Portable terminal device

• US 20030083816A1
• Filed: 10/30/2002
• Published: 05/01/2003
• Est. Priority Date: 10/31/2001
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Umehara, Yoshiaki, Tsuji, Naoki, Nakahara, Fumiharu, Imakado, Yoshitaka
• Application Number:
  US10/283,344
• Publication Number:
  US 20030083816A1
• Time in Patent Office: Days
• US Class Current: 701/213
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/09 providing processing capability normally carried out by the receiver
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 2205/008 using a mobile telephone network

Abstract

A portable terminal device including GPS correctly detects a position thereof by preventing an error due to a state of an environment thereof. In a portable telephone including a GPS receiver capable of receiving a GPS signal according to GPS assist information sent from a reference GPS receiver server continuously receiving GPS signals from GPS satellites, a result of acquisition of each GPS signal received by the telephone using the GPS assist information and the like is evaluated to produce GPS information to be reported to the server.

Claims

1. A portable terminal device, comprising:

a first receiving section which receives elevation information regarding an elevation angle of a satellite viewed from a base station;

a second receiving section capable of receiving signals sent from a plurality of satellites;

a selecting section which selects, when the second receiving section receives signals sent from at least N satellites (N is an integer equal to or more than one), M signals (M is an integer equal to or more than one) from the N or more signals, the M signals having high values of the elevation information;

a first transmitting section which transmits the signals selected by the selecting section to the base station; and

a second transmitting section which transmits, when the second receiving section receives signals sent from at most (N−

1) satellites, the signals received by the second receiving section to the base station.

2. A portable terminal device according to claim 1, wherein when the second receiving section receives signals sent from at least N satellites, width or timing of a search window to receive signals sent from the satellites is changed according to the elevation information.

3. A portable terminal device according to claim 1, further comprising a setting section which sets a period of time required for the second receiving section to acquire a signal sent from a satellite, wherein

width of a search window is changed according to the period of time set by the setting section.

4. A portable terminal device according to claim 1, further comprising an input section which inputs information regarding a state of an environment of the portable terminal device.

5. A portable terminal device, comprising:

a receiving section capable of receiving signals sent from a plurality of satellites;

a selecting section which selects, when the receiving section receives signals sent from at least N satellites (N is an integer equal to or more than one), M signals (M is an integer equal to or more than one) from the N or more signals according to field intensity of the N or more signals;

a first transmitting section which transmits the signals selected by the selecting section to the base station; and

a second transmitting section which transmits, when the receiving section receives signals sent from at most (N−

1) satellites, the signals received by the receiving section to the base station.

6. A portable terminal device according to claim 5, wherein the receiving section comprises:

an antenna; and

a detecting section which detects a direction or a tilt of the antenna.