Merge remote-tracking branch 'origin/RSS_ImuFactor' into feature/scenarios

Conflicts:
	gtsam/navigation/ScenarioRunner.h
	gtsam/navigation/tests/testScenarioRunner.cpp

gtsam/navigation/Scenario.h

@@ -21,78 +21,68 @@
 
 namespace gtsam {
 
-/**
+/// Simple trajectory simulator.
- * Simple IMU simulator with constant twist 3D trajectory.
- * It is also assumed that gravity is magically counteracted and has no effect
- * on trajectory. Hence, a simulated IMU yields the actual body angular
- * velocity, and negative G acceleration plus the acceleration created by the
- * rotating body frame.
- */
 class Scenario {
+ public:
+  // Quantities a Scenario needs to specify:
+
+  virtual Pose3 pose(double t) const = 0;
+  virtual Vector3 omega_b(double t) const = 0;
+  virtual Vector3 velocity_n(double t) const = 0;
+  virtual Vector3 acceleration_n(double t) const = 0;
+
+  // Derived quantities:
+
+  virtual Rot3 rotation(double t) const { return pose(t).rotation(); }
+
+  Vector3 velocity_b(double t) const {
+    const Rot3 nRb = rotation(t);
+    return nRb.transpose() * velocity_n(t);
+  }
+
+  Vector3 acceleration_b(double t) const {
+    const Rot3 nRb = rotation(t);
+    return nRb.transpose() * acceleration_n(t);
+  }
+};
+
+/// Scenario with constant twist 3D trajectory.
+class ExpmapScenario : public Scenario {
  public:
   /// Construct scenario with constant twist [w,v]
-  Scenario(const Vector3& w, const Vector3& v,
+  ExpmapScenario(const Vector3& w, const Vector3& v)
-           double imuSampleTime = 1.0 / 100.0, double gyroSigma = 0.17,
-           double accSigma = 0.01)
       : twist_((Vector6() << w, v).finished()),
-        imuSampleTime_(imuSampleTime),
+        a_b_(twist_.head<3>().cross(twist_.tail<3>())) {}
-        gyroNoiseModel_(noiseModel::Isotropic::Sigma(3, gyroSigma)),
-        accNoiseModel_(noiseModel::Isotropic::Sigma(3, accSigma)) {}
 
-  const double& imuSampleTime() const { return imuSampleTime_; }
-
-  // NOTE(frank): hardcoded for now with Z up (gravity points in negative Z)
-  // also, uses g=10 for easy debugging
-  Vector3 gravity() const { return Vector3(0, 0, -10.0); }
-
-  const noiseModel::Diagonal::shared_ptr& gyroNoiseModel() const {
-    return gyroNoiseModel_;
-  }
-
-  const noiseModel::Diagonal::shared_ptr& accNoiseModel() const {
-    return accNoiseModel_;
-  }
-
-  Matrix3 gyroCovariance() const { return gyroNoiseModel_->covariance(); }
-  Matrix3 accCovariance() const { return accNoiseModel_->covariance(); }
-
-  Vector3 angularVelocityInBody() const { return twist_.head<3>(); }
-  Vector3 linearVelocityInBody() const { return twist_.tail<3>(); }
-
-  /// Rotation of body in nav frame at time t
-  Rot3 rotAtTime(double t) const {
-    return Rot3::Expmap(angularVelocityInBody() * t);
-  }
-
-  /// Pose of body in nav frame at time t
   Pose3 pose(double t) const { return Pose3::Expmap(twist_ * t); }
-
+  Rot3 rotation(double t) const { return Rot3::Expmap(twist_.head<3>() * t); }
-  /// Velocity in nav frame at time t
+  Vector3 omega_b(double t) const { return twist_.head<3>(); }
-  Vector3 velocity(double t) const {
+  Vector3 velocity_n(double t) const { return rotation(t) * twist_.tail<3>(); }
-    const Rot3 nRb = rotAtTime(t);
+  Vector3 acceleration_n(double t) const { return rotation(t) * a_b_; }
-    return nRb * linearVelocityInBody();
-  }
-
-  // acceleration in nav frame
-  Vector3 acceleration(double t) const {
-    const Vector3 centripetalAcceleration =
-        angularVelocityInBody().cross(linearVelocityInBody());
-    const Rot3 nRb = rotAtTime(t);
-    return nRb * centripetalAcceleration - gravity();
-  }
-
-  // acceleration in body frame frame
-  Vector3 accelerationInBody(double t) const {
-    const Vector3 centripetalAcceleration =
-        angularVelocityInBody().cross(linearVelocityInBody());
-    const Rot3 nRb = rotAtTime(t);
-    return centripetalAcceleration - nRb.transpose() * gravity();
-  }
 
