Abstract: An Adaptive Position Transmission Algorithm (APTA) for mobile radio device where position information is required, using any transmission medium such as high frequency (HF), very high frequency (VHF), ultra high frequency (UHF), Satellite Communications (SATCOM), etc. A mobile radio device employing the APTA provides accurate and automatic position reporting and thus, in a tactical environment improves situation awareness and reduces the probability of fratricide. A mobile radio device employing the APTA also reduces the number of options available to the user thereby simplifying the operation thereof while improving overall performance in most applications. The APTA accomplishes this by monitoring position, time and radio network parameters to determine when stand alone messages will be transmitted. The APTA factors radio network loading with movement and periodic thresholds.

Abstract: In a digital communications system for transmitting and receiving digital data over a CSMA-type network having a source for transmitting a source signal comprising a synchronization interval and a data interval and at least one receiver for receiving a second signal having a second synchronization interval and a second data interval corresponding to the data interval of the source signal, comprising: receiver means responsive to the source signal for synchronizing the source within the synchronization interval and providing a retransmit request signal indicative of the source signal; transmitter means responsive to the retransmit request signal for synchronizing at least one receiver within one CSMA time interval delay of the synchronization interval and for transmitting the second data interval to the at least one receiver within one CSMA time interval delay of the source data interval; and interface means for synchronizing the receiver means with the transmitter means to enable data transmission therebetwee

Abstract: The present invention is directed toward a navigation system and method for a high orbit spacecraft, which passively utilizes UHF signals carrying intersatellite ranging data transmitted by a constellation of satellites that travel in lower orbits around a celestial sphere. The navigation system enables the high orbit spacecraft to self locate its position relative to an earth centered coordinate frame and comprises a receiver for receiving the UHF signal, carrying the intersatellite ranging data and a Kalman or optimum filter coupled to the receiver for processing the ranging data received by the receiver and generating and updating spacecraft position data.