sfwa/trical

Straightforward UKF-based scale and bias calibration for magnetometers (and other tri-axial field sensors).

trical's Issues

Usage in a mobile app

I have manage to interact with the library to some degree from C#.

The raw magnetometer on iphone11 on the left and the calibrated_reading float array values to the right as System.Numerics.Vector3:

<-83.00697, 16.52205, -389.2053> ---> <-80.01025, 17.02175, -388.8991>
50.01
<-83.33554, 16.6873, -389.5024> ---> <NaN, NaN, NaN>
50.02
Thread started: #19
<-83.27498, 16.83936, -388.3975> ---> <NaN, NaN, NaN>
50.02999
<-82.71381, 16.61551, -389.6036> ---> <NaN, NaN, NaN>
50.03999

I can set and get norm just fine.
The first app update I get values back, but then there is only NaN values.

Here is the update code in the C# wrapper library:

public float[] Update(float[] raw)
{
    TRICALWrapper.TRICAL_estimate_update(handle, raw, ExpectedField);

    float[] calibrated_reading = new float[3];
    TRICALWrapper.TRICAL_measurement_calibrate(handle, raw, calibrated_reading);
    return calibrated_reading;
}

The handle is some sort of pointer to the TRICAL_instance.t, being of TRICALSafeHandle : SafeHandleZeroOrMinusOneIsInvalid in C#

// added two wrapper methods in TRICAL.cpp
TRICAL_instance_t* CreateTRICAL()
{
    return new TRICAL_instance_t();
}

void DisposeTRICAL(TRICAL_instance_t* ptr)
{
    if (ptr != nullptr)
    {
        delete ptr;
        ptr = nullptr;
    }
}

Also I had to change c -> cpp and remove retsrict keyword to remove error. The dll building guide seem to require cpp.

So is this problem, communicating between C# <---> C++, or what could be the problem?

Make error on restrict pointer: need C99 mode

I got the following error when building:

error: expected ‘;’, ‘,’ or ‘)’ before ‘instance’
 void TRICAL_measurement_calibrate(TRICAL_instance_t *restrict instance,

I was able to fix this by including -std=c99 in the set(CMAKE_C_FLAGS string in CMakeLists.txt

googletest repository not up to date

The SVN repository seems not to exist anymore. So line 14 in the CMakeLists in test throws an error.

It works with this:

GIT_REPOSITORY https://github.com/google/googletest

Regards

Philipp

Some compiler flags not supported

I needed to remove -Weverything and -Wno-documentation from the set(CMAKE_C_FLAGS string in CMakeLists.txt.

Unable to compile under Ubuntu 14.04 with cmake 2.8.12.2 and GCC 4.7.3

Dear all,

Thanks for making your code available to the public! I was trying to compile your software, but wasn't able to get it to run under Linux (Ubuntu 14.04) ... if I simply try with

mkdir TRICAL_build
cd TRICAL_build
cmake ..
make

I get the following error:

Scanning dependencies of target TRICAL
[ 25%]
Building C object CMakeFiles/TRICAL.dir/src/TRICAL.c.o
cc: error: unrecognized command line option ‘-Weverything’
make[2]: *** [CMakeFiles/TRICAL.dir/src/TRICAL.c.o] Error 1
make[1]: *** [CMakeFiles/TRICAL.dir/all] Error 2
make: *** [all] Error 2

If I change the flags in CMakeLists.txt to

set(CMAKE_C_FLAGS "-O3 -Werror -Wno-padded -Wno-unknown-pragmas -fPIC")

as suggested in #2

I get the following error:

/home/auerl/TRICAL/src/TRICAL.c:154:54: error: expected ‘;’, ‘,’ or ‘)’ before ‘instance’
/home/auerl/TRICAL/src/TRICAL.c:173:58: error: expected ‘;’, ‘,’ or ‘)’ before ‘instance’
/home/auerl/TRICAL/src/TRICAL.c:215:63: error: expected ‘;’, ‘,’ or ‘)’ before ‘instance’
make[2]: *** [CMakeFiles/TRICAL.dir/src/TRICAL.c.o] Error 1
make[1]: *** [CMakeFiles/TRICAL.dir/all] Error 2
make: *** [all] Error 2

Does anybody have an idea what the issue could be? My compiler is GCC 4.7.

Best wishes and thanks in advance,

Ludwig

I always get non-positive-definite covariance matrix

I always get non-positive-definite covariance matrix in the c ++ algorithm. The range of input values mx, my, mz from -1 to 1.
The coefficients are defined as
#define TRICAL_ALPHA_2 (1.0f)
#define TRICAL_BETA (0.0f)
#define TRICAL_KAPPA (1.0f)
what should i change?

Clarification about using TRICAL_estimate_update()

Hi,

I am getting X, Y, Z values from magnetometer in uT units.

I am using following tool to identify magnetic field in my location, and the value is 50uT (though my calibrated reading are usually around ~55uT).

I don't understand which value should be used for expected_field argument in TRICAL_estimate_update(&global_instance, sensor_reading, expected_field). Can you please tell me what values should be put there?

Below is the pseudocode that I am using, can you please check that the usage is correct?

TRICAL_instance_t global_instance;

int main(void) {
  TRICAL_init(&global_instance);
  TRICAL_norm_set(&global_instance, 50.0);
  TRICAL_noise_set(&global_instance, 1.5);

  float bias_estimate[3];
  float scale_estimate[9];
  float sensor_reading[3];
  float expected_field[3];

  // for holding data received from magnetometer, in uT.
  float mag_x, mag_y, mag_z;

  while(true) {
    // get the latest sensor reading
    read_magnetometer(mag_x, mag_y, mag_z);
    sensor_reading[0] = mag_x;
    sensor_reading[1] = mag_y;
    sensor_reading[2] = mag_z;

    // What should be passed to expected field?
    TRICAL_estimate_update(&global_instance, sensor_reading, expected_field);

    TRICAL_estimate_get(&global_instance, bias_estimate, scale_estimate);

    printf("[%f %f %f]\n", bias_estimate[0], bias_estimate[1], bias_estimate[2]);
   }

return 0;
}

Memory corruption

When I try to run TRICAL, I get a memory corruption error:

ipython -m TRICAL 9.81 1e-4 html accel_multiaxis.csv accel_multiaxis.html
*** Error in `/usr/bin/python': malloc(): memory corruption: 0x0000000001a6db20 ***
Aborted (core dumped)

I'm using Ubuntu 14.04. I modified __main__.py to look for an .so file instead of .dylib