus will use the solar power to transmit. In other words, no the battery does not directly charge the tag for transmission, but does keep the tag “on” and ensures the release mechanism can fire.
Does the ST-MOD gather position data through the magnetometer, and what is the daily error value?
You are correct. In general, and on average, the location error is about 35 nautical miles. I made a very brief video on how it works. You could let them know that it is an improvement on location quality from the miniPAT without having to use sea surface filtering, land avoidance, Kalman filtering and other filters.
Can the magnetometer provide body tilt data?
No, we do not use the magnetometer as a compass which is how it is used when you want to acquire body tilt data. You could use the accelerometer to acquire the tag's orientation though and from that you could inter the angle of the fish (along with acceleration of course). In general, studies like these require the tag to be recovered because of the amount of data that is being stored onboard.
With the SeaTag-MOD equipped with 300 PSI MSI, how deep can it go?
We rate this option at 300m nominal service depth. It is recommended for use with animals or in waters that do not exceed 300m depth, in order to get improved depth sensing accuracy. Compared to the standard 3000 PSI depth sensor, a 300PSI depth sensor will be 10x as accurate but have only 1/10th of the depth range within which it is considered accurate.
The depth sensor itself is rated for 300PSI / 200m. We operate up to 300m, which is OK but may cause a slight degradation of accuracy when operated above 200m,reverting to normal when below 200m. For marine animal tracking, accuracy is generally most important near the surface,not at depth.
This option is set with a calibration script crush depth release of 600m, equaling 900 PSI. This is so the M89 data sheet specified 3x pressure overload is not violated (see attached data sheet). Beyond that, the sensor may become damaged.
The burst pressure for the sensor, exceeding which could conceivably lead to some damage to the tag itself (although not likely because the sensor is potted away from other stuff) is 4x rated pressure, or 1200PSI / 800m. The actual crush pressure of the tag itself remains at 2000m. If one were to disable crush depth release, or set it to 2000m, the tag will likely survive but its depth sensor may be blown out on a deeper dive.
How are your tags priced so low?
Economies of scale, modular technology, and leadership of the young.
My deployment team didn't get to tag any fish today, How do I reset the tag?
If you have previously programmed the tags for deployment and have since received them back from your fishermen or anglers who were planning to deploy them here are some easy steps to take to make sure they will be stored correctly and ready for their next deployment.
When first dissembling the tags make sure to have safety goggles on or some for of eye protection for safety purposes. From there you will want to plug in your tag (ST-MOD), drop in your tag to your dock and wait for it to connect. Once you have gotten the tag to connect you will want to locate the missions settings tab and select that. Once there you will see an option on the top left area that has 3 selections real time tracking, PSAT with RT tracking or sleep mode. If you are planning on putting the tags away for a week or two you will want to put the tag in to Sleep mode, so select that. Once you have selected that you will want to move to the tag tab at the top of SeaDock and select write to tag. This will enable the tag to be placed in sleep mode so that it does not transmit while in this mode. You will go through your standard programming steps to get the tag ready for deployment on your next mission.
More information can be found here.
Is the factory-programmed version of this tag available?
Yes, however CLS processing is not yet available.
What magnetic field properties are measured, and why?
SeaTag measures the total intensity of the earth magnetic field in order to determine latitude. In most but not all ocean areas, field intensity changes predictably and significantly with latitude. For example, off the California coast the gradient is approx. 10 nT per nautical mile of latitude. Off the Atlantic coast, it's stronger. However, there are also areas of little gradient, such as offshore Uruguay. Including near Madagascar, where the lines of equal intensity run mostly north-south and are therefore of little use for determining latitude. The attached PDF file shows the Intensity component of the International Geomagnetic Reference Field (IGRF).
An alternative to measuring total field intensity would have been to measure the field inclination. The IGRF for inclination shows similar utility. However, unlike total field intensity, measuring inclination requires the use of a gravity reference in addition to the magnetometer. That would typically be an accelerometer, the reading of which adds more noise. In addition, any acceleration of the animal would have to be cancelled out, further complicating the situation. So, in summary, we believe that field intensity is the most straightforward and accurate way to measure latitude by magnetic means in a small tag.
How accurate or precise are the latitude measurements?
