Motorola i860 Global Positioning System GPS Section, SIM Cards, Removing and Inserting a SIM Card

OVERVIEW: Global Positioning System (GPS) Section

1.3Global Positioning System (GPS) Section

The U.S. Department of Defense (DoD) has built a 24-satellite constellation for the purpose of pinpointing locations anywhere on the planet. The satellites circle the earth every 12 hours, transmitting radio signals at a fixed frequency of 1575.42 MHz. The satellites share the 1575.42 MHz spectrum with each other through the use of CDMA modulation.

To determine a location on earth, a receiver must be built that can receive the simultaneous signals from the satellites that are in view of the receiver and use that information to calculate the location of the receiver. The receiver must pick up the signals from 4 satellites. Once the 4 satellites are located, the receiver measures the time it took for the satellite signals to arrive. From this timing information, the distance between the receiver and each satellite can be calculated. The four satellites’ ephemeris data provide the satellite’s X, Y, and Z positions. The range, R, is the receiver measurement made by calculating the time it took for the signal to reach the receiver. The user’s position, (Ux, Uy, Uz), and the clock bias, Cb, is then calculated.

To use the GPS, a receiver that can receive the spread-spectrum signals must be built. The detected signals are then converted from RF signals into appropriate digital input formats. These digital inputs are processed and converted into position information. Once the position coordinates are determined, they are communicated to the handset microprocessor and displayed on the screen or transmitted to the base station as required.

1.4SIM Cards

This unit is designed to work with a mini Subscriber Identity Module (SIM). The SIM card contains all of the personal data required to access iDEN services. Data held by the SIM card includes:

•Temporary Mobile Subscriber Identity

•Services to which the user subscribes

•PIN and unblocking codes

•Call barring codes

The SIM card is also capable of storing phone numbers and names.

Available SIM cards for this unit are 64 kB and prepaid.

1.4.1Removing and Inserting a SIM Card

NOTE: When a SIM card is defective and must be replaced with a new one, the following information will be erased:

•The recent calls list

•Call forwarding settings

•Net alerts

•Mobile originated text messages, drafts, and quick notes

•Information stored in Memo

•3 most recent GPS enabled locations

•Voice records

•Voice names

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