Fusion.h revision f66684a6fb2a2991e84a085673629db2a0494fc6 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_FUSION_H
18#define ANDROID_FUSION_H
19
20#include <utils/Errors.h>
21
22#include "quat.h"
23#include "mat.h"
24#include "vec.h"
25
26namespace android {
27
28typedef mat<float, 3, 4> mat34_t;
29
30enum FUSION_MODE{
31    FUSION_9AXIS, // use accel gyro mag
32    FUSION_NOMAG, // use accel gyro (game rotation, gravity)
33    FUSION_NOGYRO, // use accel mag (geomag rotation)
34    NUM_FUSION_MODE
35};
36
37class Fusion {
38    /*
39     * the state vector is made of two sub-vector containing respectively:
40     * - modified Rodrigues parameters
41     * - the estimated gyro bias
42     */
43    quat_t  x0;
44    vec3_t  x1;
45
46    /*
47     * the predicated covariance matrix is made of 4 3x3 sub-matrices and it is
48     * semi-definite positive.
49     *
50     * P = | P00  P10 | = | P00  P10 |
51     *     | P01  P11 |   | P10t P11 |
52     *
53     * Since P01 = transpose(P10), the code below never calculates or
54     * stores P01.
55     */
56    mat<mat33_t, 2, 2> P;
57
58    /*
59     * the process noise covariance matrix
60     */
61    mat<mat33_t, 2, 2> GQGt;
62
63public:
64    Fusion();
65    void init(int mode = FUSION_9AXIS);
66    void handleGyro(const vec3_t& w, float dT);
67    status_t handleAcc(const vec3_t& a, float dT);
68    status_t handleMag(const vec3_t& m);
69    vec4_t getAttitude() const;
70    vec3_t getBias() const;
71    mat33_t getRotationMatrix() const;
72    bool hasEstimate() const;
73
74private:
75    struct Parameter {
76        float gyroVar;
77        float gyroBiasVar;
78        float accStdev;
79        float magStdev;
80    } mParam;
81
82    mat<mat33_t, 2, 2> Phi;
83    vec3_t Ba, Bm;
84    uint32_t mInitState;
85    float mGyroRate;
86    vec<vec3_t, 3> mData;
87    size_t mCount[3];
88    int mMode;
89
90    enum { ACC=0x1, MAG=0x2, GYRO=0x4 };
91    bool checkInitComplete(int, const vec3_t& w, float d = 0);
92    void initFusion(const vec4_t& q0, float dT);
93    void checkState();
94    void predict(const vec3_t& w, float dT);
95    void update(const vec3_t& z, const vec3_t& Bi, float sigma);
96    static mat34_t getF(const vec4_t& p);
97    static vec3_t getOrthogonal(const vec3_t &v);
98};
99
100}; // namespace android
101
102#endif // ANDROID_FUSION_H
103