What is a signal gap?
A tracker reports a position now and then. A signal gap is a stretch of time with no report. An export shows the last report before the silence and the first one after it.
A gap alone does not say why the device went quiet. It says where to look. The tool measures four things around each gap: how long it lasted, how far the vehicle moved, whether the position jumped, and whether the same thing happens again at the same place or hour.
Why does a tracker go quiet?
Most gaps are ordinary. The table lists common causes and what each tends to leave in an export.
| Cause | What the file usually shows |
|---|---|
| Dead zone or tunnel | A gap at the same place on every trip. Reports resume where the signal returns. |
| Parked and asleep | Ignition off before the gap and the same position after it. |
| SIM, data plan or network fault | Gaps on many vehicles on the same day or on the same network. |
| Power loss or loose connection | Sudden silence while moving. The last fix was good. |
| Poor sky view | Few satellites or a high HDOP before and after the gap. |
| GNSS interference | A weak fix before the gap, a long silence and a position jump when reports resume. It can repeat at the same place. |
| Deliberate disconnection | Silence at a similar place or hour on different days. The other causes can leave the same signs. |
The same pattern can fit more than one cause. Use the list to choose where to ask a question, and add power events, SIM status and the route before you decide anything.
What does the tool check?
Seven checks run on every gap. The limits are inputs you can change in the tool. The starting values are typical, not a standard.
| Check | Rule | Starting limit |
|---|---|---|
| Gap | Time to the next report is longer than the limit. | 10 min typical |
| Gap, ignition off | A longer limit applies when ignition was off at the start. | 120 min typical |
| Moved | The first report after the gap is at least this far from the last one before it. | 1 km typical |
| Jump | Distance divided by elapsed time is above the jump speed and the distance is at least 0.5 km. | 200 km/h typical |
| Repeated place | Gap starts of one vehicle fall inside the radius, at least the repeat count of them. | 300 m, 3 times typical |
| Repeated hour | Gap starts of one vehicle fall inside one window, on at least the repeat count of different days. | 60 min, 3 days typical |
| Weak fix | Satellites below the limit or HDOP above it in the 3 reports before or after the gap. | 5 satellites, HDOP 5 typical |
Typical values. Replace them with your own policy.
How is a gap scored?
Each gap starts at 1 point and gains one point for every sign below. The total sets the level. The level is a prompt to look, not a verdict.
- Worth a review: 4 or more
- Check: 2 to 3
- Note: 1
- Parked and quiet: not scored
A gap that starts with the ignition off, and ends within the moved limit of where it started, is parked and quiet. It is counted on its own and left out of the score. This keeps nights and weekends from filling the list. It needs an ignition column.
Worked example
The sample in the tool is one vehicle that reports every 5 minutes on three mornings. Each morning it goes quiet at 08:40 at the same spot.
- Gaps on the three mornings last 35, 35 and 20 minutes. A fourth gap, on the first day at 10:30, lasts 15 minutes.
- Across a 35-minute gap the vehicle is 21.4 km from where it went quiet. That is 21.4 / (35 / 60) = 36.7 km/h, a normal speed, so it is not a jump.
- The 35-minute gap scores 1 + 1 long (35 is at least 3 x 10) + 1 moved + 1 repeated place + 1 repeated hour + 1 weak fix (3 satellites in the last report before it) = 6, worth a review.
- The 15-minute gap scores 1 + 1 moved = 2, check.
- On the second day one position is 45 km off for a single report. The tool shows it as one jump of 540 km/h and not as two.
- Total silence is 105 minutes. The two nights with ignition off are parked and quiet. The share of active time is 105 / 540 = 19%.
What should you do with a gap?
- Check the ordinary causes first. Look at SIM and data status, power events and known dead zones.
- Look at the repeated places. Open one on a map, or visit it, and check the sky view and the signal.
- Ask for the reason in neutral words. Record the answer next to the gap.
- Compare with other records. Fuel, route and job records show whether the quiet time matters.
- Decide with your policy, not with the list. Keep the export with the record, and use your tamper policy and the signed undertaking.
Your file
The file is read and analyzed in your browser. The sample is made up. Your settings, and the text when it is short, are sent to our server and kept for up to 45 days only if you ask for the emailed report, because the link in the email carries them. A share link carries the text only when it is short, and only because you copied the link yourself.
Assumptions and limits
- Time stamps are compared as written. A file with no time zone mark is read as one clock, which is right for a single export.
- Reports with the same time stamp are counted once. Rows are sorted by time before they are compared.
- Distances are straight lines between reports. They are not road distances.
- The tool cannot see radio. It cannot tell GNSS interference from a dead zone. It shows patterns that can fit it.
- The tool reads up to 200,000 rows and 400 vehicles. A larger file is cut and the page says so.
- The limits are typical starting values. The levels are indicative.