Abstract: A method for establishing downlink telemetry communication to a downhole system involves placing into a drillstring a telemetry transcoder, and advancing the drillstring so the telemetry transcoder is below the surface. The method then transmits downlink EM telemetry signals from surface equipment. These signals are received at the telemetry transcoder which retransmits the signals as mud pulse signals. The mud pulse signals are received at the downhole system.

Abstract: A telemetry system useful in drilling operations receives and displays telemetry data. The telemetry system also determines and displays information regarding the status of the telemetry transmission. The telemetry system may display which data will be updated next, when the update is expected to be complete, and how reliable is the currently displayed data. The system can facilitate efficient drilling operations.

Abstract: A downhole system provides a data interface to a first downhole tool such as a steerable rotary tool. The data interface uses a close proximity data connection such as a connection between inductive loops or coils or a direct wired or optical connection. The interface provides data to a second downhole tool in a drill string section adjacent to the first downhole tool. In some embodiments data is passed to a third downhole tool that includes a telemetry transmitter. The third downhole tool may comprise a MWD (measurement while drilling) tool.

Abstract: A method for establishing downlink telemetry communication to a downhole system involves placing into a drillstring a telemetry transcoder, and advancing the drillstring so the telemetry transcoder is below the surface. The method then transmits downlink EM telemetry signals from surface equipment. These signals are received at the telemetry transcoder which retransmits the signals as mud pulse signals. The mud pulse signals are received at the downhole system.

Abstract: A downhole system provides a data interface to a first downhole tool such as a steerable rotary tool. The data interface uses a close proximity data connections such as a connection between inductive loops or coils or a direct wired or optical connection. The interface provides data to a second downhole tool in a drill string section adjacent to the first downhole tool. In some embodiments data is passed to a third downhole tool that includes a telemetry transmitter. The third downhole tool may comprise a MWD (measurement while drilling) tool.

Abstract: A telemetry system useful in drilling operations receives and displays telemetry data. The telemetry system also determines and displays information regarding the status of the telemetry transmission. The telemetry system may display which data will be updated next, when the update is expected to be complete, and how reliable is the currently displayed data. The system can facilitate efficient drilling operations.

Abstract: A two-way paging system includes one or more transmitters, a plurality of receivers, and at least one two-way personal paging unit or pager. The two-way pager receives pages from the transmitter, and sends response signals which are detected by the receivers. The response signals are in the form of digital packets, including forward error correction encoding and digital symbols that each consists of a predetermined number of bits. The receivers detecting the response signals decode the response packets to verify their accuracy and to identify the digital symbols. At the receivers, "accuracy indicators" can be associated with the detected symbols, providing an indication of the probability of accuracy. In one embodiment ("microdiversity receiver") two receiver components are provided at a single receiver site, with a separate antenna for each receiver component.

Abstract: A communications network for GPS systems is configured so that the service area (i.e., the geographical area to which GPS service is provided) is divided into relatively small sections. Each section has a unique code assigned to it. The satellites of the GPS system transmit the GPS "base data" in the standard manner, which is then processed by a conventional reference GPS network to determine the aiding data. The communications network receives the aiding data determines differential data corresponding to each section. The communications network includes communications base stations that are distributed through the service area, which broadcasts the aiding data and the differential data to the sections. Each communication base station also includes the code of the section in which it is located. Thus, a remote unit in a given section will generally receive transmissions with the code corresponding to the section in which the remote unit is located.

Abstract: A two-way paging system includes one or more transmitters, a plurality of receivers, and at least one two-way personal paging unit or pager. The two-way pager receives pages from the transmitter, and sends response signals which are detected by the receivers. The response signals are in the form of digital packets, including forward error correction encoding and digital symbols that each consists of a predetermined number of bits. The receivers detecting the response signals decode the response packets to verify their accuracy and to identify the digital symbols. At the receivers, "accuracy indicators" can be associated with the detected symbols, providing an indication of the probability of accuracy. In one embodiment ("microdiversity receiver") two receiver components are provided at a single receiver site, with a separate antenna for each receiver component.