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FINAL REPORT 

BIT MISSION 7058 

1 June 1965 
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FINAL REPORT 

BIT MISSION 7058 

1. MISSION SUMMARY. 

1. 1 N1f■ Program Objectives. 

The objective of the BIT program is to determine if and when 

the radar system associated with the signal acquires and tracks 

the Agena vehicle. The BIT system, designed to fulfill this objective, 

covers the frequency range from 153 to 163 Mc and accepts only those 

signals which have characteristics similar to On those signals 

which qualify, the system will measure frequency, PRF, and signal 

amplitude along with the time of intercept to enable an analyst to identify 

the signal characteristics and to estimate a geographical area within 

which the emitter is located. 

1. 2 ""tEp.). Mission Highlights. 

There were no intercepts made of the signal during this 

mission which was prematurely terminated by a commutator failure 

after orbit 100. The BIT system functioned properly during the useful 

life of the mission which covered the period from approximately 2200Z 

on 29 April to 0600Z on 6 May 1965. 

An unidentified signal was intercepted on 5 May 1965 at 2320Z 

(orbit 96) while the vehicle passed over the Arctic Ocean northwest of 

Alaska. From the characteristics of this intercept, it is concluded 

that the emitter neither detected nor tracked the Agena vehicle. 

1. 3 Flight Summary. 

Vehicle Number 1614 

Launch Time 2140Z 

Launch Date 29 April 1965 

Inclination 85 degrees 

Apogee 264 nautical miles 

Perigee 100 nautical miles 

Period 91 minutes 

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2. MISSION COVERAGE. 

2. 1 **(46).....„Operational Coverage. 

The BIT system was programm ed on during each of the 100 

orbits of the useful mission life while the vehicle was over the northern 

hemisphere with an emphasis on the coverage over Europe, the USSR, 

and Asia. On 15 of the orbits the unit was programmed on throughout 

the period while the vehicle was over the southern hemisphere. Data 

were received from all of the.orbits which were programmed for operation. 

2. System Coverage. 

The BIT system shown in Figure 1, monitors the 154 to 162 Mc 

frequency range with a receiver sensitivity of -55 dbm. With the 

inclusion of the effects of the antenna pattern with different polarizations 

and aspect angles, the over-all detection sensitivity of the system 

ranges from -58 dbm to -46 dbm. Signals intercepted by the receiver 

are checked by a pulse width qualifier to determine if the pulse width is 

greater than -25 microseconds. The pulses which qualify are counted 

in a total pulse counter, PRC, over the commutator read-in interval 

of 400 milliseconds and are measured to determine their amplitude and 

RF frequency. On previous systems, the amplitude and frequency 

measurements also required PRF qualification but on this unit and 

succeeding units the PRF Qualifier is bypassed. The PRF Qualifier is, 

however, still used to accurately check the PRF to determine if it 

falls within the 94 to 100 pps acceptance band or harmonics of this 

range. If a signal has a power level at the receiver in excess of -30 dbm,, 

its amplitude will be measured in the PLD-A channel regardless of PRF 

or pulse width. The RF frequency of the high amplitude pulses will 

not be read unless the signal also satisfies the pulse width criterion. 

3. MISSION RESULTS. 

3. 1 PRF Qualified Intercepts. 

3. 2 Non Qualified Intercepts. 

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3. 2 -- Continued. 

4. SYSTEM PERFORMANCE. 

4, 1 System Specifications. 

A summary of the system specifications for the BIT system used 

on this mission is given below. A block diagram of the system is shown 

in Figure 1. 

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4. 1 '(*S.1,.. -- Continued. 

Minimum Detectable Signal -55 dbm PLD-B 

-30 dbm PLD-A 

Minimum Acceptable Pulse Width 25 microseconds 

PRF Qualifier Range 94-100 pps 

188-201 pps (2nd Harmonic) 

RF Passband 

-52 dbm 153. 8 to 162.1 Mc 

-25 dbm 147.3 to 169.8 Mc 

4. 2 'Sk System Operation. 

The BIT system functioned normally throughout the useful 

mission life which ended after orbit 100 when the commutator failed. 

The scheduled mission life was 200 orbits. The system response to the 

Signal Simulator indicated the qualification circuitry operated properly 

and that the measurement circuitry maintained their original calibration 

levels. 

The BIT unit used on this mission had to be rewired so that 

the commutator would run, continuously rather than be programmed on 

and off with the system. This failure indicates that the wiring modification 

is not the complete solution to the commutator reliability problem. During 

the last few orbits, the speed of the commutator was varying over about a 

25 per cent range. Sometime after read in on orbit 100 and read out on 

orbit 101, the device slowed to a complete stop. This was a failure 

mode different from those noted previously. 

This system, along with three of the remaining four units, was 

modified so that PRF Qualification was not required to get low range 

amplitude (Channel B) and frequency measurements. The pulses which 

pass the Pulse Width Qualifier are used 'to generate the enable gates 

to permit measuring the amplitude and frequency on a pulse-by-pulse 

basis. The PRF Qualifier is still used to indicate when a PRF falls 

within the 94 to 100 pps range but it no longer has a gate control function.