Signal Strength

In order to calculate signature strengths, the first thing to determine is the Probe Sensor Strength.

Probe Sensor Strength

Probe Sensor Strength is determined by multiplying the probe's Base Sensor Strength with the Sensor Strength Multiplier.

Probe Base Sensor Strengths
Scan Probe Base Sensor Strength
Combat Scanner Probe I 20
Core Scanner Probe I 40
RSS Core Scanner Probe 45
Sisters Combat Scanner Probe 22
Sisters Core Scanner Probe 24
Sensor Strength Multipliers
Type Name (Max)Bonus Notes
Ship Racial Scanning Frigate 25.0% 5% per skill level
Covert Ops 50.0% 10% per skill level
Strategic Cruiser with Emergent Locus Analyzer 50.0% 10% per skill level
Skills Astrometrics 25.0% 5% per skill level
Astrometric Rangefinding 25.0% 5% per skill level
Probe Launcher T2 Launchers 5.0%
Sisters Launchers 10.0%
Rigs Gravity Capacitor Upgrade I 10.0%
Gravity Capacitor Upgrade II 15.0%
2 × Gravity Capacitor Upgrade I 21.0%
Implants 'Prospector' AR-802 2.0%
'Prospector' AR-806 6.0%
'Prospector' AR-810 10.0%
Faction implants Low-grade Virtue up to 33.83% varies per implant

So, a maximum skilled capsuleer with 'Prospector' AR-810 implant and a full Low-grade Virtue set plugged in, flying in a Covert-ops frigate which has been improved with 2 Gravity Capacitor Upgrade I rigs, using RSS Core Scanner Probes launched from a Sisters Core Probe Launcher has the maximum Probe Sensor Strength of 198.39

Signal Strength

Each cosmic signature has a Signature Strength. The maximum Signal Strength picked up by your scan probes is determinded by the formula (downloadable excel sheet):

Maximum Signal Strength = Base Signature Strength × Probe Sensor Strength × Probe Multiplier
where:
Signature Strength is site specific,
Probe Sensor Strength is described above,
Probe Multiplier is 0.257743125942 when using a single probe*).
For each step above the probes minimum radius (= maximum strength), the maximum Signal Strength is divided by 2

The actual, Reported Signal Strength is commonly lower than the maximum: the distance to the target will influence the results. With multiple probes, the angles between the probes to the target signature also have a major effect on the signature strength reported in the scan results.

The scan probe deviation mainly affects the reported location and distance to the target signature. It does not seem to affect reported signature strength.

*) The value can be calculated by the empircal probe multiplier formula:

Y = a / (b + (X + c)d) - offset

Where
Y is the probe multiplier
X is the number of probes
With constants
a = 2.27127967384994E-09
b = 1.12344005211905E-09
c = 13.4252377061721
d = -7.73088260552265
offset = 0.766607925235115