  private:
-  Vector6 twist_;
+  const Vector6 twist_;
-  double imuSampleTime_;
+  const Vector3 a_b_;  // constant centripetal acceleration in body = w_b * v_b
-  noiseModel::Diagonal::shared_ptr gyroNoiseModel_, accNoiseModel_;
+};
+
+/// Accelerating from an arbitrary initial state
+class AcceleratingScenario : public Scenario {
+ public:
+  /// Construct scenario with constant twist [w,v]
+  AcceleratingScenario(const Rot3& nRb, const Point3& p0, const Vector3& v0,
+                       const Vector3& accelerationInBody)
+      : nRb_(nRb), p0_(p0.vector()), v0_(v0), a_n_(nRb_ * accelerationInBody) {}
+
+  Pose3 pose(double t) const {
+    return Pose3(nRb_, p0_ + v0_ * t + a_n_ * t * t / 2.0);
+  }
+  Vector3 omega_b(double t) const { return Vector3::Zero(); }
+  Vector3 velocity_n(double t) const { return v0_ + a_n_ * t; }
+  Vector3 acceleration_n(double t) const { return a_n_; }
+
+ private:
+  const Rot3 nRb_;
+  const Vector3 p0_, v0_, a_n_;
 };
 
 }  // namespace gtsam

gtsam/navigation/ScenarioRunner.h

@@ -30,7 +30,29 @@ static const Matrix3 kIntegrationErrorCovariance = intNoiseVar * I_3x3;
 /// Simple class to test navigation scenarios
 class ScenarioRunner {
  public:
-  ScenarioRunner(const Scenario& scenario) : scenario_(scenario) {}
+  ScenarioRunner(const Scenario* scenario, double imuSampleTime = 1.0 / 100.0,
+                 double gyroSigma = 0.17, double accSigma = 0.01)
+      : scenario_(scenario),
+        imuSampleTime_(imuSampleTime),
+        gyroNoiseModel_(noiseModel::Isotropic::Sigma(3, gyroSigma)),
+        accNoiseModel_(noiseModel::Isotropic::Sigma(3, accSigma)) {}
+
+  const double& imuSampleTime() const { return imuSampleTime_; }
+
+  // NOTE(frank): hardcoded for now with Z up (gravity points in negative Z)
+  // also, uses g=10 for easy debugging
+  Vector3 gravity_n() const { return Vector3(0, 0, -10.0); }
+
+  const noiseModel::Diagonal::shared_ptr& gyroNoiseModel() const {
+    return gyroNoiseModel_;
+  }
+
+  const noiseModel::Diagonal::shared_ptr& accNoiseModel() const {
+    return accNoiseModel_;
+  }
+
+  Matrix3 gyroCovariance() const { return gyroNoiseModel_->covariance(); }
+  Matrix3 accCovariance() const { return accNoiseModel_->covariance(); }
 
   /// Integrate measurements for T seconds into a PIM
   ImuFactor::PreintegratedMeasurements integrate(
@@ -40,17 +62,18 @@ class ScenarioRunner {
     const bool use2ndOrderIntegration = true;
 
     ImuFactor::PreintegratedMeasurements pim(
-        zeroBias, scenario_.accCovariance(), scenario_.gyroCovariance(),
+        zeroBias, accCovariance(), gyroCovariance(),
         kIntegrationErrorCovariance, use2ndOrderIntegration);
 
