# ERS SAR Data Products

The following ERS SAR image mode products are available:

- ERS1.SAR.RAW - SAR Annotated Raw Data
- ERS1.SAR.FDC - SAR Fast Delivery Image
- ERS1.SAR.SLC - SAR Single Look Complex Image
- ERS1.SAR.PRI - SAR Precision Image

## SAR Annotated Raw Data

This product consists of the SAR telemetry data corresponding to 16 seconds of data collection; it also contains all required auxiliary data necessary for data processing.

The product serves two purposes:

- the testing of ERS-1 SAR processors independently from the HDDR system
- Users interested in full SAR data processing.

### Product characteristics

    Scene area (range)          100 km
               (azimuth)        110 km
    Scene size (range)          5616 samples per line
               (azimuth)        27000 lines
    Pixel depth                 16 bits (8 bits I, 8 bits Q)
    Total product volume        ~ 300 Mbytes
    Projection                  slant range

### Media

- Exabyte 8200
- Exabyte 8500
- CDROM

## SAR Fast Delivery Image

The product is a multi-look (speckle-reduced), ground range, digital image intended for near real-time applications. No correction is applied for the SAR antenna pattern or range-spreading loss.

### Product characteristics

    Pixel size (range - across track)          20.0 m
               (azimuth - along track)       ~ 15.9 m
    Scene area (range - across track)          100 km
    (azimuth - along track)                  ~ 96 km
    Scene size (range - pixels)                5000 pixels per line
    (azimuth - lines)                          6300 lines
    Pixel depth                                16 bits
    Product location accuracy                  1000 m
    Total product volume                     ~ 63 Mbytes
    Projection                                 ground range
    Number of looks                            3

### Media

- CCT
- Exabyte 8200
- Exabyte 8500
- CDROM

## SAR Single Look Complex Image

This product presents SAR data following preprocessing, but retains every sample as complex data. The product is single-look (i.e. no speckle reduction by multi-look processing), and in slant range. Phase continuity is preserved within the image.

Three areas of application are:

- testing of SAR processing algorithms
- development of techniques using phase preservation, e.g. SAR interferometry
- application of SAR post-processing algorithms, e.g. geocoding from complex, slant-range data

There are two forms of the single-look complex product:

ERS-1.SAR.SLCF - a full-scene product.

ERS-1.SAR.SLC - a product of quarter scenes or quadrants.

### Product characteristics

                                    ERS-1.SAR.SLC           ERS-1.SAR.SLCF

    Scene size (range)              2500 samples            4992 samples
               (azimuth)            15000 lines             26368 lines
    Pixel depth                     16I, 16Q complex        16I, 16Q complex
    Product location accuarcy       200 m                   200 m
    Total volume                    ~ 150 Mbytes            ~ 530 Mbytes
    Projection                      slant range             slant range
    Number of looks                 1                       1

### Media

- CCT (Not for ERS-1.SAR.SLCF)
- Exabyte 8200
- Exabyte 8500
- CDROM

## SAR Precision Image

The Precision Image is a multi-look (speckle-reduced), ground range, system corrected image. It is the product applicable for most users interested in remote sensing applications.

The product is calibrated and corrected for the SAR antenna pattern and range-spreading loss: radar backscatter can be derived from the product for geophysical modelling, but no correction is applied for terrain-induced radiometric effects. The image is not geocoded, and terrain distortion (foreshortening and layover) has not been removed.

### Product characteristics

    Pixel size (range - across track)       12.5 m
               (azimuth - across track)     12.5 m
    Scene area (range - across track)       100 km
               (azimuth - along track)      at least 102.5 km
    Scene size (range - pixels)             8000 pixels per line
               (azimuth - lines)            at least 8200 lines
    Pixel depth                             16 bits
    Product location accuracy               200 m
    Total product volume                    ~ 131 Mbytes
    Annotation in image                     lat./long. of scene centre and
                                            the four corners
    Projection                              ground-range
    Number of looks                         3

### Media

- CCT
- Exabyte 8200
- Exabyte 8500
- CDROM

## Active Microwave Instrument

  AMI Technical Details
  SAR Image Mode
  SAR Data Products

ESA Earth Observation