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FINAL REPORT 

BIT MISSION 7054 . 

5 FEBRUARY 1965 
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File No. H-1173 Page 1 

FINAL REPC 

BIT MISSION 4 

1.'13.4 MISSION SUMMARY. 

1.1 SL Program Objectives. 

As part of the over-all problem of determining the vulnerability 

of the Agena satellites to Soviet radar detection and tracking, 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 Mission Highlights. 

No signals of interest were intercepted during the effective 

mission life which started with orbit 1 and lasted until orbit 206. 

Datawere not recorded from orbit 89 through orbit 137 because the 

vehicle was temporarily deactivated during this period. Data were 

not recovered from orbits 33 and 142 due to tracking station problems. 

The Signal Simulator and Activity Indicator in the BIT showed that the 

system was functioning properly during the entire mission for which 

data were available. 

1 3 .".(S.),, Flight Summary. 

Vehicle Number 1607 

Launch Date 19 December 1964 

Launch Time 2117 GMT 

Inclination 75 degrees • 

Apogee 234.4 nautical miles 

Perigee 98.4 nautical miles 

Period 90.5 minutes 

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DATA ANALYSIS. 

System Coverage. 

The BIT system was programmed on during 160 orbits of the 

206-orbit mission life while the vehicle was over the northern hemisphere 

with an emphasis on the coverage over Europe, the USSR and Asia. 

On 21 occasions, the unit was on throughout the period while the vehicle 

was over the southern hemisphere. 

The system monitors the 153- to 163-Mc frequency range with 

a receiver sensitivity of -53 dbm. With the inclusion of the antenna 

pattern, the over-all system sensitivity varies from approximately 

-43 dbm at the horizon to -51 dbm looking straight down. Signals 

intercepted by the system are rejected by qualification circuitry if 

the pulse widths are less than 14 microseconds and if the PRFs do 

not fall within the 95- to 101-pps PRF acceptance band or harmonics 

of this band. The system measures amplitude, frequency, and PRF 

on those signals which qualify. If a signal has a power level at the 

receiver of -26 dbm or greater, it will also be fed into a high level 

channel which requires no qualification other than amplitude and 

which measures only the signal amplitude. 

2. 2 Mission Results. 

2.2. 1 Is< Qualified Intercepts. 

2. 2. 2 Nonqualified Intercepts. 

2. 

2. 1 

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2.2.2 N'•) -- Continued. 

3. SYSTEM PERFORMANCE EVALUATION. 

3.1 System Description. . 

A block diagram of the BIT system is shown in Figure 1 although. 

it is labeled by its in-house name of FIRE BOX. It is basically a TRF 

(tuned radio frequency) receiver with video logic for signal recognition 

and circuits for parameter measurement. An intercepted signal which 

exceeds the Detector B threshold of -53 dbm is amplitude standardized 

in the video threshold circuit and then qualified. If the pulse width 

is greater than 14 microseconds, the signal will be passed to the Pulse 

Rate Counter (PRC) and the PRF Qualifier. The PRC counts the total 

number of pulses received during one commutator read-in cycle (400 

milliseconds) and the PRF Qualifier examines the pulse train for a 

PRF of 95 to 101 pps or harmonics of this PRF range. It the PRF 

qualifies, a pulse-by-pulse gate is generated which opens the two gates 

to permit the Peak Level Detectors (PLD) to read amplitude and frequency. 

The PLD's store the lowest frequency and the highest pulse amplitude 

intercepted during the 400-millisecond read-in period. If the signal 

level exceeds -26 dbm at the receiver, the signal amplitude will be 

read in the Detector A channel without qualification. A Time Reference 

Generator provides a parallel octal time code reference for the system. 

It is also used to trigger the Signal Simulator on for four seconds every 

256 seconds. The Simulator generates a 98-pps signal at a frequency 

of 160 Mc and a power level of -28 dbm which is used to list the system 

for proper operation plus providing a one-point calibration check of 

the system. 

A Signal Activity Indicator, designated as PRC-B, has been 

added to the system to provide a check on the operational status of 

the antenna and the RF input line. The circuit, which is connected 

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3.1 1`6.).... -- Continued. 

to the output of the Video Threshold circuit, counts every pulse received 

regardless of pulse width or PRF. Since it is primarily intended to 

indicate the presence of activity and it is an "add on" modification, no 

attempt was made to achieve accurate pulse count measurements. 

A summary of the system specifications for the BIT system 

used in this mission is given below. 

Minimum Detectable Signal 

PRC Minimum Acceptable 

Pulse Width 

Frequency/Amplitude PLD 

Minimum Pulse Width 

-53 dbm (PLD-B) 

-26 dbm (PLD-A) 

14 microseconds 

23 microseconds 

PRF Qualifier Acceptance Range 95-101 pps (Fundamental) 

191-201 pps (2nd Harmonic) 

RF Passband at -50 dbm 152.9 to 163.3 Mc 

3.2%*1`54...., SystemPerformance, 

The BIT system performed as designed for the duration of the 

useful life of the mission. Comparison of the system's response to 

the Signal Simulator during the mission with its response prior to 

launch showed that the detection sensitivity and the calibrations for 

frequency, amplitude, and PRF maintained their original levels. The 

system's operating temperature was 59 degrees Fahrenheit during 

the mission. No malfunctions were noted. 

SPEC:V. L 7.;LAN.DLING