ESTKALMAN: WARNING: Kalman prediction rate low (94)

[mouhyemen]

I am using LH base stations V1. I calibrated the LH positioning from the cfclient and estimating the geometry. I looked at the position estimates in the Plotter and it looked reasonable. But I am getting ESTKALMAN warning and can't fly the CF2.1

SYS: ----------------------------
SYS: Crazyflie 2.1 is up and running!
SYS: Build 0:8c606d1f8f89 (2022.05) CLEAN
SYS: I am 0x20373357594B50070025002C and I have 1024KB of flash!
CFGBLK: v1, verification [OK]
DECK_CORE: 1 deck(s) found
DECK_CORE: Calling INIT on driver bcLighthouse4 for deck 0
IMU: BMI088: Using I2C interface.
IMU: BMI088 Gyro connection [OK].
IMU: BMI088 Accel connection [OK]
IMU: BMP388 I2C connection [OK]
ESTIMATOR: Using Kalman (2) estimator
CONTROLLER: Using PID (1) controller
MTR-DRV: Using brushed motor driver
SYS: About to run tests in system.c.
SYS: NRF51 version: 2022.0
EEPROM: I2C connection [OK].
STORAGE: Storage check [OK].
IMU: BMI088 gyro self-test [OK]
SYS: Self test passed!
STAB: Wait for sensor calibration...
SYS: Free heap: 19240 bytes
LHFL: Lighthouse bootloader version: 2
STAB: Ready to fly.
LHFL: Bitstream CRC32: 112BC794 [PASS]
LHFL: Firmware version 6 verified, booting deck!
ESTKALMAN: State out of bounds, resetting
ESTKALMAN: WARNING: Kalman prediction rate low (97)
ESTKALMAN: WARNING: Kalman prediction rate low (95)
ESTKALMAN: WARNING: Kalman prediction rate low (98)
ESTKALMAN: WARNING: Kalman prediction rate low (94)

Here's the task dump output by waiting 4-5 seconds between two sessions.

ESTKALMAN: WARNING: Kalman prediction rate low (98)
SYSLOAD: Task dump
SYSLOAD: Load	Stack left	Name
SYSLOAD: 2.89 	205 	Tmr Svc
SYSLOAD: 41.99 	127 	IDLE
SYSLOAD: 0.0 	76 	PWRMGNT
SYSLOAD: 1.34 	211 	CRTP-RX
SYSLOAD: 18.82 	53 	LH
SYSLOAD: 0.0 	255 	CMDHL
SYSLOAD: 0.0 	115 	PLATFORM-
SYSLOAD: 0.0 	249 	LOG
SYSLOAD: 0.0 	221 	MEM
SYSLOAD: 0.01 	258 	PARAM
SYSLOAD: 0.34 	126 	SYSTEM
SYSLOAD: 0.23 	61 	CRTP-TX
SYSLOAD: 2.03 	175 	SYSLINK
SYSLOAD: 2.27 	87 	LEDSEQCMD
SYSLOAD: 0.63 	107 	CRTP-SRV
SYSLOAD: 5.02 	367 	STABILIZE
SYSLOAD: 6.92 	144 	SENSORS
SYSLOAD: 17.42 	281 	KALMAN
SYSLOAD: 0.0 	113 	USBLINK
ESTKALMAN: WARNING: Kalman prediction rate low (96)
ESTKALMAN: WARNING: Kalman prediction rate low (96)
ESTKALMAN: WARNING: Kalman prediction rate low (98)
ESTKALMAN: WARNING: Kalman prediction rate low (94)
ESTKALMAN: WARNING: Kalman prediction rate low (98)
ESTKALMAN: WARNING: Kalman prediction rate low (98)
ESTKALMAN: WARNING: Kalman prediction rate low (91)
ESTKALMAN: WARNING: Kalman prediction rate low (96)
SYSLOAD: Task dump
SYSLOAD: Load	Stack left	Name
SYSLOAD: 3.15 	171 	Tmr Svc
SYSLOAD: 39.72 	127 	IDLE
SYSLOAD: 0.66 	107 	CRTP-SRV
SYSLOAD: 0.0 	76 	PWRMGNT
SYSLOAD: 1.42 	211 	CRTP-RX
SYSLOAD: 7.04 	144 	SENSORS
SYSLOAD: 19.55 	53 	LH
SYSLOAD: 0.0 	115 	PLATFORM-
SYSLOAD: 0.0 	249 	LOG
SYSLOAD: 0.0 	221 	MEM
SYSLOAD: 0.0 	258 	PARAM
SYSLOAD: 0.31 	126 	SYSTEM
SYSLOAD: 0.25 	61 	CRTP-TX
SYSLOAD: 5.12 	367 	STABILIZE
SYSLOAD: 18.19 	281 	KALMAN
SYSLOAD: 2.13 	175 	SYSLINK
SYSLOAD: 2.39 	87 	LEDSEQCMD
SYSLOAD: 0.0 	113 	USBLINK
SYSLOAD: 0.0 	255 	CMDHL
ESTKALMAN: WARNING: Kalman prediction rate low (98)
ESTKALMAN: WARNING: Kalman prediction rate low (92)

I tried following the steps in multi-base-stations link to calibrate and run the script multi_bs_geometry_estimation.py.

After following all the steps, I get this error:

Step 6. Estimating geometry...
/home/mouhyemen/.local/lib/python3.8/site-packages/cflib/localization/lighthouse_types.py:61: ComplexWarning: Casting complex values to real discards the imaginary part
  return Pose(Rotation.from_quat(R_quat).as_matrix(), t_vec)
Initial guess base stations at:
Traceback (most recent call last):
  File "multi_bs_geometry_estimation.py", line 364, in <module>
    connect_and_estimate(uri)
  File "multi_bs_geometry_estimation.py", line 347, in connect_and_estimate
    bs_poses = estimate_geometry(origin, x_axis, xy_plane, samples)
  File "multi_bs_geometry_estimation.py", line 219, in estimate_geometry
    print_base_stations_poses(initial_guess.bs_poses)
AttributeError: 'dict' object has no attribute 'bs_poses'

What should I do to solve the issue?

[krichardsson]

Hi!

ESTKALMAN: WARNING: Kalman prediction rate low

This warning just means that the task that runs the kalman estimator does not manage to run the estimation at 100 Hz, it does not prevent the Crazyflie from taking off. A prediction rate slightly less than 100 is probably not a problem but it is interesting to understand why. Is your firmware modified in any way?

I tried following the steps in multi-base-stations link to calibrate and run the script multi_bs_geometry_estimation.py

We have done some work on this lately, including fixing a bug related to LH V1. It is possible that your issue is related to this.
The multi base station estimation is now supported by the client and can be started from the Lighthouse tab in the client.
You will have to update both firmware, python lib as well as the client as there are dependencies in all of them.

[mouhyemen]

Is your firmware modified in any way?
I don't think so. I flashed the latest firmware using the cfclient. I used 2022.05.

Are you referring to the cfclient's Lighthouse tab which allows geometry readings and estimations? I have done that in order to calibrate my system.

[krichardsson]

I did ran a test in our flight lab with our lighthouse V1 system and I actually got the same warnings. For some reason it seems as the kalman task does not get enough CPU time or is blocked. It does not seem to affect the positioning but I will create an issue for further investigations.

[krichardsson]

Issue in bitcraze/crazyflie-firmware#1112