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.6. 1 . • 

FINAL REPORT - BIT MISSION 7051 

1. MISSION SUMMARY. 

1.1 1.6.), 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 signalliMacquires and tracks the Agena 

vehicle. The BIT system, designed to fulfill this objective, covers 

the frequency range from 150 to 164 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 .1`S.),... Mission Highlights. 

During the mission life of 112 orbits, the BIT system intercepted 

one signal which passed the system's qualification requirements but 

which is not the signal of interest, :i,ii'i,' The signal, intercepted 

.123°E), is identified as 

for six seconds while the vehicle was over Shenyang, China (42. 2°N, a ma which is deployed in China. It is 

concluded that the mitter did not detect or track the Agena 

vehicle during the intercept. Although the system functioned properly 

throughout the duration of the mission, the signal intercepted 

on orbit 77 was the only signal of interest intercepted during the operation. 

1. 3 "(.€4.,.. Flight Summary. 

Vehicle Number 1170 

Launch Date 5 October 1964 

Launch Time 2150 GMT 

Inclination 80 degrees 

Apogee 240 nautical miles 

Perigee 99 nautical miles 

Period 90. 7 minutes 

This Document Consists of „7 _Pages. 

ropy of 7 Copies, Series - EDL 

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2. t.S4 DATA ANALYSIS. 

2. 1 1Sk System Coverage. 

The BIT system was programmed on during every orbit 

throughout the mission life while the vehicle was over the northern 

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

and Asia. On seven occasions, the unit was on throughout the entire 

orbit to make periodic checks in the southern hemisphere. 

The system monitors the 150- to 164-Mc frequency range with 

a receiver sensitivity of -54 dbm. With the inclusion of the antenna 

pattern, the over-all system sensitivity varies from approximately 

-44 dbm at the horizon to -52 dbm looking straight down. Signals 

intercepted by the system are rejected by qualification circuitry if 

the pulse widths are less than approximately 18 microseconds and 

if the PRFs do not fall within the 95- to 101-pps PRI' 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 -28 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 I.S•)■ Mission Results. 

2. 2. 1 t'S)... Qualified Intercept. 

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2. 2. 1 Continued. 

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2. 2. 1 ts,) -- Continued. 

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2. 2. 2 T3.).%-- Continued. 

3. N.) SYSTEM PERFORMANCE EVALUATION. 

3.1 IS.) 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 -54 dbm is amplitude 

standardized in the video threshold circuit and then qualified. If 

the pulse width is greater than 18 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. 

If the PRF qualifies, a pulse-by-pulse gate pulse 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 -30 dbm at the receiver, 

the signal amplitude will be read in the Detector A channel without 

qualification. A Time Reference Generator provides a parallel 

orbital 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 -35 dbm which is used to test the entire system for 

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

system. 

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3. 1 "N.— Continued. 

A summary of, the system s--, Ifications for the BIT system 

used in this mission is given bey. ,Lnd a plot of the system's detection 

sensitivity is shown in Figure 

Minimum -DetectableSignal 

PRC Minimum Acceptable 

Pulse Width 

Frequency/Amplitude PLD 

Minimum Pulse Width 

PRF Qualifier Acceptance Range 

RF Passband at -51 dbm 

-54 dbm (PLD-B) 

-28 dbm (PLD-A) 

18 microseconds 

24 n:.icroseconds 

95-101 pps (fundamental) 

193-202 pps (2nd harmonic) 

150. 2 to 164. 3 Mc 

3. 2 IS.)„.. System Performance. 

The BIT system performed as designed for the duration 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 and 

PRF maintained their original levels. The system's operating 

temperature was 110 degrees Fahrenheit initially and gradually. 

cooled to 80 degrees Fahrenheit on orbit 16 and to 66 degrees Fahrenheit 

during the final day of the mission. 

The only problem noted was a fluctuating level of the frequency 

measuring Peak Level Detector (PLD-C) during the signal simulator 

calibration checks. During a four-second check, the PLD would show 

the correct Simulator frequency with the exception that two to four of 

the twenty commutator samples would show a lower frequency (higher 

peak voltage). This condition was not noted during the prelaunch 

check and it did not occur on every Simulator check. It may have been 

due to occasional pulses from the external signal environment getting 

into the frequency channel during the 700-microsecond acceptance 

gate which is generated for each of the 98 pps of the simulated signal. 

4. 1S‹ COMMENTS AND RECOMMENDATIONS. 

4. 1 Data Analysis. 

The data for this mission were received at a relatively slow 

rate from the processing group at Lockheed. The initial data indicating 

that the system was working was received one day after launch but 

the receipt of the remainder of the data was sporadic. Approximately 

seventy per cent of the data were received by 22 October. The remainder, 

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4. 1 •S.) - Continued. 

with the exception of two orbits, was received by 29 October and the 

last two orbits were received on 3 November. Part of the problem 

was in setting up the procedures for the generation and flow of the 

data for this new program and a second cause of delay was some higher 

priority, interfering work which had to be performed by the data 

processing group. It is expected that the data flow will be more rapid 

and timely on following missions. 

Additional information which will be required on a more timely 

basis is a post launch ephemeris and a post launch tabulation of the 

actual event times of the vehicle programmer. Fortunately, the orbit 

of this vehicle followed the predicted orbit very closely and the 

prelaunch information was sufficient for determining event times and 

vehicle locations. This, however, may not be the case in later missions. 

4. 2 `fg.). System Modifications. 

The data from this mission demonstrated the need for an activity 

indicator in the system which would show that signals of any type are 

being received by BIT. The Signal Simulator shows that the system 

is working and it provides a one-point calibration check but it does 

not provide a check of the antenna or antenna lead in. Because of the 

system's qualification circuitry, intercepts are relatively scarce 

and in order to determine that a lack of intercepts is due to the lack 

of qualifying signals rather than to a damaged antenna or broken 

lead-in line, an activity indicator is needed. All units for the following 

missions will be equipped with a crude pulse rate counter which will 

respond to received pulses of any width or rate to show that the antenna 

input is good. 

As an aid to data analysis, the 256-second step output of the 

Time Reference Generator will be connected directly to the commutator 

so that it will appear on the stored data as well as on the real time 

data. This will enable determining the actual time an event occurred 

without having to rely on the post launch tabulation of event times for 

the vehicle programmer. 

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