[Spaceships, Ultra-Tech] On-board Sensors

[Pectus Solentis]

In GURPS Spaceships 1 and 4, 0.5ton Enhanced Sensor Array (for SM+4 spacecrafts) costs $20K and it has 64x magnifications (Sensor Level 6) at TL11.

But in GURPS Ultra-Tech, Large Multi-mode Radar (p.UT65) costs $100K and weighs 100 lbs. And Hyperspectral Imaging Sensors Array (p.UT61) costs $160K, weighs 50 lbs and x128 magnifications at TL11.

Why are the Spaceship Sensor Array so cheap and low-performanced?

I guess Spaceship Sensor Arrays are more bulky than Ground-Vehicle Sensor Arrays so there may be no need for compactizations which increases its cost, but then why are the Spaceship Sensor low-performanced than Ground-Vehicle Sensor Arrays...? I think it makes no sense that 0.5tons of Spacecraft Sensor Arrays have low performance than much lighter Ground-Vehicle Sensor Arrays.

Below is my Planet Surface Exploration Robot. Its sheet is made from GURPS Spaceship's rules. Well, is it senseless that making Ground Robots' sheet with GURPS Spaceship's rule?

*SM +4, Loaded mass 10ton, TL11
*Front
**System 1 : Armor, Metallic Laminate, dDR 2.
**System 2 : Armor, Metallic Laminate, dDR 2.
**System 3 : Cargo Hold, 0.5ton
**System 4 : Cargo Hold, 0.5ton
**System 5 : Cargo Hold, 0.5ton
**System 6 : Cargo Hold, 0.5ton
**Core System : Control Room : C7 computers. Essentially operated with 1 pilot, but unmanned operation is posibble.
*Central
**System 1 : Armor, Metallic Laminate, dDR 2.
**System 2 : Armor, Metallic Laminate, dDR 2.
**System 3 ! Weapons, Major Battery, 1.5MJ Blasters Turret * 2 : 2 Blasters that each of it has 1.5MJ output, equipped on the shoulders of this robot. Used for demolition, but in emergency it can be used as weapons.
***It is my house-rule equipment, made from GURPS Ultra-Tech's descriptions and my imagination.
**System 4 : Enhanced Sensor Array
**System 5 : Robot Arms, dST 15
**System 6 : Robot Arms, dST 15
**Core System : Fusion Reactor (2!)
*Rear
**System 1 : Armor, Metallic Laminate, dDR 2.
**System 2 : Armor, Metallic Laminate, dDR 2.
**System 3 : Cargo Hold, 0.5ton
**System 4 : Cargo Hold, 0.5ton
**System 5 ! Robot Legs : 2 Robot Legs.
**System 6 : Robot Legs
**Core System : N/A
*Costs 0.945M$
*It has stealth and dynamic chameleon hull options
*Equipped emergency ejection system.