-    const double dt = scenario_.imuSampleTime();
+    const double dt = imuSampleTime();
     const double sqrt_dt = std::sqrt(dt);
     const size_t nrSteps = T / dt;
     double t = 0;
     for (size_t k = 0; k < nrSteps; k++, t += dt) {
-      Vector3 measuredOmega = scenario_.angularVelocityInBody();
+      Rot3 bRn = scenario_->rotation(t).transpose();
+      Vector3 measuredOmega = scenario_->omega_b(t);
       if (gyroSampler) measuredOmega += gyroSampler->sample() / sqrt_dt;
-      Vector3 measuredAcc = scenario_.accelerationInBody(t);
+      Vector3 measuredAcc = scenario_->acceleration_b(t) - bRn * gravity_n();
       if (accSampler) measuredAcc += accSampler->sample() / sqrt_dt;
       pim.integrateMeasurement(measuredAcc, measuredOmega, dt);
     }
@@ -63,12 +86,10 @@ class ScenarioRunner {
       const ImuFactor::PreintegratedMeasurements& pim) const {
     // TODO(frank): allow non-zero bias, omegaCoriolis
     const imuBias::ConstantBias zeroBias;
-    const Pose3 pose_i = Pose3::identity();
-    const Vector3 vel_i = scenario_.velocity(0);
     const Vector3 omegaCoriolis = Vector3::Zero();
     const bool use2ndOrderCoriolis = true;
-    return pim.predict(pose_i, vel_i, zeroBias, scenario_.gravity(),
+    return pim.predict(scenario_->pose(0), scenario_->velocity_n(0), zeroBias,
-                       omegaCoriolis, use2ndOrderCoriolis);
+                       gravity_n(), omegaCoriolis, use2ndOrderCoriolis);
   }
 
   /// Return pose covariance by re-arranging pim.preintMeasCov() appropriately
@@ -76,8 +97,8 @@ class ScenarioRunner {
       const ImuFactor::PreintegratedMeasurements& pim) const {
     Matrix9 cov = pim.preintMeasCov();
     Matrix6 poseCov;
-    poseCov << cov.block<3, 3>(0, 0), cov.block<3, 3>(0, 3),  //
+    poseCov << cov.block<3, 3>(6, 6), cov.block<3, 3>(6, 0),  //
-        cov.block<3, 3>(3, 0), cov.block<3, 3>(3, 3);
+        cov.block<3, 3>(0, 6), cov.block<3, 3>(0, 0);
     return poseCov;
   }
 
@@ -87,8 +108,8 @@ class ScenarioRunner {
     Pose3 prediction = predict(integrate(T)).pose;
 
     // Create two samplers for acceleration and omega noise
-    Sampler gyroSampler(scenario_.gyroNoiseModel(), 10);
+    Sampler gyroSampler(gyroNoiseModel(), 10);
-    Sampler accSampler(scenario_.accNoiseModel(), 29284);
+    Sampler accSampler(accNoiseModel(), 29284);
 
     // Sample !
     Matrix samples(9, N);
@@ -114,7 +135,9 @@ class ScenarioRunner {
   }
 
  private:
-  Scenario scenario_;
+  const Scenario* scenario_;
+  double imuSampleTime_;
+  noiseModel::Diagonal::shared_ptr gyroNoiseModel_, accNoiseModel_;
 };
 
 }  // namespace gtsam

gtsam/navigation/tests/testScenario.cpp

@@ -27,9 +27,15 @@ static const double degree = M_PI / 180.0;
 /* ************************************************************************* */
 TEST(Scenario, Forward) {
   const double v = 2;  // m/s
-  Scenario forward(Vector3::Zero(), Vector3(v, 0, 0));
+  const Vector3 W(0, 0, 0), V(v, 0, 0);
+  const ExpmapScenario scenario(W, V);
 
-  const Pose3 T15 = forward.pose(15);
+  const double T = 15;
+  EXPECT(assert_equal(W, scenario.omega_b(T), 1e-9));
+  EXPECT(assert_equal(V, scenario.velocity_b(T), 1e-9));
+  EXPECT(assert_equal(W.cross(V), scenario.acceleration_b(T), 1e-9));
+
+  const Pose3 T15 = scenario.pose(T);
   EXPECT(assert_equal(Vector3(0, 0, 0), T15.rotation().xyz(), 1e-9));
   EXPECT(assert_equal(Point3(30, 0, 0), T15.translation(), 1e-9));
 }
@@ -38,11 +44,17 @@ TEST(Scenario, Forward) {
 TEST(Scenario, Circle) {
   // Forward velocity 2m/s, angular velocity 6 degree/sec around Z
   const double v = 2, w = 6 * degree;
-  Scenario circle(Vector3(0, 0, w), Vector3(v, 0, 0));
+  const Vector3 W(0, 0, w), V(v, 0, 0);
+  const ExpmapScenario scenario(W, V);
+
+  const double T = 15;
+  EXPECT(assert_equal(W, scenario.omega_b(T), 1e-9));
+  EXPECT(assert_equal(V, scenario.velocity_b(T), 1e-9));
+  EXPECT(assert_equal(W.cross(V), scenario.acceleration_b(T), 1e-9));
 
