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US 8,275,498 B2Granted
System and method for assessing the risk of conjunction of a rocket body with orbiting and non-orbiting platforms
AssigneeAnalytical Graphics, Inc.
InventorSalvatore Alfano
Life of this patent
Estimating the term…
Abstract
A system and method for assessing the risk of conjunction of a rocket body with orbiting and non-orbiting platforms. Two-body orbital dynamics are used to initially determine the kinematic access for a ballistic vehicle. The access may be represented in two ways: as a volume relative to its launcher and also as a geographical footprint relative to a target position that encompasses all possible launcher locations.
Claims20
A target access volume determination apparatus comprising:
- a rocket processing unit, wherein the rocket processing unit comprises a first processor and wherein the first processor is configured with software executable instructions to cause the rocket processing unit to perform operations comprising:
- receiving a latitude and an altitude of a launcher from which the rocket will be launched and a rocket velocity and a specified trajectory;
- receiving a target altitude (altsat) and a topocentric firing azimuth (AZtopocentric) from a set of desired target altitudes and topocentric firing azimuths;
- initializing the processor with values for a launcher firing angle relative to a horizon (φ), wherein φ is small and positive, an increment of φ (dφ), a range of the rocket (α) equal to zero, and an altitude at burnout (altbo) equal to the altitude of the rocket launcher (altlauncher);
- for each desired target altitude (altsat) and topocentric firing azimuth (AZtopocentric), determining:
- a magnitude of a rotating earth rocket velocity (Vsez);
- whether the rocket has sufficient energy to reach altsat and insufficient energy to achieve orbit;
- when the rocket has sufficient energy to reach altsat and insufficient energy to achieve orbit:
- determining a value of the rocket's angular range α and an eccentricity (ecc);
- determining the rocket's a, ecc, α, β, and TOF in an inertial frame, wherein a is the semi-major axis, β is a target's off-nadir angle to the rocket launcher, and TOF is a time of flight of the rocket from the rocket launcher to the target;
- determining when the current value of α is greater than a previous value of α;
- when the current α is less than or equal to the previous value of α, then setting αMAX equal to the previous value of α and aMAX, eccMAX, βMAX, and TOFMAX equal to the previous values of a, ecc, β, and TOF;
- and
- when the current α is greater than the previous value of α, then incrementing φ by dφ and determine a next value of α;
- and
- an access volume processing unit, wherein the access volume processing unit comprises a second processor and wherein the second processor is configured with software executable instructions to cause the access volume processing unit to perform operations comprising:
- for each desired target altitude (altsat) and topocentric firing azimuth (AZtopocentric):
- receiving αMAX aMAX, eccMAX, βMAX, and TOFMAX;
- determining a latitude of the satellite latsat and a longitudinal offset (ΔN) corresponding to αMAX aMAX, eccMAX, βMAX, and TOFMAX;
- identifying a point defined by altsat, latsat, and ΔN in an inertial frame relative to a launcher location;
- and
- defining a volume surface from the points determined for each altsat and AZtopocentric in the set of desired target altitudes and topocentric firing azimuths;
- and
- a display and alert processing unit, wherein display and alert processing unit comprises a third processor and wherein the third processor is configured with software executable instructions to cause the display and alert processing unit to perform operations comprising:
- receiving the volume surface from the access volume processing unit;
- generating a visual representation of a access volume;
- and
- sending the visual representation to a display device for display.
25 more elements
A method for determining the accessibility of a target to an earth-launched rocket for a specified trajectory comprising:
- receiving at a rocket processing unit a latitude and an altitude of a launcher from which the rocket will be launched and a velocity of the rocket, wherein the rocket processing unit comprises a first processor;
- receiving at the rocket processing unit a target altitude (altsat) and a topocentric firing azimuth (AZtopocentric) from a set of desired target altitudes and topocentric firing azimuths;
- initializing the first processor with values for a launcher firing angle relative to a horizon (φ), wherein φ is small and positive, an increment of φ (dφ), a range of the rocket (α) equal to zero, and an altitude at burnout (altbo) equal to the altitude of the rocket launcher (altlauncher);
- for each desired target altitude (altsat) and topocentric firing azimuth (AZtopocentric):
- using the first processor to determine a magnitude of a rotating earth rocket velocity (Vsez);
- and
- using the first processor to determine whether the rocket has sufficient energy to reach altsat and insufficient energy to achieve orbit;
- when the rocket has sufficient energy to reach altsat and insufficient energy to achieve orbit:
- using the first processor to determine a value of the rocket's angular range α and an eccentricity (ecc);
- using the first processor to determine the rocket's a, ecc, α, β, and TOF in an inertial frame, wherein a is the semi-major axis, β is a target's off-nadir angle to the rocket launcher, and TOF is a time of flight of the rocket from the rocket launcher to the target;
- and
- using the first processor to determine when the current value of α is greater than a previous value of α;
- when the current α is less than or equal to the previous value of α, then using the first processor for setting αMAX equal to the previous value of α and aMAX, eccMAX, βMAX, and TOFMAX equal to the previous values of a, ecc, β, and TOF;
- and
- when the current α is greater than the previous value of α, then using the first processor for incrementing φ by dφ and for determining a next value of α;
- and
- for each desired target altitude (altsat) and topocentric firing azimuth (AZtopocentric):
- receiving at an access volume processing unit αMAX aMAX, eccMAX, βMAX, and TOFMAX,
- wherein the access volume processing unit comprises a second processor;
- using the second processor to determine a latitude of the satellite latsat and a longitudinal offset (ΔN) corresponding to αMAX aMAX, eccMAX, βMAX, and TOFMAX;
- using the second processor to identify a point defined by altsat, latsat, and ΔN in an inertial frame relative to a launcher location;
- and
- using the second processor to define a volume surface from the points determined for each altsat and AZtopocentric;
- and
- receiving the volume surface from the access volume processing unit at a display and alert processing unit, wherein the display and alert processing unit comprises a third processor;
- using the third processor to generate a visual representation of a access volume;
- and
- using the third processor to send the visual representation to a display device for display.
