Every time the Nano saves a flight it writes a flight info page beside the log, named flightinfo…-N.html to match flightlog…-N.aclz. It is an ordinary web page: open it straight off the Nano's drive in any browser, with no internet connection needed, and it gives you the flight at a glance plus a detailed record of how the Nano recorded and processed it. This page walks through what each section shows.
iGood to know
The flight info page is for reading. The flight log itself is what you upload and what carries the signature, so there is no need to keep or upload the info page for your flight to count. If you ever need help with a flight, attaching its info page to your email tells us almost everything we need.
The top of the page shows the apogee in large figures and how long after launch it came. Underneath are the device serial number, the hardware revision, the firmware version, and where the flight was saved from: Flight memory for a normal save, or Recovered from flash buffer if the Nano rebuilt it at start-up after losing power mid-flight (see the log recovery page).
Two buttons sit below it. Download flight log downloads the log file that sits beside this page, so it works when you open the page from the Nano's drive, or from a folder where you copied both files together. Upload to Altimeter Cloud opens the Altimeter Cloud upload page.
!Altimeter movement detected
On Rev4 and later boards, if the Nano detects that it shifted inside the rocket during the motor burn, a warning box appears at the top. It means the rail angle, and any orientation, tilt or spin figures, were measured against a mounting that moved and should be treated as unreliable. Altitude, velocity and apogee are unaffected, because they come from the barometer. Mounting the Nano more firmly fixes it; see the installing the altimeter page.
The key figures of the flight, all taken from the processed altitude:
| Row | What it means |
|---|---|
| Apogee | The highest point, in metres above the launch point, and when it happened |
| Burnout | When the motor stopped pushing (Rev4 and later, when a burnout was found) |
| Landing | When the Nano judged it had landed, and the height it came to rest at |
| Landing velocity | How fast it was coming down just before landing |
| Max velocity (up) / (down) | The fastest climb and the fastest descent |
| Flight duration | Launch to landing |
| Powered on before launch | How long the Nano had been switched on when the launch came |
| Sample count / Average sample rate | How many samples are in the log, and the average rate across the whole flight. With hybrid mode on this is well below your sample speed, because the descent is logged at a lower rate |
Two small tables side by side showing the samples around the peak: the raw barometer readings on one side and the processed altitude on the other, over the same window. It shows exactly what the processing did at the top of the flight, which is where an ejection charge or a gust is most likely to upset the barometer.
How the saved altitude was produced: the order the steps ran in (raw barometer, then TrueFuse, then TruePath), what the saved altitude and velocity columns contain, and where the untouched raw altitude is kept in the log. It finishes with the Raw apogee and the Processed apogee side by side, with the difference between them in metres and seconds. On a clean flight the two are within a few centimetres; a bigger difference is the processing removing something that was not really height, such as an ejection spike.
The record of what TrueFuse did on this flight. Filter version shows the filter version, and Status says whether it was applied, or why not (for example no motion data, or a recording too short). The counts that follow say how many times it held the altitude against the accelerometer on the pad, bridged the launch, or carried the trace across a pressure disturbance, and Largest correction gives the biggest amount it moved the trace away from the barometer. The rows marked 2F are details of the newest refinements. Most people only need the Status and Largest correction rows.
The equivalent record for TruePath: its version, what it was given (the TrueFuse output), how many samples it cleaned out of the total, and the settings it chose for this flight. These are mainly for us when we look into a flight.
TrueFuse in depthTruePath in depth
| Row | What it means |
|---|---|
| Rail angle | The angle of the rocket from vertical as it left the pad, with its uncertainty, and whether the mount stayed fixed, moved or is unknown. If it could not be measured the row says why |
| Rail angle detail | The measurements behind the rail angle, for anyone who wants to check it |
| IMU saturation | Whether the accelerometer or gyroscope reached the limit of its range (±32 G, ±2000 °/s) during the flight. "None" is what you want; if either did, readings at those moments were clipped. The accuracy page has a tip for flights beyond 32 G |
| Spin rate | The fastest and average rotation rate about each axis. The Z axis is roll when the Nano is mounted upright |
| Sensor sync | Whether the pressure and motion data were lined up, and by how much |
| Accel calibration / Calibration quality | The calibration offsets in use and how well the calibration went. The page explains how to read the quality figures; if it says the device has never been calibrated, see the calibrating the IMU page |
The conditions the flight was recorded under: the standard sea level pressure and temperature used for the height (1013.25 hPa and 15 °C), the sensor temperature and the battery voltage at the start and end of the flight, the pressure sensor settings, the hybrid mode, and the details of the ground reference the Nano took on the pad (its start-up readings and the ground level it locked in at launch). The battery figures are a handy check that the pack was healthy for the flight.
How long each part of the save took, and a set of health figures from the flight: loop timing, memory use, any power dips and how well the log compressed. These are there for diagnostics and are mainly useful to us; if something ever looks wrong with a flight, they help us see why.
At the bottom are three small charts drawn from the flight: the altitude over the whole flight, a close-up of the altitude two seconds either side of apogee, and the acceleration during the motor burn. They are a quick visual check before you upload; the Altimeter Cloud gives you the full interactive charts.