Method for determining astronomic azimuth
First Claim
Patent Images
1. A method for determining astronomic azimuth between a fixed site and a target comprising the steps of:
- (a) determining geodetic azimuth, α
, from the fixed site where geodetic azimuth is defined as the angle from true north (mean polar axis of the earth) to the target in a plane normal to an ellipsoidal model of the gravity vector;
(b) determining at the fixed site a gravity deflection of the vertical, comprising η
the east component and ξ
the north component which when combined is the angular difference between an actual gravity vector direction and the ellipsoidal model gravity vector direction; and
(c) calculating astronomic azimuth, A, defined as the angle from true north to the target in a plane normal to the actual gravity vector, from geodetic azimuth using relationships derived from gravity vertical deflections;
Aα
+η
tan φ
+(ξ
sin α
-η
cos α
) cot z where φ
=geodetic latitude at the fixed site z=geodetic zenith distance (generally, z ≈
90° and
cot z ≈
0)
1 Assignment
0 Petitions
Accused Products
Abstract
An improved method for fixing position of a land-based target site with respect to a reference site in the natural coordinate frame comprising the steps of determining geodetic azimuth between the target site and the reference target using Global Positioning System (GPS) satellites and relative positioning survey techniques; then calculating a relationship using gravity vertical deflections; and then coverting the geodetic azimuth to astronomic azimuth. This method has several advantages over conventional methods of targeting, including speed, the ability to work in all weather conditions, and improved accuracy.
-
Citations
7 Claims
-
1. A method for determining astronomic azimuth between a fixed site and a target comprising the steps of:
-
(a) determining geodetic azimuth, α
, from the fixed site where geodetic azimuth is defined as the angle from true north (mean polar axis of the earth) to the target in a plane normal to an ellipsoidal model of the gravity vector;(b) determining at the fixed site a gravity deflection of the vertical, comprising η
the east component and ξ
the north component which when combined is the angular difference between an actual gravity vector direction and the ellipsoidal model gravity vector direction; and(c) calculating astronomic azimuth, A, defined as the angle from true north to the target in a plane normal to the actual gravity vector, from geodetic azimuth using relationships derived from gravity vertical deflections;
Aα
+η
tan φ
+(ξ
sin α
-η
cos α
) cot z where φ
=geodetic latitude at the fixed site z=geodetic zenith distance (generally, z ≈
90° and
cot z ≈
0) - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
Specification
-
- Resources
Litigation Campaign Assessment
Thank you for your request. You will receive a custom alert email when the Litigation Campaign Assessment is available.
×
-
Current Assigneethe united states of america as represented by the secretary of the navy
-
Original Assigneethe united states of america as represented by the secretary of the navy
-
InventorsStein, William L., Evans, Alan G.
-
Primary Examiner(s)Lobo, Ian J.
-
Application NumberUS07/376,278Time in Patent Office426 DaysField of Search342/356, 342/357, 342/352, 364/455, 364/459, 33/268US Class Current342/357.36CPC Class CodesG01S 19/54 using carrier phase measure...
