초록 ▼

A cellular network protocol which maintains the reliability of assisted GPS based positioning is taught. An Integrity Monitor (IM) informs mobile stations, their users, or networks of measurement quality and it warns them of failing and failed GPS satellites by isolating them from the effects of the

A cellular network protocol which maintains the reliability of assisted GPS based positioning is taught. An Integrity Monitor (IM) informs mobile stations, their users, or networks of measurement quality and it warns them of failing and failed GPS satellites by isolating them from the effects of these failures. Whenever an unhealthy satellite is detected, its corresponding assistance data will be excluded for delivery or for position determination. In other words, there are two specific aspects to the Integrity Monitor (IM). For DGPS users, it predicts the reliability or quality of the DGPS corrections. For all users, it isolats the mobile position calculation from the effects of GPS satellite failures. The UDRE parameter, nominally output by a reference DGPS receiver, is used to communicate the DGPS quality information, and DGPS corrections are simply excluded for failed satellites. For autonomous GPS users, a special integrity message is required and defined to communicate the satellite failure status information.

대표청구항 ▼

1. A method for maintaining the integrity of a mobile handset's location determination in a system comprising the mobile handset, radio communication infrastructure and a Differential Global Positioning System (DGPS) reference receiver coupled to the radio communication infrastructure and installed

1. A method for maintaining the integrity of a mobile handset's location determination in a system comprising the mobile handset, radio communication infrastructure and a Differential Global Positioning System (DGPS) reference receiver coupled to the radio communication infrastructure and installed at a predetermined location, the method comprising the steps of:said radio communication infrastructure receiving DGPS information from the DGPS reference receiver; deriving differential correction data from said DGPS information; determining whether said differential correction data will produce off-nominal errors in said mobile handset's location determination by calculating a location of the DGPS reference receiver based on said differential correction data and measurement data generated by the DGPS reference receiver; and transmitting a measurement quality indicator identifying off-nominal errors to said mobile handset when said determining step determines that said differential correction data will produce off-nominal errors in said mobile handset's location determination.