US 6,779,752 B1 · Projectile guidance with accelerometers and a GPS receiver

Abstract

A projectile guidance system without gyros in which the projectile has an orthogonal body cordinate system. The projectile has a triax of accelerometers providing x, y and z acceleration data measured along the x, y and z axes respectively. A GPS antenna and receiver means provides onboard GPS position and velocity data in earth referenced navigational coordinates. A computer and program means stores and accesses time indexed GPS position and GPS velocity data and transforms x, y and z axis acceleration data from body to navigation coordinates. The program means is responsive to corresponding time indexed acceleration data and to GPS velocity and position data for calculating and outputing an estimated-projectile roll, pitch and yaw angle via optimal smoothing techniques with respect to local level for each time index iteration of present position to a flight control system for guiding the projectile to a predetermined location.

Claims36

Dependent claims

A projectile guidance system with accelerometers and a GPS receiver comprising:

a projectile having a triax of accelerometers mounted in the projectile and providing roll, pitch and azimuth axis acceleration data;
a GPS antenna and receiver means mounted in the projectile for providing and updating present position data;
and
a computer and memory mounted in the projectile and executing a guidance program;
wherein the guidance program is responsive to the roll, pitch and azimuth axis acceleration data and to the sampled present position data for calculating and outputing time indexed roll, pitch and azimuth angles, time indexed present position and velocity to a flight control system for guiding the projectile to a predetermined target location;
wherein the GPS antenna and receiver means comprises a GPS jamming detector configured to detect the presence of GPS jamming in the present position data;
and
wherein the GPS antenna and receiver means further comprises anti-jamming means.

5 more elements

A projectile guidance system without gyros comprising:

a projectile or vehicle in flight after launch, the projectile having an orthogonal body coordinate system with
a longitudinal or x-axis for roll measurement,
a y-axis for pitch measurement, and a
a z-axis for yaw measurement,
the projectile having at least a triax of accelerometers comprising an x accelerometer for providing x-axis acceleration data measured along the x-axis, a accelerometer for providing yaxis acceleration data measured along the y-axis and a z-accelerometer for providing z-axis acceleration data measured along the z-axis,
a GPS antenna and receiver means for providing onboard GPS position and GPS velocity data in earth referenced navigational coordinates,
a computer and memory and program means for storing and accessing time indexed GPS position and GPS velocity data and for transforming
the x, y and z axis acceleration data from body to navigation coordinates, the acceleration data being arrayed and having time indexes common with the OPS position and velocity data,
the program means being responsive to corresponding time indexed acceleration data and to GPS velocity and position data for calculating and outputing an estimated projectile roll, pitch and yaw angle with respect to local level for each time index iteration of present position, velocity and acceleration data to a flight control system for guiding the projectile to a predetermined target location;
wherein the GPS antenna and receiver means comprises a GPS jamming detector configured to detect the presence of GPS jamming in the present position data;
and
wherein the GPS antenna and receiver means further comprises anti-jamming means.

9 more elements

A process for the guidance of a vehicle or projectile, the vehicle having been launched and having an orthogonal coordinate system with a longitudinal or x-axis for roll measurement, a y-axis for pitch measurement, and a z-axis for yaw measurement, a triax of accelerometers outputing x, y and z axis acceleration, and a GPS antenna and receiver means for providing GPS position and GPS velocity data in earth referenced navigational coordinates, the process comprising the steps of:

receiving, indexing and storing GPS position and velocity data with concurrent x, y and z axis acceleration data;
calculate a trajectory for the set;
converting the x, y and z axis acceleration data to a local level navigational reference system;
solving a set of time indexed state equations to update the system's estimated state;
computing a time indexed pitch, roll and yaw angle in locally level coordinates;
outputing the time indexed pitch, roll and yaw angle in locally level coordinates with a corresponding time indexed present position;
guiding the projectile to a destination using the outputted time indexed pitch, roll, yaw angle and time indexed present position data;
the detecting presence of GPS jamming in the present position data;
and
counteracting the GPS jamming in the present position data.

7 more elements

Dependencies are inferred from the claim text.

Projectile guidance with accelerometers and a GPS receiver

Life of this patent

Projectile guidance with accelerometers and a GPS receiver

Life of this patent

Abstract

Claims36