Satellite and space communications systems

A system for communicating intelligence between the earth and a space station having an antenna which may at times have a null orientation with respect to radio waves received from any one station on earth, the combination comprising:

• at least two stations on earth each comprising transmitting and receiving means and being sufficiently widely spaced that said antenna can have at most a null orientation with respect to radio waves originating with one of said stations but still permitting line-of-sight communication between each said earth station and said space station, means at each earth station for modulating a carrier frequency wave transmitted from that station according to the intelligence to be transmitted to said space station, means at said space station including demodulator means responsive only to the strongest of the carrier waves energizing said antenna, modulator means at said space station for modulating a carrier wave according to the intelligence to be transmitted to earth and energizing said antenna with the resulting modulating carrier wave to radiate said wave toward said earth stations, said receiving means including a receiving antenna at each earth station, and means connected electrically to each said receiving means at the respective stations and being responsive to the intelligence transmitted by said space station and being received by the associated receiving means.

Means for communicating between two bodies in space having a substantial radial velocity component therebetween resulting in a substantial frequency shift in a a received radio wave as compared to the frequency of the transmitted wave and comprising, receiving and transmitting means at both said bodies with both transmitting means transmitting normally on respectively different nominal frequencies, first means at one of said bodies producing a first signal having a value representative of the frequency transmitted from the other of said bodies, means at said one body coupled to said receiving means responsive to said first signal for producing an output having at least one characteristic thereof which is proportional to the Doppler difference in frequency between the signal received at said one body from the other said body and the signal transmitted from said other body, second means at said one body producing a second signal having a value representative of the pass-band of frequencies of the receiving means for the other of said bodies, frequency-control means at said one body responsive to said output and to said second signal for controlling the frequency of the signal transmitted by said transmitting means from said one body to differ from its said nominal frequency by an amount substantially proportional to the amount of said Doppler frequency difference, said frequency control means shifting the frequency transmitted from said one body in a direction opposite to the direction of the frequency shift in the signal received from the other body, said receiving means on said other body being responsive only within a pass-band that encompasses said nominal frequency of said transmitting means at said one body.

Means for communicating between two stations in space having a substantial radial velocity component therebetween such that a radio wave transmitted from one station is received with a substantial Doppler frequency shift at the other of said stations, the combination comprising:

• first transmitting means of one of said stations for transmitting a carrier wave on a fixed predetermined frequency, first receiving means at said one station for receiving carrier waves occurring within a predetermined pass-band, second receiving means at the other of said stations receiving the carrier frequency wave transmitted from said one station, first means at said other station generating a signal representative of said fixed predetermined frequency, control means coupled to said second receiving means and responsive to said signal and being distinctively controlled according to the frequency difference between the carrier wave received from said one station and the predetermined frequency transmitted from said one station, variable frequency transmitting means at said other station operating at a frequency range other than said fixed predetermined frequency, said control means and said second means jointly varying the frequency of the carrier wave transmitted by said variable frequency transmitting means by an amount proportional to the frequency shift of the carrier wave received from said one station to thereby cause said carrier wave transmitted by said variable frequency transmitting means to be received by said first receiving means within said pass-band.

The method of communicating the same signal intelligence from each of at least two transmitting stations on one body in space to a receiving station on a second body in space comprising the steps of:

• transmitting carrier waves from both of said two stations to said second body in space;
• modulating each of said carrier waves with the signal intelligence to be transmitted to said receiving station on said second body in space;
• measuring the difference in distance between each respective one of said transmitting stations on said first body in space to said receiving station on said second body in space;
• and delaying the modulating signal intelligence to that transmitting station which is nearer said body in space relative to the same modulating signal intelligence for the other of said transmitting stations and by an amount substantially equal to the transmission time of said carrier wave in space over the distance measured in the immediately preceding step;
• whereby said signal intelligence is received at said receiving station in substantial phase coincidence for both of said transmitting stations.

A system for communicating electromagnetic intelligence signals between bodies in space, said signals while being radiated between said bodies in space being subject to space propagation phenomena including spin fading, amplitude scintillation, frequency scintillation, polarization fading, signal reflection, signal ducting, and signal black-out, said system comprising,

• means on said one body including a first directive antenna means transmitting a first signal in a highly directive beam toward the other said body in space,
• means on said one body including a second directive antenna means for directionally receiving a second signal from said other body in space,
• signal direction finding means on said one body responsive to a signal from said other body which is subject to said space propagation phenomena substantially the same as said first transmitted signal and also substantially the same as said second received signal for continually controlling the direction of transmission of said first directive antenna means in both azimuth and elevation to maximize the intensity of signal reception of said first signal at said other body and for also continually controlling the direction of reception of said second directive antenna means in both azimuth and elevation to maximize the intensity of reception of said second signal received from said other body,
• said direction finding means including at least one antenna means having a single axis of directivity and means responsive to coincidence of said axis with the direction of signal reception from said other body for controlling said direction of transmission of said first directive antenna means and also the direction of reception of said second antenna means.