In Standard C, the first three file descriptors are usually standard in,
out, and error. However, ArduPilot doesn't have a concept of this and
other backends (such as LittleFS) don't bother to reject them.
Remove this logic to simplify implementation and allow use of more open
files.
To connect loadFactor to airspeed we can use formula of balancing between lift force and gravity force:
liftForce = loadFactor * gravityForce; on the other hand lift force can be expressed as
liftForce = 0.5 * lifCoefficient * airDensity * sq(airspeed) * referenceArea; minimum airseepd is at loadFactor = 1
and lift force only balances the gravit force, so gravity force (which is same as lift force at minimum airspeed) with minimum airspeed can be expressed as
gravityForce = 0.5 * lifCoefficient * airDensity * sq(airspeed_min) * referenceArea; substituting gravit force in previous formula gives us
0.5 * lifCoefficient * airDensity * sq(airspeed) * referenceArea = loadFactor * 0.5 * lifCoefficient * airDensity * sq(airspeed_min) * referenceArea;
from where we get:
loadFactor = sq(airspeed / airspeed_min); and_TASmin should be
_TASmin *= safe_sqrt(_load_factor);
lseek must return the current file position. Previously, the littlefs
version always returned 0, which broke terrain I/O as it checks that the
position returned is the one it seeked to. Fix to return the current
position, which is correctly returned from littlefs.
This problem was originally and incorrectly diagnosed as an issue with
littlefs seeking past the end of the file, but this functionality works
fine and fixing the incorrect return completely fixes terrain.
Terrain functionality was verified using `TERRAIN_DEBUG` on
KakuteH7Mini-Nand running sim on HW. Terrain data is correctly
downloaded from the GCS and loaded from the filesystem after reboot.
../../libraries/GCS_MAVLink/GCS_Common.cpp: In member function 'void GCS_MAVLINK::send_highres_imu()':
../../libraries/GCS_MAVLink/GCS_Common.cpp:2184:27: error: unused variable 'HIGHRES_IMU_UPDATED_XMAG' [-Werror=unused-variable]
2184 | static const uint16_t HIGHRES_IMU_UPDATED_XMAG = 0x40;
| ^~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated due to -Wfatal-errors.
cc1plus: all warnings being treated as errors
don't cache connection result and return appropriate error if connection fails.
don't wait 1s to send first serial passthrough message
retry failed cmd_DeviceInitFlash as per betaflight
ensure the bootinfo structure is large enough
In file included from ../../libraries/AP_HAL_SITL/RCInput.cpp:6:
../../libraries/AP_HAL_SITL/RCInput.h:22:17: warning: private field '_sitlState' is not used [-Wunused-private-field]
22 | SITL_State *_sitlState;
| ^
../../libraries/AP_HAL_SITL/RCInput.h:23:10: warning: private field 'using_rc_protocol' is not used [-Wunused-private-field]
23 | bool using_rc_protocol;
| ^
../../libraries/AP_Airspeed/AP_Airspeed_AUAV.h:68:11: warning: private field 'pressure_abs_L' is not used [-Wunused-private-field]
68 | float pressure_abs_L;