I have attached a spreadsheet that provides some supporting data from our NOAA SBIR work. The first call would be that absolute accuracy is an average of around 32 nautical miles in areas with a magnetic field intensity gradient similar to California's. That's based on a test of seven beach hikes designed to simulate the motion of a fish. Essentially, we were hiking down beaches for 45 minutes while making sure to avoid any obvious man-made magnetics. Yet, this data set also uses the data from the same seven hikes to determine the common 'magnetometer output to nanoTesla' conversion factor (i.e. calibration) that is then applied to each individual set. You could also assume the 81 nautical miles number, which includes data from Costa Rica and Key Largo in addition to the hikes, but under less controlled circumstances (magnetic objects such as a boat engine and dock hardware was known to be nearby on all but one of these tests). Finally, on two occasions where we repeated a test in a given location on successive days (Costa Rica and Del Monte Beach), we found an agreement of the latitude to within 13 and two miles respectively.
How does the data compare to measuring position by light only?
My estimation is that on average magnetic augmented positioning will prove substantially more robust than light based data alone. The approach is certainly far more simple: First, SeaTag measures longitude based on finding the mid-point in time between the sunrise and the sunset threshold. It then runs down this line of longitude within any set bounds to find the best magnetometer match for latitude. In some cases (if searching pole to pole), there may be more than one latitude match but they will tend to be very far apart and can probably be excluded based on the known range of the animal.
Unlike a light-only measurement, this method does not require actually establishing the exact points of sunrise and sunset (i.e. length of day). Length of day, which is needed for light based latitude, can be difficult to determine. Sensor fouling for example may cause a light attenuation. Yet, such factors would equally affect sunrise and sunset and thus still allow us to find the mid-point with good accuracy; the only thing we need when using magnetics for latitude.
Magnetics are quite robust in that sensor fouling really isn't an issue. It's 'almost' like sticking a probe into the air and reading your latitude directly.
What are the risk factors of the method?
Three that come to mind are:
First, we did notice that the magnetic sensor can experience an offset shift if subjected to very strong magnetic fields - on the order of 5x to 10x the earth field. In practice, this is probably unlikely to happen on a tagged animal because static magnetic fields, such as from a piece of nearby wreckage, decline as a function of the cube of the distance. So, the tag on the animal would pretty much have to rub up against a fairly strong magnet. Our bigger concern is a magnetic event encountered in shipping or preparation. For example, a strong magnet on your desk. We will however provide a method to verify the calibration, and recommend that be done before any deployment.
Second is a fairly simple algorithm for noon time detection (light level thresholding). We started with light thresholding as a noon-time detection method in order to establish a performance baseline against which more sophisticated algorithms could be judged. However, first tests with a SeaTag device placed on the Desert Star building found quite good performance with this simple approach. An average error of 21 nautical miles for a 37-day data set (one position per day). While this test was under good conditions in terms of static placement in a sunlight exposed spot, it was also subject to frequently substantially different light conditions between sunrise and sunset on account of the marine layer, i.e. foggy conditions during sunrise matched with sunny at sunset for example.
37-day test for longitude determination by light based noon time measurements. The average longitude error was 21 nautical miles.
Finally, field test data available for SeaTag is still limited. Our strategy here is a combination of algorithm transparency in combination with an ability to upgrade the software on SeaTag devices in the field. The SeaTag application software, including geo-positioning algorithms, will be published on our web site. We will publish any performance data that we develop or becomes available from our customers. A developer’s kit will make it possible to modify the application software, for example to test improved algorithms or add new features.
Does SeaTag GEO compute its own position?
No. SeaTag GEO stores a brief daily log that includes the average magnetic field strength for the day, and the noon time determined by light measurements. In addition, it can acquire and store sensor data with higher time resolution, subject to mission duration and available memory. SeaTag GEO samples light levels and magnetic field intensity once every four minutes.
This data is downloaded to the PC, where a PC based application computes longitude and latitude. The final data output is a delimited text file for use with Excel or any analysis software, plus a .KML file that can be displayed directly in Google Earth.
Storing and reporting sensor data rather than processed positions provides flexibility in post processing, such as correcting for or using magnetic anomalies to obtain improved accuracy.
What differentiates this tag from the SeaTag-GEO?
A higher memory capacity and depth sensor allow the user to explore vertical habitat utilization of the tagged specimen.
What is the SeaTag-TT meant for?
The "Turtle Tag" is a versatile low-weight tag designed to be mounted on shell of a sea-turtle.
When will this tag be available?
DSS is currently partnering with a number of Pioneer Customers that are helping us develop and refine our technology. The AirTag is still in this Engineering Development phase and will become available once it has been successfully refined to be customer-ready.