25 more elements
A target access volume determination apparatus comprising:
- a rocket processing unit, wherein the rocket processing unit comprises a first processor and wherein the first processor is configured with software executable instructions to cause the rocket processing unit to perform operations comprising:
- receiving a set of desired arrival azimuths of a rocket γ, a muzzle velocity Vm of the rocket, an altitude of the rocket launcher (altlauncher) from which the rocket will be launched, a specific launch trajectory, and a target altitude altsat;
- initializing the first processor by setting a value for a rotating earth rocket velocity (Vsez) to Vm;
- for each desired arrival azimuth of a rocket γ at the target altitude altsat:
- (a) determining the rocket's a, ecc, α, β, and TOF in an inertial frame, wherein a is the semi-major axis, β is a target's off-nadir angle to the rocket launcher, and TOF is a time of flight of the rocket from the rocket launcher to the target;
- and
- (b) determining a current value of the rocket's angular range α;
- (c) when the current α is not equal to π or to 0, then determining a current value of the rotating earth rocket velocity (Vsez);
- and
- (d) determining when the current value of Vsez is approximately equal to a just previous value of Vsez;
- when the current value of Vsez is not approximately equal to a just previous value of Vsez, then initializing the first processor with the current Vsez and performing operations (a)-(d);
- and
- when the current value of Vsez is approximately equal to the just previous value of Vsez, then determining latlauncher and longitudinal offset (ΔN);
- and
- an access volume processing unit, wherein the access volume processing unit comprises a second processor and wherein the second processor is configured with software executable instructions to cause the access volume processing unit to perform operations comprising:
- receiving the latlauncher and longitudinal offset (ΔN), wherein latlauncher and longitudinal offset (ΔN) determine a point in an inertial frame relative to the target;
- and
- identifying a accessibility region constructed from points determined for the selected altsat over the set of desired arrival azimuths γ;
- and
- a display and alert processing unit, wherein display and alert processing unit comprises a third processor and wherein the third processor is configured with software executable instructions to cause the display and alert processing unit to perform operations comprising:
- receiving the region from the access accessibility processing unit;
- using the third processor to generate a visual representation of a accessibility region;
- and
- using the third processor to send the visual representation to a display device for display.
21 more elements
A method for determining the accessibility of a target to an earth-launched rocket comprising:
- receiving at a rocket processing unit a set of desired arrival azimuths of a rocket γ, a muzzle velocity Vm of the rocket, an altitude of the rocket launcher (altlauncher) from which the rocket will be launched, and a target altitude altsat, wherein the rocket processing unit comprises a first processor;
- initializing the first processor by setting a value for a rotating earth rocket velocity (Vsez) to Vm;
- for each desired arrival azimuth of a rocket γ at the target altitude altsat:
- (a) using the first processor to determine the rocket's a, ecc, α, β, and TOF in an inertial frame, wherein a is the semi-major axis, β is a target's off-nadir angle to the rocket launcher, and TOF is a time of flight of the rocket from the rocket launcher to the target;
- and
- (b) using the first processor to determine a current value of the rocket's angular range α;
- (c) when the current α is not equal to π or to 0, then using the first processor to determine a current value of the rotating earth rocket velocity (Vsez);
- and
- (d) using the first processor to determine when the current value of Vsez is approximately equal to a just previous value of Vsez;
- when the current value of Vsez is not approximately equal to a just previous value of Vsez, then initializing the first processor with the current Vsez and performing steps (a)-(d);
- when the current value of Vsez is approximately equal to the just previous value of Vsez, then using the first processor to determine latlauncher and longitudinal offset (ΔN);
- receiving at a accessibility processing unit the latlauncher and longitudinal offset (ΔN), wherein the access volume processing unit comprises a second processor and wherein latlauncher and longitudinal offset (ΔN) determine a point in an inertial frame relative to the target;
- using the second processor to identify a accessibility region constructed from points determined for the selected altsat over the set of desired arrival azimuths γ;
- receiving the region from the access accessibility processing unit at a display and alert processing unit, wherein the display and alert processing unit comprises a third processor;
- using the third processor to generate a visual representation of a accessibility region;
- and
- using the third processor to send the visual representation to a display device for display.
14 more elements
Dependencies are inferred from the claim text.