Global position system receiver with map coordinate system outputs

• US 5,422,814 A
• Filed: 10/25/1993
• Issued: 06/06/1995
• Est. Priority Date: 10/25/1993
• Status: Expired due to Fees

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Tiwari, Anil, Sprague, David S., Woo, Arthur
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/143,281
• Time in Patent Office: 589 Days
• Field of Search: 364/449, 364/444, 364/448, 364/460, 342/357, 342/451, 342/457, 340/995
• US Class Current: 701/213
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01S 19/13 Receivers

Abstract

An embodiment of the present invention comprises a GPS receiver including a conversion table memory index for storing latitude-longitude lookup conversions to standardized map coordinates and scale factors.

Claims

1. A global positioning system (GPS) receiver, comprising:

radio frequency (RF) stage connected to an antenna for receiving radio signals from orbiting navigation satellites and for amplifying and down converting said radio signals;

a navigation computer connected to the RF stage for providing a current position fix from range information in said radio signals;

a database of geographical map coordinates for a plurality of geographical region, area and detail map pages in a hard copy map atlas that relate to their respective page and grid identifications;

database map indexing means connected to the database and the navigation computer for converting a position fix obtained from the navigation computer into a map page and grid reference; and

output means connected to the database map indexing means for displaying said map page and grid reference.

2. The GPS receiver of claim 1, further comprising:

input means for accepting a plurality of waypoints and a designation of one of said waypoints as a goal from a user;

history means connected to the navigation computer for collecting a series of current position fixes from the navigation computer;

heading means connected to the history means for deriving a user course vector of a user from the history means;

target track means connected to the input means and the heading means for comparing the heading to said waypoint selected as a goal and said user course vector; and

display means connected to the target track means for indicating to a user with the output means a direction orientation to proceed on to said goal.

3. The GPS receiver of claim 1, further comprising:

input means for accepting a coordinate for a datum related to a particular hard copy map and for accepting a scale associated with said map from a user;

position differencing means connected to the input means and the navigation computer for subtracting said datum from said current position fix obtained by the navigation computer and finding a coordinate difference;

scale application means connected to the input means and position differencing means for converting said coordinate difference into a map "over and up" dimension using said scale input by the input means; and

display means connected to the scale application means and position differencing means for indicating to a user with the output means a measure on said map over and up from said datum that represents a user'"'"'s current position on said map,

4. A global positioning system (GPS) receiver, comprising:

a radio frequency (RF) stage connected to an antenna for receiving radio signals from orbiting navigation satellites and for amplifying and down converting said radio signals;

a navigation computer connected to the RF stage for providing a current position fix from range information in said radio signals;

inputs means for accepting a coordinate for a datum related to a particular hard copy map and for accepting a scale associated with said map from a user;

position differencing means connected to the input means and the navigation computer for subtracting said datum from said current position fix obtained by the navigation computer and finding a coordinate difference;

scale application means connected to the position differencing means for converting said coordinate difference into a map "over and up" dimension using said scale input by the input means; and

display means connected to the position differencing means and scale application means for indicating to said user a measure on said map over and up from said datum that represents a user'"'"'s current position on said map.

5. A global positioning system (GPS) receiver, comprising:

a radio frequency (RF) stage connected to an antenna for receiving radio signals from orbiting navigation satellites and for amplifying and down converting said radio signals;

a navigation computer connected to the RF stage for providing a current position fix from range information in said radio signals;

a database of map coordinates for a plurality of region, area and detail map pages in a hard copy map atlas that relate to their respective page and grid identifications;

database map indexing means connected to the database and the navigation computer for converting a position fix obtained from the navigation computer into a map page and grid reference;

output means connected to the database map indexing means for displaying said map page and grid reference;

first input means for accepting a plurality of waypoints and a designation of one of said waypoints as a goal;

history means connected to the navigation computer for collecting a series of current position fixes from the navigation computer;

heading means connected to the history means for deriving a course vector of a user from the position fixes;

target track means connected to the heading means and first input means for comparing the heading to said waypoint selected as a goal and said user course vector;

display means connected to the navigation computer for indicating to a user with the output means a direction orientation to proceed on to said goal;

second input means for accepting a coordinate for a datum related to a particular hard copy map and for accepting a scale associated with said map;

position differencing means connected to the navigation computer and the second input means for subtracting said datum from said current position fix obtained by the navigation computer and finding a coordinate difference;

scale application means connected to the position differencing means and the second input means for converting said coordinate difference into a map "over and up" dimension using said scale input by the input means; and

display means connected to the scale application means for indicating to a user a measure on said map over and up from said datum that represents a user'"'"'s current position on said map.

6. The GPS receiver of claim 5, wherein:

the navigation computer includes a microprocessor connected to a static random access memory (SRAM), a read only memory (ROM), a real time clock (RTC), a GPS digital signal processor and a computer-implemented program for the database of map coordinates, the database map indexing means, the history means, the heading means, the target track means, the position differencing means and the scale application means.

7. The GPS receiver of claim 6, further including:

an X-Y chart recorder connected to the navigation computer and providing for a hard copy printout of a path just traveled by said GPS receiver over a period of time.

8. A method of informing a user of the user'"'"'s position represented on a printed, published map where the scale of the map is known and a reference point on the map has its position identified, the method comprising the steps of:

requesting said user to input at a keyboard of a navigation satellite receiver a value representing said scale of the map, wherein said navigation satellite receiver comprises an antenna to receive radio signals from orbiting navigation satellites, a radio frequency stage to amplify and downconvert such radio signals and a navigation computer for estimating a position of said navigation satellite receiver, in terms of three-dimensional XYZ earth coordinates, from said radio signals;

storing said value representing said scale of the map in a random access memory as a map scale value;

requesting said user to input at said keyboard of said navigation satellite receiver a set of values representing said reference point on the map;

storing said values representing said reference point on the map in said random access memory as a reference point value;

determining in said navigation computer a current position estimate for said navigation satellite receiver in three-dimensional XYZ earth coordinates;

converting said current position estimate from said three-dimensional XYZ earth coordinates to a coordinate system, without an altitude value, to a set of values that corresponds to a coordinate system included in said set of values representing said reference point on the map;

subtracting said set of values representing said current position estimate from said set of values representing said reference point on the map;

multiplying said map scale value by a value representing a longitudinal difference obtained in the step of subtracting between said current position estimate and said reference point to obtain a horizontal ruler measure related to a point on said map from said reference point that corresponds to said current position estimate;

multiplying said map scale value by a value representing a latitudinal difference obtained in the step of subtracting between said current position estimate and said reference point to obtain a vertical ruler measure related to a point on said map from said reference point that corresponds to said current position estimate;

displaying said horizontal and vertical ruler measures to said user; and

manually plotting on said map said point that corresponds to said current position estimate with said horizontal and vertical ruler measures from said reference point.