   // R = v/w, so test if circle is of right size
   const double R = v / w;
-  const Pose3 T15 = circle.pose(15);
+  const Pose3 T15 = scenario.pose(T);
   EXPECT(assert_equal(Vector3(0, 0, 90 * degree), T15.rotation().xyz(), 1e-9));
   EXPECT(assert_equal(Point3(R, R, 0), T15.translation(), 1e-9));
 }
@@ -52,15 +64,44 @@ TEST(Scenario, Loop) {
   // Forward velocity 2m/s
   // Pitch up with angular velocity 6 degree/sec (negative in FLU)
   const double v = 2, w = 6 * degree;
-  Scenario loop(Vector3(0, -w, 0), Vector3(v, 0, 0));
+  const Vector3 W(0, -w, 0), V(v, 0, 0);
+  const ExpmapScenario scenario(W, V);
+
+  const double T = 30;
+  EXPECT(assert_equal(W, scenario.omega_b(T), 1e-9));
+  EXPECT(assert_equal(V, scenario.velocity_b(T), 1e-9));
+  EXPECT(assert_equal(W.cross(V), scenario.acceleration_b(T), 1e-9));
 
   // R = v/w, so test if loop crests at 2*R
   const double R = v / w;
-  const Pose3 T30 = loop.pose(30);
+  const Pose3 T30 = scenario.pose(30);
   EXPECT(assert_equal(Vector3(-M_PI, 0, -M_PI), T30.rotation().xyz(), 1e-9));
   EXPECT(assert_equal(Point3(0, 0, 2 * R), T30.translation(), 1e-9));
 }
 
+/* ************************************************************************* */
+TEST(Scenario, Accelerating) {
+  // Set up body pointing towards y axis, and start at 10,20,0 with velocity
+  // going in X. The body itself has Z axis pointing down
+  const Rot3 nRb(Point3(0, 1, 0), Point3(1, 0, 0), Point3(0, 0, -1));
+  const Point3 P0(10, 20, 0);
+  const Vector3 V0(50, 0, 0);
+
+  const double a_b = 0.2;  // m/s^2
+  const AcceleratingScenario scenario(nRb, P0, V0, Vector3(a_b, 0, 0));
+
+  const double T = 3;
+  const Vector3 A = nRb * Vector3(a_b, 0, 0);
+  EXPECT(assert_equal(Vector3(0, 0, 0), scenario.omega_b(T), 1e-9));
+  EXPECT(assert_equal(Vector3(V0 + T * A), scenario.velocity_n(T), 1e-9));
+  EXPECT(assert_equal(A, scenario.acceleration_n(T), 1e-9));
+
+  const Pose3 T3 = scenario.pose(3);
+  EXPECT(assert_equal(nRb, T3.rotation(), 1e-9));
+  EXPECT(assert_equal(Point3(10 + T * 50, 20 + a_b * T * T / 2, 0),
+                      T3.translation(), 1e-9));
+}
+
 /* ************************************************************************* */
 int main() {
   TestResult tr;

gtsam/navigation/tests/testScenarioRunner.cpp

@@ -30,14 +30,13 @@ static const double kAccelerometerSigma = 0.1;
 /* ************************************************************************* */
 TEST(ScenarioRunner, Forward) {
   const double v = 2;  // m/s
-  Scenario forward(Vector3::Zero(), Vector3(v, 0, 0), kDeltaT, kGyroSigma,
+  ExpmapScenario scenario(Vector3::Zero(), Vector3(v, 0, 0));
-                   kAccelerometerSigma);
 
