Fixed range indicating system for use in a vehicle travel path indicating apparatus

• US 4,663,629 A
• Filed: 06/18/1984
• Issued: 05/05/1987
• Est. Priority Date: 10/27/1980
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Yasui, Shinichiro, Sugimura, Masao, Takahashi, Tsuneo, Tagami, Katsutoshi
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/621,481
• Time in Patent Office: 1,051 Days
• Field of Search: 340/988, 340/989, 340/990, 340/992, 340/993, 340/994, 340/995, 364/424, 364/434, 364/449
• US Class Current: 340/995.28
• CPC Class Codes: G01C 21/367 Details, e.g. road map scale, orientation, zooming, illumination, level of detail, scrolling of road map or positioning of current position marker

Abstract

A fixed range indicating system is provided for the vehicle travel path indicating apparatus. The vehicle travel path indicating apparatus includes a locational data source having a pulse generator and producing vehicle locational data, memories for successively storing the vehicle locational data, a data reader for reading the travel path data from the memories, and a display unit for displaying a travel path of the vehicle on a display screen based on the travel path data read out by the data reader. The fixed range indicating system in such apparatus comprises a pulse counter for counting the pulses from the pulse generator, a data extractor for extracting a fraction of the locational data each time the travel distance is increased by a predetermined distance and for delivering the extracted data fraction as stored locational data to the memories to form stored travel path data, and a data restoring circuit for preparing restored travel path data based on the stored travel path data read out by the data reader from the memories and the locational data issued from the locational data source, the display means displaying the travel path of the vehicle on the display screen based on the restored travel path data.

Claims

1. In a vehicle travel path indicating apparatus, including:

a locational data source which comprises a pulse generator for generating a pulse each time the travel distance of the vehicle is increased by a predetermined first distance, an azimuth sensor for generating an azimuth signal corresponding to the heading of the vehicle, and computing means for computing changes in the location of the vehicle as two-dimensional coordinates from said first distance and said azimuth signal each time said pulse is received and for accumulating the location changes to produce vehicle locational data which is updated each time said pulse is received;

memory means for successively storing the vehicle locational data issued from said locational data source to form a travel path data;

reader means for reading said travel path data from said memory means; and

display means for displaying a travel path of the vehicle on a display screen based on said travel path data read out by said reader means,

a fixed range indicating system comprising;

(a) a pulse counter for counting the pulses from said pulse generator;

(b) data extracting means for extracting a portion of said locational data from said locational data source each time said travel distance is increased by a predetermined second distance and for delivering the extracted data portion to said memory to form stored travel path data, said second distance being greater than said first distance;

(c) data restoring means for preparing restored travel path data based on said stored travel path data read out by said reader means from said memory means and said locational data issued from said locational data source; and

(d) said display means displaying the travel path of the vehicle on the display screen based on said restored travel path data.

2. A fixed range indicating system according to claim 1, further including a scale selector for generating a selected-scale signal indicative of a display scale selected among a plurality of predetermined display scales, wherein:

said memory means comprises a plurality of memory banks respectively for said plurality of predetermined display scales;

said second distance is predetermined according to each of said display scales; and

said reader means is responsive to said selected-scale signal for starting to read out said stored travel path data for said selected display scale from one of said memory banks corresponding to said selected display scale each time the travel distance of the vehicle is increased by a fixed distance and delivering said stored travel path data to said data restoring means, said fixed distance being greater than said second distance.

3. A fixed range indicating system according to claim 2, wherein:

said data restoring means comprises a first subtractor for sequentially determining and delivering differences between two successive said stored locational data, an accumulator for accumulating said locational data differences and delivering a cumulative value each time one data difference is delivered so as to issue a sequence of cumulative values, and a second subtractor for sequentially determining differences between said locational data delivered from said locational data source and each one of said sequential cumulative values.