LDR20K1 vs LDR25K1: Which 3km Module Fits?
These two modules sit in the same range class but are built for different integration constraints. Choosing between them is not a matter of picking the higher number.
Specification comparison
| Parameter | LDR20K1 | LDR25K1 |
|---|---|---|
| Pulse energy | ≥ 20 mJ | ≥ 25 mJ |
| Beam divergence | ≤ 0.6 mrad | not published |
| Ranging accuracy | ±1 m | ±2 m |
| Mass | ≤ 290 g | ≤ 380 g |
| Envelope | ≤ 92 × 67 × 53 mm | 68 × 52 × 90 mm |
| Wavelength | 1064 nm | 1064 nm |
Both are 1064 nm diode-pumped modules with ranging and designation channels. Neither publishes a maximum range figure without a target definition, which is the honest approach.
The interesting inversion
The LDR25K1 has 25% more pulse energy but specifies ±2 m accuracy against the LDR20K1's ±1 m, and weighs 90 g more.
That combination is not a defect. It reflects a different design emphasis: the higher-energy module is aimed at designation stand-off and longer range against marginal targets, where an extra metre of range error is less important than getting a return at all. The LDR20K1 is tuned for precise range reporting in a smaller, lighter package.
Which to choose
| If your priority is | Choose |
|---|---|
| Lowest mass on a small UAV | LDR20K1 (≤ 290 g) |
| Longer designation stand-off | LDR25K1 (≥ 25 mJ) |
| Tight range accuracy for fire control | LDR20K1 (±1 m) |
| Elongated envelope (68 × 52 × 90 mm) | LDR25K1 |
| Shallow envelope (53 mm tall) | LDR20K1 |
The envelope difference is often decisive. The LDR25K1 is narrow but 90 mm tall; the LDR20K1 is wider but only 53 mm tall. On a flat gimbal plate, that 37 mm difference can decide the entire mechanical layout.
Divergence and what it means
The LDR20K1's 0.6 mrad divergence gives a spot of about 1.8 m at 3 km and 6 m at 10 km. On a vehicle-sized target at 3 km, that is fine. At 10 km it is not — which is why neither module is marketed as a 10 km unit.
The LDR25K1 does not publish divergence. Ask for it before committing: without it, you cannot assess how the extra 5 mJ is distributed at range.
What both give you
- Ranging and designation in one module
- RS-422 command interface
- Self-test and status reporting
- Environmentally qualified construction
Frequently asked questions
Is the LDR25K1 better because it has more energy?
Only if designation stand-off matters more than range accuracy and mass. On a mass-limited UAV with a fire-control role, the LDR20K1 is often the better fit.
Can either reach 10 km?
Neither is specified as a 10 km class module. Use the LDR60K1 or LDR80K1 for that range.
Why does the lighter module have better accuracy?
Accuracy is set by the timing chain and signal processing, not by pulse energy. The two designs optimise different things.
Which has better designation stand-off?
The LDR25K1, on pulse energy. Confirm the actual figure against your seeker sensitivity.
See both on the designator collection, or read the selection guide.