-  ScenarioRunner runner(forward);
+  ScenarioRunner runner(&scenario, kDeltaT, kGyroSigma, kAccelerometerSigma);
   const double T = 0.1;  // seconds
 
   ImuFactor::PreintegratedMeasurements pim = runner.integrate(T);
-  EXPECT(assert_equal(forward.pose(T), runner.predict(pim).pose, 1e-9));
+  EXPECT(assert_equal(scenario.pose(T), runner.predict(pim).pose, 1e-9));
 
   Matrix6 estimatedCov = runner.estimatePoseCovariance(T);
   EXPECT(assert_equal(estimatedCov, runner.poseCovariance(pim), 1e-5));
@@ -47,14 +46,13 @@ TEST(ScenarioRunner, Forward) {
 TEST(ScenarioRunner, Circle) {
   // Forward velocity 2m/s, angular velocity 6 kDegree/sec
   const double v = 2, w = 6 * kDegree;
-  Scenario circle(Vector3(0, 0, w), Vector3(v, 0, 0), kDeltaT, kGyroSigma,
+  ExpmapScenario scenario(Vector3(0, 0, w), Vector3(v, 0, 0));
-                  kAccelerometerSigma);
 
-  ScenarioRunner runner(circle);
+  ScenarioRunner runner(&scenario, kDeltaT, kGyroSigma, kAccelerometerSigma);
   const double T = 0.1;  // seconds
 
   ImuFactor::PreintegratedMeasurements pim = runner.integrate(T);
-  EXPECT(assert_equal(circle.pose(T), runner.predict(pim).pose, 0.1));
+  EXPECT(assert_equal(scenario.pose(T), runner.predict(pim).pose, 0.1));
 
   Matrix6 estimatedCov = runner.estimatePoseCovariance(T);
   EXPECT(assert_equal(estimatedCov, runner.poseCovariance(pim), 1e-5));
@@ -65,19 +63,39 @@ TEST(ScenarioRunner, Loop) {
   // Forward velocity 2m/s
   // Pitch up with angular velocity 6 kDegree/sec (negative in FLU)
   const double v = 2, w = 6 * kDegree;
-  Scenario loop(Vector3(0, -w, 0), Vector3(v, 0, 0), kDeltaT, kGyroSigma,
+  ExpmapScenario scenario(Vector3(0, -w, 0), Vector3(v, 0, 0));
-                kAccelerometerSigma);
 
-  ScenarioRunner runner(loop);
+  ScenarioRunner runner(&scenario, kDeltaT, kGyroSigma, kAccelerometerSigma);
   const double T = 0.1;  // seconds
 
   ImuFactor::PreintegratedMeasurements pim = runner.integrate(T);
-  EXPECT(assert_equal(loop.pose(T), runner.predict(pim).pose, 0.1));
+  EXPECT(assert_equal(scenario.pose(T), runner.predict(pim).pose, 0.1));
 
   Matrix6 estimatedCov = runner.estimatePoseCovariance(T);
   EXPECT(assert_equal(estimatedCov, runner.poseCovariance(pim), 1e-5));
 }
 
+/* ************************************************************************* */
+TEST(ScenarioRunner, Accelerating) {
+  // Set up body pointing towards y axis, and start at 10,20,0 with velocity
+  // going in X. The body itself has Z axis pointing down
+  const Rot3 nRb(Point3(0, 1, 0), Point3(1, 0, 0), Point3(0, 0, -1));
+  const Point3 P0(10, 20, 0);
+  const Vector3 V0(50, 0, 0);
+
+  const double a_b = 0.2;  // m/s^2
+  const AcceleratingScenario scenario(nRb, P0, V0, Vector3(a_b, 0, 0));
+
+  const double T = 3;  // seconds
+  ScenarioRunner runner(&scenario, T / 10, kGyroSigma, kAccelerometerSigma);
+
+  ImuFactor::PreintegratedMeasurements pim = runner.integrate(T);
+  EXPECT(assert_equal(scenario.pose(T), runner.predict(pim).pose, 1e-9));
+
+  Matrix6 estimatedCov = runner.estimatePoseCovariance(T);
+  EXPECT(assert_equal(estimatedCov, runner.poseCovariance(pim), 0.1));
+}
+
 /* ************************************************************************* */
 int main() {
   TestResult tr;